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Commit 940c8107 authored by Ken Sumrall's avatar Ken Sumrall
Browse files

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
parent ed6b39cc

toolbox/mount.c

+19 −11
Original line number Diff line number Diff line
@@ -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 void add_extra_option(struct extra_opts *extra, char *s) 
}



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 @@ parse_mount_options(char *arg, unsigned long rwflag, struct extra_opts *extra, i 
		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 struct extra_opts extra; 
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 @@ do_mount(char *dev, char *dir, char *type, unsigned long rwflag, void *data, int 


        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 @@ do_mount(char *dev, char *dir, char *type, unsigned long rwflag, void *data, int 


        close(file_fd);

        close(device_fd);

        dev = LOOP_DEVICE;

        dev = loopdev;

    }



	while ((s = strsep(&type, ",")) != NULL) {
@@ -268,6 +275,7 @@ int mount_main(int argc, char *argv[]) 
	char *dir = NULL;

	int c;

	int loop = 0;

	char loopdev[LOOPDEV_MAXLEN];



	progname = argv[0];

	rwflag = MS_VERBOSE;
@@ -281,7 +289,7 @@ int mount_main(int argc, char *argv[]) 
			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 @@ int mount_main(int argc, char *argv[]) 
		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 */

}

toolbox/umount.c

+24 −8
Original line number Diff line number Diff line
@@ -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 @@ static int is_loop_mount(const char* path) 
    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 @@ static int is_loop_mount(const char* path) 
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 @@ int umount_main(int argc, char *argv[]) 


    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;

        }