Merge pull request #959 from libexpat/tests-benchmark-improve

`tests/benchmark`: Fix a harmless TOCTTOU + upfront refactorings + improve error messages

expat/tests/benchmark/benchmark.c

@@ -32,10 +32,18 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#define _POSIX_C_SOURCE 1 // fdopen
+
+#if defined(_MSC_VER)
+#  include <io.h> // _open, _close
+#else
+#  include <unistd.h> // close
+#endif
+
+#include <fcntl.h> // open
 #include <sys/stat.h>
 #include <assert.h>
 #include <stddef.h> // ptrdiff_t
-#include <stdlib.h>
 #include <stdio.h>
 #include <time.h>
 #include "expat.h"
@@ -52,17 +60,18 @@
 #  define XML_FMT_STR "s"
 #endif
 
-static void
+static int
 usage(const char *prog, int rc) {
   fprintf(stderr, "usage: %s [-n] filename bufferSize nr_of_loops\n", prog);
-  exit(rc);
+  return rc;
 }
 
 int
 main(int argc, char *argv[]) {
   XML_Parser parser;
   char *XMLBuf, *XMLBufEnd, *XMLBufPtr;
-  FILE *fd;
+  int fd;
+  FILE *file;
   struct stat fileAttr;
   int nrOfLoops, bufferSize, i, isFinal;
   size_t fileSize;
@@ -76,34 +85,45 @@ main(int argc, char *argv[]) {
         ns = 1;
         j = 1;
       } else
-        usage(argv[0], 1);
+        return usage(argv[0], 1);
     }
   }
 
   if (argc != j + 4)
-    usage(argv[0], 1);
+    return usage(argv[0], 1);
 
-  if (stat(argv[j + 1], &fileAttr) != 0) {
-    fprintf(stderr, "could not access file '%s'\n", argv[j + 1]);
+  fd = open(argv[j + 1], O_RDONLY);
+  if (fd == -1) {
+    fprintf(stderr, "could not open file '%s'\n", argv[j + 1]);
     return 2;
   }
 
-  fd = fopen(argv[j + 1], "r");
-  if (! fd) {
-    fprintf(stderr, "could not open file '%s'\n", argv[j + 1]);
-    exit(2);
+  if (fstat(fd, &fileAttr) != 0) {
+    close(fd);
+    fprintf(stderr, "could not fstat file '%s'\n", argv[j + 1]);
+    return 2;
+  }
+
+  file = fdopen(fd, "r");
+  if (! file) {
+    close(fd);
+    fprintf(stderr, "could not fdopen file '%s'\n", argv[j + 1]);
+    return 2;
   }
 
   bufferSize = atoi(argv[j + 2]);
   nrOfLoops = atoi(argv[j + 3]);
   if (bufferSize <= 0 || nrOfLoops <= 0) {
+    fclose(file);
+    close(fd);
     fprintf(stderr, "buffer size and nr of loops must be greater than zero.\n");
-    exit(3);
+    return 3;
   }
 
   XMLBuf = malloc(fileAttr.st_size);
-  fileSize = fread(XMLBuf, sizeof(char), fileAttr.st_size, fd);
-  fclose(fd);
+  fileSize = fread(XMLBuf, sizeof(char), fileAttr.st_size, file);
+  fclose(file);
+  close(fd);
 
   if (ns)
     parser = XML_ParserCreateNS(NULL, '!');
@@ -132,7 +152,7 @@ main(int argc, char *argv[]) {
                 XML_GetCurrentColumnNumber(parser));
         free(XMLBuf);
         XML_ParserFree(parser);
-        exit(4);
+        return 4;
       }
       XMLBufPtr += bufferSize;
     } while (! isFinal);