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* Unable to open(2) ep0 in ConfigFG FunctionFS Gadget
@ 2020-05-20 16:22 Sid Spry
  2020-05-26 19:51 ` Sid Spry
  0 siblings, 1 reply; 4+ messages in thread
From: Sid Spry @ 2020-05-20 16:22 UTC (permalink / raw)
  To: linux-usb

Crossreffing https://github.com/torvalds/linux/blob/2f4c53349961c8ca480193e47da4d44fdb8335a8/tools/usb/ffs-test.c it looks like all I have to do is open "ep0" in the proper directory, but I do just that and it fails on first and subsequent runs.

gadget.cc:

```
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

#include <linux/usb/ch9.h>
#include <usbg/usbg.h>

#define VENDOR  0x1d6b
#define PRODUCT 0x0104

int usbg_setup(
        usbg_state **s,
        usbg_gadget **g,
        usbg_config **c,
        usbg_function **f_ffs0,
        usbg_function **f_ncm0
);      

int main(int argc, char *argv[]) {
        usbg_state *s;
        usbg_gadget *g;
        usbg_config *c;
        usbg_function *f_ffs0, *f_ncm0;

        if (int rc = usbg_setup(&s, &g, &c, &f_ffs0, &f_ncm0);
                rc != 0) {
                puts("gadget exists or libcomposite needs to be loaded.");
        } else {
                puts("gadget created.");
        }

        int ffs_fd = open("/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
                O_RDONLY);
        if (int rc = fchdir(ffs_fd); rc != 0) {
                fprintf(stderr, "unable to chdir to ffs directory: %s\n",
                        strerror(errno));
        }

        int ffs_fd_ep0 = open("ep0",
                O_RDWR);
        if (ffs_fd_ep0 < 0) {
                fprintf(stderr, "unable to create ep0: %d : %s\n",
                        errno, strerror(errno));
        }

        close(ffs_fd);
}

int usbg_setup(
        usbg_state **s,
        usbg_gadget **g,
        usbg_config **c,
        usbg_function **f_ffs0,
        usbg_function **f_ncm0
) {
        struct usbg_gadget_attrs g_attrs = {
                .bcdUSB = 0x0200,
                .bDeviceClass = USB_CLASS_PER_INTERFACE,
                .bDeviceSubClass = 0x00,
                .bDeviceProtocol = 0x00,
                .bMaxPacketSize0 = 64,
                .idVendor = VENDOR,
                .idProduct = PRODUCT,
                .bcdDevice = 0x0000
        };

        struct usbg_gadget_strs g_strs = {
                .manufacturer = "Foo Inc.",
                .product = "Bar Gadget",
                .serial = "0000000000"
        };

        struct usbg_config_strs c_strs = {
                .configuration = "Default"
        };

        if (usbg_error rc = 
                        (usbg_error)usbg_init("/sys/kernel/config", s);
                rc != USBG_SUCCESS) {
                goto error_exit;
        }

        if (usbg_error rc =
                        (usbg_error)usbg_create_gadget(*s, "g1", &g_attrs, &g_strs, g);
                rc != USBG_SUCCESS) {
                goto error_exit;
        }

        if (usbg_error rc =
                        (usbg_error)usbg_create_function(*g,
                                USBG_F_NCM, "dev0", NULL, f_ncm0);
                rc != USBG_SUCCESS) {
                goto error_exit;
        }

        if (usbg_error rc =
                        (usbg_error)usbg_create_function(*g,
                                USBG_F_FFS, "dev0", NULL, f_ffs0);
                rc != USBG_SUCCESS) {
                //fprintf(stderr, "Error: %s : %s\n", usbg_error_name(rc),
                //      usbg_strerror(rc));
                goto error_exit;
        }
        
        return 0;

error_exit:
        return -2;
}
```

