Symlink application lib directory when on SD card

This will help legacy games that use dlopen() to directly access the
/data/data/<app>/lib directory before the
ApplicationInfo.nativeLibraryDir was part of the API.

Change-Id: Ie9f3e7239b6334708b5d086ffafe66a507f6d9da

3 files changed, 168 insertions, 0 deletions

diff --git a/cmds/installd/commands.c b/cmds/installd/commands.c
index f6f80d1..a5b3e0e 100644
--- a/cmds/installd/commands.c
+++ b/cmds/installd/commands.c
@@ -936,3 +936,157 @@ int movefiles()
 done:
     return 0;
 }
+
+int linklib(const char* dataDir, const char* asecLibDir)
+{
+    char libdir[PKG_PATH_MAX];
+    struct stat s, libStat;
+    int rc = 0;
+
+    const size_t libdirLen = strlen(dataDir) + strlen(PKG_LIB_POSTFIX);
+    if (libdirLen >= PKG_PATH_MAX) {
+        LOGE("library dir len too large");
+        rc = -1;
+        goto out;
+    }
+
+    if (snprintf(libdir, sizeof(libdir), "%s%s", dataDir, PKG_LIB_POSTFIX) != (ssize_t)libdirLen) {
+        LOGE("library dir not written successfully: %s\n", strerror(errno));
+        rc = -1;
+        goto out;
+    }
+
+    if (stat(dataDir, &s) < 0) return -1;
+
+    if (chown(dataDir, 0, 0) < 0) {
+        LOGE("failed to chown '%s': %s\n", dataDir, strerror(errno));
+        return -1;
+    }
+
+    if (chmod(dataDir, 0700) < 0) {
+        LOGE("failed to chmod '%s': %s\n", dataDir, strerror(errno));
+        rc = -1;
+        goto out;
+    }
+
+    if (lstat(libdir, &libStat) < 0) {
+        LOGE("couldn't stat lib dir: %s\n", strerror(errno));
+        rc = -1;
+        goto out;
+    }
+
+    if (S_ISDIR(libStat.st_mode)) {
+        if (delete_dir_contents(libdir, 1, 0) < 0) {
+            rc = -1;
+            goto out;
+        }
+    } else if (S_ISLNK(libStat.st_mode)) {
+        if (unlink(libdir) < 0) {
+            rc = -1;
+            goto out;
+        }
+    }
+
+    if (symlink(asecLibDir, libdir) < 0) {
+        LOGE("couldn't symlink directory '%s' -> '%s': %s\n", libdir, asecLibDir, strerror(errno));
+        rc = -errno;
+        goto out;
+    }
+
+    if (lchown(libdir, AID_SYSTEM, AID_SYSTEM) < 0) {
+        LOGE("cannot chown dir '%s': %s\n", libdir, strerror(errno));
+        unlink(libdir);
+        rc = -errno;
+        goto out;
+    }
+
+out:
+    if (chmod(dataDir, s.st_mode) < 0) {
+        LOGE("failed to chmod '%s': %s\n", dataDir, strerror(errno));
+        return -errno;
+    }
+
+    if (chown(dataDir, s.st_uid, s.st_gid) < 0) {
+        LOGE("failed to chown '%s' : %s\n", dataDir, strerror(errno));
+        return -errno;
+    }
+
+    return rc;
+}
+
+int unlinklib(const char* dataDir)
+{
+    char libdir[PKG_PATH_MAX];
+    struct stat s, libStat;
+    int rc = 0;
+
+    const size_t libdirLen = strlen(dataDir) + strlen(PKG_LIB_POSTFIX);
+    if (libdirLen >= PKG_PATH_MAX) {
+        return -1;
+    }
+
+    if (snprintf(libdir, sizeof(libdir), "%s%s", dataDir, PKG_LIB_POSTFIX) != (ssize_t)libdirLen) {
+        LOGE("library dir not written successfully: %s\n", strerror(errno));
+        return -1;
+    }
+
+    if (stat(dataDir, &s) < 0) {
+        LOGE("couldn't state data dir");
+        return -1;
+    }
+
+    if (chown(dataDir, 0, 0) < 0) {
+        LOGE("failed to chown '%s': %s\n", dataDir, strerror(errno));
+        return -1;
+    }
+
+    if (chmod(dataDir, 0700) < 0) {
+        LOGE("failed to chmod '%s': %s\n", dataDir, strerror(errno));
+        rc = -1;
+        goto out;
+    }
+
+    if (lstat(libdir, &libStat) < 0) {
+        LOGE("couldn't stat lib dir: %s\n", strerror(errno));
+        rc = -1;
+        goto out;
+    }
+
+    if (S_ISDIR(libStat.st_mode)) {
+        if (delete_dir_contents(libdir, 1, 0) < 0) {
+            rc = -1;
+            goto out;
+        }
+    } else if (S_ISLNK(libStat.st_mode)) {
+        if (unlink(libdir) < 0) {
+            rc = -1;
+            goto out;
+        }
+    }
+
+    if (mkdir(libdir, 0755) < 0) {
+        LOGE("cannot create dir '%s': %s\n", libdir, strerror(errno));
+        rc = -errno;
+        goto out;
+    }
+
+    if (chown(libdir, AID_SYSTEM, AID_SYSTEM) < 0) {
+        LOGE("cannot chown dir '%s': %s\n", libdir, strerror(errno));
+        unlink(libdir);
+        rc = -errno;
+        goto out;
+    }
+
+out:
+    if (chmod(dataDir, s.st_mode) < 0) {
+        LOGE("failed to chmod '%s': %s\n", dataDir, strerror(errno));
+        return -1;
+    }
+
+    if (chown(dataDir, s.st_uid, s.st_gid) < 0) {
+        LOGE("failed to chown '%s' : %s\n", dataDir, strerror(errno));
+        return -1;
+    }
+
+    return rc;
+}
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index c991845..9ba6402 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -101,6 +101,16 @@ static int do_movefiles(char **arg, char reply[REPLY_MAX])
     return movefiles();
 }
 
+static int do_linklib(char **arg, char reply[REPLY_MAX])
+{
+    return linklib(arg[0], arg[1]);
+}
+
+static int do_unlinklib(char **arg, char reply[REPLY_MAX])
+{
+    return unlinklib(arg[0]);
+}
+
 struct cmdinfo {
     const char *name;
     unsigned numargs;
@@ -121,6 +131,8 @@ struct cmdinfo cmds[] = {
     { "getsize",              4, do_get_size },
     { "rmuserdata",           2, do_rm_user_data },
     { "movefiles",            0, do_movefiles },
+    { "linklib",              2, do_linklib },
+    { "unlinklib",            1, do_unlinklib },
 };
 
 static int readx(int s, void *_buf, int count)
diff --git a/cmds/installd/installd.h b/cmds/installd/installd.h
index 479e4b2..59475e9 100644
--- a/cmds/installd/installd.h
+++ b/cmds/installd/installd.h
@@ -111,3 +111,5 @@ int get_size(const char *pkgname, const char *apkpath, const char *fwdlock_apkpa
 int free_cache(int64_t free_size);
 int dexopt(const char *apk_path, uid_t uid, int is_public);
 int movefiles();
+int linklib(const char* target, const char* source);
+int unlinklib(const char* libPath);