shaba/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd.git synced 2025-03-09 12:58:26 +03:00
Code

udev: mention that the kernel silently truncates lo_file_name if too long

Browse Source 
Resolves the confusion in https://github.com/systemd/systemd/pull/26693#discussion_r1131151335.
This commit is contained in:
Yu Watanabe 2023-03-13 23:28:58 +09:00
parent a5c0ad9a9a
commit e551954def
1 changed files with 8 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/udev/udev-builtin-blkid.c
View File

@ -287,12 +287,14 @@ static int read_loopback_backing_inode(
if (isempty((char*) info.lo_file_name) ||
strnlen((char*) info.lo_file_name, sizeof(info.lo_file_name)-1) == sizeof(info.lo_file_name)-1)
/* Don't pick up file name if it is unset or possibly truncated. (Note: we can't really know
* the file file name is truncated if it uses sizeof(info.lo_file_name)-1 as length; it could
* also just mean the string is just that long and wasn't truncated — but the fact is simply
* that we cannot know in that case if it was truncated or not, hence we assume the worst and
* suppress — at least for now. For shorter strings we know for sure it wasn't truncated,
* hence that's always safe.) */
/* Don't pick up file name if it is unset or possibly truncated. (Note: the kernel silently
* truncates the string passed from userspace by LOOP_SET_STATUS64 ioctl. See
* loop_set_status_from_info() in drivers/block/loop.c. Hence, we can't really know the file
* name is truncated if it uses sizeof(info.lo_file_name)-1 as length; it could also mean the
* string is just that long and wasn't truncated — but the fact is simply that we cannot know
* in that case if it was truncated or not. Thus, we assume the worst and suppress — at least
* for now. For shorter strings we know for sure it wasn't truncated, hence that's always
* safe.) */
fn = NULL;
else {
fn = memdup_suffix0(info.lo_file_name, sizeof(info.lo_file_name));