diff options
Diffstat (limited to 'mount.c')
| -rw-r--r-- | mount.c | 139 |
1 files changed, 125 insertions, 14 deletions
@@ -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 */ |