[Qemu-devel] [PATCH v5 0/6] linux-user: A set of miscellaneous patches

[Qemu-devel] [PATCH v5 0/6] linux-user: A set of miscellaneous patches

[Aleksandar Markovic]

From: Aleksandar Markovic <amarkovic@wavecomp.com>

This is a collection of misc patches for Linux user that I recently
accumulated from variuous sources. All of them originate from problems
observed on mips target. However, these changes actually affect and fix
problems on multiple targets.

v4->v5:

  - added the patch on statx() support
  - improved the patch on IPV6_<ADD|DROP>_MEMBERSHIP to take into
    account the possibility of different names for a field
  - minor corrections in commit messages

v3->v4:

  - improved commit messages (fixed some typos, improved relevance)

v2->v3:

  - updated and improved commit messages
  - added IPV6_DROP_MEMBERSHIP support to the patch on setsockopt()'s
    option

v1->v2:

  - added the patch on setsockopt()'s option IPV6_ADD_MEMBERSHIP
  - improved the commit message of interp_info sanitizing patch

Aleksandar Markovic (2):
  linux-user: Fix support for SIOCATMARK and SIOCGPGRP ioctls for xtensa
  linux-user: Add support for SIOCSPGRP ioctl for all targets

Aleksandar Rikalo (1):
  linux-user: Add support for statx() syscall

Daniel Santos (1):
  linux-user: Sanitize interp_info and, for mips only, init field fp_abi

Neng Chen (2):
  linux-user: Add support for SIOC<G|S>IFPFLAGS ioctls for all targets
  linux-user: Add support for setsockopt() options
    IPV6_<ADD|DROP>_MEMBERSHIP

 linux-user/elfload.c      |   5 ++
 linux-user/ioctls.h       |   3 +
 linux-user/syscall.c      | 160 +++++++++++++++++++++++++++++++++++++++++++++-
 linux-user/syscall_defs.h |  45 ++++++++++++-
 4 files changed, 211 insertions(+), 2 deletions(-)

-- 
2.7.4

[Qemu-devel] [PATCH v5 1/6] linux-user: Fix support for SIOCATMARK and SIOCGPGRP ioctls for xtensa

[Aleksandar Markovic]

From: Aleksandar Markovic <amarkovic@wavecomp.com>

Fix support for the SIOCATMARK and SIOCGPGRP ioctls for xtensa by
correcting corresponding macro definition.

Values for TARGET_SIOCATMARK and TARGET_SIOCGPGRP are determined by
Linux kernel. Following relevant lines (obtained by grep) are from
the kernel source tree:

arch/ia64/include/uapi/asm/sockios.h:#define SIOCATMARK    0x8905
arch/mips/include/uapi/asm/sockios.h:#define SIOCATMARK    _IOR('s', 7, int)
arch/parisc/include/uapi/asm/sockios.h:#define SIOCATMARK  0x8905
arch/sh/include/uapi/asm/sockios.h:#define SIOCATMARK      _IOR('s', 7, int)
arch/xtensa/include/uapi/asm/sockios.h:#define SIOCATMARK  _IOR('s', 7, int)
arch/alpha/include/uapi/asm/sockios.h:#define SIOCATMARK   _IOR('s', 7, int)
arch/sparc/include/uapi/asm/sockios.h:#define SIOCATMARK   0x8905
include/uapi/asm-generic/sockios.h:#define SIOCATMARK	   0x8905

arch/ia64/include/uapi/asm/sockios.h:#define SIOCGPGRP     0x8904
arch/mips/include/uapi/asm/sockios.h:#define SIOCGPGRP     _IOR('s', 9, pid_t)
arch/parisc/include/uapi/asm/sockios.h:#define SIOCGPGRP   0x8904
arch/sh/include/uapi/asm/sockios.h:#define SIOCGPGRP       _IOR('s', 9, pid_t)
arch/xtensa/include/uapi/asm/sockios.h:#define SIOCGPGRP   _IOR('s', 9, pid_t)
arch/alpha/include/uapi/asm/sockios.h:#define SIOCGPGRP    _IOR('s', 9, pid_t)
arch/sparc/include/uapi/asm/sockios.h:#define SIOCGPGRP    0x8904
include/uapi/asm-generic/sockios.h:#define SIOCGPGRP       0x8904

It is visible from above that xtensa should have the same definitions
as alpha, mips and sh4 already do. This patch brings QEMU to the accurate
state wrt these two ioctls.

Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall_defs.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 12c8407..1e86fb9 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -736,7 +736,8 @@ struct target_pollfd {
 #define TARGET_KDSETLED        0x4B32	/* set led state [lights, not flags] */
 #define TARGET_KDSIGACCEPT     0x4B4E
 
-#if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SH4)
+#if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SH4) ||    \
+       defined(TARGET_XTENSA)
 #define TARGET_SIOCATMARK      TARGET_IOR('s', 7, int)
 #define TARGET_SIOCGPGRP       TARGET_IOR('s', 9, pid_t)
 #else
-- 
2.7.4

[Qemu-devel] [PATCH v5 2/6] linux-user: Add support for SIOCSPGRP ioctl for all targets

[Aleksandar Markovic]

From: Aleksandar Markovic <amarkovic@wavecomp.com>

Add support for setting the process (or process group) to receive SIGIO
or SIGURG signals when I/O becomes possible or urgent data is available,
using SIOCSPGRP ioctl.

The ioctl numeric values for SIOCSPGRP are platform-dependent and are
determined by following files in Linux kernel source tree:

arch/ia64/include/uapi/asm/sockios.h:#define SIOCSPGRP    0x8902
arch/mips/include/uapi/asm/sockios.h:#define SIOCSPGRP    _IOW('s', 8, pid_t)
arch/parisc/include/uapi/asm/sockios.h:#define SIOCSPGRP  0x8902
arch/sh/include/uapi/asm/sockios.h:#define SIOCSPGRP      _IOW('s', 8, pid_t)
arch/xtensa/include/uapi/asm/sockios.h:#define SIOCSPGRP  _IOW('s', 8, pid_t)
arch/alpha/include/uapi/asm/sockios.h:#define SIOCSPGRP   _IOW('s', 8, pid_t)
arch/sparc/include/uapi/asm/sockios.h:#define SIOCSPGRP   0x8902
include/uapi/asm-generic/sockios.h:#define SIOCSPGRP      0x8902

Hence the different definition for alpha, mips, sh4, and xtensa.

Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/ioctls.h       | 1 +
 linux-user/syscall_defs.h | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index ae89516..c37adc5 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -218,6 +218,7 @@
   IOCTL(SIOCSRARP, IOC_W, MK_PTR(MK_STRUCT(STRUCT_arpreq)))
   IOCTL(SIOCGRARP, IOC_R, MK_PTR(MK_STRUCT(STRUCT_arpreq)))
   IOCTL(SIOCGIWNAME, IOC_W | IOC_R, MK_PTR(MK_STRUCT(STRUCT_char_ifreq)))
+  IOCTL(SIOCSPGRP, IOC_W, MK_PTR(TYPE_INT)) /* pid_t */
   IOCTL(SIOCGPGRP, IOC_R, MK_PTR(TYPE_INT)) /* pid_t */
   IOCTL(SIOCGSTAMP, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timeval)))
   IOCTL(SIOCGSTAMPNS, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timespec)))
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 1e86fb9..2941231 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -739,11 +739,14 @@ struct target_pollfd {
 #if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SH4) ||    \
        defined(TARGET_XTENSA)
 #define TARGET_SIOCATMARK      TARGET_IOR('s', 7, int)
+#define TARGET_SIOCSPGRP       TARGET_IOW('s', 8, pid_t)
 #define TARGET_SIOCGPGRP       TARGET_IOR('s', 9, pid_t)
 #else
 #define TARGET_SIOCATMARK      0x8905
+#define TARGET_SIOCSPGRP       0x8902
 #define TARGET_SIOCGPGRP       0x8904
 #endif
+
 #define TARGET_SIOCGSTAMP      0x8906          /* Get stamp (timeval) */
 #define TARGET_SIOCGSTAMPNS    0x8907          /* Get stamp (timespec) */
 
-- 
2.7.4

[Qemu-devel] [PATCH v5 3/6] linux-user: Add support for SIOC<G|S>IFPFLAGS ioctls for all targets

[Aleksandar Markovic]

From: Neng Chen <nchen@wavecomp.com>

Add support for getting and setting extended private flags of a
network device via SIOCSIFPFLAGS and SIOCGIFPFLAGS ioctls.

