[Qemu-devel] [PATCH] use g_path_get_basename instead of basename

[Julia Suvorova]

basename(3) and dirname(3) modify their argument and may return
pointers to statically allocated memory which may be overwritten by
subsequent calls.
g_path_get_basename and g_path_get_dirname have no such issues, and
therefore more preferable.

Signed-off-by: Julia Suvorova <address@hidden>
---
 fsdev/virtfs-proxy-helper.c |  6 +++++-
 hw/s390x/s390-ccw.c         | 17 +++++++++++------
 hw/vfio/ccw.c               |  7 +++++--
 hw/vfio/pci.c               |  6 ++++--
 hw/vfio/platform.c          |  6 ++++--
 qemu-io.c                   |  8 +++++++-
 qemu-nbd.c                  |  5 ++++-
 qga/commands-posix.c        |  4 ++--
 8 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/fsdev/virtfs-proxy-helper.c b/fsdev/virtfs-proxy-helper.c
index 8e48500..da3452f 100644
--- a/fsdev/virtfs-proxy-helper.c
+++ b/fsdev/virtfs-proxy-helper.c
@@ -787,6 +787,8 @@ error:
 
 static void usage(char *prog)
 {
+    char *base_filename = g_path_get_basename(prog);
+
     fprintf(stderr, "usage: %s\n"
             " -p|--path <path> 9p path to export\n"
             " {-f|--fd <socket-descriptor>} socket file descriptor to be 
used\n"
@@ -795,7 +797,9 @@ static void usage(char *prog)
             " access to this socket\n"
             " \tNote: -s & -f can not be used together\n"
             " [-n|--nodaemon] Run as a normal program\n",
-            basename(prog));
+            base_filename);
+
+    g_free(base_filename);
 }
 
 static int process_reply(int sock, int type,
diff --git a/hw/s390x/s390-ccw.c b/hw/s390x/s390-ccw.c
index 7fc1c60..460dbab 100644
--- a/hw/s390x/s390-ccw.c
+++ b/hw/s390x/s390-ccw.c
@@ -34,7 +34,7 @@ static void s390_ccw_get_dev_info(S390CCWDevice *cdev,
                                   Error **errp)
 {
     unsigned int cssid, ssid, devid;
-    char dev_path[PATH_MAX] = {0}, *tmp;
+    char dev_path[PATH_MAX] = {0}, *dir_name, *dir_path;
 
     if (!sysfsdev) {
         error_setg(errp, "No host device provided");
@@ -48,18 +48,23 @@ static void s390_ccw_get_dev_info(S390CCWDevice *cdev,
         return;
     }
 
-    cdev->mdevid = g_strdup(basename(dev_path));
+    cdev->mdevid = g_path_get_basename(dev_path);
 
-    tmp = basename(dirname(dev_path));
-    if (sscanf(tmp, "%2x.%1x.%4x", &cssid, &ssid, &devid) != 3) {
-        error_setg_errno(errp, errno, "Failed to read %s", tmp);
-        return;
+    dir_path = g_path_get_dirname(dev_path);
+    dir_name = g_path_get_basename(dir_path);
+    if (sscanf(dir_name, "%2x.%1x.%4x", &cssid, &ssid, &devid) != 3) {
+        error_setg_errno(errp, errno, "Failed to read %s", dir_name);
+        goto out;
     }
 
     cdev->hostid.cssid = cssid;
     cdev->hostid.ssid = ssid;
     cdev->hostid.devid = devid;
     cdev->hostid.valid = true;
+
+out:
+    g_free(dir_path);
+    g_free(dir_name);
 }
 
 static void s390_ccw_realize(S390CCWDevice *cdev, char *sysfsdev, Error **errp)
diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index 16713f2..c0566a9 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -300,7 +300,7 @@ static void vfio_put_device(VFIOCCWDevice *vcdev)
 
 static VFIOGroup *vfio_ccw_get_group(S390CCWDevice *cdev, Error **errp)
 {
-    char *tmp, group_path[PATH_MAX];
+    char *tmp, *group_name, group_path[PATH_MAX];
     ssize_t len;
     int groupid;
 
@@ -317,10 +317,13 @@ static VFIOGroup *vfio_ccw_get_group(S390CCWDevice *cdev, 
Error **errp)
 
     group_path[len] = 0;
 
