[LEDE-DEV] [PATCH 1/3] fstools: support for ext4fs overlay

josua.mayer97 at gmail.com josua.mayer97 at gmail.com
Tue Aug 9 08:08:38 PDT 2016


From: Ram Chandra Jangir <rjangi at codeaurora.org>

This change will enables eMMC (ext4 fs) boot support, when we try to boot
from eMMC card then it will read partition names from
/sys/block/mmcblkX/mmcblkXY/uevent
file and will mount the rootfs_data partition as ext4fs overlay.

Signed-off-by: Ram Chandra Jangir <rjangi at codeaurora.org>
---
 CMakeLists.txt          |   1 +
 libfstools/ext4.c       | 193 ++++++++++++++++++++++++++++++++++++++++++++++++
 libfstools/find.c       |   3 +-
 libfstools/libfstools.h |   1 +
 libfstools/overlay.c    |  14 ++++
 libfstools/volume.h     |   1 +
 mount_root.c            |   2 +
 7 files changed, 214 insertions(+), 1 deletion(-)
 create mode 100644 libfstools/ext4.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7db28c0..7c89685 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,7 @@ ADD_LIBRARY(fstools SHARED
 		libfstools/overlay.c
 		libfstools/volume.c
 		libfstools/mtd.c
+		libfstools/ext4.c
 		libfstools/mount.c
 		libfstools/ubi.c
 		libfstools/find.c)
diff --git a/libfstools/ext4.c b/libfstools/ext4.c
new file mode 100644
index 0000000..f648aa8
--- /dev/null
+++ b/libfstools/ext4.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <asm/byteorder.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <mtd/mtd-user.h>
+#include <glob.h>
+
+#include "libfstools.h"
+
+#include "volume.h"
+
+#define ext4_sysfs_path "/sys/block/mmcblk*/mmcblk*/uevent"
+#define MAX_SIZE	128
+
+#define EXT_SB_OFF	0x400
+#define EXT_SB_KBOFF	(EXT_SB_OFF >> 10)
+#define EXT_SB_MAGIC	"\123\357"
+#define EXT_MAG_OFF	0x38
+
+struct ext4_priv {
+	char	*name;
+	char    *devname;
+};
+
+static struct driver ext4_driver;
+
+static int ext4_volume_init(struct volume *v)
+{
+	char buf[MAX_SIZE];
+	struct ext4_priv *p;
+
+	p = (struct ext4_priv*)v->priv;
+	snprintf(buf, sizeof(buf), "/dev/%s",p->devname);
+
+	v->name = strdup(p->name);
+	v->type = EXT4VOLUME;
+	v->blk = strdup(buf);
+	return 0;
+}
+
+static int
+ext4_part_match(char *dev, char *name, char *filename)
+{
+	FILE *fp;
+	char buf[MAX_SIZE];
+	char devname[MAX_SIZE];
+	int i;
+	int ret = -1;
+
+	fp = fopen(filename, "r");
+	if (!fp)
+		return ret;
+
+	while (fgets(buf, sizeof(buf), fp))  {
+		if (strstr(buf, "DEVNAME"))  {
+			strcpy(devname, buf + strlen("DEVNAME="));
+			continue;
+		}
+		/* Match partition name */
+		if (strstr(buf, name))  {
+			ret = 0;
+			break;
+		}
+	}
+
+	fclose(fp);
+
+	/* make sure the string is \0 terminated */
+	devname[sizeof(devname) - 1] = '\0';
+
+	/* remove trailing whitespace */
+	i = strlen(devname) - 1;
+	while (i > 0 && devname[i] <= ' ')
+		devname[i--] = '\0';
+
+	strcpy(dev, devname);
+	return ret;
+}
+
+static int ext4_find_devname(char *dev, char *name)
+{
+	int i;
+	glob_t gl;
+
+	if (glob(ext4_sysfs_path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl) < 0)
+		return -1;
+
+	for (i = 0; i < gl.gl_pathc; i++) {
+		if (!ext4_part_match(dev, name, gl.gl_pathv[i])) {
+			globfree(&gl);
+			return 0;
+		}
+	}
+
+	globfree(&gl);
+	return -1;
+}
+
+static int check_for_mtd(const char *mtd)
+{
+	FILE *fp;
+	char dev[MAX_SIZE];
+
+	if ((fp = fopen("/proc/mtd", "r"))) {
+		while (fgets(dev, sizeof(dev), fp)) {
+			if (strstr(dev, mtd)) {
+				fclose(fp);
+				return -1;
+			}
+		}
+	}
+	fclose(fp);
+	return 0;
+}
+
+static int ext4_volume_find(struct volume *v, char *name)
+{
+	char buf[MAX_SIZE];
+	struct ext4_priv *p;
+
+	if (find_filesystem("ext4"))
+		return -1;
+
+	if (check_for_mtd(name))
+		return -1;
+
+	if (ext4_find_devname(buf, name))
+		return -1;
+
+        p = calloc(1, sizeof(struct ext4_priv));
+        if (!p)
+                return -1;
+
+        v->priv = p;
+        v->drv = &ext4_driver;
+
+        p->devname = strdup(buf);
+        p->name = strdup(name);
+        return ext4_volume_init(v);
+}
+
+static int ext4_volume_identify(struct volume *v)
+{
+	char magic[32] = { 0 };
+	int off = (EXT_SB_KBOFF * 1024) + EXT_MAG_OFF;
+	int fd;
+
+	fd = open(v->blk, O_RDONLY);
+	if (fd == -1)
+		return -1;
+
+	lseek(fd, off, SEEK_SET);
+	read(fd, magic, sizeof(EXT_SB_MAGIC) - 1);
+	close(fd);
+
+	if (v->type == EXT4VOLUME &&
+	    !memcmp(EXT_SB_MAGIC, magic, sizeof(EXT_SB_MAGIC) - 1)) {
+		return FS_EXT4FS;
+	}
+
+	ULOG_ERR("ext4 is not ready - marker found\n");
+	return FS_DEADCODE;
+}
+
+static struct driver ext4_driver = {
+        .name = "ext4",
+        .find = ext4_volume_find,
+        .init = ext4_volume_init,
+        .identify = ext4_volume_identify,
+};
+
+DRIVER(ext4_driver);
diff --git a/libfstools/find.c b/libfstools/find.c
index 0440052..9fd83c9 100644
--- a/libfstools/find.c
+++ b/libfstools/find.c
@@ -102,7 +102,8 @@ find_mount_point(char *block, int mtd_only)
 