strace:

```
execve("./gadget", ["./gadget"], 0xbece77a0 /* 19 vars */) = 0
brk(NULL)                               = 0x1017000
uname({sysname="Linux", nodename="nanopiduo", ...}) = 0
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6f5e000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=35157, ...}) = 0
mmap2(NULL, 35157, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f55000
close(3)                                = 0
openat(AT_FDCWD, "/usr/local/lib/libusbgx.so.2", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\314I\0\0004\0\0\0"..., 512) = 512
_llseek(3, 362460, [362460], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
_llseek(3, 50996, [50996], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 362460, [362460], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
_llseek(3, 50996, [50996], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 362460, [362460], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
_llseek(3, 50996, [50996], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 362460, [362460], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
_llseek(3, 50996, [50996], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 362460, [362460], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
_llseek(3, 50996, [50996], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0755, st_size=363860, ...}) = 0
mmap2(NULL, 116508, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6f1b000
mprotect(0xb6f27000, 61440, PROT_NONE)  = 0
mmap2(0xb6f36000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xb000) = 0xb6f36000
close(3)                                = 0
openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libconfig.so.9", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\"\0\0004\0\0\0"..., 512) = 512
_llseek(3, 29420, [29420], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 960) = 960
_llseek(3, 29096, [29096], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 29420, [29420], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 960) = 960
_llseek(3, 29096, [29096], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 29420, [29420], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 960) = 960
_llseek(3, 29096, [29096], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 29420, [29420], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 960) = 960
_llseek(3, 29096, [29096], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 29420, [29420], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 960) = 960
_llseek(3, 29096, [29096], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0644, st_size=30380, ...}) = 0
mmap2(NULL, 94636, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6f03000
mprotect(0xb6f0a000, 61440, PROT_NONE)  = 0
mmap2(0xb6f19000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0xb6f19000
close(3)                                = 0
openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libstdc++.so.6", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\270\346\6\0004\0\0\0"..., 512) = 512
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
_llseek(3, 1018532, [1018532], SEEK_SET) = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1240) = 1240
_llseek(3, 1017936, [1017936], SEEK_SET) = 0
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 51) = 51
fstat64(3, {st_mode=S_IFREG|0644, st_size=1019772, ...}) = 0
mmap2(NULL, 1091308, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6df8000
mprotect(0xb6eeb000, 61440, PROT_NONE)  = 0
mmap2(0xb6efa000, 28672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xf2000) = 0xb6efa000
mmap2(0xb6f01000, 5868, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f01000
close(3)                                = 0
openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libm.so.6", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\250r\0\0004\0\0\0"..., 512) = 512
_llseek(3, 434644, [434644], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 434288, [434288], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 53) = 53
_llseek(3, 434644, [434644], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 434288, [434288], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 53) = 53
_llseek(3, 434644, [434644], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 434288, [434288], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 53) = 53
fstat64(3, {st_mode=S_IFREG|0644, st_size=435724, ...}) = 0
mmap2(NULL, 499832, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6d7d000
mprotect(0xb6de7000, 61440, PROT_NONE)  = 0
mmap2(0xb6df6000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x69000) = 0xb6df6000
close(3)                                = 0
openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libgcc_s.so.1", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\321\0\0004\0\0\0"..., 512) = 512
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
_llseek(3, 98916, [98916], SEEK_SET)    = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
_llseek(3, 98556, [98556], SEEK_SET)    = 0
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0644, st_size=99996, ...}) = 0
mmap2(NULL, 164148, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6d54000
mprotect(0xb6d6c000, 61440, PROT_NONE)  = 0
mmap2(0xb6d7b000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0xb6d7b000
close(3)                                = 0
openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libc.so.6", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\09v\1\0004\0\0\0"..., 512) = 512
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
_llseek(3, 949188, [949188], SEEK_SET)  = 0
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 2840) = 2840
_llseek(3, 945756, [945756], SEEK_SET)  = 0
read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 53) = 53
fstat64(3, {st_mode=S_IFREG|0755, st_size=952028, ...}) = 0
mmap2(NULL, 1020732, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6c5a000
mprotect(0xb6d3e000, 65536, PROT_NONE)  = 0
mmap2(0xb6d4e000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe4000) = 0xb6d4e000
mmap2(0xb6d51000, 9020, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d51000
close(3)                                = 0
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6f53000
set_tls(0xb6f534d0)                     = 0
mprotect(0xb6d4e000, 8192, PROT_READ)   = 0
mprotect(0xb6d7b000, 4096, PROT_READ)   = 0
mprotect(0xb6df6000, 4096, PROT_READ)   = 0
mprotect(0xb6efa000, 20480, PROT_READ)  = 0
mprotect(0xb6f19000, 4096, PROT_READ)   = 0
mprotect(0xb6f36000, 4096, PROT_READ)   = 0
mprotect(0x491000, 4096, PROT_READ)     = 0
mprotect(0xb6f60000, 4096, PROT_READ)   = 0
munmap(0xb6f55000, 35157)               = 0
brk(NULL)                               = 0x1017000
brk(0x1038000)                          = 0x1038000
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/class/udc", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
getdents64(3, /* 3 entries */, 32768)   = 88
getdents64(3, /* 0 entries */, 32768)   = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
getdents64(3, /* 3 entries */, 32768)   = 72
getdents64(3, /* 0 entries */, 32768)   = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/UDC", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0
read(3, "\n", 4096)                     = 1
read(3, "", 4096)                       = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
getdents64(3, /* 4 entries */, 32768)   = 112
getdents64(3, /* 0 entries */, 32768)   = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/configs", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
getdents64(3, /* 2 entries */, 32768)   = 48
getdents64(3, /* 0 entries */, 32768)   = 0
close(3)                                = 0
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/os_desc", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
getdents64(3, /* 5 entries */, 32768)   = 144
getdents64(3, /* 0 entries */, 32768)   = 0
close(3)                                = 0
write(2, "usbg_create_gadget()  duplicate "..., 46usbg_create_gadget()  duplicate gadget name
 
) = 46
fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(0x4, 0x40), ...}) = 0
ioctl(1, TCGETS, {B115200 opost isig icanon echo ...}) = 0
write(1, "gadget exists.\n", 15gadget exists.
)        = 15
openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0", O_RDONLY) = 3
fchdir(3)                               = 0
openat(AT_FDCWD, "ep0", O_RDWR)         = -1 ENOENT (No such file or directory)
write(2, "unable to create ep0: 2 : No suc"..., 52unable to create ep0: 2 : No such file or directory
) = 52
close(3)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++

```

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Unable to open(2) ep0 in ConfigFG FunctionFS Gadget
  2020-05-20 16:22 Unable to open(2) ep0 in ConfigFG FunctionFS Gadget Sid Spry
@ 2020-05-26 19:51 ` Sid Spry
  2020-05-26 20:03   ` Krzysztof Opasiak
  0 siblings, 1 reply; 4+ messages in thread
From: Sid Spry @ 2020-05-26 19:51 UTC (permalink / raw)
  To: linux-usb

