diff options
| author | Karel Zak <kzak@redhat.com> | 2025-10-16 11:42:03 +0200 |
|---|---|---|
| committer | Karel Zak <kzak@redhat.com> | 2025-10-21 11:17:47 +0200 |
| commit | 04619aacdb31ecdf451f07fa2cf93b67387c1638 (patch) | |
| tree | b4b2f9f02243ae030f4aaa21ca98c002e20ea854 | |
| parent | 7b62b2dd72d4f004e66234cc63abf8da94e1926e (diff) | |
| download | util-linux-04619aacdb31ecdf451f07fa2cf93b67387c1638.tar.gz | |
lib/loopdev: introduce loopcxt_get_device_nr() helper
Add a new static helper function loopcxt_get_device_nr() to extract
the loop device number from the device path. This eliminates code
duplication in loopcxt_remove_device() and loopcxt_add_device().
The helper function supports both /dev/loop<N> and /dev/loop/<N>
formats and provides consistent error handling with debug logging.
Signed-off-by: Karel Zak <kzak@redhat.com>
| -rw-r--r-- | lib/loopdev.c | 57 |
1 files changed, 43 insertions, 14 deletions
diff --git a/lib/loopdev.c b/lib/loopdev.c index 5ef4394407..7ba425e7cd 100644 --- a/lib/loopdev.c +++ b/lib/loopdev.c @@ -1601,6 +1601,45 @@ int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize) return 0; } +/* + * @lc: context + * @nr: returns loop device number + * + * Extracts the loop device number from the device path. + * Supports both /dev/loop<N> and /dev/loop/<N> formats. + * + * Returns: 0 on success, <0 on error + */ +static int loopcxt_get_device_nr(struct loopdev_cxt *lc, int *nr) +{ + const char *p, *dev; + int rc = -EINVAL; + + errno = 0; + if (!lc || !nr) + goto done; + + dev = loopcxt_get_device(lc); + if (!dev) + goto done; + + p = strrchr(dev, '/'); + if (!p) + goto done; + + if (sscanf(p, "/loop%d", nr) != 1 && sscanf(p, "/%d", nr) != 1) + goto done; + + if (*nr < 0) + goto done; + rc = 0; +done: + if (rc && !errno) + errno = -rc; + DBG(CXT, ul_debugobj(lc, "get_device_nr [nr=%d]", *nr)); + return rc; +} + int loopcxt_detach_device(struct loopdev_cxt *lc) { int rc, fd = loopcxt_get_fd(lc); @@ -1624,19 +1663,14 @@ int loopcxt_remove_device(struct loopdev_cxt *lc) { int rc = -EINVAL; int ctl, nr = -1; - const char *p, *dev = loopcxt_get_device(lc); - - if (!dev) - goto done; if (!(lc->flags & LOOPDEV_FL_CONTROL)) { rc = -ENOSYS; goto done; } - p = strrchr(dev, '/'); - if (!p || (sscanf(p, "/loop%d", &nr) != 1 && sscanf(p, "/%d", &nr) != 1) - || nr < 0) + rc = loopcxt_get_device_nr(lc, &nr); + if (rc) goto done; ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); @@ -1655,19 +1689,14 @@ int loopcxt_add_device(struct loopdev_cxt *lc) { int rc = -EINVAL; int ctl, nr = -1; - const char *p, *dev = loopcxt_get_device(lc); - - if (!dev) - goto done; if (!(lc->flags & LOOPDEV_FL_CONTROL)) { rc = -ENOSYS; goto done; } - p = strrchr(dev, '/'); - if (!p || (sscanf(p, "/loop%d", &nr) != 1 && sscanf(p, "/%d", &nr) != 1) - || nr < 0) + rc = loopcxt_get_device_nr(lc, &nr); + if (rc) goto done; ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); |