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-rw-r--r--mounts.c215
1 files changed, 215 insertions, 0 deletions
diff --git a/mounts.c b/mounts.c
new file mode 100644
index 000000000..e8b69e832
--- /dev/null
+++ b/mounts.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/mount.h>
+
+#include "mounts.h"
+
+typedef struct {
+ MountedVolume *volumes;
+ int volumes_allocd;
+ int volume_count;
+} MountsState;
+
+static MountsState g_mounts_state = {
+ NULL, // volumes
+ 0, // volumes_allocd
+ 0 // volume_count
+};
+
+static inline void
+free_volume_internals(const MountedVolume *volume, int zero)
+{
+ free((char *)volume->device);
+ free((char *)volume->mount_point);
+ free((char *)volume->filesystem);
+ free((char *)volume->flags);
+ if (zero) {
+ memset((void *)volume, 0, sizeof(*volume));
+ }
+}
+
+#define PROC_MOUNTS_FILENAME "/proc/mounts"
+
+int
+scan_mounted_volumes()
+{
+ char buf[2048];
+ const char *bufp;
+ int fd;
+ ssize_t nbytes;
+
+ if (g_mounts_state.volumes == NULL) {
+ const int numv = 32;
+ MountedVolume *volumes = malloc(numv * sizeof(*volumes));
+ if (volumes == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ g_mounts_state.volumes = volumes;
+ g_mounts_state.volumes_allocd = numv;
+ memset(volumes, 0, numv * sizeof(*volumes));
+ } else {
+ /* Free the old volume strings.
+ */
+ int i;
+ for (i = 0; i < g_mounts_state.volume_count; i++) {
+ free_volume_internals(&g_mounts_state.volumes[i], 1);
+ }
+ }
+ g_mounts_state.volume_count = 0;
+
+ /* Open and read the file contents.
+ */
+ fd = open(PROC_MOUNTS_FILENAME, O_RDONLY);
+ if (fd < 0) {
+ goto bail;
+ }
+ nbytes = read(fd, buf, sizeof(buf) - 1);
+ close(fd);
+ if (nbytes < 0) {
+ goto bail;
+ }
+ buf[nbytes] = '\0';
+
+ /* Parse the contents of the file, which looks like:
+ *
+ * # cat /proc/mounts
+ * rootfs / rootfs rw 0 0
+ * /dev/pts /dev/pts devpts rw 0 0
+ * /proc /proc proc rw 0 0
+ * /sys /sys sysfs rw 0 0
+ * /dev/block/mtdblock4 /system yaffs2 rw,nodev,noatime,nodiratime 0 0
+ * /dev/block/mtdblock5 /data yaffs2 rw,nodev,noatime,nodiratime 0 0
+ * /dev/block/mmcblk0p1 /sdcard vfat rw,sync,dirsync,fmask=0000,dmask=0000,codepage=cp437,iocharset=iso8859-1,utf8 0 0
+ *
+ * The zeroes at the end are dummy placeholder fields to make the
+ * output match Linux's /etc/mtab, but don't represent anything here.
+ */
+ bufp = buf;
+ while (nbytes > 0) {
+ char device[64];
+ char mount_point[64];
+ char filesystem[64];
+ char flags[128];
+ int matches;
+
+ /* %as is a gnu extension that malloc()s a string for each field.
+ */
+ matches = sscanf(bufp, "%63s %63s %63s %127s",
+ device, mount_point, filesystem, flags);
+
+ if (matches == 4) {
+ device[sizeof(device)-1] = '\0';
+ mount_point[sizeof(mount_point)-1] = '\0';
+ filesystem[sizeof(filesystem)-1] = '\0';
+ flags[sizeof(flags)-1] = '\0';
+
+ MountedVolume *v =
+ &g_mounts_state.volumes[g_mounts_state.volume_count++];
+ v->device = strdup(device);
+ v->mount_point = strdup(mount_point);
+ v->filesystem = strdup(filesystem);
+ v->flags = strdup(flags);
+ } else {
+printf("matches was %d on <<%.40s>>\n", matches, bufp);
+ }
+
+ /* Eat the line.
+ */
+ while (nbytes > 0 && *bufp != '\n') {
+ bufp++;
+ nbytes--;
+ }
+ if (nbytes > 0) {
+ bufp++;
+ nbytes--;
+ }
+ }
+
+ return 0;
+
+bail:
+//TODO: free the strings we've allocated.
+ g_mounts_state.volume_count = 0;
+ return -1;
+}
+
+const MountedVolume *
+find_mounted_volume_by_device(const char *device)
+{
+ if (g_mounts_state.volumes != NULL) {
+ int i;
+ for (i = 0; i < g_mounts_state.volume_count; i++) {
+ MountedVolume *v = &g_mounts_state.volumes[i];
+ /* May be null if it was unmounted and we haven't rescanned.
+ */
+ if (v->device != NULL) {
+ if (strcmp(v->device, device) == 0) {
+ return v;
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+const MountedVolume *
+find_mounted_volume_by_mount_point(const char *mount_point)
+{
+ if (g_mounts_state.volumes != NULL) {
+ int i;
+ for (i = 0; i < g_mounts_state.volume_count; i++) {
+ MountedVolume *v = &g_mounts_state.volumes[i];
+ /* May be null if it was unmounted and we haven't rescanned.
+ */
+ if (v->mount_point != NULL) {
+ if (strcmp(v->mount_point, mount_point) == 0) {
+ return v;
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+int
+unmount_mounted_volume(const MountedVolume *volume)
+{
+ /* Intentionally pass NULL to umount if the caller tries
+ * to unmount a volume they already unmounted using this
+ * function.
+ */
+ int ret = umount(volume->mount_point);
+ if (ret == 0) {
+ free_volume_internals(volume, 1);
+ return 0;
+ }
+ return ret;
+}
+
+int
+remount_read_only(const MountedVolume* volume)
+{
+ return mount(volume->device, volume->mount_point, volume->filesystem,
+ MS_NOATIME | MS_NODEV | MS_NODIRATIME |
+ MS_RDONLY | MS_REMOUNT, 0);
+}