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_MODE_0444                  = 1 << 11,
  30         WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL = 1 << 12,
  31
  32         /* And before you wonder, why write_string_file_atomic_label_ts() is a separate function instead of just one
  33            more flag here: it's about linking: we don't want to pull -lselinux into all users of write_string_file()
  34            and friends. */
  35
  36 } WriteStringFileFlags;
  37
  38 typedef enum {
  39         READ_FULL_FILE_SECURE              = 1 << 0, /* erase any buffers we employ internally, after use */
  40         READ_FULL_FILE_UNBASE64            = 1 << 1, /* base64 decode what we read */
  41         READ_FULL_FILE_UNHEX               = 1 << 2, /* hex decode what we read */
  42         READ_FULL_FILE_WARN_WORLD_READABLE = 1 << 3, /* if regular file, log at LOG_WARNING level if access mode above 0700 */
  43         READ_FULL_FILE_CONNECT_SOCKET      = 1 << 4, /* if socket inode, connect to it and read off it */
  44         READ_FULL_FILE_FAIL_WHEN_LARGER    = 1 << 5, /* fail loading if file is larger than specified size */
  45 } ReadFullFileFlags;
  46
  47 int fdopen_unlocked(int fd, const char *options, FILE **ret);
  48 int take_fdopen_unlocked(int *fd, const char *options, FILE **ret);
  49 FILE* take_fdopen(int *fd, const char *options);
  50 DIR* take_fdopendir(int *dfd);
  51 FILE* open_memstream_unlocked(char **ptr, size_t *sizeloc);
  52 FILE* fmemopen_unlocked(void *buf, size_t size, const char *mode);
  53
  54 int write_string_stream_ts(FILE *f, const char *line, WriteStringFileFlags flags, const struct timespec *ts);
  55 static inline int write_string_stream(FILE *f, const char *line, WriteStringFileFlags flags) {
  56         return write_string_stream_ts(f, line, flags, NULL);
  57 }
  58 int write_string_file_ts_at(int dir_fd, const char *fn, const char *line, WriteStringFileFlags flags, const struct timespec *ts);
  59 static inline int write_string_file_ts(const char *fn, const char *line, WriteStringFileFlags flags, const struct timespec *ts) {
  60         return write_string_file_ts_at(AT_FDCWD, fn, line, flags, ts);
  61 }
  62 static inline int write_string_file_at(int dir_fd, const char *fn, const char *line, WriteStringFileFlags flags) {
  63         return write_string_file_ts_at(dir_fd, fn, line, flags, NULL);
  64 }
  65 static inline int write_string_file(const char *fn, const char *line, WriteStringFileFlags flags) {
  66         return write_string_file_ts(fn, line, flags, NULL);
  67 }
  68
  69 int write_string_filef(const char *fn, WriteStringFileFlags flags, const char *format, ...) _printf_(3, 4);
  70
  71 int read_one_line_file_at(int dir_fd, const char *filename, char **ret);
  72 static inline int read_one_line_file(const char *filename, char **ret) {
  73         return read_one_line_file_at(AT_FDCWD, filename, ret);
  74 }
  75 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);
  76 static inline int read_full_file_at(int dir_fd, const char *filename, char **ret_contents, size_t *ret_size) {
  77         return read_full_file_full(dir_fd, filename, UINT64_MAX, SIZE_MAX, 0, NULL, ret_contents, ret_size);
  78 }
  79 static inline int read_full_file(const char *filename, char **ret_contents, size_t *ret_size) {
  80         return read_full_file_full(AT_FDCWD, filename, UINT64_MAX, SIZE_MAX, 0, NULL, ret_contents, ret_size);
  81 }
  82
  83 int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size);
  84 int read_virtual_file_at(int dir_fd, const char *filename, size_t max_size, char **ret_contents, size_t *ret_size);
  85 static inline int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
  86         return read_virtual_file_at(AT_FDCWD, filename, max_size, ret_contents, ret_size);
  87 }
  88 static inline int read_full_virtual_file(const char *filename, char **ret_contents, size_t *ret_size) {
