mount.c

 

http://www.koders.com/c/fid840A8124E3B838F1EC7B690C35A7A6F9BF10277B.aspx

 

/* vi: set sw=4 ts=4: *//* * Mini mount implementation for busybox * * Copyright (C) 1995, 1996 by Bruce Perens <[e-mail]>. * * 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 * * 3/21/1999Charles P. Wright <[e-mail]> *searches through fstab when -a is passed *will try mounting stuff with all fses when passed -t auto * * 1999-04-17Dave Cinege...Rewrote -t auto. Fixed ro mtab. * * 1999-10-07Erik Andersen <[e-mail]>, <[e-mail]>. *              Rewrite of a lot of code. Removed mtab usage (I plan on *              putting it back as a compile-time option some time),  *              major adjustments to option parsing, and some serious  *              dieting all around. * * 1999-11-06mtab suppport is back - andersee * * 2000-01-12   Ben Collins <[e-mail]>, Borrowed utils-linux's *              mount to add loop support. */#include "internal.h"#include <stdlib.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <stdio.h>#include <mntent.h>#include <ctype.h>#if defined BB_FEATURE_USE_DEVPS_PATCH#include <linux/devmtab.h> /* For Erik's nifty devmtab device driver */#endif#define MS_MGC_VAL0xc0ed0000 /* Magic number indicatng "new" flags */#define MS_RDONLY        1      /* Mount read-only */#define MS_NOSUID        2      /* Ignore suid and sgid bits */#define MS_NODEV         4      /* Disallow access to device special files */#define MS_NOEXEC        8      /* Disallow program execution */#define MS_SYNCHRONOUS  16      /* Writes are synced at once */#define MS_REMOUNT      32      /* Alter flags of a mounted FS */#define MS_MANDLOCK     64      /* Allow mandatory locks on an FS */#define S_QUOTA         128     /* Quota initialized for file/directory/symlink */#define S_APPEND        256     /* Append-only file */#define S_IMMUTABLE     512     /* Immutable file */#define MS_NOATIME      1024    /* Do not update access times. */#define MS_NODIRATIME   2048    /* Do not update directory access times */#if defined BB_FEATURE_MOUNT_LOOP#include <fcntl.h>#include <sys/ioctl.h>static int use_loop = FALSE;#endifextern int mount (__const char *__special_file, __const char *__dir,__const char *__fstype, unsigned long int __rwflag,__const void *__data);extern int umount (__const char *__special_file);extern int umount2 (__const char *__special_file, int __flags);extern const char mtab_file[];/* Defined in utility.c */static const char mount_usage[] = "mount [flags] device directory [-o options,more-options]\n"#ifndef BB_FEATURE_TRIVIAL_HELP"\nMount a filesystem\n\n""Flags:\n" "\t-a:\t\tMount all filesystems in fstab.\n"#ifdef BB_MTAB"\t-f:\t\t\"Fake\" mount. Add entry to mount table but don't mount it.\n""\t-n:\t\tDon't write a mount table entry.\n"#endif"\t-o option:\tOne of many filesystem options, listed below.\n""\t-r:\t\tMount the filesystem read-only.\n""\t-t fs-type:\tSpecify the filesystem type.\n""\t-w:\t\tMount for reading and writing (default).\n""\n""Options for use with the \"-o\" flag:\n""\tasync/sync:\tWrites are asynchronous / synchronous.\n""\tatime/noatime:\tEnable / disable updates to inode access times.\n""\tdev/nodev:\tAllow use of special device files / disallow them.\n""\texec/noexec:\tAllow use of executable files / disallow them.\n"#if defined BB_FEATURE_MOUNT_LOOP"\tloop:\t\tMounts a file via loop device.\n"#endif"\tsuid/nosuid:\tAllow set-user-id-root programs / disallow them.\n""\tremount:\tRe-mount a currently-mounted filesystem, changing its flags.\n""\tro/rw:\t\tMount for read-only / read-write.\n""\nThere are EVEN MORE flags that are specific to each filesystem.\n""You'll have to see the written documentation for those.