On Wed, May 20, 2020, at 11:22 AM, Sid Spry wrote:
> Crossreffing 
> https://github.com/torvalds/linux/blob/2f4c53349961c8ca480193e47da4d44fdb8335a8/tools/usb/ffs-test.c it looks like all I have to do is open "ep0" in the proper directory, but I do just that and it fails on first and subsequent runs.
> 
> gadget.cc:
> 
> ```
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> #include <fcntl.h>
> #include <string.h>
> #include <errno.h>
> 
> #include <linux/usb/ch9.h>
> #include <usbg/usbg.h>
> 
> #define VENDOR  0x1d6b
> #define PRODUCT 0x0104
> 
> int usbg_setup(
>         usbg_state **s,
>         usbg_gadget **g,
>         usbg_config **c,
>         usbg_function **f_ffs0,
>         usbg_function **f_ncm0
> );      
> 
> int main(int argc, char *argv[]) {
>         usbg_state *s;
>         usbg_gadget *g;
>         usbg_config *c;
>         usbg_function *f_ffs0, *f_ncm0;
> 
>         if (int rc = usbg_setup(&s, &g, &c, &f_ffs0, &f_ncm0);
>                 rc != 0) {
>                 puts("gadget exists or libcomposite needs to be loaded.");
>         } else {
>                 puts("gadget created.");
>         }
> 
>         int ffs_fd = open("/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
>                 O_RDONLY);
>         if (int rc = fchdir(ffs_fd); rc != 0) {
>                 fprintf(stderr, "unable to chdir to ffs directory: %s\n",
>                         strerror(errno));
>         }
> 
>         int ffs_fd_ep0 = open("ep0",
>                 O_RDWR);
>         if (ffs_fd_ep0 < 0) {
>                 fprintf(stderr, "unable to create ep0: %d : %s\n",
>                         errno, strerror(errno));
>         }
> 
>         close(ffs_fd);
> }
> 
> int usbg_setup(
>         usbg_state **s,
>         usbg_gadget **g,
>         usbg_config **c,
>         usbg_function **f_ffs0,
>         usbg_function **f_ncm0
> ) {
>         struct usbg_gadget_attrs g_attrs = {
>                 .bcdUSB = 0x0200,
>                 .bDeviceClass = USB_CLASS_PER_INTERFACE,
>                 .bDeviceSubClass = 0x00,
>                 .bDeviceProtocol = 0x00,
>                 .bMaxPacketSize0 = 64,
>                 .idVendor = VENDOR,
>                 .idProduct = PRODUCT,
>                 .bcdDevice = 0x0000
>         };
> 
>         struct usbg_gadget_strs g_strs = {
>                 .manufacturer = "Foo Inc.",
>                 .product = "Bar Gadget",
>                 .serial = "0000000000"
>         };
> 
>         struct usbg_config_strs c_strs = {
>                 .configuration = "Default"
>         };
> 
>         if (usbg_error rc = 
>                         (usbg_error)usbg_init("/sys/kernel/config", s);
>                 rc != USBG_SUCCESS) {
>                 goto error_exit;
>         }
> 
>         if (usbg_error rc =
>                         (usbg_error)usbg_create_gadget(*s, "g1", 
> &g_attrs, &g_strs, g);
>                 rc != USBG_SUCCESS) {
>                 goto error_exit;
>         }
> 
>         if (usbg_error rc =
>                         (usbg_error)usbg_create_function(*g,
>                                 USBG_F_NCM, "dev0", NULL, f_ncm0);
>                 rc != USBG_SUCCESS) {
>                 goto error_exit;
>         }
> 
>         if (usbg_error rc =
>                         (usbg_error)usbg_create_function(*g,
>                                 USBG_F_FFS, "dev0", NULL, f_ffs0);
>                 rc != USBG_SUCCESS) {
>                 //fprintf(stderr, "Error: %s : %s\n", usbg_error_name(rc),
>                 //      usbg_strerror(rc));
>                 goto error_exit;
>         }
>         
>         return 0;
> 
> error_exit:
>         return -2;
> }
> ```
> 
> strace:
> 
> ```
> execve("./gadget", ["./gadget"], 0xbece77a0 /* 19 vars */) = 0
> brk(NULL)                               = 0x1017000
> uname({sysname="Linux", nodename="nanopiduo", ...}) = 0
> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 
> 0) = 0xb6f5e000
> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or 
> directory)
> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=35157, ...}) = 0
> mmap2(NULL, 35157, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f55000
> close(3)                                = 0
> openat(AT_FDCWD, "/usr/local/lib/libusbgx.so.2", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\314I\0\0004\0\0\0"..., 
> 512) = 512
> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1400) = 1400
> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1400) = 1400
> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1400) = 1400
> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1400) = 1400
> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1400) = 1400
> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> fstat64(3, {st_mode=S_IFREG|0755, st_size=363860, ...}) = 0
> mmap2(NULL, 116508, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6f1b000
> mprotect(0xb6f27000, 61440, PROT_NONE)  = 0
> mmap2(0xb6f36000, 8192, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xb000) = 0xb6f36000
> close(3)                                = 0
> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libconfig.so.9", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\"\0\0004\0\0\0"..., 
> 512) = 512
> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 960) = 960
> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 960) = 960
> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 960) = 960
> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 960) = 960
> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 960) = 960
> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> fstat64(3, {st_mode=S_IFREG|0644, st_size=30380, ...}) = 0
> mmap2(NULL, 94636, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6f03000
