lib/clean-temp.h

   1 /* Temporary directories and temporary files with automatic cleanup.
   2    Copyright (C) 2006, 2011-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2006.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _CLEAN_TEMP_H
  19 #define _CLEAN_TEMP_H
  20
  21 /* This file uses _GL_ATTRIBUTE_DEALLOC.  */
  22 #if !_GL_CONFIG_H_INCLUDED
  23  #error "Please include config.h first."
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <sys/types.h>
  28
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33
  34 /* Temporary directories and temporary files should be automatically removed
  35    when the program exits either normally or through a fatal signal.  We can't
  36    rely on the "unlink before close" idiom, because it works only on Unix and
  37    also - if no signal blocking is used - leaves a time window where a fatal
  38    signal would not clean up the temporary file.
  39
  40    Also, open file descriptors need to be closed before the temporary files
  41    and the temporary directories can be removed, because only on Unix
  42    (excluding Cygwin) can one remove directories containing open files.
  43
  44    There are two modules:
  45      - 'clean-temp' provides support for temporary directories and temporary
  46        files inside these temporary directories,
  47      - 'clean-temp-simple' provides support for temporary files without
  48        temporary directories.
  49    The temporary directories and files are automatically cleaned up (at the
  50    latest) when the program exits or dies from a fatal signal such as SIGINT,
  51    SIGTERM, SIGHUP, but not if it dies from a fatal signal such as SIGQUIT,
  52    SIGKILL, or SIGABRT, SIGSEGV, SIGBUS, SIGILL, SIGFPE.
  53
  54    For the cleanup in the normal case, programs that use this module need to
  55    call 'cleanup_temp_dir' for each successful return of 'create_temp_dir'.
  56    The cleanup in the case of a fatal signal such as SIGINT, SIGTERM, SIGHUP,
  57    is done entirely automatically by the functions of this module.
  58
  59    Limitations: Files or directories can still be left over if
  60      - the program is dies from a fatal signal such as SIGQUIT, SIGKILL, or
  61        SIGABRT, SIGSEGV, SIGBUS, SIGILL, SIGFPE, or
  62      - in a multithreaded program, the fatal signal handler is already running
  63        while another thread of the program creates a new temporary directory
  64        or temporary file, or
  65      - on native Windows, some temporary files are used by a subprocess while
  66        the fatal signal interrupts the program.
  67  */
  68
  69
  70 /* ============= Temporary files without temporary directories ============= */
  71
  72 #include "clean-temp-simple.h"
  73
  74 /* ========= Temporary directories and temporary files inside them ========= */
  75
  76 struct temp_dir
  77 {
  78   /* The absolute pathname of the directory.  */
  79   const char * const dir_name;
  80   /* Whether errors during explicit cleanup are reported to standard error.  */
  81   bool cleanup_verbose;
  82   /* More fields are present here, but not public.  */
  83 };
  84
  85 /* Remove all registered files and subdirectories inside DIR and DIR itself.
  86    DIR cannot be used any more after this call.
  87    Return 0 upon success, or -1 if there was some problem.  */
  88 extern int cleanup_temp_dir (struct temp_dir *dir);
  89
  90 /* Create a temporary directory.
  91    PREFIX is used as a prefix for the name of the temporary directory. It
  92    should be short and still give an indication about the program.
  93    PARENTDIR can be used to specify the parent directory; if NULL, a default
  94    parent directory is used (either $TMPDIR or /tmp or similar).
  95    CLEANUP_VERBOSE determines whether errors during explicit cleanup are
  96    reported to standard error.
  97    Return a fresh 'struct temp_dir' on success.  Upon error, an error message
  98    is shown and NULL is returned.  */
  99 extern struct temp_dir * create_temp_dir (const char *prefix,
 100                                           const char *parentdir,
 101                                           bool cleanup_verbose)
 102   _GL_ATTRIBUTE_DEALLOC (cleanup_temp_dir, 1);
 103
 104 /* Register the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
 105    needs to be removed before DIR can be removed.
