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Diffstat (limited to 'libbb/loop.c')
-rw-r--r--libbb/loop.c44
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;
}