root/maint/gnulib/lib/clean-temp.h

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INCLUDED FROM

   1 /* Temporary directories and temporary files with automatic cleanup.
   2    Copyright (C) 2006, 2011-2021 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 #include <stdbool.h>
  22 #include <stdio.h>
  23 #include <sys/types.h>
  24 
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28 
  29 
  30 /* Temporary directories and temporary files should be automatically removed
  31    when the program exits either normally or through a fatal signal.  We can't
  32    rely on the "unlink before close" idiom, because it works only on Unix and
  33    also - if no signal blocking is used - leaves a time window where a fatal
  34    signal would not clean up the temporary file.
  35 
  36    Also, open file descriptors need to be closed before the temporary files
  37    and the temporary directories can be removed, because only on Unix
  38    (excluding Cygwin) can one remove directories containing open files.
  39 
  40    There are two modules:
  41      - 'clean-temp' provides support for temporary directories and temporary
  42        files inside these temporary directories,
  43      - 'clean-temp-simple' provides support for temporary files without
  44        temporary directories.
  45    The temporary directories and files are automatically cleaned up (at the
  46    latest) when the program exits or dies from a fatal signal such as SIGINT,
  47    SIGTERM, SIGHUP, but not if it dies from a fatal signal such as SIGQUIT,
  48    SIGKILL, or SIGABRT, SIGSEGV, SIGBUS, SIGILL, SIGFPE.
  49 
  50    For the cleanup in the normal case, programs that use this module need to
  51    call 'cleanup_temp_dir' for each successful return of 'create_temp_dir'.
  52    The cleanup in the case of a fatal signal such as SIGINT, SIGTERM, SIGHUP,
  53    is done entirely automatically by the functions of this module.
  54 
  55    Limitations: Files or directories can still be left over if
  56      - the program is dies from a fatal signal such as SIGQUIT, SIGKILL, or
  57        SIGABRT, SIGSEGV, SIGBUS, SIGILL, SIGFPE, or
  58      - in a multithreaded program, the fatal signal handler is already running
  59        while another thread of the program creates a new temporary directory
  60        or temporary file, or
  61      - on native Windows, some temporary files are used by a subprocess while
  62        the fatal signal interrupts the program.
  63  */
  64 
  65 
  66 /* ============= Temporary files without temporary directories ============= */
  67 
  68 #include "clean-temp-simple.h"
  69 
  70 /* ========= Temporary directories and temporary files inside them ========= */
  71 
  72 struct temp_dir
  73 {
  74   /* The absolute pathname of the directory.  */
  75   const char * const dir_name;
  76   /* Whether errors during explicit cleanup are reported to standard error.  */
  77   bool cleanup_verbose;
  78   /* More fields are present here, but not public.  */
  79 };
  80 
  81 /* Remove all registered files and subdirectories inside DIR and DIR itself.
  82    DIR cannot be used any more after this call.
  83    Return 0 upon success, or -1 if there was some problem.  */
  84 extern int cleanup_temp_dir (struct temp_dir *dir);
  85 
  86 /* Create a temporary directory.
  87    PREFIX is used as a prefix for the name of the temporary directory. It
  88    should be short and still give an indication about the program.
  89    PARENTDIR can be used to specify the parent directory; if NULL, a default
  90    parent directory is used (either $TMPDIR or /tmp or similar).
  91    CLEANUP_VERBOSE determines whether errors during explicit cleanup are
  92    reported to standard error.
  93    Return a fresh 'struct temp_dir' on success.  Upon error, an error message
  94    is shown and NULL is returned.  */
  95 extern struct temp_dir * create_temp_dir (const char *prefix,
  96                                           const char *parentdir,
  97                                           bool cleanup_verbose)
  98   _GL_ATTRIBUTE_DEALLOC (cleanup_temp_dir, 1);
  99 
 100 /* Register the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
 101    needs to be removed before DIR can be removed.
 102    Should be called before the file ABSOLUTE_FILE_NAME is created.  */
 103 extern void register_temp_file (struct temp_dir *dir,
 104                                 const char *absolute_file_name);
 105 
 106 /* Unregister the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
 107    needs to be removed before DIR can be removed.