The ioctl numeric values are platform-independent and determined by
the file include/uapi/linux/sockios.h in Linux kernel source code:

  #define SIOCSIFPFLAGS 0x8934
  #define SIOCGIFPFLAGS	0x8935

These ioctls get (or set) the field ifr_flags of type short in the
structure ifreq. Such functionality is achieved in QEMU by using
MK_STRUCT() and MK_PTR() macros with an appropriate argument, as
it was done for existing similar cases.

Signed-off-by: Neng Chen <nchen@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <1554839486-3527-1-git-send-email-aleksandar.markovic@rt-rk.com>
---
 linux-user/ioctls.h       | 2 ++
 linux-user/syscall_defs.h | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index c37adc5..76375df 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -206,6 +206,8 @@
   IOCTL(SIOCADDMULTI, IOC_W, MK_PTR(MK_STRUCT(STRUCT_sockaddr_ifreq)))
   IOCTL(SIOCDELMULTI, IOC_W, MK_PTR(MK_STRUCT(STRUCT_sockaddr_ifreq)))
   IOCTL(SIOCGIFINDEX, IOC_W | IOC_R, MK_PTR(MK_STRUCT(STRUCT_int_ifreq)))
+  IOCTL(SIOCSIFPFLAGS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
+  IOCTL(SIOCGIFPFLAGS, IOC_W | IOC_R, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
   IOCTL(SIOCSIFLINK, 0, TYPE_NULL)
   IOCTL_SPECIAL(SIOCGIFCONF, IOC_W | IOC_R, do_ioctl_ifconf,
                 MK_PTR(MK_STRUCT(STRUCT_ifconf)))
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 2941231..8904d35 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -781,6 +781,8 @@ struct target_pollfd {
 #define TARGET_SIOCADDMULTI    0x8931          /* Multicast address lists      */
 #define TARGET_SIOCDELMULTI    0x8932
 #define TARGET_SIOCGIFINDEX    0x8933
+#define TARGET_SIOCSIFPFLAGS   0x8934          /* set extended flags          */
+#define TARGET_SIOCGIFPFLAGS   0x8935          /* get extended flags          */
 
 /* Bridging control calls */
 #define TARGET_SIOCGIFBR       0x8940          /* Bridging support             */
-- 
2.7.4

[Qemu-devel] [PATCH v5 4/6] linux-user: Add support for setsockopt() options IPV6_<ADD|DROP>_MEMBERSHIP

[Aleksandar Markovic]

From: Neng Chen <nchen@wavecomp.com>

Add support for options IPV6_ADD_MEMBERSHIP and IPV6_DROP_MEMPEMBERSHIP
of the syscall setsockopt(). These options control membership in
multicast groups. Their argument is a pointer to a struct ipv6_mreq,
which is in turn defined in IP v6 headers as:

struct ipv6_mreq {
    /* IPv6 multicast address of group */
    struct  in6_addr  ipv6mr_multiaddr;
    /* local IPv6 address of interface */
    int     ipv6mr_interface;
};

...whereas its definition in kernel (include/uapi/linux/in6.h) is:

struct ipv6_mreq {
    /* IPv6 multicast address of group */
    struct  in6_addr ipv6mr_multiaddr;
    /* local IPv6 address of interface */
    int     ipv6mr_ifindex;
};

The first field of ipv6_mreq has the same name ("ipv6mr_multiaddr")
and type ("in6_addr") in both cases. Moreover, the in6_addr structure
consists of fields that are always big-endian (on host of any endian),
therefore the ipv6_mreq's field ipv6mr_multiaddr doesn't need any
endian conversion.

The second field of ipv6_mreq may, however, depending on the build
environment, have different names. This is the reason why the line
"#if __UAPI_DEF_IPV6_MREQ" is used in this patch - to establish the
right choice for the field name. Also, endian conversion is needed
fot this field, since it is of type "int".

Signed-off-by: Neng Chen <nchen@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
---
 linux-user/syscall.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 96cd4bf..d8f95c5 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1892,6 +1892,31 @@ static abi_long do_setsockopt(int sockfd, int level, int optname,
                                        &pki, sizeof(pki)));
             break;
         }
+        case IPV6_ADD_MEMBERSHIP:
+        case IPV6_DROP_MEMBERSHIP:
+        {
+            struct ipv6_mreq ipv6mreq;
+
+            if (optlen < sizeof(ipv6mreq)) {
+                return -TARGET_EINVAL;
+            }
+
+            if (copy_from_user(&ipv6mreq, optval_addr, sizeof(ipv6mreq))) {
+                return -TARGET_EFAULT;
+            }
+
+#if __UAPI_DEF_IPV6_MREQ
+            ipv6mreq.ipv6mr_ifindex = tswap32(ipv6mreq.ipv6mr_ifindex);
+#else
+            ipv6mreq.ipv6mr_interface = tswap32(ipv6mreq.ipv6mr_interface);
+#endif /* __UAPI_DEF_IVP6_MREQ */
+
+            ipv6mreq.ipv6mr_interface = tswap32(ipv6mreq.ipv6mr_interface);
+
+            ret = get_errno(setsockopt(sockfd, level, optname,
+                                       &ipv6mreq, sizeof(ipv6mreq)));
+            break;
+        }
         default:
             goto unimplemented;
         }
-- 
2.7.4

