Precise free space calculation for magisk.img

1. Introduce new applet: imgtool for better separation from the main program
2. Actually mount the image and check statvfs for free space in the image

This shall eliminate any possible module installation failure from image resizing issues.
This commit is contained in:
topjohnwu
2018-06-22 06:18:06 +08:00
parent 058dbc9f9e
commit 7265450e2e
6 changed files with 175 additions and 173 deletions

View File

@@ -8,11 +8,18 @@
#include <sys/wait.h>
#include <sys/mount.h>
#include <sys/sendfile.h>
#include <sys/statvfs.h>
#include <linux/loop.h>
#include "magisk.h"
#include "utils.h"
struct fs_info {
unsigned size;
unsigned free;
unsigned used;
};
static int e2fsck(const char *img) {
// Check and repair ext4 image
char buffer[128];
@@ -51,59 +58,86 @@ static char *loopsetup(const char *img) {
return strdup(device);
}
static void check_filesystem(struct fs_info *info, const char *img, const char *mount) {
struct stat st;
struct statvfs vfs;
stat(img, &st);
statvfs(mount, &vfs);
info->size = st.st_size / 1048576;
info->free = vfs.f_bfree * vfs.f_frsize / 1048576;
info->used = (vfs.f_blocks - vfs.f_bfree) * vfs.f_frsize / 1048576;
}
static void usage() {
fprintf(stderr,
"ImgTool v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") (by topjohnwu) - EXT4 Image Tools\n"
"\n"
"Usage: imgtool <action> [args...]\n"
"\n"
"Actions:\n"
" create IMG SIZE create ext4 image. SIZE is interpreted in MB\n"
" resize IMG SIZE resize ext4 image. SIZE is interpreted in MB\n"
" mount IMG PATH mount IMG to PATH and prints the loop device\n"
" umount PATH LOOP unmount PATH and delete LOOP device\n"
);
exit(1);
}
int imgtool_main(int argc, char *argv[]) {
if (argc < 2)
usage();
if (strcmp(argv[1], "create") == 0) {
if (argc < 4)
usage();
return create_img(argv[2], atoi(argv[3]));
} else if (strcmp(argv[1], "resize") == 0) {
if (argc < 4)
usage();
return resize_img(argv[2], atoi(argv[3]), 1);
} else if (strcmp(argv[1], "mount") == 0) {
if (argc < 4)
usage();
char *loop = mount_image(argv[2], argv[3]);
if (loop == NULL) {
fprintf(stderr, "Cannot mount image!\n");
return 1;
} else {
printf("%s\n", loop);
free(loop);
return 0;
}
} else if (strcmp(argv[1], "umount") == 0) {
if (argc < 4)
usage();
umount_image(argv[2], argv[3]);
return 0;
}
usage();
return 1;
}
int create_img(const char *img, int size) {
if (size == 128) /* WTF...? */
size = 132;
unlink(img);
LOGI("Create %s with size %dM\n", img, size);
int ret;
char size_str[16];
snprintf(size_str, sizeof(size_str), "%dM", size);
ret = exec_command_sync("/system/bin/make_ext4fs", "-b", "4096", "-l", size_str, img, NULL);
if (ret < 0) {
if (access("/system/bin/make_ext4fs", X_OK) == 0)
return exec_command_sync("/system/bin/make_ext4fs", "-b", "4096", "-l", size_str, img, NULL);
else if (access("/system/bin/mke2fs", X_OK) == 0)
// On Android P there is no make_ext4fs, use mke2fs
ret = exec_command_sync("/system/bin/mke2fs", "-b", "4096", "-t", "ext4", img, size_str, NULL);
}
return ret;
return exec_command_sync("/system/bin/mke2fs", "-b", "4096", "-t", "ext4", img, size_str, NULL);
else
return 1;
}
int get_img_size(const char *img, int *used, int *total) {
if (access(img, R_OK) == -1)
return 1;
char buffer[PATH_MAX];
int pid, fd = -1, status = 1;
pid = exec_command(1, &fd, NULL, "/system/bin/e2fsck", "-n", img, NULL);
if (pid < 0)
return 1;
while (fdgets(buffer, sizeof(buffer), fd)) {
if (strstr(buffer, img)) {
char *tok = strtok(buffer, ",");
while(tok != NULL) {
if (strstr(tok, "blocks")) {
status = 0;
break;
}
tok = strtok(NULL, ",");
}
if (status) continue;
sscanf(tok, "%d/%d", used, total);
*used = (*used + 255) / 256;
*total = (*total + 128) / 256;
break;
}
}
close(fd);
waitpid(pid, NULL, 0);
return 0;
}
int resize_img(const char *img, int size) {
int resize_img(const char *img, int size, int enforce) {
LOGI("Resize %s to %dM\n", img, size);
if (e2fsck(img))
return 1;
char buffer[128];
int pid, fd = -1, used, total;
int pid, fd = -1;
snprintf(buffer, sizeof(buffer), "%dM", size);
