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 /* Create a temporary directory.
82 PREFIX is used as a prefix for the name of the temporary directory. It
83 should be short and still give an indication about the program.
84 PARENTDIR can be used to specify the parent directory; if NULL, a default
85 parent directory is used (either $TMPDIR or /tmp or similar).
86 CLEANUP_VERBOSE determines whether errors during explicit cleanup are
87 reported to standard error.
88 Return a fresh 'struct temp_dir' on success. Upon error, an error message
89 is shown and NULL is returned. */
90 extern struct temp_dir * create_temp_dir (const char *prefix,
91 const char *parentdir,
92 bool cleanup_verbose);
93
94 /* Register the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
95 needs to be removed before DIR can be removed.
96 Should be called before the file ABSOLUTE_FILE_NAME is created. */
97 extern void register_temp_file (struct temp_dir *dir,
98 const char *absolute_file_name);
99
100 /* Unregister 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 when the file ABSOLUTE_FILE_NAME could not be created. */
103 extern void unregister_temp_file (struct temp_dir *dir,
104 const char *absolute_file_name);
105
106 /* Register the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
107 that needs to be removed before DIR can be removed.
108 Should be called before the subdirectory ABSOLUTE_DIR_NAME is created. */
109 extern void register_temp_subdir (struct temp_dir *dir,
110 const char *absolute_dir_name);
111
112 /* Unregister 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 when the subdirectory ABSOLUTE_DIR_NAME could not be
115 created. */
116 extern void unregister_temp_subdir (struct temp_dir *dir,
117 const char *absolute_dir_name);
118
119 /* Remove the given ABSOLUTE_FILE_NAME and unregister it.
120 Return 0 upon success, or -1 if there was some problem. */
121 extern int cleanup_temp_file (struct temp_dir *dir,
122 const char *absolute_file_name);
123
124 /* Remove the given ABSOLUTE_DIR_NAME and unregister it.
125 Return 0 upon success, or -1 if there was some problem. */
126 extern int cleanup_temp_subdir (struct temp_dir *dir,
127 const char *absolute_dir_name);
128
129 /* Remove all registered files and subdirectories inside DIR.
130 Return 0 upon success, or -1 if there was some problem. */
131 extern int cleanup_temp_dir_contents (struct temp_dir *dir);
132
133 /* Remove all registered files and subdirectories inside DIR and DIR itself.
134 DIR cannot be used any more after this call.
135 Return 0 upon success, or -1 if there was some problem. */
136 extern int cleanup_temp_dir (struct temp_dir *dir);
137
138 /* ================== Opening and closing temporary files ================== */
139
140 /* Open a temporary file in a temporary directory.
141 FILE_NAME must already have been passed to register_temp_file.
142 Registers the resulting file descriptor to be closed.
143 DELETE_ON_CLOSE indicates whether the file can be deleted when the resulting
144 file descriptor or stream is closed. */
145 extern int open_temp (const char *file_name, int flags, mode_t mode,
146 bool delete_on_close);
147 extern FILE * fopen_temp (const char *file_name, const char *mode,
148 bool delete_on_close);
149
150 /* Open a temporary file, generating its name based on FILE_NAME_TMPL.
151 FILE_NAME_TMPL must match the rules for mk[s]temp (i.e. end in "XXXXXX",
152 possibly with a suffix). The name constructed does not exist at the time
153 of the call. FILE_NAME_TMPL is overwritten with the result.
154 A safe choice for MODE is S_IRUSR | S_IWUSR, a.k.a. 0600.
155 Registers the file for deletion.
156 Opens the file, with the given FLAGS and mode MODE.
157 Registers the resulting file descriptor to be closed. */
158 extern int gen_register_open_temp (char *file_name_tmpl, int suffixlen,
159 int flags, mode_t mode);
160
161 /* Close a temporary file.
162 FD must have been returned by open_temp or gen_register_open_temp.
163 Unregisters the previously registered file descriptor. */
164 extern int close_temp (int fd);
165
166 /* Close a temporary file.
167 FP must have been returned by fopen_temp, or by fdopen on a file descriptor
168 returned by open_temp or gen_register_open_temp.
169 Unregisters the previously registered file descriptor. */
170 extern int fclose_temp (FILE *fp);
171
172 /* Like fwriteerror.
173 FP must have been returned by fopen_temp, or by fdopen on a file descriptor
174 returned by open_temp or gen_register_open_temp.
175 Unregisters the previously registered file descriptor. */
176 extern int fwriteerror_temp (FILE *fp);
177
178 /* Like close_stream.
179 FP must have been returned by fopen_temp, or by fdopen on a file descriptor
180 returned by open_temp or gen_register_open_temp.
181 Unregisters the previously registered file descriptor. */
182 extern int close_stream_temp (FILE *fp);
183
184
185 #ifdef __cplusplus
186 }
187 #endif
188
189 #endif /* _CLEAN_TEMP_H */