 108    Should be called when the file ABSOLUTE_FILE_NAME could not be created.  */
 109 extern void unregister_temp_file (struct temp_dir *dir,
 110                                   const char *absolute_file_name);
 111 
 112 /* Register the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
 113    that needs to be removed before DIR can be removed.
 114    Should be called before the subdirectory ABSOLUTE_DIR_NAME is created.  */
 115 extern void register_temp_subdir (struct temp_dir *dir,
 116                                   const char *absolute_dir_name);
 117 
 118 /* Unregister the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
 119    that needs to be removed before DIR can be removed.
 120    Should be called when the subdirectory ABSOLUTE_DIR_NAME could not be
 121    created.  */
 122 extern void unregister_temp_subdir (struct temp_dir *dir,
 123                                     const char *absolute_dir_name);
 124 
 125 /* Remove the given ABSOLUTE_FILE_NAME and unregister it.
 126    Return 0 upon success, or -1 if there was some problem.  */
 127 extern int cleanup_temp_file (struct temp_dir *dir,
 128                               const char *absolute_file_name);
 129 
 130 /* Remove the given ABSOLUTE_DIR_NAME and unregister it.
 131    Return 0 upon success, or -1 if there was some problem.  */
 132 extern int cleanup_temp_subdir (struct temp_dir *dir,
 133                                 const char *absolute_dir_name);
 134 
 135 /* Remove all registered files and subdirectories inside DIR.
 136    Return 0 upon success, or -1 if there was some problem.  */
 137 extern int cleanup_temp_dir_contents (struct temp_dir *dir);
 138 
 139 /* ================== Opening and closing temporary files ================== */
 140 
 141 /* Open a temporary file in a temporary directory.
 142    FILE_NAME must already have been passed to register_temp_file.
 143    Registers the resulting file descriptor to be closed.
 144    DELETE_ON_CLOSE indicates whether the file can be deleted when the resulting
 145    file descriptor or stream is closed.  */
 146 extern int open_temp (const char *file_name, int flags, mode_t mode,
 147                       bool delete_on_close);
 148 extern FILE * fopen_temp (const char *file_name, const char *mode,
 149                           bool delete_on_close);
 150 
 151 /* Open a temporary file, generating its name based on FILE_NAME_TMPL.
 152    FILE_NAME_TMPL must match the rules for mk[s]temp (i.e. end in "XXXXXX",
 153    possibly with a suffix).  The name constructed does not exist at the time
 154    of the call.  FILE_NAME_TMPL is overwritten with the result.
 155    A safe choice for MODE is S_IRUSR | S_IWUSR, a.k.a. 0600.
 156    Registers the file for deletion.
 157    Opens the file, with the given FLAGS and mode MODE.
 158    Registers the resulting file descriptor to be closed.  */
 159 extern int gen_register_open_temp (char *file_name_tmpl, int suffixlen,
 160                                    int flags, mode_t mode);
 161 
 162 /* Close a temporary file.
 163    FD must have been returned by open_temp or gen_register_open_temp.
 164    Unregisters the previously registered file descriptor.  */
 165 extern int close_temp (int fd);
 166 
 167 /* Close a temporary file.
 168    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 169    returned by open_temp or gen_register_open_temp.
 170    Unregisters the previously registered file descriptor.  */
 171 extern int fclose_temp (FILE *fp);
 172 
 173 /* Like fwriteerror.
 174    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 175    returned by open_temp or gen_register_open_temp.
 176    Unregisters the previously registered file descriptor.  */
 177 extern int fwriteerror_temp (FILE *fp);
 178 
 179 /* Like close_stream.
 180    FP must have been returned by fopen_temp, or by fdopen on a file descriptor
 181    returned by open_temp or gen_register_open_temp.
 182    Unregisters the previously registered file descriptor.  */
 183 extern int close_stream_temp (FILE *fp);
 184 
 185 
 186 #ifdef __cplusplus
 187 }
 188 #endif
 189 
 190 #endif /* _CLEAN_TEMP_H */
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