  89         return read_virtual_file(filename, SIZE_MAX, ret_contents, ret_size);
  90 }
  91
  92 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);
  93 static inline int read_full_stream(FILE *f, char **ret_contents, size_t *ret_size) {
  94         return read_full_stream_full(f, NULL, UINT64_MAX, SIZE_MAX, 0, ret_contents, ret_size);
  95 }
  96
  97 int verify_file_at(int dir_fd, const char *fn, const char *blob, bool accept_extra_nl);
  98 static inline int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
  99         return verify_file_at(AT_FDCWD, fn, blob, accept_extra_nl);
 100 }
 101
 102 int executable_is_script(const char *path, char **interpreter);
 103
 104 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field);
 105
 106 DIR *xopendirat(int dirfd, const char *name, int flags);
 107
 108 typedef enum XfopenFlags {
 109         XFOPEN_UNLOCKED = 1 << 0, /* call __fsetlocking(FSETLOCKING_BYCALLER) after opened */
 110         XFOPEN_SOCKET   = 1 << 1, /* also try to open unix socket */
 111 } XfopenFlags;
 112
 113 int xfopenat_full(
 114                 int dir_fd,
 115                 const char *path,
 116                 const char *mode,
 117                 int open_flags,
 118                 XfopenFlags flags,
 119                 const char *bind_name,
 120                 FILE **ret);
 121 static inline int xfopenat(int dir_fd, const char *path, const char *mode, int open_flags, FILE **ret) {
 122         return xfopenat_full(dir_fd, path, mode, open_flags, 0, NULL, ret);
 123 }
 124 static inline int fopen_unlocked_at(int dir_fd, const char *path, const char *mode, int open_flags, FILE **ret) {
 125         return xfopenat_full(dir_fd, path, mode, open_flags, XFOPEN_UNLOCKED, NULL, ret);
 126 }
 127 static inline int fopen_unlocked(const char *path, const char *mode, FILE **ret) {
 128         return fopen_unlocked_at(AT_FDCWD, path, mode, 0, ret);
 129 }
 130
 131 int fdopen_independent(int fd, const char *mode, FILE **ret);
 132
 133 int search_and_open(const char *path, int mode, const char *root, char **search, int *ret_fd, char **ret_path);
 134 static inline int search_and_access(const char *path, int mode, const char *root, char**search, char **ret_path) {
 135         return search_and_open(path, mode, root, search, NULL, ret_path);
 136 }
 137 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **ret_file, char **ret_path);
 138 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **ret_file, char **ret_path);
 139
 140 int fflush_and_check(FILE *f);
 141 int fflush_sync_and_check(FILE *f);
 142
 143 int write_timestamp_file_atomic(const char *fn, usec_t n);
 144 int read_timestamp_file(const char *fn, usec_t *ret);
 145
 146 int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space);
 147
 148 typedef enum ReadLineFlags {
 149         READ_LINE_ONLY_NUL  = 1 << 0,
 150         READ_LINE_IS_A_TTY  = 1 << 1,
 151         READ_LINE_NOT_A_TTY = 1 << 2,
 152 } ReadLineFlags;
 153
 154 int read_line_full(FILE *f, size_t limit, ReadLineFlags flags, char **ret);
 155
 156 static inline bool file_offset_beyond_memory_size(off_t x) {
 157         if (x < 0) /* off_t is signed, filter that out */
 158                 return false;
 159         return (uint64_t) x > (uint64_t) SIZE_MAX;
 160 }
 161
 162 static inline int read_line(FILE *f, size_t limit, char **ret) {
 163         return read_line_full(f, limit, 0, ret);
 164 }
 165
 166 static inline int read_nul_string(FILE *f, size_t limit, char **ret) {
 167         return read_line_full(f, limit, READ_LINE_ONLY_NUL, ret);
 168 }
 169
 170 int read_stripped_line(FILE *f, size_t limit, char **ret);
 171
 172 int safe_fgetc(FILE *f, char *ret);
 173
 174 int warn_file_is_world_accessible(const char *filename, struct stat *st, const char *unit, unsigned line);
 175
 176 int fopen_mode_to_flags(const char *mode);