[Qemu-devel] [PATCH 03/17] virtio-9p: Implement P9_TATTACH

[Anthony Liguori <aliguori@us.ibm.com>]

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 Makefile.target      |    2 +-
 hw/virtio-9p-local.c |   84 +++++++++++++++++++++++++++
 hw/virtio-9p.c       |  155 +++++++++++++++++++++++++++++++++++++++++++++++---
 hw/virtio-9p.h       |   33 +++++++++++
 4 files changed, 264 insertions(+), 10 deletions(-)
 create mode 100644 hw/virtio-9p-local.c

diff --git a/Makefile.target b/Makefile.target
index 8f240ea..ff5fc4b 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -173,7 +173,7 @@ obj-y = vl.o async.o monitor.o pci.o pci_host.o pcie_host.o machine.o gdbstub.o
 # virtio has to be here due to weird dependency between PCI and virtio-net.
 # need to fix this properly
 obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-pci.o virtio-serial-bus.o
-obj-y += virtio-9p.o virtio-9p-debug.o
+obj-y += virtio-9p.o virtio-9p-debug.o virtio-9p-local.o
 obj-y += rwhandler.o
 obj-$(CONFIG_KVM) += kvm.o kvm-all.o
 obj-$(CONFIG_ISA_MMIO) += isa_mmio.o
diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
new file mode 100644
index 0000000..204437c
--- /dev/null
+++ b/hw/virtio-9p-local.c
@@ -0,0 +1,84 @@
+/*
+ * Virtio 9p Posix callback
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#include "virtio.h"
+#include "pc.h"
+#include "qemu_socket.h"
+#include "virtio-9p.h"
+#include <sys/uio.h>
+#include <arpa/inet.h>
+#include <assert.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+static const char *base_path;
+
+static const char *rpath(const char *path)
+{
+    /* FIXME: so wrong... */
+    static char buffer[4096];
+    snprintf(buffer, sizeof(buffer), "%s/%s", base_path, path);
+    return buffer;
+}
+
+static int local_lstat(void *opaque, const char *path, struct stat *stbuf)
+{
+    return lstat(rpath(path), stbuf);
+}
+
+static int local_setuid(void *opaque, uid_t uid)
+{
+    struct passwd *pw;
+    gid_t groups[33];
+    int ngroups;
+    static uid_t cur_uid = -1;
+
+    if (cur_uid == uid)
+	return 0;
+
+    if (setreuid(0, 0))
+	return -1;
+
+    pw = getpwuid(uid);
+    if (pw == NULL)
+	return -1;
+
+    ngroups = 33;
+    if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups) == -1)
+	return -1;
+
+    if (setgroups(ngroups, groups))
+	return -1;
+
+    if (setregid(-1, pw->pw_gid))
+	return -1;
+
+    if (setreuid(-1, uid))
+	return -1;
+
+    cur_uid = uid;
+
+    return 0;
+}
+
+static V9fsPosixFileOperations ops = {
+    .lstat = local_lstat,
+    .setuid = local_setuid,
+};
+
+V9fsPosixFileOperations *virtio_9p_init_local(const char *path)
+{
+	base_path = path;
+	return &ops;
+}
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index a057fbb..c63ac80 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -82,6 +82,7 @@ typedef struct V9fsState
     V9fsPDU pdus[MAX_REQ];
     V9fsPDU *free_pdu;
     V9fsFidState *fid_list;
+    V9fsPosixFileOperations *ops;
     char *root;
     uid_t uid;
 } V9fsState;
@@ -91,6 +92,123 @@ int debug_9p_pdu = 1;
 
 extern void pprint_pdu(V9fsPDU *pdu);
 
