file_utils: cleanup macros and improvements

src/lxc/file_utils.c

@@ -73,7 +73,7 @@ int lxc_write_openat(const char *dir, const char *filename, const void *buf,
 int lxc_write_to_file(const char *filename, const void *buf, size_t count,
 		      bool add_newline, mode_t mode)
 {
-	int fd, saved_errno;
+	__do_close_prot_errno int fd = -EBADF;
 	ssize_t ret;
 
 	fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode);
@@ -82,30 +82,23 @@ int lxc_write_to_file(const char *filename, const void *buf, size_t count,
 
 	ret = lxc_write_nointr(fd, buf, count);
 	if (ret < 0)
-		goto out_error;
+		return -1;
 
 	if ((size_t)ret != count)
-		goto out_error;
+		return -1;
 
 	if (add_newline) {
 		ret = lxc_write_nointr(fd, "\n", 1);
 		if (ret != 1)
-			goto out_error;
+			return -1;
 	}
 
-	close(fd);
 	return 0;
-
-out_error:
-	saved_errno = errno;
-	close(fd);
-	errno = saved_errno;
-	return -1;
 }
 
 int lxc_read_from_file(const char *filename, void *buf, size_t count)
 {
-	int fd = -1, saved_errno;
+	__do_close_prot_errno int fd = -EBADF;
 	ssize_t ret;
 
 	fd = open(filename, O_RDONLY | O_CLOEXEC);
@@ -126,19 +119,16 @@ int lxc_read_from_file(const char *filename, void *buf, size_t count)
 		ret = lxc_read_nointr(fd, buf, count);
 	}
 
-	saved_errno = errno;
-	close(fd);
-	errno = saved_errno;
 	return ret;
 }
 
 ssize_t lxc_write_nointr(int fd, const void *buf, size_t count)
 {
 	ssize_t ret;
-again:
-	ret = write(fd, buf, count);
-	if (ret < 0 && errno == EINTR)
-		goto again;
+
+	do {
+		ret = write(fd, buf, count);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }
@@ -146,10 +136,10 @@ again:
 ssize_t lxc_send_nointr(int sockfd, void *buf, size_t len, int flags)
 {
 	ssize_t ret;
-again:
-	ret = send(sockfd, buf, len, flags);
-	if (ret < 0 && errno == EINTR)
-		goto again;
+
+	do {
+		ret = send(sockfd, buf, len, flags);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }
@@ -157,10 +147,10 @@ again:
 ssize_t lxc_read_nointr(int fd, void *buf, size_t count)
 {
 	ssize_t ret;
-again:
-	ret = read(fd, buf, count);
-	if (ret < 0 && errno == EINTR)
-		goto again;
+
+	do {
+		ret = read(fd, buf, count);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }
@@ -168,10 +158,10 @@ again:
 ssize_t lxc_recv_nointr(int sockfd, void *buf, size_t len, int flags)
 {
 	ssize_t ret;
-again:
-	ret = recv(sockfd, buf, len, flags);
-	if (ret < 0 && errno == EINTR)
-		goto again;
+
+	do {
+		ret = recv(sockfd, buf, len, flags);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }
@@ -180,21 +170,20 @@ ssize_t lxc_recvmsg_nointr_iov(int sockfd, struct iovec *iov, size_t iovlen,
 			       int flags)
 {
 	ssize_t ret;
-	struct msghdr msg;
+	struct msghdr msg = {
+		.msg_iov = iov,
+		.msg_iovlen = iovlen,
+	};
 
-	memset(&msg, 0, sizeof(msg));
-	msg.msg_iov = iov;
-	msg.msg_iovlen = iovlen;
-
-again:
-	ret = recvmsg(sockfd, &msg, flags);
-	if (ret < 0 && errno == EINTR)
-		goto again;
+	do {
+		ret = recvmsg(sockfd, &msg, flags);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }
 
-ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count, const void *expected_buf)
+ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count,
+			       const void *expected_buf)
 {
 	ssize_t ret;
 
