[LibOS] Add regression test for reading large directory

LibOS/shim/test/regression/large_dir_read.c

@@ -0,0 +1,101 @@
+#define _GNU_SOURCE
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+unsigned int FILES_NO = 10000;
+
+int main(int argc, char *argv[]) {
+    int fd = 0, ret = 0;
+    char name[0x10] = { 0 };
+    DIR* dir = NULL;
+    struct dirent* x = NULL;
+    unsigned long i, count = 0;
+    char* tmp_name = NULL;
+    char* old_wd = NULL;
+
+    setbuf(stdout, NULL);
+    setbuf(stderr, NULL);
+
+    if (argc != 2 && argc != 3) {
+        fprintf(stderr, "Usage: %s tmp_folder_name [files_count]\n", argv[0]);
+        return 1;
+    }
+
+    tmp_name = argv[1];
+
+    if (argc > 2) {
+        FILES_NO = atol(argv[2]);
+    }
+
+    if ((old_wd = get_current_dir_name()) == NULL) {
+        err(1, "getcwd");
+    }
+
+    if (mkdir(tmp_name, S_IRWXU | S_IRWXG | S_IRWXO) < 0 || chdir(tmp_name) < 0) {
+        err(1, "mkdir & chdr");
+    }
+
+    for (i = 0; i < FILES_NO; ++i) {
+        sprintf(name, "%010lu", i);
+        fd = open(name, O_CREAT | O_RDWR, S_IRWXU | S_IRWXG | S_IRWXO);
+        if (fd < 0) {
+            fprintf(stderr, "cannot create file %lu\n", i);
+            ret = 1;
+            goto cleanup;
+        }
+        if (close(fd) < 0) {
+            fprintf(stderr, "close failed with: %s\n", strerror(errno));
+        }
+    }
+
+    dir = opendir(".");
+    if (!dir) {
+        fputs("cannot open \".\"", stderr);
+        ret = 1;
+        goto cleanup;
+    }
+
+    while (1) {
+        errno = 0;
+        x = readdir(dir);
+        if (!x) {
+            if (errno != 0) {
+                fprintf(stderr, "error: readdir: %s\n", strerror(errno));
+                ret = 1;
+                goto cleanup;
+            } else {
+                break;
+            }
+        }
+        count++;
+    }
+
+    printf("count: %lu\n", count);
+
+cleanup:
+    if (dir) {
+        closedir(dir);
+    }
+
+    for (i = 0; i < FILES_NO; ++i) {
+        sprintf(name, "%010lu", i);
+        unlink(name);
+    }
+
+    if (chdir(old_wd) < 0) {
+        fprintf(stderr, "could not change directory to original (%s): %s\n", old_wd, strerror(errno));
+    }
+    free(old_wd);
+
+    rmdir(tmp_name);
+
+    return ret;
+}