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* Added -o loop option for mount, and support in umount for loop

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devices. Support is toggled by MOUNT_LOOP feature -- Ben Collins
    <bcollins@debian.org>

 -Erik
This commit is contained in:
Erik Andersen
2000-01-13 06:38:14 +00:00
parent 05df239ed9
commit b7cc49d992
6 changed files with 392 additions and 44 deletions
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139
util-linux/mount.c
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@@ -28,7 +28,10 @@
* putting it back as a compile-time option some time),
* major adjustments to option parsing, and some serious
* dieting all around.
*/
*
* 2000-01-12 Ben Collins <bcollins@debian.org>, Borrowed utils-linux's
* mount to add loop support.
*/
#include "internal.h"
#include <stdlib.h>
@@ -41,6 +44,17 @@
#include <ctype.h>
#include <fstab.h>
#if defined BB_FEATURE_MOUNT_LOOP
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/loop.h>
static int set_loop(const char *device, const char *file, int offset, int *loopro);
static char *find_unused_loop_device (void);
static int use_loop = 0;
#endif
extern const char mtab_file[]; /* Defined in utility.c */
static const char mount_usage[] = "\tmount [flags]\n"
@@ -61,6 +75,9 @@ static const char mount_usage[] = "\tmount [flags]\n"
"\tasync / sync:\tWrites are asynchronous / synchronous.\n"
"\tdev / nodev:\tAllow use of special device files / disallow them.\n"
"\texec / noexec:\tAllow use of executable files / disallow them.\n"
#if defined BB_FEATURE_MOUNT_LOOP
"\tloop: Mounts a file via loop device.\n"
#endif
"\tsuid / nosuid:\tAllow set-user-id-root programs / disallow them.\n"
"\tremount: Re-mount a currently-mounted filesystem, changing its flags.\n"
"\tro / rw: Mount for read-only / read-write.\n"
@@ -91,28 +108,48 @@ static const struct mount_options mount_options[] = {
{0, 0, 0}
};
#if ! defined BB_MTAB
#define do_mount(specialfile, dir, filesystemtype, flags, string_flags, useMtab, fakeIt, mtab_opts) \
mount(specialfile, dir, filesystemtype, flags, string_flags)
#else
static int
do_mount(char* specialfile, char* dir, char* filesystemtype,
long flags, void* string_flags, int useMtab, int fakeIt, char* mtab_opts)
{
int status=0;
#if defined BB_MTAB
if (fakeIt==FALSE)
#endif
{
#if defined BB_FEATURE_MOUNT_LOOP
if (use_loop) {
int loro = flags & MS_RDONLY;
char *lofile = specialfile;
specialfile = find_unused_loop_device();
if (specialfile == NULL) {
fprintf(stderr, "Could not find a spare loop device\n");
exit(1);
}
if (set_loop (specialfile, lofile, 0, &loro)) {
fprintf(stderr, "Could not setup loop device\n");
exit(1);
}
if (!(flags & MS_RDONLY) && loro) { /* loop is ro, but wanted rw */
fprintf(stderr, "WARNING: loop device is read-only\n");
flags &= ~MS_RDONLY;
}
}
#endif
status=mount(specialfile, dir, filesystemtype, flags, string_flags);
if ( status == 0 ) {
if ( useMtab==TRUE )
}
#if defined BB_MTAB
if (status == 0) {
if (useMtab==TRUE)
write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
return 0;
}
else
return( status);
}
else
#endif
return(status);
}
#if defined BB_MTAB
@@ -148,16 +185,20 @@ parse_mount_options ( char *options, unsigned long *flags, char *strflags)
}
f++;
}
#if defined BB_FEATURE_MOUNT_LOOP
if (gotone==FALSE && !strcasecmp ("loop", options)) { /* loop device support */
use_loop = 1;
gotone=TRUE;
}
#endif
if (*strflags && strflags!= '\0' && gotone==FALSE) {
char *temp=strflags;
temp += strlen (strflags);
*temp++ = ',';
*temp++ = '\0';
}
if (gotone==FALSE) {
if (gotone==FALSE)
strcat (strflags, options);
gotone=FALSE;
}
if (comma) {
*comma = ',';
options = ++comma;
@@ -356,3 +397,73 @@ extern int mount_main (int argc, char **argv)
goodbye:
usage( mount_usage);
}
#if defined BB_FEATURE_MOUNT_LOOP
static int set_loop(const char *device, const char *file, int offset, int *loopro)
{
struct loop_info loopinfo;
int fd, ffd, mode;
mode = *loopro ? O_RDONLY : O_RDWR;
if ((ffd = open (file, mode)) < 0 && !*loopro
&& (errno != EROFS || (ffd = open (file, mode = O_RDONLY)) < 0)) {
perror (file);
return 1;
}
if ((fd = open (device, mode)) < 0) {
close(ffd);
perror (device);
return 1;
}
*loopro = (mode == O_RDONLY);
memset(&loopinfo, 0, sizeof(loopinfo));
strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
loopinfo.lo_offset = offset;
loopinfo.lo_encrypt_key_size = 0;
if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
perror("ioctl: LOOP_SET_FD");
exit(1);
}
if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
(void) ioctl(fd, LOOP_CLR_FD, 0);
perror("ioctl: LOOP_SET_STATUS");
exit(1);
}
close(fd);
close(ffd);
return 0;
}
static char *find_unused_loop_device (void)
{
char dev[20];
int i, fd, somedev = 0, someloop = 0;
struct stat statbuf;
struct loop_info loopinfo;
for(i = 0; i < 256; i++) {
sprintf(dev, "/dev/loop%d", i);
if (stat (dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
somedev++;
fd = open (dev, O_RDONLY);
if (fd >= 0) {
if(ioctl (fd, LOOP_GET_STATUS, &loopinfo) == 0)
someloop++; /* in use */
else if (errno == ENXIO) {
close (fd);
return strdup(dev); /* probably free */
}
close (fd);
}
continue;
}
if (i >= 7)
break;
}
return NULL;
}
#endif /* BB_FEATURE_MOUNT_LOOP */