[Qemu-devel] [PATCH v5 5/6] linux-user: Sanitize interp_info and, for mips only, init field fp_abi

[Aleksandar Markovic]

From: Daniel Santos <daniel.santos@pobox.com>

Sanitize interp_info structure in load_elf_binary() and, for MIPS only,
init its field fp_abi to MIPS_ABI_FP_UNKNOWN. This fixes appearances of
"Unexpected FPU mode" message in some MIPS use cases. Currently, this
bug is a complete stopper for some MIPS binaries.

In load_elf_binary(), struct image_info interp_info is used without
being properly initialized. One result is that when the ELF's program
header doesn't contain an entry for the ABI flags, then the value of
the struct image_info's fp_abi field is set to whatever happened to
be in stack memory at the time.

Backporting to 4.0 and, if possible, to 3.1 is recommended.

Fixes: https://bugs.launchpad.net/qemu/+bug/1825002

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/elfload.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index c1a2602..7f09d57 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2698,6 +2698,11 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
     char *elf_interpreter = NULL;
     char *scratch;
 
+    memset(&interp_info, 0, sizeof(interp_info));
+#ifdef TARGET_MIPS
+    interp_info.fp_abi = MIPS_ABI_FP_UNKNOWN;
+#endif
+
     info->start_mmap = (abi_ulong)ELF_START_MMAP;
 
     load_elf_image(bprm->filename, bprm->fd, info,
-- 
2.7.4

[Qemu-devel] [PATCH v5 6/6] linux-user: Add support for statx() syscall

[Aleksandar Markovic]

From: Aleksandar Rikalo <arikalo@wavecomp.com>

Implement support for translation of system call statx(). The
implementation includes invoking other (more mature) system calls
(from the same 'stat' family) on the host side. This way, the
problems of potential lack of statx() availability of on the host
side are avoided.

Support for statx() in kernel and glibc was unfortunately introduced
in different points of time (the difference is more than a year):

  - kernel: Linux 4.11 (30 April 2017)
  - glibc: glibc 2.28 (1 Aug 2018)

In this patch, the availability of statx() support is established
via __NR_statx (if it is defined, statx() is considered available).
This coincedes with statx() introduction in kernel.

However, the structure statx may not be available for hosts with
glibc older than 2.28, even though the statx() functionality may
be supported in kernel, if the kernel is not older than 4.11. Hence,
a structure "target_statx" is defined in this patch, to remove that
dependency on glibc headers. It is used for both target and host
structures statx (of course, endian conversion is done in all
needed cases).

Signed-off-by: Aleksandar Rikalo <arikalo@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
---
 linux-user/syscall.c      | 135 +++++++++++++++++++++++++++++++++++++++++++++-
 linux-user/syscall_defs.h |  37 +++++++++++++
 2 files changed, 171 insertions(+), 1 deletion(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d8f95c5..aea2000 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -43,6 +43,7 @@
 #include <sys/times.h>
 #include <sys/shm.h>
 #include <sys/sem.h>
+#include <sys/stat.h>
 #include <sys/statfs.h>
 #include <utime.h>
 #include <sys/sysinfo.h>
@@ -6429,6 +6430,48 @@ static inline abi_long host_to_target_stat64(void *cpu_env,
 }
 #endif
 