 			if (mtd_only &&
 			    strncmp(t, "jffs2", 5) &&
-			    strncmp(t, "ubifs", 5)) {
+			    strncmp(t, "ubifs", 5) &&
+			    strncmp(t, "ext4", 4)) {
 				fclose(fp);
 				ULOG_ERR("block is mounted with wrong fs\n");
 				return NULL;
diff --git a/libfstools/libfstools.h b/libfstools/libfstools.h
index 31d9f9e..940c504 100644
--- a/libfstools/libfstools.h
+++ b/libfstools/libfstools.h
@@ -26,6 +26,7 @@ enum {
 	FS_JFFS2,
 	FS_DEADCODE,
 	FS_UBIFS,
+	FS_EXT4FS,
 };
 
 enum fs_state {
diff --git a/libfstools/overlay.c b/libfstools/overlay.c
index cdac23e..f8088f9 100644
--- a/libfstools/overlay.c
+++ b/libfstools/overlay.c
@@ -245,6 +245,16 @@ jffs2_switch(struct volume *v)
 			ret = -1;
 		}
 		break;
+
+	case FS_EXT4FS:
+		ret = overlay_mount(v, "ext4");
+		if (ret)
+			break;
+		if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
+			ULOG_ERR("switching to ext4fs failed\n");
+			ret = -1;
+		}
+		break;
 	}
 
 	if (ret)
@@ -270,6 +280,10 @@ static int overlay_mount_fs(struct volume *v)
 	case FS_UBIFS:
 		fstype = "ubifs";
 		break;
+
+	case FS_EXT4FS:
+		fstype = "ext4";
+		break;
 	}
 
 	volume_init(v);
diff --git a/libfstools/volume.h b/libfstools/volume.h
index 9c679f7..b74bd50 100644
--- a/libfstools/volume.h
+++ b/libfstools/volume.h
@@ -47,6 +47,7 @@ enum {
 	NANDFLASH,
 	NORFLASH,
 	UBIVOLUME,
+	EXT4VOLUME,
 };
 
 struct volume {
diff --git a/mount_root.c b/mount_root.c
index 6e06b45..608ce5d 100644
--- a/mount_root.c
+++ b/mount_root.c
@@ -72,6 +72,7 @@ start(int argc, char *argv[1])
 
 	case FS_JFFS2:
 	case FS_UBIFS:
+	case FS_EXT4FS:
 		mount_overlay(data);
 		break;
 
@@ -110,6 +111,7 @@ done(int argc, char *argv[1])
 
 	case FS_JFFS2:
 	case FS_UBIFS:
+	case FS_EXT4FS:
 		fs_state_set("/overlay", FS_STATE_READY);
 		break;
 	}
-- 
2.6.6




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