Linux c源码之rm递归删除文件

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/types.h>

static int usage()
{
	fprintf(stderr,"rm [-rR] <target>\n");
	return -1;
}

//递归删除文件
/* return -1 on failure, with errno set to the first error */
static int unlink_recursive(const char* name)
{
	struct stat st;
	DIR *dir;
	struct dirent *de;
	int fail = 0;

	/* is it a file or directory? */
	if (lstat(name, &st) < 0)
		return -1;

	/* a file, so unlink it */
	if (!S_ISDIR(st.st_mode))
		return unlink(name);

	/* a directory, so open handle */
	dir = opendir(name);
	if (dir == NULL)
		return -1;

	/* recurse over components */
	errno = 0;
	while ((de = readdir(dir)) != NULL) {
		char dn[PATH_MAX];
		if (!strcmp(de->d_name, "..") || !strcmp(de->d_name, "."))
			continue;
		sprintf(dn, "%s/%s", name, de->d_name);
		if (unlink_recursive(dn) < 0) {
			fail = 1;
			break;
		}
		errno = 0;
	}
	/* in case readdir or unlink_recursive failed */
	if (fail || errno < 0) {
		int save = errno;
		closedir(dir);
		errno = save;
		return -1;
	}

	/* close directory handle */
	if (closedir(dir) < 0)
		return -1;

	/* delete target directory */
	return rmdir(name);
}

int main(int argc, char *argv[])
{
	int ret;
	int i = 1;
	int recursive = 0;

	if (argc < 2)
		return usage();

	/* check if recursive */
	if (argc >=2 && (!strcmp(argv[1], "-r") || !strcmp(argv[1], "-R"))) {
		recursive = 1;
		i = 2;
	}

	/* loop over the file/directory args */
	for (; i < argc; i++) {
		int ret = recursive ? unlink_recursive(argv[i]) : unlink(argv[i]);
		if (ret < 0) {
			fprintf(stderr, "rm failed for %s, %s\n", argv[i], strerror(errno));
			return -1;
		}
	}

	return 0;
}