vold: add support for ext4 media

Depends on:
http://review.cyanogenmod.org/31202
http://review.cyanogenmod.org/31211

Result:
http://pastebin.com/nzUbvW7K

Change-Id: I5bd227e637f2a1ed4d13a2eb81390c56c953f482

5 files changed, 209 insertions, 6 deletions

diff --git a/Android.mk b/Android.mk
index 79ea6a7..b53c8e7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -48,6 +48,14 @@ ifeq ($(BOARD_VOLD_DISC_HAS_MULTIPLE_MAJORS), true)
 LOCAL_CFLAGS += -DVOLD_DISC_HAS_MULTIPLE_MAJORS
 endif
 
+ifneq ($(TARGET_FUSE_SDCARD_UID),)
+LOCAL_CFLAGS += -DFUSE_SDCARD_UID=$(TARGET_FUSE_SDCARD_UID)
+endif
+
+ifneq ($(TARGET_FUSE_SDCARD_GID),)
+LOCAL_CFLAGS += -DFUSE_SDCARD_GID=$(TARGET_FUSE_SDCARD_GID)
+endif
+
 LOCAL_MODULE := libvold
 
 LOCAL_SRC_FILES := $(common_src_files)
@@ -95,6 +103,14 @@ ifneq ($(TARGET_USE_CUSTOM_SECOND_LUN_NUM),)
 LOCAL_CFLAGS += -DCUSTOM_SECOND_LUN_NUM=$(TARGET_USE_CUSTOM_SECOND_LUN_NUM)
 endif
 
+ifneq ($(TARGET_FUSE_SDCARD_UID),)
+LOCAL_CFLAGS += -DFUSE_SDCARD_UID=$(TARGET_FUSE_SDCARD_UID)
+endif
+
+ifneq ($(TARGET_FUSE_SDCARD_GID),)
+LOCAL_CFLAGS += -DFUSE_SDCARD_GID=$(TARGET_FUSE_SDCARD_GID)
+endif
+
 LOCAL_SHARED_LIBRARIES := $(common_shared_libraries)
 
 LOCAL_STATIC_LIBRARIES := \
diff --git a/Ext4.cpp b/Ext4.cpp
index 290489e..6bc06e4 100644
--- a/Ext4.cpp
+++ b/Ext4.cpp
@@ -40,7 +40,8 @@
 
 #include "Ext4.h"
 
-#define MKEXT4FS_PATH "/system/bin/make_ext4fs";
+static char E2FSCK_PATH[] = "/system/bin/e2fsck";
+static char MKEXT4FS_PATH[] = "/system/bin/make_ext4fs";
 
 extern "C" int logwrap(int argc, const char **argv, int background);
 
@@ -67,6 +68,51 @@ int Ext4::doMount(const char *fsPath, const char *mountPoint, bool ro, bool remo
     return rc;
 }
 
+int Ext4::check(const char *fsPath) {
+    bool rw = true;
+    if (access(E2FSCK_PATH, X_OK)) {
+        SLOGW("Skipping fs checks.\n");
+        return 0;
+    }
+
+    int rc = -1;
+    do {
+        const char *args[5];
+        args[0] = E2FSCK_PATH;
+        args[1] = "-p";
+        args[2] = "-f";
+        args[3] = fsPath;
+        args[4] = NULL;
+
+        rc = logwrap(4, args, 1);
+
+        switch(rc) {
+        case 0:
+            SLOGI("EXT4 Filesystem check completed OK.\n");
+            return 0;
+        case 1:
+            SLOGI("EXT4 Filesystem check completed, errors corrected OK.\n");
+            return 0;
+        case 2:
+            SLOGE("EXT4 Filesystem check completed, errors corrected, need reboot.\n");
+            return 0;
+        case 4:
+            SLOGE("EXT4 Filesystem errors left uncorrected.\n");
+            return 0;
+        case 8:
+            SLOGE("E2FSCK Operational error.\n");
+            errno = EIO;
+            return -1;
+        default:
+            SLOGE("EXT4 Filesystem check failed (unknown exit code %d).\n", rc);
+            errno = EIO;
+            return -1;
+        }
+    } while (0);
+
+    return 0;
+}
+
 int Ext4::format(const char *fsPath) {
     int fd;
     const char *args[4];
diff --git a/Ext4.h b/Ext4.h
index a09b576..5a468b2 100644
--- a/Ext4.h
+++ b/Ext4.h
@@ -23,6 +23,7 @@ class Ext4 {
 public:
     static int doMount(const char *fsPath, const char *mountPoint, bool ro, bool remount,
             bool executable);
+    static int check(const char *fsPath);
     static int format(const char *fsPath);
 };
 
diff --git a/Volume.cpp b/Volume.cpp
index 422b566..f651277 100644
--- a/Volume.cpp
+++ b/Volume.cpp
@@ -45,11 +45,25 @@
 #include "Volume.h"
 #include "VolumeManager.h"
 #include "ResponseCode.h"
+#include "Ext4.h"
 #include "Fat.h"
 #include "Ntfs.h"
 #include "Process.h"
 #include "cryptfs.h"
 