+static int posix_lstat(V9fsState *s, V9fsString *path, struct stat *stbuf)
+{
+    return s->ops->lstat(s->ops->opaque, path->data, stbuf);
+}
+
+static int posix_setuid(V9fsState *s, uid_t uid)
+{
+    return s->ops->setuid(s->ops->opaque, uid);
+}
+
+static void v9fs_string_free(V9fsString *str)
+{
+    free(str->data);
+    str->data = NULL;
+    str->size = 0;
+}
+
+static void v9fs_string_sprintf(V9fsString *str, const char *fmt, ...)
+{
+    va_list ap;
+    int err;
+
+    v9fs_string_free(str);
+
+    va_start(ap, fmt);
+    err = vasprintf(&str->data, fmt, ap);
+    BUG_ON(err == -1);
+    va_end(ap);
+
+    str->size = err;
+}
+
+static V9fsFidState *lookup_fid(V9fsState *s, int32_t fid)
+{
+    V9fsFidState *f;
+
+    for (f = s->fid_list; f; f = f->next) {
+	if (f->fid == fid) {
+	    posix_setuid(s, f->uid);
+	    return f;
+	}
+    }
+
+    return NULL;
+}
+
+static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid)
+{
+    V9fsFidState *f;
+
+    f = lookup_fid(s, fid);
+    if (f)
+	return NULL;
+
+    f = qemu_mallocz(sizeof(V9fsFidState));
+    BUG_ON(f == NULL);
+
+    f->fid = fid;
+    f->fd = -1;
+    f->dir = NULL;
+
+    f->next = s->fid_list;
+    s->fid_list = f;
+
+    return f;
+}
+
+#define P9_QID_TYPE_DIR		0x80
+#define P9_QID_TYPE_SYMLINK	0x02
+
+#define P9_STAT_MODE_DIR	0x80000000
+#define P9_STAT_MODE_APPEND	0x40000000
+#define P9_STAT_MODE_EXCL	0x20000000
+#define P9_STAT_MODE_MOUNT	0x10000000
+#define P9_STAT_MODE_AUTH	0x08000000
+#define P9_STAT_MODE_TMP	0x04000000
+#define P9_STAT_MODE_SYMLINK	0x02000000
+#define P9_STAT_MODE_LINK	0x01000000
+#define P9_STAT_MODE_DEVICE	0x00800000
+#define P9_STAT_MODE_NAMED_PIPE	0x00200000
+#define P9_STAT_MODE_SOCKET	0x00100000
+#define P9_STAT_MODE_SETUID	0x00080000
+#define P9_STAT_MODE_SETGID	0x00040000
+#define P9_STAT_MODE_SETVTX	0x00010000
+
+#define P9_STAT_MODE_SPECIAL	(P9_STAT_MODE_NAMED_PIPE | \
+				 P9_STAT_MODE_SYMLINK | \
+				 P9_STAT_MODE_LINK | \
+				 P9_STAT_MODE_DEVICE)
+
+
+/* This is the algorithm from ufs in spfs */
+static void stat_to_qid(const struct stat *stbuf, V9fsQID *qidp)
+{
+    size_t size;
+
+    size = MIN(sizeof(stbuf->st_ino), sizeof(qidp->path));
+    memcpy(&qidp->path, &stbuf->st_ino, size);
+    qidp->version = stbuf->st_mtime ^ (stbuf->st_size << 8);
+    qidp->type = 0;
+    if (S_ISDIR(stbuf->st_mode))
+	qidp->type |= P9_QID_TYPE_DIR;
+    if (S_ISLNK(stbuf->st_mode))
+	qidp->type |= P9_QID_TYPE_SYMLINK;
+}
+
+static void fid_to_qid(V9fsState *s, V9fsFidState *fidp, V9fsQID *qidp)
+{
+    struct stat stbuf;
+    int err;
+
+    err = posix_lstat(s, &fidp->path, &stbuf);
+    BUG_ON(err == -1);
+
+    stat_to_qid(&stbuf, qidp);
+}
+
 static V9fsPDU *alloc_pdu(V9fsState *s)
 {
     V9fsPDU *pdu = NULL;
@@ -111,13 +229,6 @@ static void free_pdu(V9fsState *s, V9fsPDU *pdu)
     }
 }
 
