From: Karol Lewandowski <k.lewandowsk@samsung.com>
Date: Tue, 12 Apr 2022 15:26:17 +0000 (+0200)
Subject: block: properly detect internal/external storage when tizen is run from loop-mounted... 
X-Git-Tag: submit/tizen_6.5/20220414.114351^0
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2cdbae66ad4eb2e4f19bbe3a810d84cf0678b4e5;p=platform%2Fcore%2Fsystem%2Fstoraged.git

block: properly detect internal/external storage when tizen is run from loop-mounted image

For loop-mounted devices we have to check on which device the image file resides,
and to treat this device as internal storage.

Change-Id: I0c3e1b51e948963b2fdf0fc711539d11631f0110
(cherry picked from commit ad665e3acc10e3707309be2988a8ff14ac0bb2dd)
---

diff --git a/packaging/storaged.spec b/packaging/storaged.spec
index 2d3ad40..0b2a5c8 100644
--- a/packaging/storaged.spec
+++ b/packaging/storaged.spec
@@ -4,7 +4,7 @@
 
 Name:       storaged
 Summary:    Storaged
-Version:    1.0.0
+Version:    1.0.1
 Release:    1
 Group:      System/Management
 License:    Apache-2.0
diff --git a/src/block/block.c b/src/block/block.c
index 9456604..5e51bab 100644
--- a/src/block/block.c
+++ b/src/block/block.c
@@ -61,6 +61,7 @@
 #include "apps.h"
 #include "storaged_common.h"
 
+#define LOOP_PATH                    "/dev/loop[0-9]*"
 #define MMC_PATH                     "*/mmcblk[0-9]*"
 #define MMC_PARTITION_PATH           "mmcblk[0-9]p[0-9]*"
 /* Emulator send devlink for sdcard as \*\/sdcard\/\* */
@@ -2468,6 +2469,61 @@ out:
 	dm_task_destroy(dmt);
 }
 
+static char *loopdev_get_backing_file(int loop_id)
+{
+	char sysfile[96] = "";
+	(void)snprintf(sysfile, sizeof(sysfile), "/sys/class/block/loop%d/loop/backing_file", loop_id);
+
+	int fd = open(sysfile, O_RDONLY);
+	if (fd < 0) {
+		_W("Unable to read information about backing file for loop device %d: %m", loop_id);
+		return NULL;
+	}
+
+	char line[PATH_MAX];
+	int r = read(fd, line, sizeof line);
+	if (r < 0) {
+		_W("Unable to read from %s: %m", sysfile);
+		close(fd);
+		return NULL;
+	}
+	close(fd); // theoretically we could have one close after read (and not in if), but it would overwrite 'errno'
+
+	char *p = malloc(r + 1);
+	if (!p)
+		return NULL;
+
+	memcpy(p, line, r);
+	p[r] = '\0';
+
+	_D("Got backing file for loop device %d: %s", loop_id, p);
+
+	return p;
+}
+
+static char* trunc_one_pathlevel(char *path)
+{
+	int len = strlen(path);
+	if (len == 1) {
+		path[0] = '\0';
+		return NULL;
+	}
+
+	for (char *p = path; len > 0; len--) {
+		if (p[len] != '/')
+			continue;
+		p[len] = '\0';
+		return path;
+	}
+
+	if (strlen(path) > 0) {
+		path[1] = '\0';
+		return path;
+	}
+
+	return NULL;
+}
+
 static int get_internal_storage_number(void)
 {
 	struct libmnt_table *t = NULL;
@@ -2490,7 +2546,6 @@ static int get_internal_storage_number(void)
 	for ( dev_i = 0; dev_i < DEV_INTERNAL_COUNT; dev_i++) {
 		fs = mnt_table_find_target(t, dev_internal_list[dev_i], MNT_ITER_BACKWARD);
 
-
 		if (!fs) {
 			mnt_free_table(t);
 			return -EPERM;
@@ -2502,6 +2557,31 @@ static int get_internal_storage_number(void)
 			return -EPERM;
 		}
 
+		/* Any of filesystems we look for could be on loop device.  We have to check this case first
+		 * as the loop file can be on any of the storage we check for below.
+		 */
+		if (!fnmatch(LOOP_PATH, temp, 0)) {
+			int num = atoi(temp + sizeof("/dev/loop") - 1 /* -1 for extra zero in string literal */);
+			_D("Found %s on loop device %s (loop id %d)", dev_internal_list[dev_i], temp, num);
+
+                        char *backingfile_path = loopdev_get_backing_file(num);
+			/* We have path to file from which image was mounted, but to find from which device it originates
+			 * we have assume it might be mounted in any of directories the path points to, ie.
+			 * with backing file in /var/images/tizen/foo.img, we have to check if /var/images/tizen, /var/images, /var, /
+		         * are the mountpoints which contain the image.
+			 */
+			for (char *p = NULL; (p = trunc_one_pathlevel(backingfile_path)) != NULL;) {
+				fs = mnt_table_find_target(t, p, MNT_ITER_BACKWARD);
+				if (!fs)
+					continue;
+				const char *origtemp = temp;
+				temp = mnt_fs_get_srcpath(fs);
+				_I("%s is found under mountpoint %s on device %s (internal storage candidate)\n", origtemp, p, temp);
+				break;
+			}
+			free(backingfile_path);
+		}
+
 		name = strrchr(temp, '/');
 		if (!name) {
 			mnt_free_table(t);