src/basic/fileio.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <dirent.h>
   5 #include <fcntl.h>
   6 #include <stdbool.h>
   7 #include <stddef.h>
   8 #include <stdio.h>
   9 #include <sys/stat.h>
  10 #include <sys/types.h>
  11
  12 #include "macro.h"
  13 #include "time-util.h"
  14
  15 #define LONG_LINE_MAX (1U*1024U*1024U)
  16
  17 typedef enum {
  18         WRITE_STRING_FILE_CREATE                     = 1 << 0,
  19         WRITE_STRING_FILE_TRUNCATE                   = 1 << 1,
  20         WRITE_STRING_FILE_ATOMIC                     = 1 << 2,
  21         WRITE_STRING_FILE_AVOID_NEWLINE              = 1 << 3,
  22         WRITE_STRING_FILE_VERIFY_ON_FAILURE          = 1 << 4,
  23         WRITE_STRING_FILE_VERIFY_IGNORE_NEWLINE      = 1 << 5,
  24         WRITE_STRING_FILE_SYNC                       = 1 << 6,
  25         WRITE_STRING_FILE_DISABLE_BUFFER             = 1 << 7,
  26         WRITE_STRING_FILE_NOFOLLOW                   = 1 << 8,
  27         WRITE_STRING_FILE_MKDIR_0755                 = 1 << 9,
  28         WRITE_STRING_FILE_MODE_0600                  = 1 << 10,
  29         WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL = 1 << 11,
  30
  31         /* And before you wonder, why write_string_file_atomic_label_ts() is a separate function instead of just one
  32            more flag here: it's about linking: we don't want to pull -lselinux into all users of write_string_file()
  33            and friends. */
  34
  35 } WriteStringFileFlags;
  36
  37 typedef enum {
  38         READ_FULL_FILE_SECURE              = 1 << 0, /* erase any buffers we employ internally, after use */
  39         READ_FULL_FILE_UNBASE64            = 1 << 1, /* base64 decode what we read */
  40         READ_FULL_FILE_UNHEX               = 1 << 2, /* hex decode what we read */
  41         READ_FULL_FILE_WARN_WORLD_READABLE = 1 << 3, /* if regular file, log at LOG_WARNING level if access mode above 0700 */
  42         READ_FULL_FILE_CONNECT_SOCKET      = 1 << 4, /* if socket inode, connect to it and read off it */
  43         READ_FULL_FILE_FAIL_WHEN_LARGER    = 1 << 5, /* fail loading if file is larger than specified size */
  44 } ReadFullFileFlags;
  45
  46 int fdopen_unlocked(int fd, const char *options, FILE **ret);
  47 int take_fdopen_unlocked(int *fd, const char *options, FILE **ret);
  48 FILE* take_fdopen(int *fd, const char *options);
  49 DIR* take_fdopendir(int *dfd);
  50 FILE* open_memstream_unlocked(char **ptr, size_t *sizeloc);
  51 FILE* fmemopen_unlocked(void *buf, size_t size, const char *mode);
  52
  53 int write_string_stream_ts(FILE *f, const char *line, WriteStringFileFlags flags, const struct timespec *ts);
  54 static inline int write_string_stream(FILE *f, const char *line, WriteStringFileFlags flags) {
  55         return write_string_stream_ts(f, line, flags, NULL);
  56 }
  57 int write_string_file_ts_at(int dir_fd, const char *fn, const char *line, WriteStringFileFlags flags, const struct timespec *ts);
  58 static inline int write_string_file_ts(const char *fn, const char *line, WriteStringFileFlags flags, const struct timespec *ts) {
  59         return write_string_file_ts_at(AT_FDCWD, fn, line, flags, ts);
  60 }
  61 static inline int write_string_file_at(int dir_fd, const char *fn, const char *line, WriteStringFileFlags flags) {
  62         return write_string_file_ts_at(dir_fd, fn, line, flags, NULL);
  63 }
  64 static inline int write_string_file(const char *fn, const char *line, WriteStringFileFlags flags) {
  65         return write_string_file_ts(fn, line, flags, NULL);
  66 }
  67
  68 int write_string_filef(const char *fn, WriteStringFileFlags flags, const char *format, ...) _printf_(3, 4);
  69
  70 int read_one_line_file_at(int dir_fd, const char *filename, char **ret);
  71 static inline int read_one_line_file(const char *filename, char **ret) {
  72         return read_one_line_file_at(AT_FDCWD, filename, ret);
  73 }
  74 int read_full_file_full(int dir_fd, const char *filename, uint64_t offset, size_t size, ReadFullFileFlags flags, const char *bind_name, char **ret_contents, size_t *ret_size);
  75 static inline int read_full_file_at(int dir_fd, const char *filename, char **ret_contents, size_t *ret_size) {
  76         return read_full_file_full(dir_fd, filename, UINT64_MAX, SIZE_MAX, 0, NULL, ret_contents, ret_size);
