1 files changed, 152 insertions, 0 deletions
diff --git a/src/basic/fd-util.h b/src/basic/fd-util.h
new file mode 100644
index 0000000..d3e9192
--- /dev/null
+++ b/src/basic/fd-util.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/socket.h>
+
+#include "macro.h"
+#include "stdio-util.h"
+
+/* maximum length of fdname */
+#define FDNAME_MAX 255
+
+/* Make sure we can distinguish fd 0 and NULL */
+#define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
+#define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
+
+/* Useful helpers for initializing pipe(), socketpair() or stdio fd arrays */
+#define EBADF_PAIR { -EBADF, -EBADF }
+#define EBADF_TRIPLET { -EBADF, -EBADF, -EBADF }
+
+int close_nointr(int fd);
+int safe_close(int fd);
+void safe_close_pair(int p[static 2]);
+
+static inline int safe_close_above_stdio(int fd) {
+        if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -EBADF. */
+                return -EBADF;
+
+        return safe_close(fd);
+}
+
+void close_many(const int fds[], size_t n_fds);
+void close_many_unset(int fds[], size_t n_fds);
+void close_many_and_free(int *fds, size_t n_fds);
+
+int fclose_nointr(FILE *f);
+FILE* safe_fclose(FILE *f);
+DIR* safe_closedir(DIR *f);
+
+static inline void closep(int *fd) {
+        safe_close(*fd);
+}
+
+static inline void close_pairp(int (*p)[2]) {
+        safe_close_pair(*p);
+}
+
+static inline void fclosep(FILE **f) {
+        safe_fclose(*f);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(FILE*, pclose, NULL);
+DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(DIR*, closedir, NULL);
+
+#define _cleanup_close_ _cleanup_(closep)
+#define _cleanup_fclose_ _cleanup_(fclosep)
+#define _cleanup_pclose_ _cleanup_(pclosep)
+#define _cleanup_closedir_ _cleanup_(closedirp)
+#define _cleanup_close_pair_ _cleanup_(close_pairp)
+
+int fd_nonblock(int fd, bool nonblock);
+int fd_cloexec(int fd, bool cloexec);
+int fd_cloexec_many(const int fds[], size_t n_fds, bool cloexec);
+
+int get_max_fd(void);
+
+int close_all_fds(const int except[], size_t n_except);
+int close_all_fds_without_malloc(const int except[], size_t n_except);
+
+int same_fd(int a, int b);
+
+void cmsg_close_all(struct msghdr *mh);
+
+bool fdname_is_valid(const char *s);
+
+int fd_get_path(int fd, char **ret);
+
+int move_fd(int from, int to, int cloexec);
+
+int fd_move_above_stdio(int fd);
+
+int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
+
+static inline int make_null_stdio(void) {
+        return rearrange_stdio(-EBADF, -EBADF, -EBADF);
+}
+
+/* Like TAKE_PTR() but for file descriptors, resetting them to -EBADF */
+#define TAKE_FD(fd) TAKE_GENERIC(fd, int, -EBADF)
+
+/* Like free_and_replace(), but for file descriptors */
+#define close_and_replace(a, b)                 \
+        ({                                      \
+                int *_fdp_ = &(a);              \
+                safe_close(*_fdp_);             \
+                *_fdp_ = TAKE_FD(b);            \
+                0;                              \
+        })
+
+int fd_reopen(int fd, int flags);
+int fd_reopen_condition(int fd, int flags, int mask, int *ret_new_fd);
+int fd_is_opath(int fd);
+int read_nr_open(void);
+int fd_get_diskseq(int fd, uint64_t *ret);
+
+int path_is_root_at(int dir_fd, const char *path);
+static inline int path_is_root(const char *path) {
+        return path_is_root_at(AT_FDCWD, path);
+}
+static inline int dir_fd_is_root(int dir_fd) {
+        return path_is_root_at(dir_fd, NULL);
+}
+static inline int dir_fd_is_root_or_cwd(int dir_fd) {
+        return dir_fd == AT_FDCWD ? true : path_is_root_at(dir_fd, NULL);
+}
+
+/* The maximum length a buffer for a /proc/self/fd/<fd> path needs */
+#define PROC_FD_PATH_MAX \
+        (STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int))
+
+static inline char *format_proc_fd_path(char buf[static PROC_FD_PATH_MAX], int fd) {
+        assert(buf);
+        assert(fd >= 0);
+        assert_se(snprintf_ok(buf, PROC_FD_PATH_MAX, "/proc/self/fd/%i", fd));
+        return buf;
+}
+
+#define FORMAT_PROC_FD_PATH(fd) \
+        format_proc_fd_path((char[PROC_FD_PATH_MAX]) {}, (fd))
+
+/* The maximum length a buffer for a /proc/<pid>/fd/<fd> path needs */
+#define PROC_PID_FD_PATH_MAX \
+        (STRLEN("/proc//fd/") + DECIMAL_STR_MAX(pid_t) + DECIMAL_STR_MAX(int))
+
+char *format_proc_pid_fd_path(char buf[static PROC_PID_FD_PATH_MAX], pid_t pid, int fd);
+
+/* Kinda the same as FORMAT_PROC_FD_PATH(), but goes by PID rather than "self" symlink */
+#define FORMAT_PROC_PID_FD_PATH(pid, fd)                                \
+        format_proc_pid_fd_path((char[PROC_PID_FD_PATH_MAX]) {}, (pid), (fd))
+
+const char *accmode_to_string(int flags);
+
+/* Like ASSERT_PTR, but for fds */
+#define ASSERT_FD(fd)                           \
+        ({                                      \
+                int _fd_ = (fd);                \
+                assert(_fd_ >= 0);              \
+                _fd_;                           \
+        })