Add -o loop= option to mount, and fix error detection in mount and umount
This fixes bug http://b.android.com/18419, which complains about a bogus
error check in the mount command (it also was wrong in the umount command)
and also asks for the mount command to support more than one loopback
device, as mentioned in the FIXME comments in mount.c. This required some
corresponding changes to umount.c
Change-Id: Ib796c70926395e61557e487bad64984d3295d5f3
diff --git a/toolbox/mount.c b/toolbox/mount.c
index 82ecc56..27cf3c9 100644
--- a/toolbox/mount.c
+++ b/toolbox/mount.c
@@ -15,8 +15,8 @@
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
-// FIXME - only one loop mount is supported at a time
-#define LOOP_DEVICE "/dev/block/loop0"
+#define DEFAULT_LOOP_DEVICE "/dev/block/loop0"
+#define LOOPDEV_MAXLEN 64
struct mount_opts {
const char str[8];
@@ -87,7 +87,7 @@
}
static unsigned long
-parse_mount_options(char *arg, unsigned long rwflag, struct extra_opts *extra, int* loop)
+parse_mount_options(char *arg, unsigned long rwflag, struct extra_opts *extra, int* loop, char *loopdev)
{
char *s;
@@ -100,8 +100,15 @@
if (no)
s += 2;
+ if (strncmp(s, "loop=", 5) == 0) {
+ *loop = 1;
+ strlcpy(loopdev, s + 5, LOOPDEV_MAXLEN);
+ continue;
+ }
+
if (strcmp(s, "loop") == 0) {
*loop = 1;
+ strlcpy(loopdev, DEFAULT_LOOP_DEVICE, LOOPDEV_MAXLEN);
continue;
}
for (i = 0, res = 1; i < ARRAY_SIZE(options); i++) {
@@ -131,7 +138,8 @@
static unsigned long rwflag;
static int
-do_mount(char *dev, char *dir, char *type, unsigned long rwflag, void *data, int loop)
+do_mount(char *dev, char *dir, char *type, unsigned long rwflag, void *data, int loop,
+ char *loopdev)
{
char *s;
int error = 0;
@@ -142,14 +150,13 @@
flags = (rwflag & MS_RDONLY) ? O_RDONLY : O_RDWR;
- // FIXME - only one loop mount supported at a time
file_fd = open(dev, flags);
- if (file_fd < -1) {
+ if (file_fd < 0) {
perror("open backing file failed");
return 1;
}
- device_fd = open(LOOP_DEVICE, flags);
- if (device_fd < -1) {
+ device_fd = open(loopdev, flags);
+ if (device_fd < 0) {
perror("open loop device failed");
close(file_fd);
return 1;
@@ -163,7 +170,7 @@
close(file_fd);
close(device_fd);
- dev = LOOP_DEVICE;
+ dev = loopdev;
}
while ((s = strsep(&type, ",")) != NULL) {
@@ -268,6 +275,7 @@
char *dir = NULL;
int c;
int loop = 0;
+ char loopdev[LOOPDEV_MAXLEN];
progname = argv[0];
rwflag = MS_VERBOSE;
@@ -281,7 +289,7 @@
break;
switch (c) {
case 'o':
- rwflag = parse_mount_options(optarg, rwflag, &extra, &loop);
+ rwflag = parse_mount_options(optarg, rwflag, &extra, &loop, loopdev);
break;
case 'r':
rwflag |= MS_RDONLY;
@@ -319,6 +327,6 @@
exit(1);
}
- return do_mount(dev, dir, type, rwflag, extra.str, loop);
+ return do_mount(dev, dir, type, rwflag, extra.str, loop, loopdev);
/* We leak dev and dir in some cases, but we're about to exit */
}
diff --git a/toolbox/umount.c b/toolbox/umount.c
index 92c6076..6eb8b92 100644
--- a/toolbox/umount.c
+++ b/toolbox/umount.c
@@ -7,10 +7,24 @@
#include <unistd.h>
#include <linux/loop.h>
-// FIXME - only one loop mount is supported at a time
-#define LOOP_DEVICE "/dev/block/loop0"
+#define LOOPDEV_MAXLEN 64
+#define LOOP_MAJOR 7
-static int is_loop_mount(const char* path)
+static int is_loop(char *dev)
+{
+ struct stat st;
+ int ret = 0;
+
+ if (stat(dev, &st) == 0) {
+ if (S_ISBLK(st.st_mode) && (major(st.st_rdev) == LOOP_MAJOR)) {
+ ret = 1;
+ }
+ }
+
+ return ret;
+}
+
+static int is_loop_mount(const char* path, char *loopdev)
{
FILE* f;
int count;
@@ -29,7 +43,8 @@
do {
count = fscanf(f, "%255s %255s %255s\n", device, mount_path, rest);
if (count == 3) {
- if (strcmp(LOOP_DEVICE, device) == 0 && strcmp(path, mount_path) == 0) {
+ if (is_loop(device) && strcmp(path, mount_path) == 0) {
+ strlcpy(loopdev, device, LOOPDEV_MAXLEN);
result = 1;
break;
}
@@ -43,13 +58,14 @@
int umount_main(int argc, char *argv[])
{
int loop, loop_fd;
-
+ char loopdev[LOOPDEV_MAXLEN];
+
if(argc != 2) {
fprintf(stderr,"umount <path>\n");
return 1;
}
- loop = is_loop_mount(argv[1]);
+ loop = is_loop_mount(argv[1], loopdev);
if(umount(argv[1])){
fprintf(stderr,"failed.\n");
return 1;
@@ -57,8 +73,8 @@
if (loop) {
// free the loop device
- loop_fd = open(LOOP_DEVICE, O_RDONLY);
- if (loop_fd < -1) {
+ loop_fd = open(loopdev, O_RDONLY);
+ if (loop_fd < 0) {
perror("open loop device failed");
return 1;
}