Add more image commands

jni/Android.mk

@@ -20,6 +20,7 @@ LOCAL_SRC_FILES := \
 	utils/vector.c \
 	utils/xwrap.c \
 	utils/list.c \
+	utils/img.c \
 	daemon/daemon.c \
 	daemon/socket_trans.c \
 	daemon/log_monitor.c \

jni/daemon/bootstages.c

@@ -54,44 +54,6 @@ struct node_entry {
  * Image handling *
  ******************/
 
-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);
-}
-
-static char *mount_image(const char *img, const char *target) {
-	char *device = loopsetup(img);
-	if (device)
-		xmount(device, target, "ext4", 0, NULL);
-	return device;
-}
-
-static void umount_image(const char *target, const char *device) {
-	xumount(target);
-	int fd = xopen(device, O_RDWR);
-	ioctl(fd, LOOP_CLR_FD);
-	close(fd);
-}
-
 #define round_size(a) ((((a) / 32) + 2) * 32)
 #define SOURCE_TMP "/dev/source"
 #define TARGET_TMP "/dev/target"

jni/main.c

@@ -32,6 +32,9 @@ static void usage() {
 		"   or: %s --imgsize <PATH>\n"
 		"   or: %s --resizeimg <PATH> <SIZE>\n"
 		"       SIZE is interpreted in MB\n"
+		"   or: %s --mountimg <IMG> <PATH>\n"
+		"       Prints out the loop device\n"
+		"   or: %s --umountimg <PATH> <LOOP>\n"
 		"   or: %s --[boot stage]\n"
 		"       start boot stage service\n"
 		"   or: %s [options]\n"
@@ -46,7 +49,7 @@ static void usage() {
 		"       -V            print daemon version code\n"
 		"\n"
 		"Supported applets:\n"
-	, argv0, argv0, argv0, argv0, argv0, argv0, argv0, argv0);
+	, argv0, argv0, argv0, argv0, argv0, argv0, argv0, argv0, argv0, argv0);
 
 	for (int i = 0; applet[i]; ++i) {
 		fprintf(stderr, i ? ", %s" : "       %s", applet[i]);
@@ -99,7 +102,7 @@ int main(int argc, char *argv[]) {
 				fprintf(stderr, "Cannot check %s size\n", argv[2]);
 				return 1;
 			}
-			printf("Used: %dM\tTotal: %dM\n", used, total);
+			printf("%d %d\n", used, total);
 			return 0;
 		} else if (strcmp(argv[1], "--resizeimg") == 0) {
 			if (argc < 4) usage();
@@ -114,6 +117,21 @@ int main(int argc, char *argv[]) {
 				return 1;
 			}
 			return resize_img(argv[2], size);
+		} else if (strcmp(argv[1], "--mountimg") == 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], "--umountimg") == 0) {
+			if (argc < 4) usage();
+			umount_image(argv[2], argv[3]);
+			return 0;
 		} else if (strcmp(argv[1], "--post-fs") == 0) {
 			int fd = connect_daemon();
 			write_int(fd, POST_FS);

jni/utils/img.c

@@ -0,0 +1,128 @@
+/* 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"
+
+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 fd = xopen(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	xwrite(fd, file_contexts, sizeof(file_contexts));
+	close(fd);
+
+	char buffer[PATH_MAX];
+	snprintf(buffer, sizeof(buffer),
+		"make_ext4fs -l %dM -a /magisk -S %s %s; e2fsck -yf %s;", size, filename, img, img);
+	char *const command[] = { "sh", "-c", buffer, NULL };
+	int pid, status;
+	pid = run_command(0, NULL, "/system/bin/sh", command);
+	if (pid == -1)
+		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];
+	snprintf(buffer, sizeof(buffer), "e2fsck -n %s", img);
+	char *const command[] = { "sh", "-c", buffer, NULL };
+	int pid, fd = 0, status = 1;
+	pid = run_command(1, &fd, "/system/bin/sh", command);
+	if (pid == -1)
+		return 1;
+	while (fdgets(buffer, sizeof(buffer), fd)) {
+		LOGD("magisk_img: %s", buffer);
+		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, &status, 0);
+	return WEXITSTATUS(status);
+}
+
+int resize_img(const char *img, int size) {
+	LOGI("Resize %s to %dM\n", img, size);
+	char buffer[PATH_MAX];
+	snprintf(buffer, sizeof(buffer), "e2fsck -yf %s; resize2fs %s %dM;", img, img, size);
+	char *const command[] = { "sh", "-c", buffer, NULL };
+	int pid, status, fd = 0;
+	pid = run_command(1, &fd, "/system/bin/sh", command);
+	if (pid == -1)
+		return 1;
+	while (fdgets(buffer, sizeof(buffer), fd))
+		LOGD("magisk_img: %s", buffer);
+	close(fd);
+	waitpid(pid, &status, 0);
+	return WEXITSTATUS(status);
+}
+
+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);
+}
+
+char *mount_image(const char *img, const char *target) {
+	if (access(target, F_OK) == -1) {
+		if (mkdir(target, 0755) == -1) {
+			xmount(NULL, "/", NULL, MS_REMOUNT, NULL);
+			xmkdir(target, 0755);
+		}
+	}
+	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);
+}

