Ahem: add new faq entry to list at top of FAQ.html
[oweals/busybox.git] / util-linux / umount.c
index 86833b717c544d582beb2ec42130fff7e1e5c9b8..21c2e6e4d422d84775bcd3db1298c6409f9505a8 100644 (file)
@@ -2,9 +2,7 @@
 /*
  * Mini umount implementation for busybox
  *
- *
- * Copyright (C) 1999,2000 by Lineo, inc.
- * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
  * 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
  *
  */
 
-#include "internal.h"
+#include <limits.h>
 #include <stdio.h>
-#include <sys/mount.h>
 #include <mntent.h>
 #include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include "busybox.h"
 
-
-static const char umount_usage[] =
-       "umount [flags] filesystem|directory\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-       "Unmount file systems\n"
-       "\nFlags:\n" "\t-a:\tUnmount all file systems"
-#ifdef BB_MTAB
-       " in /etc/mtab\n\t-n:\tDon't erase /etc/mtab entries\n"
-#else
-       "\n"
-#endif
-       "\t-r:\tTry to remount devices as read-only if mount is busy\n"
-#if defined BB_FEATURE_MOUNT_FORCE
-       "\t-f:\tForce filesystem umount (i.e. unreachable NFS server)\n"
-#endif
-#if defined BB_FEATURE_MOUNT_LOOP
-       "\t-l:\tDo not free loop device (if a loop device has been used)\n"
-#endif
+/* Teach libc5 about realpath -- it includes it but the
+ * prototype is missing... */
+#if (__GLIBC__ <= 2) && (__GLIBC_MINOR__ < 1)
+extern char *realpath(const char *path, char *resolved_path);
 #endif
-;
+
+static const int MNT_FORCE = 1;
+static const int MS_MGC_VAL = 0xc0ed0000; /* Magic number indicatng "new" flags */
+static const int MS_REMOUNT = 32;      /* Alter flags of a mounted FS.  */
+static const int MS_RDONLY = 1;        /* Mount read-only.  */
+
+extern 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);
 
 struct _mtab_entry_t {
        char *device;
@@ -59,16 +55,17 @@ static struct _mtab_entry_t *mtab_cache = NULL;
 
 
 
-#if defined BB_FEATURE_MOUNT_FORCE
+#if defined CONFIG_FEATURE_MOUNT_FORCE
 static int doForce = FALSE;
 #endif
-#if defined BB_FEATURE_MOUNT_LOOP
+#if defined CONFIG_FEATURE_MOUNT_LOOP
 static int freeLoop = TRUE;
 #endif
+#if defined CONFIG_FEATURE_MTAB_SUPPORT
 static int useMtab = TRUE;
+#endif
 static int umountAll = FALSE;
 static int doRemount = FALSE;
-extern const char mtab_file[]; /* Defined in utility.c */
 
 
 
@@ -79,7 +76,7 @@ extern const char mtab_file[];        /* Defined in utility.c */
  * TODO: Perhaps switch to using Glibc's getmntent_r
  *        -Erik
  */
-void mtab_read(void)
+static void mtab_read(void)
 {
        struct _mtab_entry_t *entry = NULL;
        struct mntent *e;
@@ -88,8 +85,8 @@ void mtab_read(void)
        if (mtab_cache != NULL)
                return;
 
-       if ((fp = setmntent(mtab_file, "r")) == NULL) {
-               fprintf(stderr, "Cannot open %s\n", mtab_file);
+       if ((fp = setmntent(bb_path_mtab_file, "r")) == NULL) {
+               bb_error_msg("Cannot open %s", bb_path_mtab_file);
                return;
        }
        while ((e = getmntent(fp))) {
@@ -102,7 +99,7 @@ void mtab_read(void)
        endmntent(fp);
 }
 
-char *mtab_getinfo(const char *match, const char which)
+static char *mtab_getinfo(const char *match, const char which)
 {
        struct _mtab_entry_t *cur = mtab_cache;
 
