Magisk/jni/utils/img.c
2017-07-10 22:29:53 +08:00

149 lines
3.8 KiB
C

/* img.c - All image related functions
*/
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/mount.h>
#include <linux/loop.h>
#include "magisk.h"
#include "utils.h"
static int e2fsck(const char *img) {
// Check and repair ext4 image
char buffer[128];
int pid, fd = -1;
char *const command[] = { "e2fsck", "-yf", (char *) img, NULL };
pid = run_command(1, &fd, "/system/bin/e2fsck", command);
if (pid < 0)
return 1;
while (fdgets(buffer, sizeof(buffer), fd))
LOGD("magisk_img: %s", buffer);
waitpid(pid, NULL, 0);
close(fd);
return 0;
}
static char *loopsetup(const char *img) {
char device[20];
struct loop_info64 info;
int i, lfd, ffd;
memset(&info, 0, sizeof(info));
// First get an empty loop device
for (i = 0; i <= 7; ++i) {
sprintf(device, "/dev/block/loop%d", i);
lfd = xopen(device, O_RDWR);
if (ioctl(lfd, LOOP_GET_STATUS64, &info) == -1)
break;
close(lfd);
}
if (i == 8) return NULL;
ffd = xopen(img, O_RDWR);
if (ioctl(lfd, LOOP_SET_FD, ffd) == -1)
return NULL;
strcpy((char *) info.lo_file_name, img);
ioctl(lfd, LOOP_SET_STATUS64, &info);
close(lfd);
close(ffd);
return strdup(device);
}
int create_img(const char *img, int size) {
unlink(img);
LOGI("Create %s with size %dM\n", img, size);
// Create a temp file with the file contexts
char file_contexts[] = "/magisk(/.*)? u:object_r:system_file:s0\n";
// If not root, attempt to create in current diretory
char *filename = getuid() == UID_ROOT ? "/dev/file_contexts_image" : "file_contexts_image";
int pid, status, fd = xopen(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
xwrite(fd, file_contexts, sizeof(file_contexts));
close(fd);
char buffer[16];
snprintf(buffer, sizeof(buffer), "%dM", size);
char *const command[] = { "make_ext4fs", "-l", buffer, "-a", "/magisk", "-S", filename, (char *) img, NULL };
pid = run_command(0, NULL, "/system/bin/make_ext4fs", command);
if (pid < 0)
return 1;
waitpid(pid, &status, 0);
unlink(filename);
return WEXITSTATUS(status);
}
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;
char *const command[] = { "e2fsck", "-n", (char *) img, NULL };
pid = run_command(1, &fd, "/system/bin/e2fsck", command);
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 / 256 + 1;
*total /= 256;
break;
}
}
close(fd);
waitpid(pid, NULL, 0);
return 0;
}
int resize_img(const char *img, int size) {
LOGI("Resize %s to %dM\n", img, size);
if (e2fsck(img))
return 1;
char buffer[128];
int pid, status, fd = -1;
snprintf(buffer, sizeof(buffer), "%dM", size);
char *const command[] = { "resize2fs", (char *) img, buffer, NULL };
pid = run_command(1, &fd, "/system/bin/resize2fs", command);
if (pid < 0)
return 1;
while (fdgets(buffer, sizeof(buffer), fd))
LOGD("magisk_img: %s", buffer);
close(fd);
waitpid(pid, &status, 0);
return WEXITSTATUS(status);
}
char *mount_image(const char *img, const char *target) {
if (access(img, F_OK) == -1)
return NULL;
if (access(target, F_OK) == -1) {
if (xmkdir(target, 0755) == -1) {
xmount(NULL, "/", NULL, MS_REMOUNT, NULL);
xmkdir(target, 0755);
xmount(NULL, "/", NULL, MS_REMOUNT | MS_RDONLY, NULL);
}
}
if (e2fsck(img))
return NULL;
char *device = loopsetup(img);
if (device)
xmount(device, target, "ext4", 0, NULL);
return device;
}
void umount_image(const char *target, const char *device) {
xumount(target);
int fd = xopen(device, O_RDWR);
ioctl(fd, LOOP_CLR_FD);
close(fd);
}