jni/utils/misc.c

@@ -411,78 +411,6 @@ void get_client_cred(int fd, struct ucred *cred) {
 		PLOGE("getsockopt");
 }
 
-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";
-	int fd = xopen("/dev/file_contexts_image", O_WRONLY | O_CREAT | O_TRUNC, 0644);
-	xwrite(fd, file_contexts, sizeof(file_contexts));
-	close(fd);
-
-	char buffer[PATH_MAX];
-	snprintf(buffer, sizeof(buffer),
-		"make_ext4fs -l %dM -a /magisk -S /dev/file_contexts_image %s; e2fsck -yf %s;", size, img, img);
-	char *const command[] = { "sh", "-c", buffer, NULL };
-	int pid, status;
-	pid = run_command(0, NULL, "/system/bin/sh", command);
-	if (pid == -1)
-		return 1;
-	waitpid(pid, &status, 0);
-	unlink("/dev/file_contexts_image");
-	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];
-	snprintf(buffer, sizeof(buffer), "e2fsck -yf %s", img);
-	char *const command[] = { "sh", "-c", buffer, NULL };
-	int pid, fd = 0, status = 1;
-	pid = run_command(1, &fd, "/system/bin/sh", command);
-	if (pid == -1)
-		return 1;
-	while (fdgets(buffer, sizeof(buffer), fd)) {
-		LOGD("magisk_img: %s", buffer);
-		if (strstr(buffer, img)) {
-			char *tok;
-			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, &status, 0);
-	return WEXITSTATUS(status);
-}
-
-int resize_img(const char *img, int size) {
-	LOGI("Resize %s to %dM\n", img, size);
-	char buffer[PATH_MAX];
-	snprintf(buffer, sizeof(buffer), "resize2fs %s %dM; e2fsck -yf %s;", img, size, img);
-	char *const command[] = { "sh", "-c", buffer, NULL };
-	int pid, status, fd = 0;
-	pid = run_command(1, &fd, "/system/bin/sh", command);
-	if (pid == -1)
-		return 1;
-	while (fdgets(buffer, sizeof(buffer), fd))
-		LOGD("magisk_img: %s", buffer);
-	close(fd);
-	waitpid(pid, &status, 0);
-	return WEXITSTATUS(status);
-}
-
 int switch_mnt_ns(int pid) {
 	char mnt[32];
 	snprintf(mnt, sizeof(mnt), "/proc/%d/ns/mnt", pid);

jni/utils/utils.h

@@ -91,9 +91,14 @@ int clone_dir(const char *source, const char *target);
 int rm_rf(const char *target);
 void clone_attr(const char *source, const char *target);
 void get_client_cred(int fd, struct ucred *cred);
+int switch_mnt_ns(int pid);
+
+// img.c
 int create_img(const char *img, int size);
 int get_img_size(const char *img, int *used, int *total);
 int resize_img(const char *img, int size);
-int switch_mnt_ns(int pid);
+char *loopsetup(const char *img);
+char *mount_image(const char *img, const char *target);
+void umount_image(const char *target, const char *device);
 
 #endif