> mprotect(0xb6f0a000, 61440, PROT_NONE)  = 0
> mmap2(0xb6f19000, 8192, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0xb6f19000
> close(3)                                = 0
> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libstdc++.so.6", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\270\346\6\0004\0\0\0"..., 512) = 512
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1240) = 1240
> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 51) = 51
> fstat64(3, {st_mode=S_IFREG|0644, st_size=1019772, ...}) = 0
> mmap2(NULL, 1091308, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6df8000
> mprotect(0xb6eeb000, 61440, PROT_NONE)  = 0
> mmap2(0xb6efa000, 28672, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xf2000) = 0xb6efa000
> mmap2(0xb6f01000, 5868, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f01000
> close(3)                                = 0
> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libm.so.6", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\250r\0\0004\0\0\0"..., 
> 512) = 512
> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 53) = 53
> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 53) = 53
> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 53) = 53
> fstat64(3, {st_mode=S_IFREG|0644, st_size=435724, ...}) = 0
> mmap2(NULL, 499832, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6d7d000
> mprotect(0xb6de7000, 61440, PROT_NONE)  = 0
> mmap2(0xb6df6000, 8192, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x69000) = 0xb6df6000
> close(3)                                = 0
> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libgcc_s.so.1", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\321\0\0004\0\0\0"..., 512) = 512
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 1080) = 1080
> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"..., 
> 49) = 49
> fstat64(3, {st_mode=S_IFREG|0644, st_size=99996, ...}) = 0
> mmap2(NULL, 164148, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6d54000
> mprotect(0xb6d6c000, 61440, PROT_NONE)  = 0
> mmap2(0xb6d7b000, 8192, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0xb6d7b000
> close(3)                                = 0
> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libc.so.6", 
> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, 
> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\09v\1\0004\0\0\0"..., 
> 512) = 512
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> read(3, 
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 
> 2840) = 2840
> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"..., 
> 53) = 53
> fstat64(3, {st_mode=S_IFREG|0755, st_size=952028, ...}) = 0
> mmap2(NULL, 1020732, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
> 0) = 0xb6c5a000
> mprotect(0xb6d3e000, 65536, PROT_NONE)  = 0
> mmap2(0xb6d4e000, 12288, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe4000) = 0xb6d4e000
> mmap2(0xb6d51000, 9020, PROT_READ|PROT_WRITE, 
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d51000
> close(3)                                = 0
> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 
> 0) = 0xb6f53000
> set_tls(0xb6f534d0)                     = 0
> mprotect(0xb6d4e000, 8192, PROT_READ)   = 0
> mprotect(0xb6d7b000, 4096, PROT_READ)   = 0
> mprotect(0xb6df6000, 4096, PROT_READ)   = 0
> mprotect(0xb6efa000, 20480, PROT_READ)  = 0
> mprotect(0xb6f19000, 4096, PROT_READ)   = 0
> mprotect(0xb6f36000, 4096, PROT_READ)   = 0
> mprotect(0x491000, 4096, PROT_READ)     = 0
> mprotect(0xb6f60000, 4096, PROT_READ)   = 0
> munmap(0xb6f55000, 35157)               = 0
> brk(NULL)                               = 0x1017000
> brk(0x1038000)                          = 0x1038000
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/class/udc", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> getdents64(3, /* 3 entries */, 32768)   = 88
> getdents64(3, /* 0 entries */, 32768)   = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> getdents64(3, /* 3 entries */, 32768)   = 72
> getdents64(3, /* 0 entries */, 32768)   = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/UDC", O_RDONLY) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0
> read(3, "\n", 4096)                     = 1
> read(3, "", 4096)                       = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> getdents64(3, /* 4 entries */, 32768)   = 112
> getdents64(3, /* 0 entries */, 32768)   = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/configs", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> getdents64(3, /* 2 entries */, 32768)   = 48
> getdents64(3, /* 0 entries */, 32768)   = 0
> close(3)                                = 0
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/os_desc", 
> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> getdents64(3, /* 5 entries */, 32768)   = 144
> getdents64(3, /* 0 entries */, 32768)   = 0
> close(3)                                = 0
> write(2, "usbg_create_gadget()  duplicate "..., 46usbg_create_gadget()  
> duplicate gadget name
>  
> ) = 46
> fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(0x4, 0x40), ...}) = 0
> ioctl(1, TCGETS, {B115200 opost isig icanon echo ...}) = 0
> write(1, "gadget exists.\n", 15gadget exists.
> )        = 15
> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0", 
> O_RDONLY) = 3
> fchdir(3)                               = 0
> openat(AT_FDCWD, "ep0", O_RDWR)         = -1 ENOENT (No such file or 
> directory)
> write(2, "unable to create ep0: 2 : No suc"..., 52unable to create ep0: 
> 2 : No such file or directory
> ) = 52
> close(3)                                = 0
> exit_group(0)                           = ?
> +++ exited with 0 +++
> 
> ```
>

