3 files changed, 33 insertions, 19 deletions

diff --git a/applypatch/applypatch.cpp b/applypatch/applypatch.cpp
index eb0a2a7b5..13e4b1ae0 100644
--- a/applypatch/applypatch.cpp
+++ b/applypatch/applypatch.cpp
@@ -23,7 +23,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
-#include <sys/statfs.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -421,15 +420,6 @@ static size_t FileSink(const unsigned char* data, size_t len, int fd) {
   return done;
 }
 
-size_t FreeSpaceForFile(const std::string& filename) {
-  struct statfs sf;
-  if (statfs(filename.c_str(), &sf) != 0) {
-    PLOG(ERROR) << "Failed to statfs " << filename;
-    return -1;
-  }
-  return sf.f_bsize * sf.f_bavail;
-}
-
 int CacheSizeCheck(size_t bytes) {
   if (MakeFreeSpaceOnCache(bytes) < 0) {
     LOG(ERROR) << "Failed to make " << bytes << " bytes available on /cache";
diff --git a/applypatch/freecache.cpp b/applypatch/freecache.cpp
index 5a08a63ed..4989b7496 100644
--- a/applypatch/freecache.cpp
+++ b/applypatch/freecache.cpp
@@ -16,10 +16,12 @@
 
 #include <dirent.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/statfs.h>
 #include <unistd.h>
 
 #include <algorithm>
@@ -130,6 +132,24 @@ static unsigned int GetLogIndex(const std::string& log_name) {
   return std::numeric_limits<unsigned int>::max();
 }
 
+// Returns the amount of free space (in bytes) on the filesystem containing filename, or -1 on
+// error.
+static int64_t FreeSpaceForFile(const std::string& filename) {
+  struct statfs sf;
+  if (statfs(filename.c_str(), &sf) == -1) {
+    PLOG(ERROR) << "Failed to statfs " << filename;
+    return -1;
+  }
+
+  int64_t free_space = static_cast<int64_t>(sf.f_bsize) * sf.f_bavail;
+  if (sf.f_bsize == 0 || free_space / sf.f_bsize != sf.f_bavail) {
+    LOG(ERROR) << "Invalid block size or overflow (sf.f_bsize " << sf.f_bsize << ", sf.f_bavail "
+               << sf.f_bavail << ")";
+    return -1;
+  }
+  return free_space;
+}
+
 int MakeFreeSpaceOnCache(size_t bytes_needed) {
 #ifndef __ANDROID__
   // TODO(xunchang): Implement a heuristic cache size check during host simulation.
@@ -149,7 +169,7 @@ int MakeFreeSpaceOnCache(size_t bytes_needed) {
 }
 
 bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname,
-                            const std::function<size_t(const std::string&)>& space_checker) {
+                            const std::function<int64_t(const std::string&)>& space_checker) {
   struct stat st;
   if (stat(dirname.c_str(), &st) == -1) {
     PLOG(ERROR) << "Failed to stat " << dirname;
@@ -160,7 +180,11 @@ bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname,
     return false;
   }
 
-  size_t free_now = space_checker(dirname);
+  int64_t free_now = space_checker(dirname);
+  if (free_now == -1) {
+    LOG(ERROR) << "Failed to check free space for " << dirname;
+    return false;
+  }
   LOG(INFO) << free_now << " bytes free on " << dirname << " (" << bytes_needed << " needed)";
 
   if (free_now >= bytes_needed) {
@@ -201,6 +225,10 @@ bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname,
     }
 
     free_now = space_checker(dirname);
+    if (free_now == -1) {
+      LOG(ERROR) << "Failed to check free space for " << dirname;
+      return false;
+    }
     LOG(INFO) << "Deleted " << file << "; now " << free_now << " bytes free";
     if (free_now >= bytes_needed) {
       return true;
diff --git a/applypatch/include/applypatch/applypatch.h b/applypatch/include/applypatch/applypatch.h
index 92db59c3a..88659b86a 100644
--- a/applypatch/include/applypatch/applypatch.h
+++ b/applypatch/include/applypatch/applypatch.h
@@ -40,10 +40,6 @@ using SinkFn = std::function<size_t(const unsigned char*, size_t)>;
 
 int ShowLicenses();
 
-// Returns the amount of free space (in bytes) on the filesystem containing filename, or -1 on
-// error. filename must exist.
-size_t FreeSpaceForFile(const std::string& filename);
-
 // Checks whether /cache partition has at least 'bytes'-byte free space. Returns 0 on having
 // sufficient space.
 int CacheSizeCheck(size_t bytes);
@@ -119,8 +115,8 @@ int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value&
 
 int MakeFreeSpaceOnCache(size_t bytes_needed);
 
-// Removes the files in |dirname| until we have at least |bytes_needed| bytes of free space on
-// the partition. The size of the free space is returned by calling |space_checker|.
+// Removes the files in |dirname| until we have at least |bytes_needed| bytes of free space on the
+// partition. |space_checker| should return the size of the free space, or -1 on error.
 bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname,
-                            const std::function<size_t(const std::string&)>& space_checker);
+                            const std::function<int64_t(const std::string&)>& space_checker);
 #endif