A new tool to test how many files can be opened simultaneously.

This tool will try to simultaneously open the specified number of files
in the specified directory.  It is useful to check if hard limits are
high enough, and also check if a filesystem performs well when many files
are open at the same time.  The sdcard daemon has some issues in this
area, both in max files that can be open at once, and performance
issues when too many are open.

Change-Id: I05a1ca49208f54a27d5405e4850752f49cdca443

1 files changed, 95 insertions, 0 deletions

diff --git a/tests/storage/opentest.c b/tests/storage/opentest.c
new file mode 100644
index 00000000..05d55869
--- /dev/null
+++ b/tests/storage/opentest.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+int main(int argc, char *argv[])
+{
+    int i;
+    int nfiles;
+    int *fds;
+    char *dir;
+    struct stat statbuf;
+    char name[16];
+    struct rlimit rlim;
+
+    if (argc != 3) {
+        fprintf(stderr, "Usage: opentest <directory> <num_files>\n");
+        exit(1);
+    }
+
+    dir = argv[1];
+
+    nfiles = atoi(argv[2]);
+    if ((nfiles <= 0) || (nfiles > 65536)) {
+        fprintf(stderr, "num_files must be between 1 and 65536\n");
+        exit(1);
+    }
+
+    if (stat(dir, &statbuf)) {
+        fprintf(stderr, "Cannot stat %s\n", dir);
+        exit(1);
+    }
+
+    if (! S_ISDIR(statbuf.st_mode)) {
+        fprintf(stderr, "%s is not a directory!\n", dir);
+        exit(1);
+    }
+
+    if (access(dir, R_OK | W_OK)) {
+        fprintf(stderr, "No access to %s\n", dir);
+        exit(1);
+    }
+
+    fds = malloc(nfiles * sizeof(int));
+    if (fds == 0) {
+        fprintf(stderr, "Unable to malloc array of %d fds\n", nfiles);
+        exit(1);
+    }
+
+    if (chdir(dir)) {
+        fprintf(stderr, "Cannot chdir to %s\n", dir);
+        exit(1);
+    }
+
+    rlim.rlim_cur = nfiles + 10;
+    rlim.rlim_max = nfiles + 10;
+    if (setrlimit(RLIMIT_NOFILE, &rlim)) {
+        fprintf(stderr, "Unable to raise RLIMIT_NOFILE to %ld\n", rlim.rlim_cur);
+        exit(1);
+    }
+
+    for (i = 0; i < nfiles; i++) {
+        snprintf(name, sizeof(name), "%d", i);
+        fds[i] = open(name, O_WRONLY | O_CREAT, 0666);
+        if (fds[i] < 0) {
+            fprintf(stderr, "Unable to open %d fd\n", i);
+            exit(1);
+        }
+    }
+
+    /* Rely upon exit to cleanup! */
+    exit(0);
+}
+
+