I created the configs as well. Still can't open ep0. Really -- is there a device or UDC someone can verify has worked in the past? Seems easiest way for me to proceed.

I can get more info if it'll help, but I assume some device is already working.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Unable to open(2) ep0 in ConfigFG FunctionFS Gadget
  2020-05-26 19:51 ` Sid Spry
@ 2020-05-26 20:03   ` Krzysztof Opasiak
  2020-06-02  3:05     ` Sid Spry
  0 siblings, 1 reply; 4+ messages in thread
From: Krzysztof Opasiak @ 2020-05-26 20:03 UTC (permalink / raw)
  To: Sid Spry, linux-usb



On 26.05.2020 21:51, Sid Spry wrote:
> On Wed, May 20, 2020, at 11:22 AM, Sid Spry wrote:
>> Crossreffing
>> https://protect2.fireeye.com/url?k=c219aa9a-9fcaf18e-c21821d5-0cc47a31ce4e-c3654d6c375cfe09&q=1&u=https%3A%2F%2Fgithub.com%2Ftorvalds%2Flinux%2Fblob%2F2f4c53349961c8ca480193e47da4d44fdb8335a8%2Ftools%2Fusb%2Fffs-test.c it looks like all I have to do is open "ep0" in the proper directory, but I do just that and it fails on first and subsequent runs.
>>
>> gadget.cc:
>>
>> ```
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <unistd.h>
>> #include <fcntl.h>
>> #include <string.h>
>> #include <errno.h>
>>
>> #include <linux/usb/ch9.h>
>> #include <usbg/usbg.h>
>>
>> #define VENDOR  0x1d6b
>> #define PRODUCT 0x0104
>>
>> int usbg_setup(
>>          usbg_state **s,
>>          usbg_gadget **g,
>>          usbg_config **c,
>>          usbg_function **f_ffs0,
>>          usbg_function **f_ncm0
>> );
>>
>> int main(int argc, char *argv[]) {
>>          usbg_state *s;
>>          usbg_gadget *g;
>>          usbg_config *c;
>>          usbg_function *f_ffs0, *f_ncm0;
>>
>>          if (int rc = usbg_setup(&s, &g, &c, &f_ffs0, &f_ncm0);
>>                  rc != 0) {
>>                  puts("gadget exists or libcomposite needs to be loaded.");
>>          } else {
>>                  puts("gadget created.");
>>          }
>>
>>          int ffs_fd = open("/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
>>                  O_RDONLY);
>>          if (int rc = fchdir(ffs_fd); rc != 0) {
>>                  fprintf(stderr, "unable to chdir to ffs directory: %s\n",
>>                          strerror(errno));
>>          }
>>
>>          int ffs_fd_ep0 = open("ep0",
>>                  O_RDWR);
>>          if (ffs_fd_ep0 < 0) {
>>                  fprintf(stderr, "unable to create ep0: %d : %s\n",
>>                          errno, strerror(errno));
>>          }
>>
>>          close(ffs_fd);
>> }
>>
>> int usbg_setup(
>>          usbg_state **s,
>>          usbg_gadget **g,
>>          usbg_config **c,
>>          usbg_function **f_ffs0,
>>          usbg_function **f_ncm0
>> ) {
>>          struct usbg_gadget_attrs g_attrs = {
>>                  .bcdUSB = 0x0200,
>>                  .bDeviceClass = USB_CLASS_PER_INTERFACE,
>>                  .bDeviceSubClass = 0x00,
>>                  .bDeviceProtocol = 0x00,
>>                  .bMaxPacketSize0 = 64,
>>                  .idVendor = VENDOR,
>>                  .idProduct = PRODUCT,
>>                  .bcdDevice = 0x0000
>>          };
>>
>>          struct usbg_gadget_strs g_strs = {
>>                  .manufacturer = "Foo Inc.",
>>                  .product = "Bar Gadget",
>>                  .serial = "0000000000"
>>          };
>>
>>          struct usbg_config_strs c_strs = {
>>                  .configuration = "Default"
>>          };
>>
>>          if (usbg_error rc =
>>                          (usbg_error)usbg_init("/sys/kernel/config", s);
>>                  rc != USBG_SUCCESS) {
>>                  goto error_exit;
>>          }
>>
>>          if (usbg_error rc =
>>                          (usbg_error)usbg_create_gadget(*s, "g1",
>> &g_attrs, &g_strs, g);
>>                  rc != USBG_SUCCESS) {
>>                  goto error_exit;
>>          }
>>
>>          if (usbg_error rc =
>>                          (usbg_error)usbg_create_function(*g,
>>                                  USBG_F_NCM, "dev0", NULL, f_ncm0);
>>                  rc != USBG_SUCCESS) {
>>                  goto error_exit;
>>          }
>>
>>          if (usbg_error rc =
>>                          (usbg_error)usbg_create_function(*g,
>>                                  USBG_F_FFS, "dev0", NULL, f_ffs0);
>>                  rc != USBG_SUCCESS) {
>>                  //fprintf(stderr, "Error: %s : %s\n", usbg_error_name(rc),
>>                  //      usbg_strerror(rc));
>>                  goto error_exit;
>>          }
>>          
>>          return 0;
>>
>> error_exit:
>>          return -2;
>> }
>> ```
>>
>> strace:
>>
>> ```
>> execve("./gadget", ["./gadget"], 0xbece77a0 /* 19 vars */) = 0
>> brk(NULL)                               = 0x1017000
>> uname({sysname="Linux", nodename="nanopiduo", ...}) = 0
>> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0xb6f5e000
>> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or
>> directory)
>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=35157, ...}) = 0
>> mmap2(NULL, 35157, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f55000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/usr/local/lib/libusbgx.so.2",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\314I\0\0004\0\0\0"...,
>> 512) = 512
>> _llseek(3, 362460, [362460], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1400) = 1400
>> _llseek(3, 50996, [50996], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 362460, [362460], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1400) = 1400
>> _llseek(3, 50996, [50996], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 362460, [362460], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1400) = 1400
>> _llseek(3, 50996, [50996], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 362460, [362460], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1400) = 1400
>> _llseek(3, 50996, [50996], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 362460, [362460], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1400) = 1400
>> _llseek(3, 50996, [50996], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> fstat64(3, {st_mode=S_IFREG|0755, st_size=363860, ...}) = 0
>> mmap2(NULL, 116508, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6f1b000
>> mprotect(0xb6f27000, 61440, PROT_NONE)  = 0
>> mmap2(0xb6f36000, 8192, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xb000) = 0xb6f36000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libconfig.so.9",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\"\0\0004\0\0\0"...,
>> 512) = 512
>> _llseek(3, 29420, [29420], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 960) = 960
>> _llseek(3, 29096, [29096], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 29420, [29420], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 960) = 960
>> _llseek(3, 29096, [29096], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 29420, [29420], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 960) = 960
