X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Floop.c;h=7d2b420be13123c113b155c1962f2a0c68fd81cf;hb=dcc921e3ca1d2e30d69cd2209d2c427e78a32a30;hp=8c3ad2ce03c390f9317fe4d62d8d05236094d0b4;hpb=1e4dc96d61d1e1309b7117f0304a8ba161666f40;p=oweals%2Fbusybox.git diff --git a/libbb/loop.c b/libbb/loop.c index 8c3ad2ce0..7d2b420be 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -3,158 +3,152 @@ * 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 the GPL v2 or later, see the file LICENSE in this tarball. */ -#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... */ +/* For 2.6, use the cleaned up header to get the 64 bit API. */ #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 -#else -#define __bb_kernel_dev_t unsigned short -#endif +#include +typedef struct loop_info64 bb_loop_info; +#define BB_LOOP_SET_STATUS LOOP_SET_STATUS64 +#define BB_LOOP_GET_STATUS LOOP_GET_STATUS64 -/* Stuff stolen from linux/loop.h */ +/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */ +#else +/* 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 LOOP_SET_STATUS 0x4C02 -#define LOOP_GET_STATUS 0x4C03 -struct loop_info { +#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 = 0; - 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); - } + fd = open(device, O_RDONLY); + if (fd < 0) return 0; + if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo)) + dev = xasprintf("%ld %s", (long) loopinfo.lo_offset, + (char *)loopinfo.lo_file_name); 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); + return dev; +} - memset(&loopinfo, 0, sizeof(loopinfo)); - safe_strncpy(loopinfo.lo_name, file, LO_NAME_SIZE); - loopinfo.lo_offset = offset; +int FAST_FUNC del_loop(const char *device) +{ + int fd, rc; - 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; - } + fd = open(device, O_RDONLY); + if (fd < 0) 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) { - 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 <= 7; i++) { + /* Open the file. Barf if this doesn't work. */ + mode = O_RDWR; + ffd = open(file, mode); + if (ffd < 0) { + mode = O_RDONLY; + ffd = open(file, mode); + if (ffd < 0) + return -errno; + } + + /* Find a loop device. */ + try = *device ? : dev; + for (i = 0; rc; 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); + + /* Ran out of block devices, return failure. */ + if (stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) { + rc = -ENOENT; + break; + } + /* 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); + + /* 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)) { + if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) + 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; } - return NULL; + close(ffd); + if (!rc) { + if (!*device) + *device = xstrdup(dev); + return (mode == O_RDONLY); /* 1:ro, 0:rw */ + } + return rc; } - - -/* END CODE */ -/* -Local Variables: -c-file-style: "linux" -c-basic-offset: 4 -tab-width: 4 -End: -*/