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1 : : /* glib-unix.h - Unix specific integration
2 : : * Copyright (C) 2011 Red Hat, Inc.
3 : : * Copyright 2023 Collabora Ltd.
4 : : *
5 : : * SPDX-License-Identifier: LGPL-2.1-or-later
6 : : *
7 : : * This library is free software; you can redistribute it and/or
8 : : * modify it under the terms of the GNU Lesser General Public
9 : : * License as published by the Free Software Foundation; either
10 : : * version 2.1 of the License, or (at your option) any later version.
11 : : *
12 : : * This library is distributed in the hope that it will be useful,
13 : : * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 : : * Lesser General Public License for more details.
16 : : *
17 : : * You should have received a copy of the GNU Lesser General Public License
18 : : * along with this library; if not, see <http://www.gnu.org/licenses/>.
19 : : */
20 : :
21 : : #ifndef __G_UNIX_H__
22 : : #define __G_UNIX_H__
23 : :
24 : : /* We need to include the UNIX headers needed to use the APIs below,
25 : : * but we also take this opportunity to include a wide selection of
26 : : * other UNIX headers. If one of the headers below is broken on some
27 : : * system, work around it here (or better, fix the system or tell
28 : : * people to use a better one).
29 : : */
30 : : #include <unistd.h>
31 : : #include <errno.h>
32 : : #include <sys/wait.h>
33 : : #include <stdlib.h>
34 : : #include <fcntl.h>
35 : :
36 : : #include <glib.h>
37 : : #include <glib/gstdio.h>
38 : :
39 : : #ifndef G_OS_UNIX
40 : : #error "This header may only be used on UNIX"
41 : : #endif
42 : :
43 : : G_BEGIN_DECLS
44 : :
45 : : /**
46 : : * G_UNIX_ERROR:
47 : : *
48 : : * Error domain for API in the g_unix_ namespace. Note that there is no
49 : : * exported enumeration mapping %errno. Instead, all functions ensure that
50 : : * %errno is relevant. The code for all %G_UNIX_ERROR is always 0, and the
51 : : * error message is always generated via g_strerror().
52 : : *
53 : : * It is expected that most code will not look at %errno from these APIs.
54 : : * Important cases where one would want to differentiate between errors are
55 : : * already covered by existing cross-platform GLib API, such as e.g. #GFile
56 : : * wrapping `ENOENT`. However, it is provided for completeness, at least.
57 : : */
58 : : #define G_UNIX_ERROR (g_unix_error_quark())
59 : :
60 : : GLIB_AVAILABLE_IN_2_30
61 : : GQuark g_unix_error_quark (void);
62 : :
63 : : GLIB_AVAILABLE_IN_2_30
64 : : gboolean g_unix_open_pipe (gint *fds,
65 : : gint flags,
66 : : GError **error);
67 : :
68 : : GLIB_AVAILABLE_IN_2_30
69 : : gboolean g_unix_set_fd_nonblocking (gint fd,
70 : : gboolean nonblock,
71 : : GError **error);
72 : :
73 : : GLIB_AVAILABLE_IN_2_30
74 : : GSource *g_unix_signal_source_new (gint signum);
75 : :
76 : : GLIB_AVAILABLE_IN_2_30
77 : : guint g_unix_signal_add_full (gint priority,
78 : : gint signum,
79 : : GSourceFunc handler,
80 : : gpointer user_data,
81 : : GDestroyNotify notify);
82 : :
83 : : GLIB_AVAILABLE_IN_2_30
84 : : guint g_unix_signal_add (gint signum,
85 : : GSourceFunc handler,
86 : : gpointer user_data);
87 : :
88 : : /**
89 : : * GUnixFDSourceFunc:
90 : : * @fd: the fd that triggered the event
91 : : * @condition: the IO conditions reported on @fd
92 : : * @user_data: user data passed to g_unix_fd_add()
93 : : *
94 : : * The type of functions to be called when a UNIX fd watch source
95 : : * triggers.