>> _llseek(3, 29096, [29096], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 29420, [29420], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 960) = 960
>> _llseek(3, 29096, [29096], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 29420, [29420], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 960) = 960
>> _llseek(3, 29096, [29096], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=30380, ...}) = 0
>> mmap2(NULL, 94636, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6f03000
>> mprotect(0xb6f0a000, 61440, PROT_NONE)  = 0
>> mmap2(0xb6f19000, 8192, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0xb6f19000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libstdc++.so.6",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\270\346\6\0004\0\0\0"..., 512) = 512
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1240) = 1240
>> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
>> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 51) = 51
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=1019772, ...}) = 0
>> mmap2(NULL, 1091308, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6df8000
>> mprotect(0xb6eeb000, 61440, PROT_NONE)  = 0
>> mmap2(0xb6efa000, 28672, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xf2000) = 0xb6efa000
>> mmap2(0xb6f01000, 5868, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f01000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libm.so.6",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\250r\0\0004\0\0\0"...,
>> 512) = 512
>> _llseek(3, 434644, [434644], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 434288, [434288], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 53) = 53
>> _llseek(3, 434644, [434644], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 434288, [434288], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 53) = 53
>> _llseek(3, 434644, [434644], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 434288, [434288], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 53) = 53
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=435724, ...}) = 0
>> mmap2(NULL, 499832, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6d7d000
>> mprotect(0xb6de7000, 61440, PROT_NONE)  = 0
>> mmap2(0xb6df6000, 8192, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x69000) = 0xb6df6000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libgcc_s.so.1",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\321\0\0004\0\0\0"..., 512) = 512
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> _llseek(3, 98916, [98916], SEEK_SET)    = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1080) = 1080
>> _llseek(3, 98556, [98556], SEEK_SET)    = 0
>> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
>> 49) = 49
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=99996, ...}) = 0
>> mmap2(NULL, 164148, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6d54000
>> mprotect(0xb6d6c000, 61440, PROT_NONE)  = 0
>> mmap2(0xb6d7b000, 8192, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0xb6d7b000
>> close(3)                                = 0
>> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libc.so.6",
>> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
>> read(3,
>> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\09v\1\0004\0\0\0"...,
>> 512) = 512
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> _llseek(3, 949188, [949188], SEEK_SET)  = 0
>> read(3,
>> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 2840) = 2840
>> _llseek(3, 945756, [945756], SEEK_SET)  = 0
>> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
>> 53) = 53
>> fstat64(3, {st_mode=S_IFREG|0755, st_size=952028, ...}) = 0
>> mmap2(NULL, 1020732, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0xb6c5a000
>> mprotect(0xb6d3e000, 65536, PROT_NONE)  = 0
>> mmap2(0xb6d4e000, 12288, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe4000) = 0xb6d4e000
>> mmap2(0xb6d51000, 9020, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d51000
>> close(3)                                = 0
>> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0xb6f53000
>> set_tls(0xb6f534d0)                     = 0
>> mprotect(0xb6d4e000, 8192, PROT_READ)   = 0
>> mprotect(0xb6d7b000, 4096, PROT_READ)   = 0
>> mprotect(0xb6df6000, 4096, PROT_READ)   = 0
>> mprotect(0xb6efa000, 20480, PROT_READ)  = 0
>> mprotect(0xb6f19000, 4096, PROT_READ)   = 0
>> mprotect(0xb6f36000, 4096, PROT_READ)   = 0
>> mprotect(0x491000, 4096, PROT_READ)     = 0
>> mprotect(0xb6f60000, 4096, PROT_READ)   = 0
>> munmap(0xb6f55000, 35157)               = 0
>> brk(NULL)                               = 0x1017000
>> brk(0x1038000)                          = 0x1038000
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/class/udc",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> getdents64(3, /* 3 entries */, 32768)   = 88
>> getdents64(3, /* 0 entries */, 32768)   = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> getdents64(3, /* 3 entries */, 32768)   = 72
>> getdents64(3, /* 0 entries */, 32768)   = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/UDC", O_RDONLY) = 3
>> fstat64(3, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0
>> read(3, "\n", 4096)                     = 1
>> read(3, "", 4096)                       = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> getdents64(3, /* 4 entries */, 32768)   = 112
>> getdents64(3, /* 0 entries */, 32768)   = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/configs",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> getdents64(3, /* 2 entries */, 32768)   = 48
>> getdents64(3, /* 0 entries */, 32768)   = 0
>> close(3)                                = 0
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/os_desc",
>> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
>> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
>> getdents64(3, /* 5 entries */, 32768)   = 144
>> getdents64(3, /* 0 entries */, 32768)   = 0
>> close(3)                                = 0
>> write(2, "usbg_create_gadget()  duplicate "..., 46usbg_create_gadget()
>> duplicate gadget name
>>   
>> ) = 46
>> fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(0x4, 0x40), ...}) = 0
>> ioctl(1, TCGETS, {B115200 opost isig icanon echo ...}) = 0
>> write(1, "gadget exists.\n", 15gadget exists.
>> )        = 15
>> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
>> O_RDONLY) = 3
>> fchdir(3)                               = 0
>> openat(AT_FDCWD, "ep0", O_RDWR)         = -1 ENOENT (No such file or
>> directory)
>> write(2, "unable to create ep0: 2 : No suc"..., 52unable to create ep0:
>> 2 : No such file or directory
>> ) = 52
>> close(3)                                = 0
>> exit_group(0)                           = ?
>> +++ exited with 0 +++
>>
>> ```
>>
> 
> I created the configs as well. Still can't open ep0. Really -- is there a device or UDC someone can verify has worked in the past? Seems easiest way for me to proceed.
> 
> I can get more info if it'll help, but I assume some device is already working.