 106    Should be called before the file ABSOLUTE_FILE_NAME is created.  */
 107 extern void register_temp_file (struct temp_dir *dir,
 108                                 const char *absolute_file_name);
 109
 110 /* Unregister the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
 111    needs to be removed before DIR can be removed.
 112    Should be called when the file ABSOLUTE_FILE_NAME could not be created.  */
 113 extern void unregister_temp_file (struct temp_dir *dir,
 114                                   const char *absolute_file_name);
 115
 116 /* Register the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
 117    that needs to be removed before DIR can be removed.
 118    Should be called before the subdirectory ABSOLUTE_DIR_NAME is created.  */
 119 extern void register_temp_subdir (struct temp_dir *dir,
 120                                   const char *absolute_dir_name);
 121
 122 /* Unregister the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
 123    that needs to be removed before DIR can be removed.
 124    Should be called when the subdirectory ABSOLUTE_DIR_NAME could not be
 125    created.  */
 126 extern void unregister_temp_subdir (struct temp_dir *dir,
 127                                     const char *absolute_dir_name);
 128
 129 /* Remove the given ABSOLUTE_FILE_NAME and unregister it.
 130    Return 0 upon success, or -1 if there was some problem.  */
 131 extern int cleanup_temp_file (struct temp_dir *dir,
 132                               const char *absolute_file_name);
 133
 134 /* Remove the given ABSOLUTE_DIR_NAME and unregister it.
 135    Return 0 upon success, or -1 if there was some problem.  */
 136 extern int cleanup_temp_subdir (struct temp_dir *dir,
 137                                 const char *absolute_dir_name);
 138
 139 /* Remove all registered files and subdirectories inside DIR.
 140    Return 0 upon success, or -1 if there was some problem.  */
 141 extern int cleanup_temp_dir_contents (struct temp_dir *dir);
 142
 143 /* ================== Opening and closing temporary files ================== */
 144
 145 /* Open a temporary file in a temporary directory.
 146    FILE_NAME must already have been passed to register_temp_file.
 147    Registers the resulting file descriptor to be closed.
 148    DELETE_ON_CLOSE indicates whether the file can be deleted when the resulting
 149    file descriptor or stream is closed.  */
 150 extern int open_temp (const char *file_name, int flags, mode_t mode,
 151                       bool delete_on_close);
 152 extern FILE * fopen_temp (const char *file_name, const char *mode,
 153                           bool delete_on_close);
 154
 155 /* Open a temporary file, generating its name based on FILE_NAME_TMPL.
 156    FILE_NAME_TMPL must match the rules for mk[s]temp (i.e. end in "XXXXXX",
 157    possibly with a suffix).  The name constructed does not exist at the time
 158    of the call.  FILE_NAME_TMPL is overwritten with the result.
 159    A safe choice for MODE is S_IRUSR | S_IWUSR, a.k.a. 0600.
 160    Registers the file for deletion.
 161    Opens the file, with the given FLAGS and mode MODE.
 162    Registers the resulting file descriptor to be closed.  */
 163 extern int gen_register_open_temp (char *file_name_tmpl, int suffixlen,
 164                                    int flags, mode_t mode);
 165
 166 /* Close a temporary file.
 167    FD must have been returned by open_temp or gen_register_open_temp.
 168    Unregisters the previously registered file descriptor.  */
 169 extern int close_temp (int fd);
 170
 171 /* Close a temporary file.
 172    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 173    returned by open_temp or gen_register_open_temp.
 174    Unregisters the previously registered file descriptor.  */
 175 extern int fclose_temp (FILE *fp);
 176
 177 /* Like fwriteerror.
 178    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 179    returned by open_temp or gen_register_open_temp.
 180    Unregisters the previously registered file descriptor.  */
 181 extern int fwriteerror_temp (FILE *fp);
 182
 183 /* Like close_stream.
 184    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 185    returned by open_temp or gen_register_open_temp.
 186    Unregisters the previously registered file descriptor.  */
 187 extern int close_stream_temp (FILE *fp);
 188
 189
 190 #ifdef __cplusplus
 191 }
 192 #endif
 193
 194 #endif /* _CLEAN_TEMP_H */