96 : : *
97 : : * Returns: %FALSE if the source should be removed
98 : : **/
99 : : typedef gboolean (*GUnixFDSourceFunc) (gint fd,
100 : : GIOCondition condition,
101 : : gpointer user_data);
102 : :
103 : : GLIB_AVAILABLE_IN_2_36
104 : : GSource *g_unix_fd_source_new (gint fd,
105 : : GIOCondition condition);
106 : :
107 : : GLIB_AVAILABLE_IN_2_36
108 : : guint g_unix_fd_add_full (gint priority,
109 : : gint fd,
110 : : GIOCondition condition,
111 : : GUnixFDSourceFunc function,
112 : : gpointer user_data,
113 : : GDestroyNotify notify);
114 : :
115 : : GLIB_AVAILABLE_IN_2_36
116 : : guint g_unix_fd_add (gint fd,
117 : : GIOCondition condition,
118 : : GUnixFDSourceFunc function,
119 : : gpointer user_data);
120 : :
121 : : GLIB_AVAILABLE_IN_2_64
122 : : struct passwd *g_unix_get_passwd_entry (const gchar *user_name,
123 : : GError **error);
124 : :
125 : : /**
126 : : * GUnixPipe:
127 : : * @fds: A pair of file descriptors, each negative if closed or not yet opened.
128 : : * The file descriptor with index %G_UNIX_PIPE_END_READ is readable.
129 : : * The file descriptor with index %G_UNIX_PIPE_END_WRITE is writable.
130 : : *
131 : : * A Unix pipe. The advantage of this type over `int[2]` is that it can
132 : : * be closed automatically when it goes out of scope, using `g_auto(GUnixPipe)`,
133 : : * on compilers that support that feature.
134 : : *
135 : : * Since: 2.80
136 : : */
137 : : GLIB_AVAILABLE_TYPE_IN_2_80
138 : : typedef struct {
139 : : int fds[2];
140 : : } GUnixPipe;
141 : :
142 : : /**
143 : : * GUnixPipeEnd:
144 : : * @G_UNIX_PIPE_END_READ: The readable file descriptor 0
145 : : * @G_UNIX_PIPE_END_WRITE: The writable file descriptor 1
146 : : *
147 : : * Mnemonic constants for the ends of a Unix pipe.
148 : : *
149 : : * Since: 2.80
150 : : */
151 : : GLIB_AVAILABLE_TYPE_IN_2_80
152 : : typedef enum
153 : : {
154 : : G_UNIX_PIPE_END_READ = 0,
155 : : G_UNIX_PIPE_END_WRITE = 1
156 : : } GUnixPipeEnd;
157 : :
158 : : /**
159 : : * G_UNIX_PIPE_INIT:
160 : : *
161 : : * Initializer for a #GUnixPipe that has not yet been opened.
162 : : * Both of its file descriptors are initialized to `-1` (invalid),
163 : : * the same as if they had been closed.
164 : : *
165 : : * Since: 2.80
166 : : */
167 : : #define G_UNIX_PIPE_INIT { { -1, -1 } } GLIB_AVAILABLE_MACRO_IN_2_80
168 : :
169 : : /* Suppress "Not available before" warnings when declaring the
170 : : * implementations */
171 : : G_GNUC_BEGIN_IGNORE_DEPRECATIONS
172 : :
173 : : /**
174 : : * g_unix_pipe_open:
175 : : * @self: A pair of file descriptors
176 : : * @flags: Flags to pass to g_unix_open_pipe(), typically `O_CLOEXEC`
177 : : * @error: Used to report an error on failure
178 : : *
179 : : * Open a pipe. This is the same as g_unix_open_pipe(), but uses the
180 : : * #GUnixPipe data structure.
181 : : *
182 : : * Returns: %TRUE on success
183 : : *
184 : : * Since: 2.80
185 : : */
186 : : GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
187 : : static inline gboolean
188 : 2152 : g_unix_pipe_open (GUnixPipe *self,
189 : : int flags,
190 : : GError **error)
191 : : {
192 : 2152 : return g_unix_open_pipe (self->fds, flags, error);
193 : : }
194 : :
195 : : /**
196 : : * g_unix_pipe_get:
197 : : * @self: A pair of file descriptors
198 : : * @end: One of the ends of the pipe
199 : : *
200 : : * Return one of the ends of the pipe. It remains owned by @self.
201 : : *
202 : : * This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
203 : : * [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
204 : : * signal handler or a #GSpawnChildSetupFunc.
205 : : *
206 : : * This function preserves the value of `errno`.
207 : : *
208 : : * Returns: a non-negative file descriptor owned by @self, which must not
209 : : * be closed by the caller, or a negative number if the corresponding
210 : : * end of the pipe was already closed or stolen
211 : : *
212 : : * Since: 2.80
213 : : */
214 : : GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
215 : : static inline int
216 : 4183 : g_unix_pipe_get (GUnixPipe *self,
217 : : GUnixPipeEnd end)
218 : : {
219 : 4183 : return self->fds[end];
220 : : }
221 : :
222 : : /**
223 : : * g_unix_pipe_steal:
224 : : * @self: A pair of file descriptors
225 : : * @end: One of the ends of the pipe
226 : : *
227 : : * Return one of the ends of the pipe. It becomes owned by the caller,
228 : : * and the file descriptor in the data structure is set to `-1`,
229 : : * similar to g_steal_fd().