@@ -205,15 +194,14 @@ ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count, const void *expe
 	if ((size_t)ret != count)
 		return -1;
 
-	if (expected_buf && memcmp(buf, expected_buf, count) != 0) {
-		errno = EINVAL;
-		return -1;
-	}
+	if (expected_buf && memcmp(buf, expected_buf, count) != 0)
+		return ret_set_errno(-1, EINVAL);
 
 	return 0;
 }
 
-ssize_t lxc_read_file_expect(const char *path, void *buf, size_t count, const void *expected_buf)
+ssize_t lxc_read_file_expect(const char *path, void *buf, size_t count,
+			     const void *expected_buf)
 {
 	__do_close_prot_errno int fd = -EBADF;
 
@@ -233,7 +221,7 @@ bool file_exists(const char *f)
 
 int print_to_file(const char *file, const char *content)
 {
-	FILE *f;
+	__do_fclose FILE *f = NULL;
 	int ret = 0;
 
 	f = fopen(file, "we");
@@ -243,14 +231,13 @@ int print_to_file(const char *file, const char *content)
 	if (fprintf(f, "%s", content) != strlen(content))
 		ret = -1;
 
-	fclose(f);
 	return ret;
 }
 
 int is_dir(const char *path)
 {
-	struct stat statbuf;
 	int ret;
+	struct stat statbuf;
 
 	ret = stat(path, &statbuf);
 	if (ret == 0 && S_ISDIR(statbuf.st_mode))
@@ -264,8 +251,8 @@ int is_dir(const char *path)
  */
 int lxc_count_file_lines(const char *fn)
 {
-	FILE *f;
-	char *line = NULL;
+	__do_free char *line = NULL;
+	__do_fclose FILE *f = NULL;
 	size_t sz = 0;
 	int n = 0;
 
@@ -273,12 +260,9 @@ int lxc_count_file_lines(const char *fn)
 	if (!f)
 		return -1;
 
-	while (getline(&line, &sz, f) != -1) {
+	while (getline(&line, &sz, f) != -1)
 		n++;
-	}
 
-	free(line);
-	fclose(f);
 	return n;
 }
 
@@ -338,11 +322,9 @@ bool fhas_fs_type(int fd, fs_type_magic magic_val)
 
 FILE *fopen_cloexec(const char *path, const char *mode)
 {
-	int open_mode = 0;
-	int step = 0;
-	int fd;
-	int saved_errno = 0;
-	FILE *ret;
+	__do_close_prot_errno int fd = -EBADF;
+	int open_mode = 0, step = 0;
+	FILE *f;
 
 	if (!strncmp(mode, "r+", 2)) {
 		open_mode = O_RDWR;
@@ -366,32 +348,24 @@ FILE *fopen_cloexec(const char *path, const char *mode)
 	for (; mode[step]; step++)
 		if (mode[step] == 'x')
 			open_mode |= O_EXCL;
-	open_mode |= O_CLOEXEC;
 
-	fd = open(path, open_mode, 0660);
+	fd = open(path, open_mode | O_CLOEXEC, 0660);
 	if (fd < 0)
 		return NULL;
 
-	ret = fdopen(fd, mode);
-	saved_errno = errno;
-	if (!ret)
-		close(fd);
-	errno = saved_errno;
-	return ret;
+	f = fdopen(fd, mode);
+	if (f)
+		move_fd(fd);
+	return f;
 }
 
 ssize_t lxc_sendfile_nointr(int out_fd, int in_fd, off_t *offset, size_t count)
 {
 	ssize_t ret;
 
-again:
-	ret = sendfile(out_fd, in_fd, offset, count);
-	if (ret < 0) {
-		if (errno == EINTR)
-			goto again;
-
-		return -1;
-	}
+	do {
+		ret = sendfile(out_fd, in_fd, offset, count);
+	} while (ret < 0 && errno == EINTR);
 
 	return ret;
 }