+#if defined(TARGET_NR_statx) && defined(__NR_statx)
+static inline abi_long host_to_target_statx(struct target_statx *host_stx,
+                                            abi_ulong target_addr)
+{
+    struct target_statx *target_stx;
+
+    if (!lock_user_struct(VERIFY_WRITE, target_stx, target_addr,  0)) {
+        return -TARGET_EFAULT;
+    }
+    memset(target_stx, 0, sizeof(*target_stx));
+
+    __put_user(host_stx->stx_mask, &target_stx->stx_mask);
+    __put_user(host_stx->stx_blksize, &target_stx->stx_blksize);
+    __put_user(host_stx->stx_attributes, &target_stx->stx_attributes);
+    __put_user(host_stx->stx_nlink, &target_stx->stx_nlink);
+    __put_user(host_stx->stx_uid, &target_stx->stx_uid);
+    __put_user(host_stx->stx_gid, &target_stx->stx_gid);
+    __put_user(host_stx->stx_mode, &target_stx->stx_mode);
+    __put_user(host_stx->stx_ino, &target_stx->stx_ino);
+    __put_user(host_stx->stx_size, &target_stx->stx_size);
+    __put_user(host_stx->stx_blocks, &target_stx->stx_blocks);
+    __put_user(host_stx->stx_attributes_mask, &target_stx->stx_attributes_mask);
+    __put_user(host_stx->stx_atime.tv_sec, &target_stx->stx_atime.tv_sec);
+    __put_user(host_stx->stx_atime.tv_nsec, &target_stx->stx_atime.tv_nsec);
+    __put_user(host_stx->stx_btime.tv_sec, &target_stx->stx_atime.tv_sec);
+    __put_user(host_stx->stx_btime.tv_nsec, &target_stx->stx_atime.tv_nsec);
+    __put_user(host_stx->stx_ctime.tv_sec, &target_stx->stx_atime.tv_sec);
+    __put_user(host_stx->stx_ctime.tv_nsec, &target_stx->stx_atime.tv_nsec);
+    __put_user(host_stx->stx_mtime.tv_sec, &target_stx->stx_atime.tv_sec);
+    __put_user(host_stx->stx_mtime.tv_nsec, &target_stx->stx_atime.tv_nsec);
+    __put_user(host_stx->stx_rdev_major, &target_stx->stx_rdev_major);
+    __put_user(host_stx->stx_rdev_minor, &target_stx->stx_rdev_minor);
+    __put_user(host_stx->stx_dev_major, &target_stx->stx_dev_major);
+    __put_user(host_stx->stx_dev_minor, &target_stx->stx_dev_minor);
+
+    unlock_user_struct(target_stx, target_addr, 1);
+
+    return 0;
+}
+#endif
+
+
 /* ??? Using host futex calls even when target atomic operations
    are not really atomic probably breaks things.  However implementing
    futexes locally would make futexes shared between multiple processes
@@ -6982,7 +7025,8 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     abi_long ret;
 #if defined(TARGET_NR_stat) || defined(TARGET_NR_stat64) \
     || defined(TARGET_NR_lstat) || defined(TARGET_NR_lstat64) \
-    || defined(TARGET_NR_fstat) || defined(TARGET_NR_fstat64)
+    || defined(TARGET_NR_fstat) || defined(TARGET_NR_fstat64) \
+    || defined(TARGET_NR_statx)
     struct stat st;
 #endif
 #if defined(TARGET_NR_statfs) || defined(TARGET_NR_statfs64) \
@@ -10031,6 +10075,95 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
             ret = host_to_target_stat64(cpu_env, arg3, &st);
         return ret;
 #endif
+#if defined(TARGET_NR_statx)
+    case TARGET_NR_statx:
+        {
+            struct target_statx *target_stx;
+            int dirfd = arg1;
+            int flags = arg3;
+
+            p = lock_user_string(arg2);
+            if (p == NULL) {
+                return -TARGET_EFAULT;
+            }
+#if defined(__NR_statx)
+            {
+                /*
+                 * It is assumed that struct statx is arhitecture independent
+                 */
+                struct target_statx host_stx;
+                int mask = arg4;
+
+                ret = get_errno(syscall(__NR_statx, dirfd, p, flags, mask,
+                                        &host_stx));
+                if (!is_error(ret)) {
+                    if (host_to_target_statx(&host_stx, arg5) != 0) {
+                        unlock_user(p, arg2, 0);
+                        return -TARGET_EFAULT;
+                    }
+                }
+
+                if (ret != TARGET_ENOSYS) {
+                    unlock_user(p, arg2, 0);
+                    return ret;
+                }
+            }
+#endif
+            if ((p == NULL) || (*((char *)p) == 0)) {
+                /*
+                 * By file descriptor
+                 */
+                if (flags & AT_EMPTY_PATH) {
+                    unlock_user(p, arg2, 0);
+                    return -TARGET_ENOENT;
+                }
+                ret = get_errno(fstat(dirfd, &st));
+            } else if (*((char *)p) == '/') {
+                /*
+                 * By absolute pathname
+                 */
+                ret = get_errno(stat(path(p), &st));
+            } else {
+                if (dirfd == AT_FDCWD) {
+                    /*
+                     * By pathname relative to the current working directory
+                     */
+                    ret = get_errno(stat(path(p), &st));
+                } else {
+                    /*
+                     * By pathname relative to the directory referred to by
+                     * the file descriptor 'dirfd'
+                     */
+                    ret = get_errno(fstatat(dirfd, path(p), &st, flags));
+                }
+            }
+            unlock_user(p, arg2, 0);
+
+            if (!is_error(ret)) {
+                if (!lock_user_struct(VERIFY_WRITE, target_stx, arg5, 0)) {
+                    return -TARGET_EFAULT;
+                }
+                memset(target_stx, 0, sizeof(*target_stx));
+                __put_user(major(st.st_dev), &target_stx->stx_dev_major);
+                __put_user(minor(st.st_dev), &target_stx->stx_dev_minor);
+                __put_user(st.st_ino, &target_stx->stx_ino);
+                __put_user(st.st_mode, &target_stx->stx_mode);
+                __put_user(st.st_uid, &target_stx->stx_uid);
+                __put_user(st.st_gid, &target_stx->stx_gid);
+                __put_user(st.st_nlink, &target_stx->stx_nlink);
+                __put_user(major(st.st_rdev), &target_stx->stx_rdev_major);
+                __put_user(minor(st.st_rdev), &target_stx->stx_rdev_minor);
+                __put_user(st.st_size, &target_stx->stx_size);
+                __put_user(st.st_blksize, &target_stx->stx_blksize);
+                __put_user(st.st_blocks, &target_stx->stx_blocks);
+                __put_user(st.st_atime, &target_stx->stx_atime.tv_sec);
+                __put_user(st.st_mtime, &target_stx->stx_mtime.tv_sec);
+                __put_user(st.st_ctime, &target_stx->stx_ctime.tv_sec);
+                unlock_user_struct(target_stx, arg5, 1);
+            }
+        }
+        return ret;
+#endif
 #ifdef TARGET_NR_lchown
     case TARGET_NR_lchown:
         if (!(p = lock_user_string(arg1)))
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 8904d35..82f2ac3 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -2522,4 +2522,41 @@ struct target_user_cap_data {
 /* Return size of the log buffer */
 #define TARGET_SYSLOG_ACTION_SIZE_BUFFER   10
 