@@ -112,12 +109,13 @@ char *mtab_getinfo(const char *match, const char which)
                        if (which == MTAB_GETMOUNTPT) {
                                return cur->mountpt;
                        } else {
-#if !defined BB_MTAB
-                               if (strcmp(cur->device, "/dev/root") == 0) {
+#if !defined CONFIG_FEATURE_MTAB_SUPPORT
+                               if (strcmp(cur->device, "rootfs") == 0) {
+                                       continue;
+                               } else if (strcmp(cur->device, "/dev/root") == 0) {
                                        /* Adjusts device to be the real root device,
                                         * or leaves device alone if it can't find it */
-                                       find_real_root_device_name( cur->device);
-                                       return ( cur->device);
+                                       cur->device = find_real_root_device_name();
                                }
 #endif
                                return cur->device;
@@ -128,18 +126,7 @@ char *mtab_getinfo(const char *match, const char which)
        return NULL;
 }
 
-char *mtab_first(void **iter)
-{
-       struct _mtab_entry_t *mtab_iter;
-
-       if (!iter)
-               return NULL;
-       mtab_iter = mtab_cache;
-       *iter = (void *) mtab_iter;
-       return mtab_next(iter);
-}
-
-char *mtab_next(void **iter)
+static char *mtab_next(void **iter)
 {
        char *mp;
 
@@ -150,27 +137,36 @@ char *mtab_next(void **iter)
        return mp;
 }
 
-/* Don't bother to clean up, since exit() does that 
+static char *mtab_first(void **iter)
+{
+       struct _mtab_entry_t *mtab_iter;
+
+       if (!iter)
+               return NULL;
+       mtab_iter = mtab_cache;
+       *iter = (void *) mtab_iter;
+       return mtab_next(iter);
+}
+
+/* Don't bother to clean up, since exit() does that
  * automagically, so we can save a few bytes */
-#if 0
-void mtab_free(void)
+#ifdef CONFIG_FEATURE_CLEAN_UP
+static void mtab_free(void)
 {
        struct _mtab_entry_t *this, *next;
 
        this = mtab_cache;
        while (this) {
                next = this->next;
-               if (this->device)
-                       free(this->device);
-               if (this->mountpt)
-                       free(this->mountpt);
+               free(this->device);
+               free(this->mountpt);
                free(this);
                this = next;
        }
 }
 #endif
 
-static int do_umount(const char *name, int useMtab)
+static int do_umount(const char *name)
 {
        int status;
        char *blockDevice = mtab_getinfo(name, MTAB_GETDEVICE);
@@ -180,33 +176,31 @@ static int do_umount(const char *name, int useMtab)
 
        status = umount(name);
 
-#if defined BB_FEATURE_MOUNT_LOOP
-       if (freeLoop == TRUE && blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
+#if defined CONFIG_FEATURE_MOUNT_LOOP
+       if (freeLoop && blockDevice != NULL && !strncmp("/dev/loop", blockDevice, 9))
                /* this was a loop device, delete it */
                del_loop(blockDevice);
 #endif
-#if defined BB_FEATURE_MOUNT_FORCE
-       if (status != 0 && doForce == TRUE) {
+#if defined CONFIG_FEATURE_MOUNT_FORCE
+       if (status != 0 && doForce) {
                status = umount2(blockDevice, MNT_FORCE);
                if (status != 0) {
-                       fatalError("umount: forced umount of %s failed!\n", blockDevice);
+                       bb_error_msg_and_die("forced umount of %s failed!", blockDevice);
                }
        }
 #endif
-       if (status != 0 && doRemount == TRUE && errno == EBUSY) {
+       if (status != 0 && doRemount && errno == EBUSY) {
                status = mount(blockDevice, name, NULL,
                                           MS_MGC_VAL | MS_REMOUNT | MS_RDONLY, NULL);
                if (status == 0) {
-                       fprintf(stderr, "umount: %s busy - remounted read-only\n",
-                                       blockDevice);
+                       bb_error_msg("%s busy - remounted read-only", blockDevice);
                } else {
-                       fprintf(stderr, "umount: Cannot remount %s read-only\n",
-                                       blockDevice);
+                       bb_error_msg("Cannot remount %s read-only", blockDevice);
                }
        }
        if (status == 0) {
-#if defined BB_MTAB
-               if (useMtab == TRUE)
+#if defined CONFIG_FEATURE_MTAB_SUPPORT
+               if (useMtab)
                        erase_mtab(name);
 #endif
                return (TRUE);
@@ -214,7 +208,7 @@ static int do_umount(const char *name, int useMtab)
        return (FALSE);
 }
 
