commit b640b8dbb1f3379ad7a5b645e7c040e052f9aafc
author TreeHugger Robot <treehugger-gerrit@google.com> Tue May 14 00:25:22 2019 +0000
committer Android (Google) Code Review <android-gerrit@google.com> Tue May 14 00:25:22 2019 +0000
tree cf9b1fda373e30be205ead3f2125d656be89681b
parent 4a61502ef1f70df7223ddb522ce9d0f5cfbacfc8
parent 5420c814b23ded8e32e8138ea14fd1f30d39c7a6

Merge "fs_mgr: overlayfs: ReadFstabFromFile touches errno" into qt-dev

fs_mgr/fs_mgr_fstab.cpp

diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index da049ef..e7c175f 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -704,7 +704,9 @@
     constexpr const char kSkipMountConfig[] = "/system/etc/init/config/skip_mount.cfg";
 
     std::string skip_config;
+    auto save_errno = errno;
     if (!ReadFileToString(kSkipMountConfig, &skip_config)) {
+        errno = save_errno;  // missing file is expected
         return true;
     }
 

fs_mgr/fs_mgr_overlayfs.cpp

diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index 8a6df7d..c252ab5 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -139,7 +139,11 @@
     // If we have access issues to find out space remaining, return true
     // to prevent us trying to override with overlayfs.
     struct statvfs vst;
-    if (statvfs(mount_point.c_str(), &vst)) return true;
+    auto save_errno = errno;
+    if (statvfs(mount_point.c_str(), &vst)) {
+        errno = save_errno;
+        return true;
+    }
 
     static constexpr int kPercentThreshold = 1;  // 1%
 
@@ -265,9 +269,11 @@
 
 bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only = true) {
     Fstab fstab;
+    auto save_errno = errno;
     if (!ReadFstabFromFile("/proc/mounts", &fstab)) {
         return false;
     }
+    errno = save_errno;
     const auto lowerdir = kLowerdirOption + mount_point;
     for (const auto& entry : fstab) {
         if (overlay_only && "overlay" != entry.fs_type && "overlayfs" != entry.fs_type) continue;