diff options
Diffstat (limited to 'e2fsprogs/ext2fs/ismounted.c')
| -rw-r--r-- | e2fsprogs/ext2fs/ismounted.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/ismounted.c b/e2fsprogs/ext2fs/ismounted.c new file mode 100644 index 0000000..3f2241d --- /dev/null +++ b/e2fsprogs/ext2fs/ismounted.c @@ -0,0 +1,358 @@ +/* + * ismounted.c --- Check to see if the filesystem was mounted + * + * Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Public + * License. + * %End-Header% + */ + +#include <stdio.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#if HAVE_ERRNO_H +#include <errno.h> +#endif +#include <fcntl.h> +#ifdef HAVE_LINUX_FD_H +#include <linux/fd.h> +#endif +#ifdef HAVE_MNTENT_H +#include <mntent.h> +#endif +#ifdef HAVE_GETMNTINFO +#include <paths.h> +#include <sys/param.h> +#include <sys/mount.h> +#endif /* HAVE_GETMNTINFO */ +#include <string.h> +#include <sys/stat.h> + +#include "ext2_fs.h" +#include "ext2fs.h" + +#ifdef HAVE_MNTENT_H +/* + * Helper function which checks a file in /etc/mtab format to see if a + * filesystem is mounted. Returns an error if the file doesn't exist + * or can't be opened. + */ +static errcode_t check_mntent_file(const char *mtab_file, const char *file, + int *mount_flags, char *mtpt, int mtlen) +{ + struct mntent *mnt; + struct stat st_buf; + errcode_t retval = 0; + dev_t file_dev=0, file_rdev=0; + ino_t file_ino=0; + FILE *f; + int fd; + + *mount_flags = 0; + if ((f = setmntent (mtab_file, "r")) == NULL) + return errno; + if (stat(file, &st_buf) == 0) { + if (S_ISBLK(st_buf.st_mode)) { +#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ + file_rdev = st_buf.st_rdev; +#endif /* __GNU__ */ + } else { + file_dev = st_buf.st_dev; + file_ino = st_buf.st_ino; + } + } + while ((mnt = getmntent (f)) != NULL) { + if (strcmp(file, mnt->mnt_fsname) == 0) + break; + if (stat(mnt->mnt_fsname, &st_buf) == 0) { + if (S_ISBLK(st_buf.st_mode)) { +#ifndef __GNU__ + if (file_rdev && (file_rdev == st_buf.st_rdev)) + break; +#endif /* __GNU__ */ + } else { + if (file_dev && ((file_dev == st_buf.st_dev) && + (file_ino == st_buf.st_ino))) + break; + } + } + } + + if (mnt == 0) { +#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ + /* + * Do an extra check to see if this is the root device. We + * can't trust /etc/mtab, and /proc/mounts will only list + * /dev/root for the root filesystem. Argh. Instead we + * check if the given device has the same major/minor number + * as the device that the root directory is on. + */ + if (file_rdev && stat("/", &st_buf) == 0) { + if (st_buf.st_dev == file_rdev) { + *mount_flags = EXT2_MF_MOUNTED; + if (mtpt) + strncpy(mtpt, "/", mtlen); + goto is_root; + } + } +#endif /* __GNU__ */ + goto errout; + } +#ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */ + /* Validate the entry in case /etc/mtab is out of date */ + /* + * We need to be paranoid, because some broken distributions + * (read: Slackware) don't initialize /etc/mtab before checking + * all of the non-root filesystems on the disk. + */ + if (stat(mnt->mnt_dir, &st_buf) < 0) { + retval = errno; + if (retval == ENOENT) { +#ifdef DEBUG + printf("Bogus entry in %s! (%s does not exist)\n", + mtab_file, mnt->mnt_dir); +#endif /* DEBUG */ + retval = 0; + } + goto errout; + } + if (file_rdev && (st_buf.st_dev != file_rdev)) { +#ifdef DEBUG + printf("Bogus entry in %s! (%s not mounted on %s)\n", + mtab_file, file, mnt->mnt_dir); +#endif /* DEBUG */ + goto errout; + } +#endif /* __GNU__ */ + *mount_flags = EXT2_MF_MOUNTED; + +#ifdef MNTOPT_RO + /* Check to see if the ro option is set */ + if (hasmntopt(mnt, MNTOPT_RO)) + *mount_flags |= EXT2_MF_READONLY; +#endif + + if (mtpt) + strncpy(mtpt, mnt->mnt_dir, mtlen); + /* + * Check to see if we're referring to the root filesystem. + * If so, do a manual check to see if we can open /etc/mtab + * read/write, since if the root is mounted read/only, the + * contents of /etc/mtab may not be accurate. + */ + if (!strcmp(mnt->mnt_dir, "/")) { +is_root: +#define TEST_FILE "/.ismount-test-file" + *mount_flags |= EXT2_MF_ISROOT; + fd = open(TEST_FILE, O_RDWR|O_CREAT); + if (fd < 0) { + if (errno == EROFS) + *mount_flags |= EXT2_MF_READONLY; + } else + close(fd); + (void) unlink(TEST_FILE); + } + retval = 0; +errout: + endmntent (f); + return retval; +} + +static errcode_t check_mntent(const char *file, int *mount_flags, + char *mtpt, int mtlen) +{ + errcode_t retval; + +#ifdef DEBUG + retval = check_mntent_file("/tmp/mtab", file, mount_flags, + mtpt, mtlen); + if (retval == 0) + return 0; +#endif /* DEBUG */ +#ifdef __linux__ + retval = check_mntent_file("/proc/mounts", file, mount_flags, + mtpt, mtlen); + if (retval == 0 && (*mount_flags != 0)) + return 0; +#endif /* __linux__ */ +#if defined(MOUNTED) || defined(_PATH_MOUNTED) +#ifndef MOUNTED +#define MOUNTED _PATH_MOUNTED +#endif /* MOUNTED */ + retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen); + return retval; +#else + *mount_flags = 0; + return 0; +#endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */ +} + +#else +#if defined(HAVE_GETMNTINFO) + +static errcode_t check_getmntinfo(const char *file, int *mount_flags, + char *mtpt, int mtlen) +{ + struct statfs *mp; + int len, n; + const char *s1; + char *s2; + + n = getmntinfo(&mp, MNT_NOWAIT); + if (n == 0) + return errno; + + len = sizeof(_PATH_DEV) - 1; + s1 = file; + if (strncmp(_PATH_DEV, s1, len) == 0) + s1 += len; + + *mount_flags = 0; + while (--n >= 0) { + s2 = mp->f_mntfromname; + if (strncmp(_PATH_DEV, s2, len) == 0) { + s2 += len - 1; + *s2 = 'r'; + } + if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) { + *mount_flags = EXT2_MF_MOUNTED; + break; + } + ++mp; + } + if (mtpt) + strncpy(mtpt, mp->f_mntonname, mtlen); + return 0; +} +#endif /* HAVE_GETMNTINFO */ +#endif /* HAVE_MNTENT_H */ + +/* + * Check to see if we're dealing with the swap device. + */ +static int is_swap_device(const char *file) +{ + FILE *f; + char buf[1024], *cp; + dev_t file_dev; + struct stat st_buf; + int ret = 0; + + file_dev = 0; +#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ + if ((stat(file, &st_buf) == 0) && + S_ISBLK(st_buf.st_mode)) + file_dev = st_buf.st_rdev; +#endif /* __GNU__ */ + + if (!(f = fopen("/proc/swaps", "r"))) + return 0; + /* Skip the first line */ + fgets(buf, sizeof(buf), f); + while (!feof(f)) { + if (!fgets(buf, sizeof(buf), f)) + break; + if ((cp = strchr(buf, ' ')) != NULL) + *cp = 0; + if ((cp = strchr(buf, '\t')) != NULL) + *cp = 0; + if (strcmp(buf, file) == 0) { + ret++; + break; + } +#ifndef __GNU__ + if (file_dev && (stat(buf, &st_buf) == 0) && + S_ISBLK(st_buf.st_mode) && + file_dev == st_buf.st_rdev) { + ret++; + break; + } +#endif /* __GNU__ */ + } + fclose(f); + return ret; +} + + +/* + * ext2fs_check_mount_point() returns 1 if the device is mounted, 0 + * otherwise. If mtpt is non-NULL, the directory where the device is + * mounted is copied to where mtpt is pointing, up to mtlen + * characters. + */ +#ifdef __TURBOC__ + #pragma argsused +#endif +errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags, + char *mtpt, int mtlen) +{ + if (is_swap_device(device)) { + *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP; + strncpy(mtpt, "<swap>", mtlen); + return 0; + } +#ifdef HAVE_MNTENT_H + return check_mntent(device, mount_flags, mtpt, mtlen); +#else +#ifdef HAVE_GETMNTINFO + return check_getmntinfo(device, mount_flags, mtpt, mtlen); +#else +#ifdef __GNUC__ + #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!" +#endif + *mount_flags = 0; + return 0; +#endif /* HAVE_GETMNTINFO */ +#endif /* HAVE_MNTENT_H */ +} + +/* + * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED, + * EXT2_MF_READONLY, and EXT2_MF_ROOT + * + */ +errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags) +{ + return ext2fs_check_mount_point(file, mount_flags, NULL, 0); +} + +#ifdef DEBUG +int main(int argc, char **argv) +{ + int retval, mount_flags; + char mntpt[80]; + + if (argc < 2) { + fprintf(stderr, "Usage: %s device\n", argv[0]); + exit(1); + } + + mntpt[0] = 0; + retval = ext2fs_check_mount_point(argv[1], &mount_flags, + mntpt, sizeof(mntpt)); + if (retval) { + com_err(argv[0], retval, + "while calling ext2fs_check_if_mounted"); + exit(1); + } + printf("Device %s reports flags %02x\n", argv[1], mount_flags); + if (mount_flags & EXT2_MF_MOUNTED) + printf("\t%s is mounted.\n", argv[1]); + + if (mount_flags & EXT2_MF_SWAP) + printf("\t%s is a swap device.\n", argv[1]); + + if (mount_flags & EXT2_MF_READONLY) + printf("\t%s is read-only.\n", argv[1]); + + if (mount_flags & EXT2_MF_ISROOT) + printf("\t%s is the root filesystem.\n", argv[1]); + if (mntpt[0]) + printf("\t%s is mounted on %s.\n", argv[1], mntpt); + + exit(0); +} +#endif /* DEBUG */ |