container.c: Fix warnings of "format-overflow=" with new GCC

Change sprintf to snprintf and check the return values of snprintf
to handle this warning.

Fixes: #364

Signed-off-by: Hui Zhu <[email protected]>

src/container.c

@@ -146,7 +146,10 @@ static int container_setup_volume(struct hyper_pod *pod,
  if (hyper_mount_nfs(vol->device, path) < 0)
  return -1;
  /* nfs export has implicitly included _data part of the volume */
- sprintf(volume, "/%s/", path);
+ if (snprintf(volume, 512, "/%s/", path) < strlen("//")) {
+ fprintf(stderr, "something wrong with volume generation\n");
+ return -1;
+ }
  } else {
  fprintf(stdout, "mount %s to %s, tmp path %s\n",
  dev, vol->mountpoint, path);
@@ -164,7 +167,10 @@ static int container_setup_volume(struct hyper_pod *pod,
  perror("mount volume device failed");
  return -1;
  }
- sprintf(volume, "/%s/_data", path);
+ if (snprintf(volume, 512, "/%s/_data", path) < strlen("/_data")) {
+ fprintf(stderr, "something wrong with volume generation\n");
+ return -1;
+ }
  }
 
  if (container_check_volume(volume, &filevolume, &newvolume) < 0)
@@ -193,7 +199,10 @@ static int container_setup_volume(struct hyper_pod *pod,
  perror("create volume file failed");
  return -1;
  }
- sprintf(volume, "/%s/_data/%s", path, filevolume);
+ if (snprintf(volume, 512, "/%s/_data/%s", path, filevolume) < strlen(path)) {
+ fprintf(stderr, "something wrong with volume generation\n");
+ return -1;
+ }
  /* 0777 so that any user can read/write the new file volume */
  if (chmod(volume, 0777) < 0) {
  fprintf(stderr, "fail to chmod directory %s\n", volume);
@@ -235,7 +244,10 @@ static int container_setup_volume(struct hyper_pod *pod,
  }
  if (map->docker) {
  /* converted from volume */
- sprintf(volume, "%s/_data", path);
+ if (snprintf(volume, 512, "%s/_data", path) < strlen("/_data")) {
+ fprintf(stderr, "something wrong with volume generation\n");
+ return -1;
+ }
  src = volume;
  if (container->initialize &&
  (container_populate_volume(mountpoint, volume) < 0)) {
@@ -279,7 +291,10 @@ static int container_setup_modules(struct hyper_container *container)
  }
 
  sprintf(src, "/lib/modules/%s", uts.release);
- sprintf(dst, "./%s", src);
+ if (snprintf(dst, 512, "./%s", src) < 3) {
+ fprintf(stderr, "something wrong with dst generation\n");
+ return -1;
+ }
 
  if (stat(dst, &st) == 0) {
  struct dirent **list;
@@ -657,7 +672,10 @@ static int hyper_setup_container_rootfs(void *data)
  fprintf(stdout, "root directory for container is %s/%s, init task %s\n",
  root, container->rootfs, container->exec.argv[0]);
 
- sprintf(rootfs, "%s/%s/", root, container->rootfs);
+ if (snprintf(rootfs, 512, "%s/%s/", root, container->rootfs) < 2) {
+ fprintf(stderr, "something wrong with rootfs generation\n");
+ goto fail;
+ }
  if (mount(rootfs, rootfs, NULL, MS_BIND|MS_REC, NULL) < 0) {
  perror("failed to bind rootfs");
  goto fail;