Improve error handling in bspatch.

BUG=265456

TBR=brettw@chromium.org

Review URL: https://chromiumcodereview.appspot.com/21049006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@214750 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 49 insertions, 20 deletions

diff --git a/third_party/bspatch/README.chromium b/third_party/bspatch/README.chromium
index 262281d..ad044e3 100644
--- a/third_party/bspatch/README.chromium
+++ b/third_party/bspatch/README.chromium
@@ -12,7 +12,7 @@ Originally obtained from Mozilla's local copy/fork of bspatch; see:
 
 The license is shared in common with bsdiff.
 
-Local changes include CRC32 verification.
+Local changes include CRC32 verification and improvements in error handling.
 
 Update(08 Sep 08): Changed ApplyBinaryPatch to accept wchar_t paths
 instead of char paths.
diff --git a/third_party/bspatch/mbspatch.cc b/third_party/bspatch/mbspatch.cc
index f67aa11..164cc3c 100644
--- a/third_party/bspatch/mbspatch.cc
+++ b/third_party/bspatch/mbspatch.cc
@@ -211,35 +211,64 @@ int CalculateCrc(const unsigned char *buf, int size) {
 
 int ApplyBinaryPatch(const wchar_t *old_file, const wchar_t *patch_file,
                      const wchar_t *new_file) {
-  int ret = 0;
+  int ret = OK;
+  int ofd = -1;
+  int nfd = -1;
+  unsigned char *buf = NULL;
+
   int pfd = _wopen(patch_file, O_RDONLY | _O_BINARY);
   if (pfd < 0) return READ_ERROR;
 
-  MBSPatchHeader header;
-  if (ret = MBS_ReadHeader(pfd, &header)) return ret;
+  do {
+    MBSPatchHeader header;
+    if ((ret = MBS_ReadHeader(pfd, &header)))
+      break;
 
-  int ofd = _wopen(old_file, O_RDONLY | _O_BINARY);
-  if (ofd < 0) return READ_ERROR;
+    ofd = _wopen(old_file, O_RDONLY | _O_BINARY);
+    if (ofd < 0) {
+      ret = READ_ERROR;
+      break;
+    }
 
-  struct stat os;
-  if (ret = fstat(ofd, &os)) return READ_ERROR;
-  if (os.st_size != header.slen) return UNEXPECTED_ERROR;
+    struct stat os;
+    if ((ret = fstat(ofd, &os))) {
+      ret = READ_ERROR;
+      break;
+    }
 
-  unsigned char *buf = (unsigned char*) malloc(header.slen);
-  if (!buf) return MEM_ERROR;
+    if (os.st_size != header.slen) {
+      ret = UNEXPECTED_ERROR;
+      break;
+    }
 
-  if (read(ofd, buf, header.slen) != header.slen) return READ_ERROR;
-  if (CalculateCrc(buf, header.slen) != header.scrc32) 
-    return CRC_ERROR;
+    buf = (unsigned char*) malloc(header.slen);
+    if (!buf) {
+      ret = MEM_ERROR;
+      break;
+    }
 
-  int nfd = _wopen(new_file, O_WRONLY | O_TRUNC | O_CREAT | _O_BINARY);
-  if (nfd < 0) return READ_ERROR;
+    if (read(ofd, buf, header.slen) != header.slen) {
+      ret = READ_ERROR;
+      break;
+    }
 
-  MBS_ApplyPatch(&header, pfd, buf, nfd);
+    if (CalculateCrc(buf, header.slen) != header.scrc32) {
+      ret = CRC_ERROR;
+      break;
+    }
+
+    nfd = _wopen(new_file, O_WRONLY | O_TRUNC | O_CREAT | _O_BINARY);
+    if (nfd < 0) {
+      ret = READ_ERROR;
+      break;
+    }
+
+    MBS_ApplyPatch(&header, pfd, buf, nfd);
+  } while (0);
 
   free(buf);
   close(pfd);
-  close(ofd);
-  close(nfd);
-  return OK;
+  if (ofd >= 0) close(ofd);
+  if (nfd >= 0) close(nfd);
+  return ret;
 }