+#ifndef FUSE_SDCARD_UID
+#define FUSE_SDCARD_UID 1023
+#endif
+#ifndef FUSE_SDCARD_GID
+#define FUSE_SDCARD_GID 1023
+#endif
+
+// Stringify defined values
+#define DO_STRINGIFY(str) #str
+#define STRINGIFY(str) DO_STRINGIFY(str)
+
+static char SDCARD_DAEMON_PATH[] = "/system/bin/sdcard";
+
 extern "C" void dos_partition_dec(void const *pp, struct dos_partition *d);
 extern "C" void dos_partition_enc(void *pp, struct dos_partition *d);
 
@@ -89,6 +103,12 @@ const char *Volume::ASECDIR           = "/mnt/asec";
  */
 const char *Volume::LOOPDIR           = "/mnt/obb";
 
+/*
+ * Path for fuse
+ */
+const char *Volume::FUSEDIR           = "/mnt/fuse";
+
+
 static const char *stateToStr(int state) {
     if (state == Volume::State_Init)
         return "Initializing";
@@ -450,6 +470,7 @@ int Volume::mountVol() {
     for (i = 0; i < n; i++) {
         char devicePath[255];
         char *fstype = NULL;
+        bool isUnixFs = false;
 
         sprintf(devicePath, "/dev/block/vold/%d:%d", MAJOR(deviceNodes[i]),
                 MINOR(deviceNodes[i]));
@@ -490,6 +511,24 @@ int Volume::mountVol() {
                     continue;
                 }
 
+            } else if (strcmp(fstype, "ext4") == 0) {
+
+                isUnixFs = true;
+                if (Ext4::check(devicePath)) {
+                    errno = EIO;
+                    isUnixFs = false;
+                    /* Badness - abort the mount */
+                    SLOGE("%s failed FS checks (%s)", devicePath, strerror(errno));
+                    setState(Volume::State_Idle);
+                    free(fstype);
+                    return -1;
+                }
+
+                if (Ext4::doMount(devicePath, "/mnt/secure/staging", false, false, false)) {
+                    SLOGE("%s failed to mount via EXT4 (%s)\n", devicePath, strerror(errno));
+                    continue;
+                }
+
             } else if (strcmp(fstype, "ntfs") == 0) {
 
                 if (Ntfs::doMount(devicePath, "/mnt/secure/staging", false, false, false,
@@ -507,7 +546,15 @@ int Volume::mountVol() {
             }
 
             free(fstype);
+
+        } else {
+            // Unsupported filesystem
+            errno = ENODATA;
+            setState(Volume::State_Idle);
+            free(fstype);
+            return -1;
         }
+
         SLOGI("Device %s, target %s mounted @ /mnt/secure/staging", devicePath, getMountpoint());
 