-static void v9fs_string_free(V9fsString *str)
-{
-    free(str->data);
-    str->data = NULL;
-    str->size = 0;
-}
-
 static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
 {
     struct iovec *sg = pdu->elem.out_sg;
@@ -380,8 +491,33 @@ static void v9fs_version(V9fsState *s, V9fsPDU *pdu)
 
 static void v9fs_attach(V9fsState *s, V9fsPDU *pdu)
 {
-    if (debug_9p_pdu)
-	pprint_pdu(pdu);
+    int32_t fid, afid, n_uname;
+    V9fsString uname, aname;
+    V9fsFidState *fidp;
+    V9fsQID qid;
+    size_t offset = 7;
+    ssize_t err;
+
+    pdu_unmarshal(pdu, offset, "ddssd", &fid, &afid, &uname, &aname, &n_uname);
+
+    fidp = alloc_fid(s, fid);
+    if (fidp == NULL) {
+	err = -EINVAL;
+	goto out;
+    }
+
+    fidp->uid = n_uname;
+
+    v9fs_string_sprintf(&fidp->path, "%s", s->root);
+    fid_to_qid(s, fidp, &qid);
+
+    offset += pdu_marshal(pdu, offset, "Q", &qid);
+
+    err = offset;
+out:
+    complete_pdu(s, pdu, err);
+    v9fs_string_free(&uname);
+    v9fs_string_free(&aname);
 }
 
 static void v9fs_stat(V9fsState *s, V9fsPDU *pdu)
@@ -530,6 +666,7 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, const char *path)
     BUG_ON(s->root == NULL);
     s->uid = -1;
 
+    s->ops = virtio_9p_init_local(path);
     s->vdev.get_features = virtio_9p_get_features;
 
     return &s->vdev;
diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h
index 3945f81..10a084a 100644
--- a/hw/virtio-9p.h
+++ b/hw/virtio-9p.h
@@ -66,5 +66,38 @@ struct V9fsPDU
     V9fsPDU *next;
 };
 
+typedef struct V9fsPosixFileOpertions
+{
+    int (*lstat)(void *, const char *, struct stat *);
+    ssize_t (*readlink)(void *, const char *, char *, size_t);
+    int (*chmod)(void *, const char *, mode_t);
+    int (*chown)(void *, const char *, uid_t, gid_t);
+    int (*mknod)(void *, const char *, mode_t, dev_t);
+    int (*mksock)(void *, const char *);
+    int (*utime)(void *, const char *, const struct utimbuf *);
+    int (*remove)(void *, const char *);
+    int (*symlink)(void *, const char *, const char *);
+    int (*link)(void *, const char *, const char *);
+    int (*setuid)(void *, uid_t);
+    int (*close)(void *, int);
+    int (*closedir)(void *, DIR *);
+    DIR *(*opendir)(void *, const char *);
+    int (*open)(void *, const char *, int);
+    int (*open2)(void *, const char *, int, mode_t);
+    void (*rewinddir)(void *, DIR *);
+    off_t (*telldir)(void *, DIR *);
+    struct dirent *(*readdir)(void *, DIR *);
+    void (*seekdir)(void *, DIR *, off_t);
+    ssize_t (*readv)(void *, int, const struct iovec *, int);
+    ssize_t (*writev)(void *, int, const struct iovec *, int);
+    off_t (*lseek)(void *, int, off_t, int);
+    int (*mkdir)(void *, const char *, mode_t);
+    int (*fstat)(void *, int, struct stat *);
+    int (*rename)(void *, const char *, const char *);
+    int (*truncate)(void *, const char *, off_t);
+    void *opaque;
+} V9fsPosixFileOperations;
+
+V9fsPosixFileOperations *virtio_9p_init_local(const char *path);
 
 #endif
-- 
1.6.5.2