\n"#endif;struct mount_options {const char *name;unsigned long and;unsigned long or;};static const struct mount_options mount_options[] = {{"async", ~MS_SYNCHRONOUS, 0},{"atime", ~0, ~MS_NOATIME},{"defaults", ~0, 0},{"dev", ~MS_NODEV, 0},{"diratime", ~0, ~MS_NODIRATIME},{"exec", ~MS_NOEXEC, 0},{"noatime", ~0, MS_NOATIME},{"nodev", ~0, MS_NODEV},{"nodiratime", ~0, MS_NODIRATIME},{"noexec", ~0, MS_NOEXEC},{"nosuid", ~0, MS_NOSUID},{"remount", ~0, MS_REMOUNT},{"ro", ~0, MS_RDONLY},{"rw", ~MS_RDONLY, 0},{"suid", ~MS_NOSUID, 0},{"sync", ~0, MS_SYNCHRONOUS},{0, 0, 0}};static intdo_mount(char *specialfile, char *dir, char *filesystemtype, long flags, void *string_flags, int useMtab, int fakeIt, char *mtab_opts){int status = 0;char *lofile = NULL;#if defined BB_MTABif (fakeIt == FALSE)#endif{#if defined BB_FEATURE_MOUNT_LOOPif (use_loop==TRUE) {int loro = flags & MS_RDONLY;char *lofile = specialfile;specialfile = find_unused_loop_device();if (specialfile == NULL) {fprintf(stderr, "Could not find a spare loop device\n");return (FALSE);}if (set_loop(specialfile, lofile, 0, &loro)) {fprintf(stderr, "Could not setup loop device\n");return (FALSE);}if (!(flags & MS_RDONLY) && loro) {/* loop is ro, but wanted rw */fprintf(stderr, "WARNING: loop device is read-only\n");flags &= ~MS_RDONLY;}}#endifstatus = mount(specialfile, dir, filesystemtype, flags, string_flags);}/* If the mount was sucessful, do anything needed, then return TRUE */if (status == 0) {#if defined BB_MTABif (useMtab == TRUE) {write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);}#endifreturn (TRUE);}/* Bummer.  mount failed.  Clean up */#if defined BB_FEATURE_MOUNT_LOOPif (lofile != NULL) {del_loop(specialfile);}#endifif (errno == EPERM) {fatalError("mount: permission denied. Are you root?\n");}return (FALSE);}/* Seperate standard mount options from the nonstandard string options */static voidparse_mount_options(char *options, unsigned long *flags, char *strflags){while (options) {int gotone = FALSE;char *comma = strchr(options, ',');const struct mount_options *f = mount_options;if (comma)*comma = '\0';while (f->name != 0) {if (strcasecmp(f->name, options) == 0) {*flags &= f->and;*flags |= f->or;gotone = TRUE;break;}f++;}#if defined BB_FEATURE_MOUNT_LOOPif (gotone == FALSE && !strcasecmp("loop", options)) {/* loop device support */use_loop = TRUE;gotone = TRUE;}#endifif (*strflags && strflags != '\0' && gotone == FALSE) {char *temp = strflags;temp += strlen(strflags);*temp++ = ',';*temp++ = '\0';}if (gotone == FALSE)strcat(strflags, options);if (comma) {*comma = ',';options = ++comma;} else {break;}}}intmount_one(char *blockDevice, char *directory, char *filesystemType,  unsigned long flags, char *string_flags, int useMtab, int fakeIt,  char *mtab_opts, int whineOnErrors){int status = 0;#if defined BB_FEATURE_USE_PROCFSchar buf[255];if (strcmp(filesystemType, "auto") == 0) {FILE *f = fopen("/proc/filesystems", "r");if (f == NULL)return (FALSE);while (fgets(buf, sizeof(buf), f) != NULL) {filesystemType = buf;if (*filesystemType == '\t') {// Not a nodev filesystem// Add NULL termination to each linewhile (*filesystemType && *filesystemType != '\n')filesystemType++;*filesystemType = '\0';filesystemType = buf;filesystemType++;// hop past tabstatus = do_mount(blockDevice, directory, filesystemType,  flags | MS_MGC_VAL, string_flags,  useMtab, fakeIt, mtab_opts);if (status == TRUE)break;}}fclose(f);} else#endif#if defined BB_FEATURE_USE_DEVPS_PATCHif (strcmp(filesystemType, "auto") == 0) {int fd, i, numfilesystems;char device[] = "/dev/mtab";struct k_fstype *fslist;/* open device */ fd = open(device, O_RDONLY);if (fd < 0)fatalError("open failed for `%s': %s\n", device, strerror (errno));/* How many filesystems?  We need to know to allocate enough space */numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);if (numfilesystems<0)fatalError("\nDEVMTAB_COUNT_FILESYSTEMS: %s\n", strerror (errno));fslist = (struct k_fstype *) calloc ( numfilesystems, sizeof(struct k_fstype));/* Grab the list of available filesystems */status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);if (status<0)fatalError("\nDEVMTAB_GET_FILESYSTEMS: %s\n", strerror (errno));/* Walk the list trying to mount filesystems  * that do not claim to be nodev filesystems */for( i = 0 ; i < numfilesystems ; i++) {if (fslist[i].mnt_nodev)continue;status = do_mount(blockDevice, directory, fslist[i].mnt_type,  flags | MS_MGC_VAL, string_flags,  useMtab, fakeIt, mtab_opts);if (status == TRUE)break;}free( fslist);close(fd);} else#endif{status = do_mount(blockDevice, directory, filesystemType,  flags | MS_MGC_VAL, string_flags, useMtab,  fakeIt, mtab_opts);}if (status == FALSE) {if (whineOnErrors == TRUE) {fprintf(stderr, "Mounting %s on %s failed: %s\n",blockDevice, directory, strerror(errno));}return (FALSE);}return (TRUE);}extern int mount_main(int argc, char **argv){char string_flags_buf[1024] = "";char *string_flags = string_flags_buf;char *extra_opts = string_flags_buf;unsigned long flags = 0;char *filesystemType = "auto";char *device = NULL;char *directory = NULL;int all = FALSE;int fakeIt = FALSE;int useMtab = TRUE;int i;#if defined BB_FEATURE_USE_DEVPS_PATCHif (argc == 1) {int fd, i, numfilesystems;char device[] = "/dev/mtab";struct k_mntent *mntentlist;/* open device */ fd = open(device, O_RDONLY);if (fd < 0)fatalError("open failed for `%s': %s\n", device, strerror (errno));/* How many mounted filesystems?  We need to know to  * allocate enough space for later... */numfilesystems = ioctl (fd, DEVMTAB_COUNT_MOUNTS);if (numfilesystems<0)fatalError( "\nDEVMTAB_COUNT_MOUNTS: %s\n", strerror (errno));mntentlist = (struct k_mntent *) calloc ( numfilesystems, sizeof(struct k_mntent));/* Grab the list of mounted filesystems */if (ioctl (fd, DEVMTAB_GET_MOUNTS, mntentlist)<0)fatalError( "\nDEVMTAB_GET_MOUNTS: %s\n", strerror (errno));for( i = 0 ; i < numfilesystems ; i++) {fprintf( stdout, "%s %s %s %s %d %d\n", mntentlist[i].mnt_fsname,mntentlist[i].mnt_dir, mntentlist[i].mnt_type, mntentlist[i].mnt_opts, mntentlist[i].mnt_freq, mntentlist[i].mnt_passno);}/* Don't bother to close files or free memory.  Exit  * does that automagically, so we can save a few bytes */#if 0free( mntentlist);close(fd);#endifexit(TRUE);}#elseif (argc == 1) {FILE *mountTable = setmntent(mtab_file, "r");if (mountTable) {struct mntent *m;while ((m = getmntent(mountTable)) != 0) {char *blockDevice = m->mnt_fsname;if (strcmp(blockDevice, "/dev/root") == 0) {find_real_root_device_name( blockDevice);}printf("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,   m->mnt_type, m->mnt_opts);}endmntent(mountTable);} else {perror(mtab_file);}exit(TRUE);}#endif/* Parse options */i = --argc;argv++;while (i > 0 && **argv) {if (**argv == '-') {char *opt = *argv;while (i > 0 && *++opt)switch (*opt) {case 'o':if (--i == 0) {goto goodbye;}parse_mount_options(*(++argv), &flags, string_flags);break;case 'r':flags |= MS_RDONLY;break;case 't':if (--i == 0) {goto goodbye;}filesystemType = *(++argv);break;case 'w':flags &= ~MS_RDONLY;break;case 'a':all = TRUE;break;case 'f':fakeIt = TRUE;break;#ifdef BB_MTABcase 'n':useMtab = FALSE;break;#endifcase 'v':break; /* ignore -v */case 'h':case '-':goto goodbye;}} else {if (device == NULL)device = *argv;else if (directory == NULL)directory = *argv;else {goto goodbye;}}i--;argv++;}if (all == TRUE) {struct mntent *m;FILE *f = setmntent("/etc/fstab", "r");if (f == NULL)fatalError( "\nCannot read /etc/fstab: %s\n", strerror (errno));while ((m = getmntent(f)) != NULL) {// If the filesystem isn't noauto, // and isn't swap or nfs, then mount itif ((!strstr(m->mnt_opts, "noauto")) &&(!strstr(m->mnt_type, "swap")) &&(!strstr(m->mnt_type, "nfs"))) {flags = 0;*string_flags = '\0';parse_mount_options(m->mnt_opts, &flags, string_flags);if (mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,flags, string_flags, useMtab, fakeIt,extra_opts, FALSE)==FALSE) {/* Try again, but this time try a remount */mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,flags|MS_REMOUNT, string_flags, useMtab, fakeIt,extra_opts, TRUE);}}}endmntent(f);} else {if (device && directory) {#ifdef BB_NFSMOUNTif (strchr(device, ':') != NULL)filesystemType = "nfs";if (strcmp(filesystemType, "nfs") == 0) {int ret;ret = nfsmount (device, directory, &flags,&extra_opts, &string_flags, 1);if (ret != 0)fatalError("nfsmount failed: %s\n", strerror(errno));}#endifexit(mount_one(device, directory, filesystemType,   flags, string_flags, useMtab, fakeIt,   extra_opts, TRUE));} else {goto goodbye;}}exit(TRUE);  goodbye:usage(mount_usage);}