diff options
Diffstat (limited to 'libbb/loop.c')
-rw-r--r-- | libbb/loop.c | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/libbb/loop.c b/libbb/loop.c index 1021793..00e3d62 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -51,15 +51,30 @@ typedef struct { } bb_loop_info; #endif -extern int del_loop(const char *device) +char *query_loop(const char *device) { - int fd,rc=0; + int fd; + bb_loop_info loopinfo; + char *dev=0; + + if ((fd = open(device, O_RDONLY)) < 0) return 0; + if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo)) + dev=bb_xasprintf("%ld %s", (long) loopinfo.lo_offset, + loopinfo.lo_file_name); + close(fd); - if ((fd = open(device, O_RDONLY)) < 0) rc=1; - else { - if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1; - close(fd); - } + return dev; +} + + +int del_loop(const char *device) +{ + int fd, rc; + + if ((fd = open(device, O_RDONLY)) < 0) return 1; + rc=ioctl(fd, LOOP_CLR_FD, 0); + close(fd); + return rc; } @@ -69,9 +84,9 @@ extern int del_loop(const char *device) search will re-use an existing loop device already bound to that file/offset if it finds one. */ -extern int set_loop(char **device, const char *file, int offset) +int set_loop(char **device, const char *file, int offset) { - char dev[20]; + char dev[20], *try; bb_loop_info loopinfo; struct stat statbuf; int i, dfd, ffd, mode, rc=1; @@ -81,20 +96,21 @@ extern int set_loop(char **device, const char *file, int offset) return errno; /* Find a loop device. */ + try=*device ? : dev; for(i=0;rc;i++) { sprintf(dev, LOOP_FORMAT, i++); /* Ran out of block devices, return failure. */ - if(stat(*device ? *device : dev, &statbuf) || - !S_ISBLK(statbuf.st_mode)) { + if(stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) { rc=ENOENT; break; } /* Open the sucker and check its loopiness. */ - if((dfd=open(dev, mode))<0 && errno==EROFS) - dfd=open(dev,mode=O_RDONLY); + if((dfd=open(try, mode))<0 && errno==EROFS) + dfd=open(try,mode=O_RDONLY); if(dfd<0) continue; rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo); + /* If device free, claim it. */ if(rc && errno==ENXIO) { memset(&loopinfo, 0, sizeof(loopinfo)); @@ -110,7 +126,7 @@ extern int set_loop(char **device, const char *file, int offset) without using losetup manually is problematic.) */ } else if(strcmp(file,loopinfo.lo_file_name) - || offset!=loopinfo.lo_offset) rc=1; + || offset!=loopinfo.lo_offset) rc=-1; close(dfd); if(*device) break; } |