| Message ID | 20210106152111.20197-1-wesley.lindauer@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] raw handler: Allow symlink traversal in blkprotect | expand |
On 06.01.21 16:21, wesley.lindauer@gmail.com wrote: > From: Wes Lindauer <wesley.lindauer@gmail.com> > > If the device given in the sw-description is a symlink, this will > traverse the symlink to find if the underlying block device has a > force_ro flag. > > This is useful when using device symlinks with udev rules. i.e. > /dev/disk/by-label/boot -> /dev/mmcblk0boot0. These udev symlinks can > be helpful when using an A/B partitioning layout. > > Signed-off-by: Wes Lindauer <wesley.lindauer@gmail.com> > --- > handlers/raw_handler.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/handlers/raw_handler.c b/handlers/raw_handler.c > index 489919d..542d942 100644 > --- a/handlers/raw_handler.c > +++ b/handlers/raw_handler.c > @@ -38,6 +38,7 @@ void raw_copyimage_handler(void); > */ > static int blkprotect(struct img_type *img, bool on) > { > + char abs_path[PATH_MAX]; > const char c_sys_path[] = "/sys/class/block/%s/force_ro"; > const char c_unprot_char = '0'; > const char c_prot_char = '1'; > @@ -53,7 +54,7 @@ static int blkprotect(struct img_type *img, bool on) > return ret; > } > > - if (lstat(img->device, &sb) == -1) { > + if (stat(img->device, &sb) == -1) { > TRACE("stat for device %s failed: %s", img->device, strerror(errno)); > return ret; > } > @@ -61,7 +62,13 @@ static int blkprotect(struct img_type *img, bool on) > return ret; > } > > - ret_int = asprintf(&sysfs_path, c_sys_path, img->device + 5); // remove "/dev/" from device path > + /* If given, traverse symlink and convert to absolute path */ > + if (realpath(img->device, abs_path) == NULL) { > + ret = -errno; > + goto blkprotect_out; > + } > + > + ret_int = asprintf(&sysfs_path, c_sys_path, abs_path + 5); /* remove "/dev/" from device path */ > if(ret_int < 0) { > ret = -ENOMEM; > goto blkprotect_out; > Acked-by: Stefano Babic <sbabic@denx.de> Best regards, Stefano Babic
diff --git a/handlers/raw_handler.c b/handlers/raw_handler.c index 489919d..542d942 100644 --- a/handlers/raw_handler.c +++ b/handlers/raw_handler.c @@ -38,6 +38,7 @@ void raw_copyimage_handler(void); */ static int blkprotect(struct img_type *img, bool on) { + char abs_path[PATH_MAX]; const char c_sys_path[] = "/sys/class/block/%s/force_ro"; const char c_unprot_char = '0'; const char c_prot_char = '1'; @@ -53,7 +54,7 @@ static int blkprotect(struct img_type *img, bool on) return ret; } - if (lstat(img->device, &sb) == -1) { + if (stat(img->device, &sb) == -1) { TRACE("stat for device %s failed: %s", img->device, strerror(errno)); return ret; } @@ -61,7 +62,13 @@ static int blkprotect(struct img_type *img, bool on) return ret; } - ret_int = asprintf(&sysfs_path, c_sys_path, img->device + 5); // remove "/dev/" from device path + /* If given, traverse symlink and convert to absolute path */ + if (realpath(img->device, abs_path) == NULL) { + ret = -errno; + goto blkprotect_out; + } + + ret_int = asprintf(&sysfs_path, c_sys_path, abs_path + 5); /* remove "/dev/" from device path */ if(ret_int < 0) { ret = -ENOMEM; goto blkprotect_out;