2 * State diagram and cleanup
3 * -------------------------
5 * If the program exits while a temporary file is active, we want to
6 * make sure that we remove it. This is done by remembering the active
7 * temporary files in a linked list, `tempfile_list`. An `atexit(3)`
8 * handler and a signal handler are registered, to clean up any active
11 * Because the signal handler can run at any time, `tempfile_list` and
12 * the `tempfile` objects that comprise it must be kept in
13 * self-consistent states at all times.
15 * The possible states of a `tempfile` object are as follows:
17 * - Inactive/unallocated. The only way to get a tempfile is via a creation
18 * function like create_tempfile(). Once allocated, the tempfile is on the
19 * global tempfile_list and considered active.
21 * - Active, file open (after `create_tempfile()` or
22 * `reopen_tempfile()`). In this state:
24 * - the temporary file exists
25 * - `filename` holds the filename of the temporary file
26 * - `fd` holds a file descriptor open for writing to it
27 * - `fp` holds a pointer to an open `FILE` object if and only if
28 * `fdopen_tempfile()` has been called on the object
29 * - `owner` holds the PID of the process that created the file
31 * - Active, file closed (after `close_tempfile_gently()`). Same
32 * as the previous state, except that the temporary file is closed,
33 * `fd` is -1, and `fp` is `NULL`.
35 * - Inactive (after `delete_tempfile()`, `rename_tempfile()`, or a
36 * failed attempt to create a temporary file). The struct is removed from
37 * the global tempfile_list and deallocated.
39 * A temporary file is owned by the process that created it. The
40 * `tempfile` has an `owner` field that records the owner's PID. This
41 * field is used to prevent a forked process from deleting a temporary
42 * file created by its parent.
50 static VOLATILE_LIST_HEAD(tempfile_list
);
52 static void remove_template_directory(struct tempfile
*tempfile
,
53 int in_signal_handler
)
55 if (tempfile
->directory
) {
56 if (in_signal_handler
)
57 rmdir(tempfile
->directory
);
59 rmdir_or_warn(tempfile
->directory
);
63 static void remove_tempfiles(int in_signal_handler
)
66 volatile struct volatile_list_head
*pos
;
68 list_for_each(pos
, &tempfile_list
) {
69 struct tempfile
*p
= list_entry(pos
, struct tempfile
, list
);
71 if (!is_tempfile_active(p
) || p
->owner
!= me
)
77 if (in_signal_handler
)
78 unlink(p
->filename
.buf
);
80 unlink_or_warn(p
->filename
.buf
);
81 remove_template_directory(p
, in_signal_handler
);
85 static void remove_tempfiles_on_exit(void)
90 static void remove_tempfiles_on_signal(int signo
)
97 static struct tempfile
*new_tempfile(void)
99 struct tempfile
*tempfile
= xmalloc(sizeof(*tempfile
));
103 INIT_LIST_HEAD(&tempfile
->list
);
104 strbuf_init(&tempfile
->filename
, 0);
105 tempfile
->directory
= NULL
;
109 static void activate_tempfile(struct tempfile
*tempfile
)
111 static int initialized
;
114 sigchain_push_common(remove_tempfiles_on_signal
);
115 atexit(remove_tempfiles_on_exit
);
119 volatile_list_add(&tempfile
->list
, &tempfile_list
);
120 tempfile
->owner
= getpid();
123 static void deactivate_tempfile(struct tempfile
*tempfile
)
125 volatile_list_del(&tempfile
->list
);
126 strbuf_release(&tempfile
->filename
);
127 free(tempfile
->directory
);
131 /* Make sure errno contains a meaningful value on error */
132 struct tempfile
*create_tempfile_mode(const char *path
, int mode
)
134 struct tempfile
*tempfile
= new_tempfile();
136 strbuf_add_absolute_path(&tempfile
->filename
, path
);
137 tempfile
->fd
= open(tempfile
->filename
.buf
,
138 O_RDWR
| O_CREAT
| O_EXCL
| O_CLOEXEC
, mode
);
139 if (O_CLOEXEC
&& tempfile
->fd
< 0 && errno
== EINVAL
)
140 /* Try again w/o O_CLOEXEC: the kernel might not support it */
141 tempfile
->fd
= open(tempfile
->filename
.buf
,
142 O_RDWR
| O_CREAT
| O_EXCL
, mode
);
143 if (tempfile
->fd
< 0) {
144 deactivate_tempfile(tempfile
);
147 activate_tempfile(tempfile
);
148 if (adjust_shared_perm(tempfile
->filename
.buf
)) {
149 int save_errno
= errno
;
150 error("cannot fix permission bits on %s", tempfile
->filename
.buf
);
