diff options
author | Xiaoming Ni <nixiaoming@huawei.com> | 2022-12-12 20:41:02 +0300 |
---|---|---|
committer | Denys Vlasenko <vda.linux@googlemail.com> | 2022-12-12 20:57:09 +0300 |
commit | ddccf6cd2f519c46a6286a43ceaf680eb367301c (patch) | |
tree | ce53166de2e8bc5fa2a9459dbc0e99bc970d2634 /libbb | |
parent | 90456a6aa3a039ac1b16a09e64d13cc9589b55ee (diff) |
loop: refactor: extract subfunction get_next_free_loop()
Extract subfunction get_next_free_loop() from set_loop()
Also fix miss free(try) when stat(try) and mknod fail
function old new delta
set_loop 807 790 -17
Fixes: 3448914e8cc5 ("mount,losetup: use /dev/loop-control is it exists")
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb')
-rw-r--r-- | libbb/loop.c | 56 |
1 files changed, 26 insertions, 30 deletions
diff --git a/libbb/loop.c b/libbb/loop.c index 750642ade..8e5c915fc 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -96,6 +96,20 @@ int FAST_FUNC get_free_loop(void) return loopdevno; /* can be -1 if error */ } +static int get_next_free_loop(char *dev, int id) +{ + int loopdevno; + + loopdevno = get_free_loop(); + if (loopdevno != -1) { + /* loopdevno is -2 (use id) or >= 0 (use id = loopdevno): */ + if (loopdevno >= 0) + id = loopdevno; + sprintf(dev, LOOP_FORMAT, id); + } + return loopdevno; +} + /* Returns opened fd to the loop device, <0 on error. * *device is loop device to use, or if *device==NULL finds a loop device to * mount it on and sets *device to a strdup of that loop device name. @@ -123,30 +137,27 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse try = *device; if (!try) { - get_free_loopN: - i = get_free_loop(); - if (i == -1) { - close(ffd); - return -1; /* no free loop devices */ - } - if (i >= 0) { - try = xasprintf(LOOP_FORMAT, i); - goto open_lfd; - } - /* i == -2: no /dev/loop-control. Do an old-style search for a free device */ try = dev; } /* Find a loop device */ /* 0xfffff is a max possible minor number in Linux circa 2010 */ for (i = 0; i <= 0xfffff; i++) { - sprintf(dev, LOOP_FORMAT, i); + if (!*device) { + rc = get_next_free_loop(dev, i); + if (rc == -1) + break; /* no free loop devices (or other error in LOOP_CTL_GET_FREE) */ + if (rc >= 0) + /* /dev/loop-control gave us the next free /dev/loopN */ + goto open_lfd; + /* else: sequential /dev/loopN, needs to be tested/maybe_created */ + } IF_FEATURE_MOUNT_LOOP_CREATE(errno = 0;) if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) { if (ENABLE_FEATURE_MOUNT_LOOP_CREATE && errno == ENOENT - && try == dev + && (!*device) ) { /* Node doesn't exist, try to create it */ if (mknod(dev, S_IFBLK|0644, makedev(7, i)) == 0) @@ -179,13 +190,10 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse /* Associate free loop device with file */ if (ioctl(lfd, LOOP_SET_FD, ffd)) { /* Ouch. Are we racing with other mount? */ - if (!*device /* yes */ - && try != dev /* tried a _kernel-offered_ loopN? */ - ) { - free(try); + if (!*device) { close(lfd); //TODO: add "if (--failcount != 0) ..."? - goto get_free_loopN; + continue; } goto close_and_try_next_loopN; } @@ -209,8 +217,6 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse } if (rc == 0) { /* SUCCESS! */ - if (try != dev) /* tried a kernel-offered free loopN? */ - *device = try; /* malloced */ if (!*device) /* was looping in search of free "/dev/loopN"? */ *device = xstrdup(dev); rc = lfd; /* return this */ @@ -218,16 +224,6 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse } /* failure, undo LOOP_SET_FD */ ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary - } else { - /* device is not free (rc == 0), or error other than ENXIO */ - if (rc == 0 /* device is not free? */ - && !*device /* racing with other mount? */ - && try != dev /* tried a _kernel-offered_ loopN? */ - ) { - free(try); - close(lfd); - goto get_free_loopN; - } } close_and_try_next_loopN: close(lfd); |