X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Floop.c;h=823fba07952779d41d652b7762d6e96e6a44b7f0;hb=ac4100e103ca2b4e6e782c5814b1f43cef58c00b;hp=e5b21642e487a96e082ab522efb7baff5dc92c8b;hpb=934da82913f70ea3c68bcbcd7b184be54c2c2061;p=oweals%2Fbusybox.git diff --git a/libbb/loop.c b/libbb/loop.c index e5b21642e..823fba079 100644 --- a/libbb/loop.c +++ b/libbb/loop.c @@ -3,38 +3,34 @@ * Utility routines. * * Copyright (C) 1999-2004 by Erik Andersen + * Copyright (C) 2005 by Rob Landley * - * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. + * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ - - -#include -#include -#include -#include -#include -#include -#include #include "libbb.h" - -/* For 2.6, use the cleaned up header to get the 64 bit API. */ #include + #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) -#include + +/* 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 +# define BB_LOOP_SET_STATUS LOOP_SET_STATUS64 +# define BB_LOOP_GET_STATUS LOOP_GET_STATUS64 -/* 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 BB_LOOP_SET_STATUS 0x4C02 -#define BB_LOOP_GET_STATUS 0x4C03 + +/* 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; __kernel_dev_t lo_device; @@ -51,28 +47,32 @@ typedef struct { } bb_loop_info; #endif -char *query_loop(const char *device) +char* FAST_FUNC query_loop(const char *device) { int fd; bb_loop_info loopinfo; - char *dev=0; + char *dev = NULL; - if ((fd = open(device, O_RDONLY)) < 0) return 0; - if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo)) - dev=bb_xasprintf("%ld %s", (long) loopinfo.lo_offset, - (char *)loopinfo.lo_file_name); - close(fd); + 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); + } return dev; } - -int del_loop(const char *device) +int FAST_FUNC del_loop(const char *device) { int fd, rc; - if ((fd = open(device, O_RDONLY)) < 0) return 1; - rc=ioctl(fd, LOOP_CLR_FD, 0); + fd = open(device, O_RDONLY); + if (fd < 0) + return 1; + rc = ioctl(fd, LOOP_CLR_FD, 0); close(fd); return rc; @@ -84,59 +84,91 @@ int del_loop(const char *device) search will re-use an existing loop device already bound to that file/offset if it finds one. */ -int set_loop(char **device, const char *file, int offset) +int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, int ro) { - char dev[20], *try; + char dev[LOOP_NAMESIZE]; + char *try; bb_loop_info loopinfo; struct stat statbuf; - int i, dfd, ffd, mode, rc=-1; - + int i, dfd, ffd, mode, rc = -1; + /* Open the file. Barf if this doesn't work. */ - if((ffd = open(file, mode=O_RDWR))<0 && (ffd = open(file,mode=O_RDONLY))<0) - return -errno; + 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 ? : dev; - for(i=0;rc;i++) { + 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); - /* Ran out of block devices, return failure. */ - if(stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) { - rc=-ENOENT; + 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; } + try_to_open: /* Open the sucker and check its loopiness. */ - if((dfd=open(try, mode))<0 && errno==EROFS) - dfd=open(try, mode = O_RDONLY); - if(dfd<0) goto try_again; + 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); + rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo); - /* If device free, claim it. */ - if(rc && errno==ENXIO) { + /* 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 (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.) + * (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) - || offset!=loopinfo.lo_offset) rc=-1; + } else + if (strcmp(file, (char *)loopinfo.lo_file_name) != 0 + || offset != loopinfo.lo_offset + ) { + rc = -1; + } close(dfd); -try_again: - if(*device) break; + try_again: + if (*device) break; } close(ffd); - if(!rc) { - if(!*device) *device=strdup(dev); - return mode==O_RDONLY ? 1 : 0; - } else return rc; + if (rc == 0) { + if (!*device) + *device = xstrdup(dev); + return (mode == O_RDONLY); /* 1:ro, 0:rw */ + } + return rc; }