You cannot open ep0 because you didn't mounted ffs instance.

after you created /sys/kernel/config/usb_gadget/g1/functions/ffs.dev0 
you need to:

mount -t functionfs dev0 /some/path

then you open(/some/path/ep0);

Best regards,
-- 
Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Unable to open(2) ep0 in ConfigFG FunctionFS Gadget
  2020-05-26 20:03   ` Krzysztof Opasiak
@ 2020-06-02  3:05     ` Sid Spry
  0 siblings, 0 replies; 4+ messages in thread
From: Sid Spry @ 2020-06-02  3:05 UTC (permalink / raw)
  To: Krzysztof Opasiak, linux-usb

On Tue, May 26, 2020, at 3:03 PM, Krzysztof Opasiak wrote:
> 
> 
> On 26.05.2020 21:51, Sid Spry wrote:
> > On Wed, May 20, 2020, at 11:22 AM, Sid Spry wrote:
> >> Crossreffing
> >> https://protect2.fireeye.com/url?k=c219aa9a-9fcaf18e-c21821d5-0cc47a31ce4e-c3654d6c375cfe09&q=1&u=https%3A%2F%2Fgithub.com%2Ftorvalds%2Flinux%2Fblob%2F2f4c53349961c8ca480193e47da4d44fdb8335a8%2Ftools%2Fusb%2Fffs-test.c it looks like all I have to do is open "ep0" in the proper directory, but I do just that and it fails on first and subsequent runs.
> >>
> >> gadget.cc:
> >>
> >> ```
> >> #include <stdio.h>
> >> #include <stdlib.h>
> >> #include <unistd.h>
> >> #include <fcntl.h>
> >> #include <string.h>
> >> #include <errno.h>
> >>
> >> #include <linux/usb/ch9.h>
> >> #include <usbg/usbg.h>
> >>
> >> #define VENDOR  0x1d6b
> >> #define PRODUCT 0x0104
> >>
> >> int usbg_setup(
> >>          usbg_state **s,
> >>          usbg_gadget **g,
> >>          usbg_config **c,
> >>          usbg_function **f_ffs0,
> >>          usbg_function **f_ncm0
> >> );
> >>
> >> int main(int argc, char *argv[]) {
> >>          usbg_state *s;
> >>          usbg_gadget *g;
> >>          usbg_config *c;
> >>          usbg_function *f_ffs0, *f_ncm0;
> >>
> >>          if (int rc = usbg_setup(&s, &g, &c, &f_ffs0, &f_ncm0);
> >>                  rc != 0) {
> >>                  puts("gadget exists or libcomposite needs to be loaded.");
> >>          } else {
> >>                  puts("gadget created.");
> >>          }
> >>
> >>          int ffs_fd = open("/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
> >>                  O_RDONLY);
> >>          if (int rc = fchdir(ffs_fd); rc != 0) {
> >>                  fprintf(stderr, "unable to chdir to ffs directory: %s\n",
> >>                          strerror(errno));
> >>          }
> >>
> >>          int ffs_fd_ep0 = open("ep0",
> >>                  O_RDWR);
> >>          if (ffs_fd_ep0 < 0) {
> >>                  fprintf(stderr, "unable to create ep0: %d : %s\n",
> >>                          errno, strerror(errno));
> >>          }
> >>
> >>          close(ffs_fd);
> >> }
> >>
> >> int usbg_setup(
> >>          usbg_state **s,
> >>          usbg_gadget **g,
> >>          usbg_config **c,
> >>          usbg_function **f_ffs0,
> >>          usbg_function **f_ncm0
> >> ) {
> >>          struct usbg_gadget_attrs g_attrs = {
> >>                  .bcdUSB = 0x0200,
> >>                  .bDeviceClass = USB_CLASS_PER_INTERFACE,
> >>                  .bDeviceSubClass = 0x00,
> >>                  .bDeviceProtocol = 0x00,
> >>                  .bMaxPacketSize0 = 64,
> >>                  .idVendor = VENDOR,
> >>                  .idProduct = PRODUCT,
> >>                  .bcdDevice = 0x0000
> >>          };
> >>
> >>          struct usbg_gadget_strs g_strs = {
> >>                  .manufacturer = "Foo Inc.",
> >>                  .product = "Bar Gadget",
> >>                  .serial = "0000000000"
> >>          };
> >>
> >>          struct usbg_config_strs c_strs = {
> >>                  .configuration = "Default"
> >>          };
> >>
> >>          if (usbg_error rc =
> >>                          (usbg_error)usbg_init("/sys/kernel/config", s);
> >>                  rc != USBG_SUCCESS) {
> >>                  goto error_exit;
> >>          }
> >>
> >>          if (usbg_error rc =
> >>                          (usbg_error)usbg_create_gadget(*s, "g1",
> >> &g_attrs, &g_strs, g);
> >>                  rc != USBG_SUCCESS) {
> >>                  goto error_exit;
> >>          }
> >>
> >>          if (usbg_error rc =
> >>                          (usbg_error)usbg_create_function(*g,
> >>                                  USBG_F_NCM, "dev0", NULL, f_ncm0);
> >>                  rc != USBG_SUCCESS) {
> >>                  goto error_exit;
> >>          }
> >>
> >>          if (usbg_error rc =
> >>                          (usbg_error)usbg_create_function(*g,
> >>                                  USBG_F_FFS, "dev0", NULL, f_ffs0);
> >>                  rc != USBG_SUCCESS) {
> >>                  //fprintf(stderr, "Error: %s : %s\n", usbg_error_name(rc),
> >>                  //      usbg_strerror(rc));
> >>                  goto error_exit;
> >>          }
> >>          
> >>          return 0;
> >>
> >> error_exit:
> >>          return -2;
> >> }
> >> ```
> >>
> >> strace:
> >>
> >> ```
> >> execve("./gadget", ["./gadget"], 0xbece77a0 /* 19 vars */) = 0
> >> brk(NULL)                               = 0x1017000
> >> uname({sysname="Linux", nodename="nanopiduo", ...}) = 0
> >> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> >> 0) = 0xb6f5e000
> >> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or
> >> directory)
> >> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=35157, ...}) = 0
> >> mmap2(NULL, 35157, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f55000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/usr/local/lib/libusbgx.so.2",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\314I\0\0004\0\0\0"...,
> >> 512) = 512
> >> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1400) = 1400
> >> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1400) = 1400
> >> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1400) = 1400
> >> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1400) = 1400
> >> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 362460, [362460], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1400) = 1400
> >> _llseek(3, 50996, [50996], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> fstat64(3, {st_mode=S_IFREG|0755, st_size=363860, ...}) = 0
> >> mmap2(NULL, 116508, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6f1b000
> >> mprotect(0xb6f27000, 61440, PROT_NONE)  = 0
> >> mmap2(0xb6f36000, 8192, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xb000) = 0xb6f36000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libconfig.so.9",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\"\0\0004\0\0\0"...,
> >> 512) = 512
> >> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 960) = 960
> >> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 960) = 960
> >> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 960) = 960
> >> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 960) = 960
> >> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 29420, [29420], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 960) = 960
> >> _llseek(3, 29096, [29096], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=30380, ...}) = 0
> >> mmap2(NULL, 94636, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6f03000
> >> mprotect(0xb6f0a000, 61440, PROT_NONE)  = 0