-static int umount_all(int useMtab)
+static int umount_all(void)
 {
        int status = TRUE;
        char *mountpt;
@@ -224,18 +218,18 @@ static int umount_all(int useMtab)
                /* Never umount /proc on a umount -a */
                if (strstr(mountpt, "proc")!= NULL)
                        continue;
-               status = do_umount(mountpt, useMtab);
-               if (status != 0) {
+               if (!do_umount(mountpt)) {
                        /* Don't bother retrying the umount on busy devices */
                        if (errno == EBUSY) {
-                               perror(mountpt);
+                               bb_perror_msg("%s", mountpt);
+                               status = FALSE;
                                continue;
                        }
-                       status = do_umount(mountpt, useMtab);
-                       if (status != 0) {
+                       if (!do_umount(mountpt)) {
                                printf("Couldn't umount %s on %s: %s\n",
                                           mountpt, mtab_getinfo(mountpt, MTAB_GETDEVICE),
                                           strerror(errno));
+                               status = FALSE;
                        }
                }
        }
@@ -244,9 +238,14 @@ static int umount_all(int useMtab)
 
 extern int umount_main(int argc, char **argv)
 {
+       char path[PATH_MAX], result = 0;
+
        if (argc < 2) {
-               usage(umount_usage);
+               bb_show_usage();
        }
+#ifdef CONFIG_FEATURE_CLEAN_UP
+       atexit(mtab_free);
+#endif
 
        /* Parse any options */
        while (--argc > 0 && **(++argv) == '-') {
@@ -255,17 +254,17 @@ extern int umount_main(int argc, char **argv)
                        case 'a':
                                umountAll = TRUE;
                                break;
-#if defined BB_FEATURE_MOUNT_LOOP
+#if defined CONFIG_FEATURE_MOUNT_LOOP
                        case 'l':
                                freeLoop = FALSE;
                                break;
 #endif
-#ifdef BB_MTAB
+#ifdef CONFIG_FEATURE_MTAB_SUPPORT
                        case 'n':
                                useMtab = FALSE;
                                break;
 #endif
-#ifdef BB_FEATURE_MOUNT_FORCE
+#ifdef CONFIG_FEATURE_MOUNT_FORCE
                        case 'f':
                                doForce = TRUE;
                                break;
@@ -276,19 +275,24 @@ extern int umount_main(int argc, char **argv)
                        case 'v':
                                break; /* ignore -v */
                        default:
-                               usage(umount_usage);
+                               bb_show_usage();
                        }
        }
 
        mtab_read();
-       if (umountAll == TRUE) {
-               exit(umount_all(useMtab));
+       if (umountAll) {
+               if (umount_all())
+                       return EXIT_SUCCESS;
+               else
+                       return EXIT_FAILURE;
        }
-       if (do_umount(*argv, useMtab) == 0)
-               exit(TRUE);
-       else {
-               perror("umount");
-               exit(FALSE);
-       }
-}
 
+       do {
+               if (realpath(*argv, path) != NULL)
+                       if (do_umount(path))
+                               continue;
+               bb_perror_msg("%s", path);
+               result++;
+       } while (--argc > 0 && ++argv);
+       return result;
+}