  77 }
  78 static inline int read_full_file(const char *filename, char **ret_contents, size_t *ret_size) {
  79         return read_full_file_full(AT_FDCWD, filename, UINT64_MAX, SIZE_MAX, 0, NULL, ret_contents, ret_size);
  80 }
  81
  82 int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size);
  83 int read_virtual_file_at(int dir_fd, const char *filename, size_t max_size, char **ret_contents, size_t *ret_size);
  84 static inline int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
  85         return read_virtual_file_at(AT_FDCWD, filename, max_size, ret_contents, ret_size);
  86 }
  87 static inline int read_full_virtual_file(const char *filename, char **ret_contents, size_t *ret_size) {
  88         return read_virtual_file(filename, SIZE_MAX, ret_contents, ret_size);
  89 }
  90
  91 int read_full_stream_full(FILE *f, const char *filename, uint64_t offset, size_t size, ReadFullFileFlags flags, char **ret_contents, size_t *ret_size);
  92 static inline int read_full_stream(FILE *f, char **ret_contents, size_t *ret_size) {
  93         return read_full_stream_full(f, NULL, UINT64_MAX, SIZE_MAX, 0, ret_contents, ret_size);
  94 }
  95
  96 int verify_file_at(int dir_fd, const char *fn, const char *blob, bool accept_extra_nl);
  97 static inline int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
  98         return verify_file_at(AT_FDCWD, fn, blob, accept_extra_nl);
  99 }
 100
 101 int executable_is_script(const char *path, char **interpreter);
 102
 103 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field);
 104
 105 DIR *xopendirat(int dirfd, const char *name, int flags);
 106
 107 typedef enum XfopenFlags {
 108         XFOPEN_UNLOCKED = 1 << 0, /* call __fsetlocking(FSETLOCKING_BYCALLER) after opened */
 109         XFOPEN_SOCKET   = 1 << 1, /* also try to open unix socket */
 110 } XfopenFlags;
 111
 112 int xfopenat_full(
 113                 int dir_fd,
 114                 const char *path,
 115                 const char *mode,
 116                 int open_flags,
 117                 XfopenFlags flags,
 118                 const char *bind_name,
 119                 FILE **ret);
 120 static inline int xfopenat(int dir_fd, const char *path, const char *mode, int open_flags, FILE **ret) {
 121         return xfopenat_full(dir_fd, path, mode, open_flags, 0, NULL, ret);
 122 }
 123 static inline int fopen_unlocked_at(int dir_fd, const char *path, const char *mode, int open_flags, FILE **ret) {
 124         return xfopenat_full(dir_fd, path, mode, open_flags, XFOPEN_UNLOCKED, NULL, ret);
 125 }
 126 static inline int fopen_unlocked(const char *path, const char *mode, FILE **ret) {
 127         return fopen_unlocked_at(AT_FDCWD, path, mode, 0, ret);
 128 }
 129
 130 int fdopen_independent(int fd, const char *mode, FILE **ret);
 131
 132 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **ret, char **ret_path);
 133 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **ret, char **ret_path);
 134
 135 int fflush_and_check(FILE *f);
 136 int fflush_sync_and_check(FILE *f);
 137
 138 int write_timestamp_file_atomic(const char *fn, usec_t n);
 139 int read_timestamp_file(const char *fn, usec_t *ret);
 140
 141 int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space);
 142
 143 typedef enum ReadLineFlags {
 144         READ_LINE_ONLY_NUL  = 1 << 0,
 145         READ_LINE_IS_A_TTY  = 1 << 1,
 146         READ_LINE_NOT_A_TTY = 1 << 2,
 147 } ReadLineFlags;
 148
 149 int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret);
 150
 151 static inline bool file_offset_beyond_memory_size(off_t x) {
 152         if (x < 0) /* off_t is signed, filter that out */
 153                 return false;
 154         return (uint64_t) x > (uint64_t) SIZE_MAX;
 155 }
 156
 157 static inline int read_line(FILE *f, size_t limit, char **ret) {
 158         return read_line_full(f, limit, 0, ret);
 159 }
 160
 161 static inline int read_nul_string(FILE *f, size_t limit, char **ret) {
 162         return read_line_full(f, limit, READ_LINE_ONLY_NUL, ret);
 163 }
 164
 165 int safe_fgetc(FILE *f, char *ret);
 166
 167 int warn_file_is_world_accessible(const char *filename, struct stat *st, const char *unit, unsigned line);
 168
 169 int fopen_mode_to_flags(const char *mode);