diff options
| -rw-r--r-- | libbb/loop.c | 90 |
1 files changed, 51 insertions, 39 deletions
diff --git a/libbb/loop.c b/libbb/loop.c index 256b7ac..424c392 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -110,6 +110,51 @@ static int get_next_free_loop(char *dev, int id) return loopdevno; } +static int set_loopdev_params(int ffd, + int lfd, const char *file, + unsigned long long offset, + unsigned long long sizelimit, + unsigned flags) +{ + int rc; + bb_loop_info loopinfo; + + rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo); + + /* If device is free, try to claim it */ + if (rc && errno == ENXIO) { + /* Associate free loop device with file */ + rc = ioctl(lfd, LOOP_SET_FD, ffd); + if (rc != 0) { + /* Ouch... race: the device already has a fd */ + return -1; + } + memset(&loopinfo, 0, sizeof(loopinfo)); + safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE); + loopinfo.lo_offset = offset; + loopinfo.lo_sizelimit = sizelimit; + /* + * Used by mount to set LO_FLAGS_AUTOCLEAR. + * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file. + * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount + * is wrong (would free the loop device!) + */ + loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY); + rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo); + if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) { + /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */ + /* (this code path is not tested) */ + loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR; + rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo); + } + if (rc == 0) + return rc; /* SUCCESS! */ + /* failure, undo LOOP_SET_FD */ + ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary + } + return -1; +} + /* 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. @@ -119,7 +164,6 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse { char dev[LOOP_NAMESIZE]; char *try; - bb_loop_info loopinfo; struct stat statbuf; int i, lfd, ffd, mode, rc; @@ -183,45 +227,13 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse goto try_next_loopN; } - rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo); - - /* If device is free, try to claim it */ - if (rc && errno == ENXIO) { - /* Associate free loop device with file */ - rc = ioctl(lfd, LOOP_SET_FD, ffd); - if (rc != 0) { - /* Ouch... race: the device already has a fd */ - goto close_and_try_next_loopN; - } - memset(&loopinfo, 0, sizeof(loopinfo)); - safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE); - loopinfo.lo_offset = offset; - loopinfo.lo_sizelimit = sizelimit; - /* - * Used by mount to set LO_FLAGS_AUTOCLEAR. - * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file. - * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount - * is wrong (would free the loop device!) - */ - loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY); - rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo); - if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) { - /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */ - /* (this code path is not tested) */ - loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR; - rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo); - } - if (rc == 0) { - /* SUCCESS! */ - if (!*device) /* was looping in search of free "/dev/loopN"? */ - *device = xstrdup(dev); - rc = lfd; /* return this */ - break; - } - /* failure, undo LOOP_SET_FD */ - ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary + rc = set_loopdev_params(ffd, lfd, file, offset, sizelimit, flags); + if (rc == 0) { + /* SUCCESS! */ + if (!*device) + *device = xstrdup(dev); + break; } - close_and_try_next_loopN: close(lfd); try_next_loopN: rc = -1; |