X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Floop.c;h=823fba07952779d41d652b7762d6e96e6a44b7f0;hb=ac4100e103ca2b4e6e782c5814b1f43cef58c00b;hp=19bbf3674a882288c44155a4edf58202db9bc51e;hpb=3f6f3174e9bd7671a97b88b90e50595a8c3c4231;p=oweals%2Fbusybox.git diff --git a/libbb/loop.c b/libbb/loop.c index 19bbf3674..823fba079 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -3,158 +3,172 @@ * Utility routines. * * Copyright (C) 1999-2004 by Erik Andersen + * Copyright (C) 2005 by Rob Landley * - * 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 + * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ - -#include -#if defined (__GLIBC__) && !defined(__UCLIBC__) -#include -#endif -#include -#include -#include -#include -#include -#include #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 #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 + +/* For 2.6, use the cleaned up header to get the 64 bit API. */ +// Commented out per Rob's request +//# include "fix_u32.h" /* some old toolchains need __u64 for linux/loop.h */ +# include +typedef struct loop_info64 bb_loop_info; +# define BB_LOOP_SET_STATUS LOOP_SET_STATUS64 +# define BB_LOOP_GET_STATUS LOOP_GET_STATUS64 + #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 { +/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */ +/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels */ +# include +# define LO_NAME_SIZE 64 +# define LO_KEY_SIZE 32 +# define LOOP_SET_FD 0x4C00 +# define LOOP_CLR_FD 0x4C01 +# define BB_LOOP_SET_STATUS 0x4C02 +# define BB_LOOP_GET_STATUS 0x4C03 +typedef struct { int lo_number; - __bb_kernel_dev_t lo_device; + __kernel_dev_t lo_device; unsigned long lo_inode; - __bb_kernel_dev_t lo_rdevice; + __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]; + char lo_file_name[LO_NAME_SIZE]; unsigned char lo_encrypt_key[LO_KEY_SIZE]; unsigned long lo_init[2]; char reserved[4]; -}; +} bb_loop_info; +#endif -extern int del_loop(const char *device) +char* FAST_FUNC query_loop(const char *device) { int fd; + bb_loop_info loopinfo; + char *dev = NULL; - if ((fd = open(device, O_RDONLY)) < 0) { - bb_perror_msg("%s", device); - return (FALSE); - } - if (ioctl(fd, LOOP_CLR_FD, 0) < 0) { + fd = open(device, O_RDONLY); + if (fd >= 0) { + if (ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo) == 0) { + dev = xasprintf("%"OFF_FMT"u %s", (off_t) loopinfo.lo_offset, + (char *)loopinfo.lo_file_name); + } close(fd); - bb_perror_msg("ioctl: LOOP_CLR_FD"); - return (FALSE); } - close(fd); - return (TRUE); + + return dev; } -extern int set_loop(const char *device, const char *file, int offset, - int *loopro) +int FAST_FUNC del_loop(const char *device) { - struct loop_info loopinfo; - int fd, ffd, mode; + int fd, rc; - 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); + fd = open(device, O_RDONLY); + if (fd < 0) 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; - } + rc = ioctl(fd, LOOP_CLR_FD, 0); close(fd); - close(ffd); - return 0; + + return rc; } -extern char *find_unused_loop_device(void) +/* Returns 0 if mounted RW, 1 if mounted read-only, <0 for error. + *device is loop device to use, or if *device==NULL finds a loop device to + mount it on and sets *device to a strdup of that loop device name. This + search will re-use an existing loop device already bound to that + file/offset if it finds one. + */ +int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, int ro) { - char dev[20]; - int i, fd; + char dev[LOOP_NAMESIZE]; + char *try; + bb_loop_info loopinfo; struct stat statbuf; - struct loop_info loopinfo; + int i, dfd, ffd, mode, rc = -1; - for (i = 0; i <= CONFIG_FEATURE_MOUNT_LOOP_MAX; i++) { + /* Open the file. Barf if this doesn't work. */ + mode = ro ? O_RDONLY : O_RDWR; + ffd = open(file, mode); + if (ffd < 0) { + if (mode != O_RDONLY) { + mode = O_RDONLY; + ffd = open(file, mode); + } + if (ffd < 0) + return -errno; + } + + /* Find a loop device. */ + try = *device ? *device : dev; + /* 1048575 is a max possible minor number in Linux circa 2010 */ + for (i = 0; rc && i < 1048576; 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); + + IF_FEATURE_MOUNT_LOOP_CREATE(errno = 0;) + if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) { + if (ENABLE_FEATURE_MOUNT_LOOP_CREATE + && errno == ENOENT + && try == dev + ) { + /* Node doesn't exist, try to create it. */ + if (mknod(dev, S_IFBLK|0644, makedev(7, i)) == 0) + goto try_to_open; } + /* Ran out of block devices, return failure. */ + rc = -ENOENT; + break; } - } - return NULL; -} + try_to_open: + /* Open the sucker and check its loopiness. */ + dfd = open(try, mode); + if (dfd < 0 && errno == EROFS) { + mode = O_RDONLY; + dfd = open(try, mode); + } + if (dfd < 0) + goto try_again; + rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo); -/* END CODE */ -/* -Local Variables: -c-file-style: "linux" -c-basic-offset: 4 -tab-width: 4 -End: -*/ + /* If device is free, claim it. */ + if (rc && errno == ENXIO) { + memset(&loopinfo, 0, sizeof(loopinfo)); + safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE); + loopinfo.lo_offset = offset; + /* Associate free loop device with file. */ + if (ioctl(dfd, LOOP_SET_FD, ffd) == 0) { + if (ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo) == 0) + rc = 0; + else + ioctl(dfd, LOOP_CLR_FD, 0); + } + + /* If this block device already set up right, re-use it. + * (Yes this is racy, but associating two loop devices with the same + * file isn't pretty either. In general, mounting the same file twice + * without using losetup manually is problematic.) + */ + } else + if (strcmp(file, (char *)loopinfo.lo_file_name) != 0 + || offset != loopinfo.lo_offset + ) { + rc = -1; + } + close(dfd); + try_again: + if (*device) break; + } + close(ffd); + if (rc == 0) { + if (!*device) + *device = xstrdup(dev); + return (mode == O_RDONLY); /* 1:ro, 0:rw */ + } + return rc; +}