diff options
Diffstat (limited to 'misc/ismounted.c')
| -rw-r--r-- | misc/ismounted.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/misc/ismounted.c b/misc/ismounted.c new file mode 100644 index 0000000..6aa0e04 --- /dev/null +++ b/misc/ismounted.c @@ -0,0 +1,218 @@ +/* + * ismounted.c --- Check to see if the filesystem was mounted + * + * Copyright (C) 1995,1996,1997,1998,1999,2000,2008 Theodore Ts'o. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Public + * License. + * %End-Header% + */ + +#include "config.h" +#include <stdio.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#ifdef HAVE_STDLIB_H +#include <stdlib.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 +#include <string.h> +#include <sys/stat.h> +#include <ctype.h> + +#include "fsck.h" + +/* + * ext2fs_check_if_mounted flags + */ +#define MF_MOUNTED 1 + +#include "et/com_err.h" + +#ifdef HAVE_SETMNTENT +static char *skip_over_blank(char *cp) +{ + while (*cp && isspace(*cp)) + cp++; + return cp; +} + +static char *skip_over_word(char *cp) +{ + while (*cp && !isspace(*cp)) + cp++; + return cp; +} + +static char *parse_word(char **buf) +{ + char *word, *next; + + word = *buf; + if (*word == 0) + return 0; + + word = skip_over_blank(word); + next = skip_over_word(word); + if (*next) + *next++ = 0; + *buf = next; + return word; +} +#endif + +/* + * 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) +{ +#ifdef HAVE_SETMNTENT + struct stat st_buf; + errcode_t retval = 0; + dev_t file_dev=0, file_rdev=0; + ino_t file_ino=0; + FILE *f; + char buf[1024], *device = 0, *mnt_dir = 0, *cp; + + *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 (1) { + if (!fgets(buf, sizeof(buf), f)) { + device = mnt_dir = 0; + break; + } + buf[sizeof(buf)-1] = 0; + + cp = buf; + device = parse_word(&cp); + if (!device || *device == '#') + return 0; /* Ignore blank lines and comments */ + mnt_dir = parse_word(&cp); + + if (device[0] != '/') + continue; + + if (strcmp(file, device) == 0) + break; + if (stat(device, &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_dir == 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) && + (st_buf.st_dev == file_rdev)) + *mount_flags = MF_MOUNTED; +#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_dir, &st_buf) < 0) { + retval = errno; + if (retval == ENOENT) { +#ifdef DEBUG + printf("Bogus entry in %s! (%s does not exist)\n", + mtab_file, 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_dir); +#endif /* DEBUG */ + goto errout; + } +#endif /* __GNU__ */ + *mount_flags = MF_MOUNTED; + + retval = 0; +errout: + endmntent (f); + return retval; +#else /* !HAVE_SETMNTENT */ + return 0; +#endif /* HAVE_MNTENT_H */ +} + +int is_mounted(const char *file) +{ + errcode_t retval; + int mount_flags = 0; + +#ifdef __linux__ + retval = check_mntent_file("/proc/mounts", file, &mount_flags); + if (retval) + return 0; + if (mount_flags) + return 1; +#endif /* __linux__ */ + retval = check_mntent_file("/etc/mtab", file, &mount_flags); + if (retval) + return 0; + return (mount_flags); +} + +#ifdef DEBUG +int main(int argc, char **argv) +{ + if (argc < 2) { + fprintf(stderr, "Usage: %s device\n", argv[0]); + exit(1); + } + + if (is_mounted(argv[1])) + printf("\t%s is mounted.\n", argv[1]); + exit(0); +} +#endif /* DEBUG */ |