pid = exec_command(1, &fd, NULL, "/system/bin/resize2fs", img, buffer, NULL);
if (pid < 0)
@@ -113,29 +147,32 @@ int resize_img(const char *img, int size) {
close(fd);
waitpid(pid, NULL, 0);
// Double check our image size
get_img_size(img, &used, &total);
if (total != size) {
// Sammy crap occurs or resize2fs failed, lets create a new image!
char *dir = dirname(img);
snprintf(buffer, sizeof(buffer), "%s/tmp.img", dir);
create_img(buffer, size);
char *s_loop, *t_loop;
s_loop = mount_image(img, SOURCE_TMP);
if (s_loop == NULL) return 1;
t_loop = mount_image(buffer, TARGET_TMP);
if (t_loop == NULL) return 1;
if (enforce) {
// Check the image size
struct stat st;
stat(img, &st);
if (st.st_size / 1048576 != size) {
// Sammy crap occurs or resize2fs failed, lets create a new image!
snprintf(buffer, sizeof(buffer), "%s/tmp.img", dirname(img));
create_img(buffer, size);
char *s_loop, *t_loop;
s_loop = mount_image(img, SOURCE_TMP);
if (s_loop == NULL)
return 1;
t_loop = mount_image(buffer, TARGET_TMP);
if (t_loop == NULL)
return 1;
cp_afc(SOURCE_TMP, TARGET_TMP);
umount_image(SOURCE_TMP, s_loop);
umount_image(TARGET_TMP, t_loop);
rmdir(SOURCE_TMP);
rmdir(TARGET_TMP);
free(s_loop);
free(t_loop);
rename(buffer, img);
cp_afc(SOURCE_TMP, TARGET_TMP);
umount_image(SOURCE_TMP, s_loop);
umount_image(TARGET_TMP, t_loop);
rmdir(SOURCE_TMP);
rmdir(TARGET_TMP);
free(s_loop);
free(t_loop);
rename(buffer, img);
}
}
return 0;
}
@@ -152,11 +189,13 @@ char *mount_image(const char *img, const char *target) {
return device;
}
void umount_image(const char *target, const char *device) {
xumount(target);
int umount_image(const char *target, const char *device) {
int ret = 0;
ret |= xumount(target);
int fd = xopen(device, O_RDWR);
ioctl(fd, LOOP_CLR_FD);
ret |= ioctl(fd, LOOP_CLR_FD);
close(fd);
return ret;
}
int merge_img(const char *source, const char *target) {
@@ -178,22 +217,30 @@ int merge_img(const char *source, const char *target) {
char buffer[PATH_MAX];
// resize target to worst case
int s_used, s_total, t_used, t_total, n_total;
get_img_size(source, &s_used, &s_total);
get_img_size(target, &t_used, &t_total);
n_total = round_size(s_used + t_used);
if (n_total > t_total)
resize_img(target, n_total);
xmkdir(SOURCE_TMP, 0755);
xmkdir(TARGET_TMP, 0755);
char *s_loop, *t_loop;
s_loop = mount_image(source, SOURCE_TMP);
if (s_loop == NULL) return 1;
if (s_loop == NULL)
return 1;
t_loop = mount_image(target, TARGET_TMP);
if (t_loop == NULL) return 1;
if (t_loop == NULL)
return 1;
struct fs_info src, tgt;
check_filesystem(&src, source, SOURCE_TMP);
check_filesystem(&tgt, target, TARGET_TMP);
// resize target to worst case
if (src.used >= tgt.free) {
umount_image(TARGET_TMP, t_loop);
free(t_loop);
resize_img(target, round_size(tgt.size + src.used - tgt.free), 1);
t_loop = mount_image(target, TARGET_TMP);
}
snprintf(buffer, sizeof(buffer), "%s/%s", TARGET_TMP, "lost+found");
rm_rf(buffer);
DIR *dir;
struct dirent *entry;
if (!(dir = xopendir(SOURCE_TMP)))
@@ -207,12 +254,9 @@ int merge_img(const char *source, const char *target) {
continue;
// Cleanup old module if exists
snprintf(buffer, sizeof(buffer), "%s/%s", TARGET_TMP, entry->d_name);
if (access(buffer, F_OK) == 0) {
LOGI("Upgrade module: %s\n", entry->d_name);
if (access(buffer, F_OK) == 0)
rm_rf(buffer);
} else {
LOGI("New module: %s\n", entry->d_name);
}
LOGI("Upgrade/New module: %s\n", entry->d_name);
}
}
closedir(dir);
@@ -229,10 +273,18 @@ int merge_img(const char *source, const char *target) {
return 0;
}
void trim_img(const char *img) {
int used, total, new_size;
get_img_size(img, &used, &total);
new_size = round_size(used);
if (new_size != total)
resize_img(img, new_size);
int trim_img(const char *img, const char *mount, char *loop) {
struct fs_info info;
check_filesystem(&info, img, mount);
int new_size = round_size(info.used);
if (info.size > new_size) {
umount_image(mount, loop);
free(loop);
resize_img(img, new_size, 0);
loop = mount_image(img, mount);
if (loop == NULL)
return 1;
}
free(loop);
return 0;
}