230 : : *
231 : : * This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
232 : : * [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
233 : : * signal handler or a #GSpawnChildSetupFunc.
234 : : *
235 : : * This function preserves the value of `errno`.
236 : : *
237 : : * Returns: a non-negative file descriptor, which becomes owned by the
238 : : * caller and must be closed by the caller if required, or a negative
239 : : * number if the corresponding end of the pipe was already closed or stolen
240 : : *
241 : : * Since: 2.80
242 : : */
243 : : GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
244 : : static inline int
245 : 1134 : g_unix_pipe_steal (GUnixPipe *self,
246 : : GUnixPipeEnd end)
247 : : {
248 : 1134 : return g_steal_fd (&self->fds[end]);
249 : : }
250 : :
251 : : /**
252 : : * g_unix_pipe_close:
253 : : * @self: A pair of file descriptors
254 : : * @end: One of the ends of the pipe
255 : : * @error: Optionally used to report an error on failure
256 : : *
257 : : * Close one of the ends of the pipe and set the relevant member of @fds
258 : : * to `-1` before returning, equivalent to g_clear_fd().
259 : : *
260 : : * Like g_close(), if closing the file descriptor fails, the error is
261 : : * stored in both %errno and @error. If this function succeeds,
262 : : * %errno is undefined.
263 : : *
264 : : * This function is async-signal safe if @error is %NULL and the relevant
265 : : * member of @fds is either negative or a valid open file descriptor.
266 : : * This makes it safe to call from a signal handler or a #GSpawnChildSetupFunc
267 : : * under those conditions.
268 : : * See [`signal(7)`](man:signal(7)) and
269 : : * [`signal-safety(7)`](man:signal-safety(7)) for more details.
270 : : *
271 : : * To close both file descriptors and ignore any errors, use
272 : : * g_unix_pipe_clear() instead.
273 : : *
274 : : * Returns: %TRUE on success
275 : : *
276 : : * Since: 2.80
277 : : */
278 : : GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
279 : : static inline gboolean
280 : 8306 : g_unix_pipe_close (GUnixPipe *self,
281 : : GUnixPipeEnd end,
282 : : GError **error)
283 : : {
284 : 8306 : return g_clear_fd (&self->fds[end], error);
285 : : }
286 : :
287 : : /**
288 : : * g_unix_pipe_clear:
289 : : * @self: a #GUnixPipe
290 : : *
291 : : * Close both ends of the pipe, unless they have already been closed or
292 : : * stolen. Any errors are ignored: use g_unix_pipe_close() or g_clear_fd()
293 : : * if error-handling is required.
294 : : *
295 : : * This function is async-signal safe if @error is %NULL and each member
296 : : * of @fds are either negative or a valid open file descriptor.
297 : : * As a result, it is safe to call this function or use `g_auto(GUnixPipe)`
298 : : * (on compilers that support it) in a signal handler or a
299 : : * #GSpawnChildSetupFunc, as long as those conditions are ensured to be true.
300 : : * See [`signal(7)`](man:signal(7)) and
301 : : * [`signal-safety(7)`](man:signal-safety(7)) for more details.
302 : : *
303 : : * This function preserves the value of `errno`.
304 : : *
305 : : * Since: 2.80
306 : : */
307 : : GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
308 : : static inline void
309 : 55 : g_unix_pipe_clear (GUnixPipe *self)
310 : : {
311 : : /* Don't overwrite thread-local errno if closing the fd fails */
312 : 55 : int errsv = errno;
313 : :
314 : 55 : if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_READ, NULL))
315 : : {
316 : : /* ignore */
317 : : }
318 : :
319 : 55 : if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_WRITE, NULL))
320 : : {
321 : : /* ignore */
322 : : }
323 : :
324 : 55 : errno = errsv;
325 : 55 : }
326 : :
327 : 4 : G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC (GUnixPipe, g_unix_pipe_clear)
328 : :
329 : : GLIB_AVAILABLE_IN_2_80
330 : : int g_closefrom (int lowfd);
331 : :
332 : : GLIB_AVAILABLE_IN_2_80
333 : : int g_fdwalk_set_cloexec (int lowfd);
334 : :
335 : : G_GNUC_END_IGNORE_DEPRECATIONS
336 : :
337 : : G_END_DECLS
338 : :
339 : : #endif /* __G_UNIX_H__ */
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