diff options
Diffstat (limited to 'busybox/libbb/loop.c')
| -rw-r--r-- | busybox/libbb/loop.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/busybox/libbb/loop.c b/busybox/libbb/loop.c new file mode 100644 index 0000000..e2287b5 --- /dev/null +++ b/busybox/libbb/loop.c @@ -0,0 +1,157 @@ +/* vi: set sw=4 ts=4: */ +/* + * Utility routines. + * + * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <stdio.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include "libbb.h" + +/* Grumble... The 2.6.x kernel breaks asm/posix_types.h + * so we get to try and cope as best we can... */ +#include <linux/version.h> +#include <asm/posix_types.h> + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) +#define __bb_kernel_dev_t __kernel_old_dev_t +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +#define __bb_kernel_dev_t __kernel_dev_t +#else +#define __bb_kernel_dev_t unsigned short +#endif + +/* Stuff stolen from linux/loop.h */ +#define LO_NAME_SIZE 64 +#define LO_KEY_SIZE 32 +#define LOOP_SET_FD 0x4C00 +#define LOOP_CLR_FD 0x4C01 +#define LOOP_SET_STATUS 0x4C02 +#define LOOP_GET_STATUS 0x4C03 +struct loop_info { + int lo_number; + __bb_kernel_dev_t lo_device; + unsigned long lo_inode; + __bb_kernel_dev_t lo_rdevice; + int lo_offset; + int lo_encrypt_type; + int lo_encrypt_key_size; + int lo_flags; + char lo_name[LO_NAME_SIZE]; + unsigned char lo_encrypt_key[LO_KEY_SIZE]; + unsigned long lo_init[2]; + char reserved[4]; +}; + +extern int del_loop(const char *device) +{ + int fd; + + if ((fd = open(device, O_RDONLY)) < 0) { + bb_perror_msg("%s", device); + return (FALSE); + } + if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { + close(fd); + bb_perror_msg("ioctl: LOOP_CLR_FD"); + return (FALSE); + } + close(fd); + return (TRUE); +} + +extern 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)) { + bb_perror_msg("%s", file); + return 1; + } + if ((fd = open(device, mode)) < 0) { + close(ffd); + bb_perror_msg("%s", device); + return 1; + } + *loopro = (mode == O_RDONLY); + + memset(&loopinfo, 0, sizeof(loopinfo)); + safe_strncpy(loopinfo.lo_name, file, LO_NAME_SIZE); + + loopinfo.lo_offset = offset; + + loopinfo.lo_encrypt_key_size = 0; + if (ioctl(fd, LOOP_SET_FD, ffd) < 0) { + bb_perror_msg("ioctl: LOOP_SET_FD"); + close(fd); + close(ffd); + return 1; + } + if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) { + (void) ioctl(fd, LOOP_CLR_FD, 0); + bb_perror_msg("ioctl: LOOP_SET_STATUS"); + close(fd); + close(ffd); + return 1; + } + close(fd); + close(ffd); + return 0; +} + +extern char *find_unused_loop_device(void) +{ + char dev[20]; + int i, fd; + struct stat statbuf; + struct loop_info loopinfo; + + for (i = 0; i <= 7; i++) { + sprintf(dev, LOOP_FORMAT, i); + if (stat(dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) { + if ((fd = open(dev, O_RDONLY)) >= 0) { + if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) != 0) { + if (errno == ENXIO) { /* probably free */ + close(fd); + return strdup(dev); + } + } + close(fd); + } + } + } + return NULL; +} + + +/* END CODE */ +/* +Local Variables: +c-file-style: "linux" +c-basic-offset: 4 +tab-width: 4 +End: +*/ |