diff options
Diffstat (limited to 'losetup.c')
| -rw-r--r-- | losetup.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/losetup.c b/losetup.c new file mode 100644 index 0000000..2908dbc --- /dev/null +++ b/losetup.c @@ -0,0 +1,190 @@ +/* + * losetup.c - setup and control loop devices + */ + + +#include "internal.h" + +const char losetup_usage[] = "losetup\n" +"\n" +"\tlosetup loop_device give info\n" +"\tlosetup -d loop_device delete\n" +"\tlosetup [ -o offset ] loop_device file setup\n"; + +/* from mount-2.6d */ + +/* + * losetup.c - setup and control loop devices + */ + +#include <stdio.h> +#include <string.h> +#include <ctype.h> +#include <fcntl.h> +#include <unistd.h> +#include <getopt.h> +#include <errno.h> +#include <sys/ioctl.h> +#include <linux/fs.h> +/* #include "loop.h" */ + +/* + * include/linux/loop.h + * + * Written by Theodore Ts'o, 3/29/93. + * + * Copyright 1993 by Theodore Ts'o. Redistribution of this file is + * permitted under the GNU Public License. + */ + +#define LO_NAME_SIZE 64 +#define LO_KEY_SIZE 32 + +struct loop_info { + int lo_number; /* ioctl r/o */ + dev_t lo_device; /* ioctl r/o */ + unsigned long lo_inode; /* ioctl r/o */ + dev_t lo_rdevice; /* ioctl r/o */ + int lo_offset; + int lo_encrypt_type; + int lo_encrypt_key_size; /* ioctl w/o */ + int lo_flags; /* ioctl r/o */ + char lo_name[LO_NAME_SIZE]; + unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ + unsigned long lo_init[2]; + char reserved[4]; +}; + +/* + * IOCTL commands --- we will commandeer 0x4C ('L') + */ + +#define LOOP_SET_FD 0x4C00 +#define LOOP_CLR_FD 0x4C01 +#define LOOP_SET_STATUS 0x4C02 +#define LOOP_GET_STATUS 0x4C03 + +/* #include "lomount.h" */ + +extern int set_loop (const char *, const char *, int, int *); +extern int del_loop (const char *); + +static void show_loop(const char *device) +{ + struct loop_info loopinfo; + int fd; + + if ((fd = open(device, O_RDWR)) < 0) { + perror(device); + return; + } + if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) < 0) { + perror("Cannot get loop info"); + close(fd); + return; + } + printf("%s: [%04x]:%ld (%s) offset %d\n", + device, (unsigned int)loopinfo.lo_device, loopinfo.lo_inode, + loopinfo.lo_name, loopinfo.lo_offset); + close(fd); +} + + +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; +} + +int del_loop(const char *device) +{ + int fd; + + if ((fd = open(device, O_RDONLY)) < 0) { + perror(device); + exit(1); + } + if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { + perror("ioctl: LOOP_CLR_FD"); + exit(1); + } + close(fd); + return(0); +} + + +static int losetup_usage_fn(void) +{ + fprintf(stderr, losetup_usage); + exit(1); +} + +int losetup_main(struct FileInfo * i, int argc, char * * argv) +{ + char *offset; + int delete,off,c; + int ro = 0; + + delete = off = 0; + offset = NULL; + while ((c = getopt(argc,argv,"do:")) != EOF) { + switch (c) { + case 'd': + delete = 1; + break; + case 'o': + offset = optarg; + break; + default: + losetup_usage_fn(); + } + } + if (argc == 1) losetup_usage_fn(); + if ((delete && (argc != optind+1 || offset)) || + (!delete && (argc < optind+1 || argc > optind+2))) + losetup_usage_fn(); + if (argc == optind+1) + if (delete) + del_loop(argv[optind]); + else + show_loop(argv[optind]); + else { + if (offset && sscanf(offset,"%d",&off) != 1) + losetup_usage_fn(); + set_loop(argv[optind],argv[optind+1],off,&ro); + } + return 0; +} |