symlink benchmark tool

test.c

#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>

//const char *target = "shortlink";
const char *target = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789foobartoolchainproviderconfiguration";
//const char *target = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567";

int main(int argc, char *argv[]) {
	for (int shard=0; shard<64; shard++) {
		char dirname[16];
		snprintf(dirname, 16, "%d", shard);
		if (mkdir(dirname, 0755) < 0) {
			perror("mkdir");
			return 1;
		}
	}

	for (int i=0; i<160000; i++) {
		char linkname[64];
		snprintf(linkname, 64, "%d/%d", i % 64, i);
#if 0
		int fd = open(linkname, O_CREAT | O_WRONLY | O_EXCL, 0777);
		if (fd < 0) {
			perror("open");
			return 1;
		}
		if (write(fd, target, strlen(target)) < 0) {
			perror("write");
			return 1;
		}
		if (close(fd) < 0) {
			perror("close");
			return 1;
		}
#else
		if (symlink(target, linkname) < 0) {
			perror("symlink");
			return 1;
		}
#endif
	}

	for (int shard=0; shard<64; shard++) {
		char dirname[16];
		snprintf(dirname, 16, "%d", shard);

		DIR *dir = opendir(dirname);
		if (dir == NULL) {
			perror("opendir");
			return 1;
		}

		struct dirent *next_file;
		char filepath[256];
		while ((next_file = readdir(dir)) != NULL) {
			if (strcmp(next_file->d_name, ".") == 0 || strcmp(next_file->d_name, "..") == 0) {
				continue;
			}

			if (unlinkat(dirfd(dir), next_file->d_name, 0) < 0) {
				perror("unlinkat");
				return 1;
			}
		}

		if (closedir(dir) < 0) {
			perror("closedir");
			return 1;
		}
		
		if (rmdir(dirname) < 0) {
			perror("rmdir");
			return 1;
		}
	}

	return 0;
}