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Fix losetup so that it A) actually works again, B) has much better error

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messages, C) can show the current association (if any) when called
with only one argument.  Update the documentation a lot too.

Remind me to add a test suite for this thing.  I think I've figured out
how to handle root-only testsuites...
This commit is contained in:
Rob Landley
2005-11-29 23:47:10 +00:00
parent 70678bc5b6
commit 1d589b2e2d
4 changed files with 65 additions and 90 deletions
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44
libbb/loop.c
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@ -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;
}