         protectFromAutorunStupidity();
@@ -524,11 +571,66 @@ int Volume::mountVol() {
          * Now that the bindmount trickery is done, atomically move the
          * whole subtree to expose it to non priviledged users.
          */
-        if (doMoveMount("/mnt/secure/staging", getMountpoint(), false)) {
-            SLOGE("Failed to move mount (%s)", strerror(errno));
-            umount("/mnt/secure/staging");
-            setState(Volume::State_Idle);
-            return -1;
+        if (isUnixFs) {
+            /*
+             * In case of a unix filesystem we're using the sdcard daemon
+             * to expose the subtree to non privileged users to avoid
+             * permission issues for data created by apps.
+             */
+            const char* label = getLabel();
+            char* fuseSrc = (char*) malloc(strlen(FUSEDIR) + strlen("/") + strlen(label) + 1);
+            sprintf(fuseSrc, "%s/%s", FUSEDIR, label);
+            bool failed = false;
+
+            // Create fuse dir if not exists
+            if (access(fuseSrc, R_OK | W_OK)) {
+                if (mkdir(fuseSrc, 0775)) {
+                    SLOGE("Failed to create %s (%s)", fuseSrc, strerror(errno));
+                    failed = true;
+                }
+            }
+
+            // Move subtree to fuse dir
+            if (!failed && doMoveMount("/mnt/secure/staging", fuseSrc, false)) {
+                SLOGE("Failed to move mount (%s)", strerror(errno));
+                umount("/mnt/secure/staging");
+                failed = true;
+            }
+
+            // Set owner and group on fuse dir
+            if (!failed && chown(fuseSrc, FUSE_SDCARD_UID, FUSE_SDCARD_GID)) {
+                SLOGE("Failed to set owner/group on %s (%s)", fuseSrc, strerror(errno));
+                failed = true;
+            }
+
+            // Set permissions (775) on fuse dir
+            if (!failed && chmod(fuseSrc, S_IRWXU|S_IRWXG|S_IROTH|S_IXOTH)) {
+                SLOGE("Failed to set permissions on %s (%s)", fuseSrc, strerror(errno));
+                failed = true;
+            }
+
+            // Invoke the sdcard daemon to expose it
+            if(!failed && doFuseMount(fuseSrc, getMountpoint())) {
+                SLOGE("Failed to fuse mount (%s) -> (%s)", fuseSrc, getMountpoint());
+                failed = true;
+            }
+
+            free(fuseSrc);
+
+            if (failed) {
+                setState(Volume::State_Idle);
+                return -1;
+            }
+
+        } else {
+
+            if (doMoveMount("/mnt/secure/staging", getMountpoint(), false)) {
+                SLOGE("Failed to move mount (%s)", strerror(errno));
+                umount("/mnt/secure/staging");
+                setState(Volume::State_Idle);
+                return -1;
+            }
+
         }
         setState(Volume::State_Mounted);
         mCurrentlyMountedKdev = deviceNodes[i];
@@ -638,6 +740,27 @@ int Volume::doMoveMount(const char *src, const char *dst, bool force) {
     return -1;
 }
 
+int Volume::doFuseMount(const char *src, const char *dst) {
+    if (access(SDCARD_DAEMON_PATH, X_OK)) {
+        SLOGE("Can't invoke sdcard daemon.\n");
+        return -1;
+    }
+    const char* const args[] = { "sdcard", src, dst, STRINGIFY(FUSE_SDCARD_UID), STRINGIFY(FUSE_SDCARD_GID), NULL };
+    pid_t fusePid;
+
+    fusePid=fork();
+
+    if (fusePid == 0) {
+        SLOGW("Invoking sdcard daemon (%s) -> (%s)", src, dst);
+        if (execv(SDCARD_DAEMON_PATH, (char* const*)args) == -1) {
+            SLOGE("Failed to invoke the sdcard daemon!");
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 int Volume::doUnmount(const char *path, bool force) {
     int retries = 10;
 
@@ -675,6 +798,9 @@ int Volume::doUnmount(const char *path, bool force) {
 int Volume::unmountVol(bool force, bool revert) {
     int i, rc;
     const char* externalStorage = getenv("EXTERNAL_STORAGE");
+    const char* label = getLabel();
+    char* fuseDir = (char*) malloc(strlen(FUSEDIR) + strlen("/") + strlen(label) + 1);
+    sprintf(fuseDir, "%s/%s", FUSEDIR, label);
 
     if (getState() != Volume::State_Mounted) {
         SLOGE("Volume %s unmount request when not mounted", getLabel());
@@ -709,6 +835,16 @@ int Volume::unmountVol(bool force, bool revert) {
     }
 
     /*
+     * Unmount the actual block device from fuse dir if exists
+     */
+    if (!access(fuseDir, R_OK | W_OK)) {
+        if (doUnmount(fuseDir, force)) {
+            SLOGE("Failed to unmount %s (%s)", fuseDir, strerror(errno));
+            goto out_nomedia;
+        }
+    }
+
+    /*
      * Finally, unmount the actual block device from the staging dir
      */
     if (doUnmount(getMountpoint(), force)) {
@@ -730,6 +866,7 @@ int Volume::unmountVol(bool force, bool revert) {
 
     setState(Volume::State_Idle);
     mCurrentlyMountedKdev = -1;
+    free(fuseDir);
     return 0;
 
     /*
@@ -756,6 +893,7 @@ fail_republish:
 
 out_nomedia:
     setState(Volume::State_NoMedia);
+    free(fuseDir);
     return -1;
 }
 int Volume::initializeMbr(const char *deviceNode) {
diff --git a/Volume.h b/Volume.h
index 9dd263e..5e90740 100644
--- a/Volume.h
+++ b/Volume.h
@@ -46,6 +46,7 @@ public:
     static const char *ASECDIR;
 
     static const char *LOOPDIR;
+    static const char *FUSEDIR;
 
 protected:
     char *mLabel;
@@ -105,6 +106,7 @@ private:
     int createBindMounts();
     int doUnmount(const char *path, bool force);
     int doMoveMount(const char *src, const char *dst, bool force);
+    int doFuseMount(const char *src, const char *dst);
     void protectFromAutorunStupidity();
 };