+struct target_statx_timestamp {
+   int64_t tv_sec;
+   uint32_t tv_nsec;
+   int32_t __reserved;
+};
+
+struct target_statx {
+   /* 0x00 */
+   uint32_t stx_mask;       /* What results were written [uncond] */
+   uint32_t stx_blksize;    /* Preferred general I/O size [uncond] */
+   uint64_t stx_attributes; /* Flags conveying information about the file */
+   /* 0x10 */
+   uint32_t stx_nlink;      /* Number of hard links */
+   uint32_t stx_uid;        /* User ID of owner */
+   uint32_t stx_gid;        /* Group ID of owner */
+   uint16_t stx_mode;       /* File mode */
+   uint16_t __spare0[1];
+   /* 0x20 */
+   uint64_t stx_ino;        /* Inode number */
+   uint64_t stx_size;       /* File size */
+   uint64_t stx_blocks;     /* Number of 512-byte blocks allocated */
+   uint64_t stx_attributes_mask; /* Mask to show what is supported */
+   /* 0x40 */
+   struct target_statx_timestamp  stx_atime;  /* Last access time */
+   struct target_statx_timestamp  stx_btime;  /* File creation time */
+   struct target_statx_timestamp  stx_ctime;  /* Last attribute change time */
+   struct target_statx_timestamp  stx_mtime;  /* Last data modification time */
+   /* 0x80 */
+   uint32_t stx_rdev_major;   /* Device ID of special file [if bdev/cdev] */
+   uint32_t stx_rdev_minor;
+   uint32_t stx_dev_major; /* ID of device containing file [uncond] */
+   uint32_t stx_dev_minor;
+   /* 0x90 */
+   uint64_t __spare2[14];  /* Spare space for future expansion */
+   /* 0x100 */
+};
+
 #endif
-- 
2.7.4