-    if (sscanf(basename(group_path), "%d", &groupid) != 1) {
+    group_name = g_path_get_basename(group_path);
+    if (sscanf(group_name, "%d", &groupid) != 1) {
         error_setg(errp, "vfio: failed to read %s", group_path);
+        g_free(group_name);
         return NULL;
     }
+    g_free(group_name);
 
     return vfio_get_group(groupid, &address_space_memory, errp);
 }
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 033cc8d..ba03136 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2807,7 +2807,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         return;
     }
 
-    vdev->vbasedev.name = g_strdup(basename(vdev->vbasedev.sysfsdev));
+    vdev->vbasedev.name = g_path_get_basename(vdev->vbasedev.sysfsdev);
     vdev->vbasedev.ops = &vfio_pci_ops;
     vdev->vbasedev.type = VFIO_DEVICE_TYPE_PCI;
     vdev->vbasedev.dev = &vdev->pdev.qdev;
@@ -2824,11 +2824,13 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
 
     group_path[len] = 0;
 
-    group_name = basename(group_path);
+    group_name = g_path_get_basename(group_path);
     if (sscanf(group_name, "%d", &groupid) != 1) {
         error_setg_errno(errp, errno, "failed to read %s", group_path);
+        g_free(group_name);
         goto error;
     }
+    g_free(group_name);
 
     trace_vfio_realize(vdev->vbasedev.name, groupid);
 
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index 0d4bc0a..15dbae8 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -561,7 +561,7 @@ static int vfio_base_device_init(VFIODevice *vbasedev, 
Error **errp)
     /* @sysfsdev takes precedence over @host */
     if (vbasedev->sysfsdev) {
         g_free(vbasedev->name);
-        vbasedev->name = g_strdup(basename(vbasedev->sysfsdev));
+        vbasedev->name = g_path_get_basename(vbasedev->sysfsdev);
     } else {
         if (!vbasedev->name || strchr(vbasedev->name, '/')) {
             error_setg(errp, "wrong host device name");
@@ -590,11 +590,13 @@ static int vfio_base_device_init(VFIODevice *vbasedev, 
Error **errp)
 
     group_path[len] = 0;
 
-    group_name = basename(group_path);
+    group_name = g_path_get_basename(group_path);
     if (sscanf(group_name, "%d", &groupid) != 1) {
         error_setg_errno(errp, errno, "failed to read %s", group_path);
+        g_free(group_name);
         return -errno;
     }
+    g_free(group_name);
 
     trace_vfio_platform_base_device_init(vbasedev->name, groupid);
 
diff --git a/qemu-io.c b/qemu-io.c
index 2c00ea0..1de5fc7 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -308,6 +308,11 @@ static char *get_prompt(void)
     return prompt;
 }
 
+static void free_progname(void)
+{
+    g_free(progname);
+}
+
 static void GCC_FMT_ATTR(2, 3) readline_printf_func(void *opaque,
                                                     const char *fmt, ...)
 {
@@ -504,7 +509,8 @@ int main(int argc, char **argv)
 #endif
 
     module_call_init(MODULE_INIT_TRACE);
-    progname = basename(argv[0]);
+    progname = g_path_get_basename(argv[0]);
+    atexit(free_progname);
     qemu_init_exec_dir(argv[0]);
 
     qcrypto_init(&error_fatal);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index ed5d9b5..36bafe7 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -893,8 +893,11 @@ int main(int argc, char **argv)
     }
 
     if (device != NULL && sockpath == NULL) {
+        char *base_filename = g_path_get_basename(device);
+
         sockpath = g_malloc(128);
-        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
+        snprintf(sockpath, 128, SOCKET_PATH, base_filename);
+        g_free(base_filename);
     }
 
     server = qio_net_listener_new();
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 9670614..53a29e3 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -808,7 +808,7 @@ static char *get_pci_driver(char const *syspath, int 
pathlen, Error **errp)
     len = readlink(dpath, buf, sizeof(buf) - 1);
     if (len != -1) {
         buf[len] = 0;
-        driver = g_strdup(basename(buf));
+        driver = g_path_get_basename(buf);
     }
     g_free(dpath);
     g_free(path);
@@ -1053,7 +1053,7 @@ static void build_guest_fsinfo_for_device(char const 
*devpath,
     }
 
     if (!fs->name) {
-        fs->name = g_strdup(basename(syspath));
+        fs->name = g_path_get_basename(syspath);
     }
 
     g_debug("  parse sysfs path '%s'", syspath);
-- 
2.1.4