> >> mmap2(0xb6f19000, 8192, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0xb6f19000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libstdc++.so.6",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\270\346\6\0004\0\0\0"..., 512) = 512
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> _llseek(3, 1018532, [1018532], SEEK_SET) = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1240) = 1240
> >> _llseek(3, 1017936, [1017936], SEEK_SET) = 0
> >> read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 51) = 51
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=1019772, ...}) = 0
> >> mmap2(NULL, 1091308, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6df8000
> >> mprotect(0xb6eeb000, 61440, PROT_NONE)  = 0
> >> mmap2(0xb6efa000, 28672, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xf2000) = 0xb6efa000
> >> mmap2(0xb6f01000, 5868, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f01000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libm.so.6",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\250r\0\0004\0\0\0"...,
> >> 512) = 512
> >> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 53) = 53
> >> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 53) = 53
> >> _llseek(3, 434644, [434644], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 434288, [434288], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 53) = 53
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=435724, ...}) = 0
> >> mmap2(NULL, 499832, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6d7d000
> >> mprotect(0xb6de7000, 61440, PROT_NONE)  = 0
> >> mmap2(0xb6df6000, 8192, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x69000) = 0xb6df6000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libgcc_s.so.1",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\360\321\0\0004\0\0\0"..., 512) = 512
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> _llseek(3, 98916, [98916], SEEK_SET)    = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 1080) = 1080
> >> _llseek(3, 98556, [98556], SEEK_SET)    = 0
> >> read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\4\22"...,
> >> 49) = 49
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=99996, ...}) = 0
> >> mmap2(NULL, 164148, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6d54000
> >> mprotect(0xb6d6c000, 61440, PROT_NONE)  = 0
> >> mmap2(0xb6d7b000, 8192, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0xb6d7b000
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libc.so.6",
> >> O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> >> read(3,
> >> "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\09v\1\0004\0\0\0"...,
> >> 512) = 512
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> _llseek(3, 949188, [949188], SEEK_SET)  = 0
> >> read(3,
> >> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> >> 2840) = 2840
> >> _llseek(3, 945756, [945756], SEEK_SET)  = 0
> >> read(3, "A4\0\0\0aeabi\0\1*\0\0\0\0057-A\0\6\n\7A\10\1\t\2\n\3\f"...,
> >> 53) = 53
> >> fstat64(3, {st_mode=S_IFREG|0755, st_size=952028, ...}) = 0
> >> mmap2(NULL, 1020732, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> >> 0) = 0xb6c5a000
> >> mprotect(0xb6d3e000, 65536, PROT_NONE)  = 0
> >> mmap2(0xb6d4e000, 12288, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe4000) = 0xb6d4e000
> >> mmap2(0xb6d51000, 9020, PROT_READ|PROT_WRITE,
> >> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d51000
> >> close(3)                                = 0
> >> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> >> 0) = 0xb6f53000
> >> set_tls(0xb6f534d0)                     = 0
> >> mprotect(0xb6d4e000, 8192, PROT_READ)   = 0
> >> mprotect(0xb6d7b000, 4096, PROT_READ)   = 0
> >> mprotect(0xb6df6000, 4096, PROT_READ)   = 0
> >> mprotect(0xb6efa000, 20480, PROT_READ)  = 0
> >> mprotect(0xb6f19000, 4096, PROT_READ)   = 0
> >> mprotect(0xb6f36000, 4096, PROT_READ)   = 0
> >> mprotect(0x491000, 4096, PROT_READ)     = 0
> >> mprotect(0xb6f60000, 4096, PROT_READ)   = 0
> >> munmap(0xb6f55000, 35157)               = 0
> >> brk(NULL)                               = 0x1017000
> >> brk(0x1038000)                          = 0x1038000
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/class/udc",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> getdents64(3, /* 3 entries */, 32768)   = 88
> >> getdents64(3, /* 0 entries */, 32768)   = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> getdents64(3, /* 3 entries */, 32768)   = 72
> >> getdents64(3, /* 0 entries */, 32768)   = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/UDC", O_RDONLY) = 3
> >> fstat64(3, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0
> >> read(3, "\n", 4096)                     = 1
> >> read(3, "", 4096)                       = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> getdents64(3, /* 4 entries */, 32768)   = 112
> >> getdents64(3, /* 0 entries */, 32768)   = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/configs",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> getdents64(3, /* 2 entries */, 32768)   = 48
> >> getdents64(3, /* 0 entries */, 32768)   = 0
> >> close(3)                                = 0
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/os_desc",
> >> O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
> >> fstat64(3, {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
> >> getdents64(3, /* 5 entries */, 32768)   = 144
> >> getdents64(3, /* 0 entries */, 32768)   = 0
> >> close(3)                                = 0
> >> write(2, "usbg_create_gadget()  duplicate "..., 46usbg_create_gadget()
> >> duplicate gadget name
> >>   
> >> ) = 46
> >> fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(0x4, 0x40), ...}) = 0
> >> ioctl(1, TCGETS, {B115200 opost isig icanon echo ...}) = 0
> >> write(1, "gadget exists.\n", 15gadget exists.
> >> )        = 15
> >> openat(AT_FDCWD, "/sys/kernel/config/usb_gadget/g1/functions/ffs.dev0",
> >> O_RDONLY) = 3
> >> fchdir(3)                               = 0
> >> openat(AT_FDCWD, "ep0", O_RDWR)         = -1 ENOENT (No such file or
> >> directory)
> >> write(2, "unable to create ep0: 2 : No suc"..., 52unable to create ep0:
> >> 2 : No such file or directory
> >> ) = 52
> >> close(3)                                = 0
> >> exit_group(0)                           = ?
> >> +++ exited with 0 +++
> >>
> >> ```
> >>
> > 
> > I created the configs as well. Still can't open ep0. Really -- is there a device or UDC someone can verify has worked in the past? Seems easiest way for me to proceed.
> > 
> > I can get more info if it'll help, but I assume some device is already working.
> 
> You cannot open ep0 because you didn't mounted ffs instance.
> 
> after you created /sys/kernel/config/usb_gadget/g1/functions/ffs.dev0 
> you need to:
> 
> mount -t functionfs dev0 /some/path
> 
> then you open(/some/path/ep0);
> 

Sigh... Thanks.

> Best regards,
> -- 
> Krzysztof Opasiak
> Samsung R&D Institute Poland
> Samsung Electronics
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, back to index

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-20 16:22 Unable to open(2) ep0 in ConfigFG FunctionFS Gadget Sid Spry
2020-05-26 19:51 ` Sid Spry
2020-05-26 20:03   ` Krzysztof Opasiak
2020-06-02  3:05     ` Sid Spry

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