151 delete_tempfile(&tempfile
);
159 struct tempfile
*register_tempfile(const char *path
)
161 struct tempfile
*tempfile
= new_tempfile();
162 strbuf_add_absolute_path(&tempfile
->filename
, path
);
163 activate_tempfile(tempfile
);
167 struct tempfile
*mks_tempfile_sm(const char *filename_template
, int suffixlen
, int mode
)
169 struct tempfile
*tempfile
= new_tempfile();
171 strbuf_add_absolute_path(&tempfile
->filename
, filename_template
);
172 tempfile
->fd
= git_mkstemps_mode(tempfile
->filename
.buf
, suffixlen
, mode
);
173 if (tempfile
->fd
< 0) {
174 deactivate_tempfile(tempfile
);
177 activate_tempfile(tempfile
);
181 struct tempfile
*mks_tempfile_tsm(const char *filename_template
, int suffixlen
, int mode
)
183 struct tempfile
*tempfile
= new_tempfile();
186 tmpdir
= getenv("TMPDIR");
190 strbuf_addf(&tempfile
->filename
, "%s/%s", tmpdir
, filename_template
);
191 tempfile
->fd
= git_mkstemps_mode(tempfile
->filename
.buf
, suffixlen
, mode
);
192 if (tempfile
->fd
< 0) {
193 deactivate_tempfile(tempfile
);
196 activate_tempfile(tempfile
);
200 struct tempfile
*mks_tempfile_dt(const char *directory_template
,
201 const char *filename
)
203 struct tempfile
*tempfile
;
205 struct strbuf sb
= STRBUF_INIT
;
209 if (!ends_with(directory_template
, "XXXXXX")) {
214 tmpdir
= getenv("TMPDIR");
218 strbuf_addf(&sb
, "%s/%s", tmpdir
, directory_template
);
219 directorylen
= sb
.len
;
220 if (!mkdtemp(sb
.buf
)) {
221 int orig_errno
= errno
;
227 strbuf_addf(&sb
, "/%s", filename
);
228 fd
= open(sb
.buf
, O_CREAT
| O_EXCL
| O_RDWR
, 0600);
230 int orig_errno
= errno
;
231 strbuf_setlen(&sb
, directorylen
);
238 tempfile
= new_tempfile();
239 strbuf_swap(&tempfile
->filename
, &sb
);
240 tempfile
->directory
= xmemdupz(tempfile
->filename
.buf
, directorylen
);
242 activate_tempfile(tempfile
);
246 struct tempfile
*xmks_tempfile_m(const char *filename_template
, int mode
)
248 struct tempfile
*tempfile
;
249 struct strbuf full_template
= STRBUF_INIT
;
251 strbuf_add_absolute_path(&full_template
, filename_template
);
252 tempfile
= mks_tempfile_m(full_template
.buf
, mode
);
254 die_errno("Unable to create temporary file '%s'",
257 strbuf_release(&full_template
);
261 FILE *fdopen_tempfile(struct tempfile
*tempfile
, const char *mode
)
263 if (!is_tempfile_active(tempfile
))
264 BUG("fdopen_tempfile() called for inactive object");
266 BUG("fdopen_tempfile() called for open object");
268 tempfile
->fp
= fdopen(tempfile
->fd
, mode
);
272 const char *get_tempfile_path(struct tempfile
*tempfile
)
274 if (!is_tempfile_active(tempfile
))
275 BUG("get_tempfile_path() called for inactive object");
276 return tempfile
->filename
.buf
;
279 int get_tempfile_fd(struct tempfile
*tempfile
)
281 if (!is_tempfile_active(tempfile
))
282 BUG("get_tempfile_fd() called for inactive object");
286 FILE *get_tempfile_fp(struct tempfile
*tempfile
)
288 if (!is_tempfile_active(tempfile
))
289 BUG("get_tempfile_fp() called for inactive object");
293 int close_tempfile_gently(struct tempfile
*tempfile
)
299 if (!is_tempfile_active(tempfile
) || tempfile
->fd
< 0)
321 int reopen_tempfile(struct tempfile
*tempfile
)
323 if (!is_tempfile_active(tempfile
))
324 BUG("reopen_tempfile called for an inactive object");
325 if (0 <= tempfile
->fd
)
326 BUG("reopen_tempfile called for an open object");
327 tempfile
->fd
= open(tempfile
->filename
.buf
, O_WRONLY
|O_TRUNC
);
331 int rename_tempfile(struct tempfile
**tempfile_p
, const char *path
)
333 struct tempfile
*tempfile
= *tempfile_p
;
335 if (!is_tempfile_active(tempfile
))
336 BUG("rename_tempfile called for inactive object");
338 if (close_tempfile_gently(tempfile
)) {
339 delete_tempfile(tempfile_p
);
343 if (rename(tempfile
->filename
.buf
, path
)) {
344 int save_errno
= errno
;
345 delete_tempfile(tempfile_p
);
350 deactivate_tempfile(tempfile
);
355 void delete_tempfile(struct tempfile
**tempfile_p
)
357 struct tempfile
*tempfile
= *tempfile_p
;
359 if (!is_tempfile_active(tempfile
))
362 close_tempfile_gently(tempfile
);
363 unlink_or_warn(tempfile
->filename
.buf
);
364 remove_template_directory(tempfile
, 0);
365 deactivate_tempfile(tempfile
);