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1/* File descriptors.
2 Copyright (C) 1993-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#ifndef _HURD_FD_H
20
21#define _HURD_FD_H 1
22#include <features.h>
23
24#include <cthreads.h>
25
26#include <hurd/hurd_types.h>
27#include <hurd/port.h>
28#include <sys/socket.h>
29#include <sys/select.h>
30#include <fcntl.h>
31#include <bits/types/sigset_t.h>
32
33
34/* Structure representing a file descriptor. */
35
36struct hurd_fd
37 {
38 struct hurd_port port; /* io server port. */
39 int flags; /* fcntl flags; locked by port.lock. */
40
41 /* Normal port to the ctty. When `port' is our ctty, this is a port to
42 the same io object but which never returns EBACKGROUND; when not,
43 this is nil. */
44 struct hurd_port ctty;
45 };
46
47
48/* Current file descriptor table. */
49
50extern int _hurd_dtablesize;
51extern struct hurd_fd **_hurd_dtable;
52extern struct mutex _hurd_dtable_lock; /* Locks those two variables. */
53
54#include <hurd/signal.h>
55
56#ifndef _HURD_FD_H_EXTERN_INLINE
57#define _HURD_FD_H_EXTERN_INLINE __extern_inline
58#endif
59
60/* Returns the descriptor cell for FD. If FD is invalid or unused, return
61 NULL. The cell is unlocked; when ready to use it, lock it and check for
62 it being unused. */
63
64extern struct hurd_fd *_hurd_fd_get (int fd);
65
66#if defined __USE_EXTERN_INLINES && defined _LIBC
67# if IS_IN (libc)
68_HURD_FD_H_EXTERN_INLINE struct hurd_fd *
69_hurd_fd_get (int fd)
70{
71 struct hurd_fd *descriptor;
72
73 HURD_CRITICAL_BEGIN;
74 __mutex_lock (&_hurd_dtable_lock);
75 if (fd < 0 || fd >= _hurd_dtablesize)
76 descriptor = NULL;
77 else
78 {
79 struct hurd_fd *cell = _hurd_dtable[fd];
80 if (cell == NULL)
81 /* No descriptor allocated at this index. */
82 descriptor = NULL;
83 else
84 {
85 __spin_lock (&cell->port.lock);
86 if (cell->port.port == MACH_PORT_NULL)
87 /* The descriptor at this index has no port in it.
88 This happens if it existed before but was closed. */
89 descriptor = NULL;
90 else
91 descriptor = cell;
92 __spin_unlock (&cell->port.lock);
93 }
94 }
95 __mutex_unlock (&_hurd_dtable_lock);
96 HURD_CRITICAL_END;
97
98 return descriptor;
99}
100# endif
101#endif
102
103
104/* Evaluate EXPR with the variable `descriptor' bound to a pointer to the
105 file descriptor structure for FD. */
106
107#define HURD_FD_USE(fd, expr) \
108 ({ struct hurd_fd *descriptor = _hurd_fd_get (fd); \
109 descriptor == NULL ? EBADF : (expr); })
110
111/* Evaluate EXPR with the variable `port' bound to the port to FD, and
112 `ctty' bound to the ctty port. */
113
114#define HURD_DPORT_USE(fd, expr) \
115 HURD_FD_USE ((fd), HURD_FD_PORT_USE (descriptor, (expr)))
116
117/* Likewise, but FD is a pointer to the file descriptor structure. */
118
119#define HURD_FD_PORT_USE(fd, expr) \
120 ({ error_t __result; \
121 struct hurd_fd *const __d = (fd); \
122 struct hurd_userlink __ulink, __ctty_ulink; \
123 io_t port, ctty; \
124 void *crit = _hurd_critical_section_lock (); \
125 __spin_lock (&__d->port.lock); \
126 if (__d->port.port == MACH_PORT_NULL) \
127 { \
128 __spin_unlock (&__d->port.lock); \
129 _hurd_critical_section_unlock (crit); \
130 __result = EBADF; \
131 } \
132 else \
133 { \
134 ctty = _hurd_port_get (&__d->ctty, &__ctty_ulink); \
135 port = _hurd_port_locked_get (&__d->port, &__ulink); \
136 _hurd_critical_section_unlock (crit); \
137 __result = (expr); \
138 _hurd_port_free (&__d->port, &__ulink, port); \
139 if (ctty != MACH_PORT_NULL) \
140 _hurd_port_free (&__d->ctty, &__ctty_ulink, ctty); \
141 } \
142 __result; })
143
144#include <errno.h>
145#include <bits/types/error_t.h>
146
147/* Check if ERR should generate a signal.
148 Returns the signal to take, or zero if none. */
149
150extern int _hurd_fd_error_signal (error_t err);
151
152#ifdef __USE_EXTERN_INLINES
153_HURD_FD_H_EXTERN_INLINE int
154_hurd_fd_error_signal (error_t err)
155{
156 switch (err)
157 {
158 case EMACH_SEND_INVALID_DEST:
159 case EMIG_SERVER_DIED:
160 /* The server has disappeared! */
161 return SIGLOST;
162 case EPIPE:
163 return SIGPIPE;
164 default:
165 /* Having a default case avoids -Wenum-switch warnings. */
166 return 0;
167 }
168}
169#endif
170
171/* Handle an error from an RPC on a file descriptor's port. You should
172 always use this function to handle errors from RPCs made on file
173 descriptor ports. Some errors are translated into signals. */
174
175extern error_t _hurd_fd_error (int fd, error_t err);
176
177#ifdef __USE_EXTERN_INLINES
178_HURD_FD_H_EXTERN_INLINE error_t
179_hurd_fd_error (int fd, error_t err)
180{
181 int signo = _hurd_fd_error_signal (err);
182 if (signo)
183 {
184 const struct hurd_signal_detail detail
185 = { exc: 0, exc_code: 0, exc_subcode: 0, code: fd, error: err };
186 _hurd_raise_signal (NULL, signo, &detail);
187 }
188 return err;
189}
190#endif
191
192/* Handle error code ERR from an RPC on file descriptor FD's port.
193 Set `errno' to the appropriate error code, and always return -1. */
194
195extern int __hurd_dfail (int fd, error_t err);
196
197#ifdef __USE_EXTERN_INLINES
198_HURD_FD_H_EXTERN_INLINE int
199__hurd_dfail (int fd, error_t err)
200{
201 errno = _hurd_fd_error (fd, err);
202 return -1;
203}
204#endif
205
206/* Likewise, but do not raise SIGPIPE on EPIPE if flags contain
207 MSG_NOSIGNAL. */
208
209extern int __hurd_sockfail (int fd, int flags, error_t err);
210
211#ifdef __USE_EXTERN_INLINES
212_HURD_FD_H_EXTERN_INLINE int
213__hurd_sockfail (int fd, int flags, error_t err)
214{
215 if (!(flags & MSG_NOSIGNAL) || err != EPIPE)
216 err = _hurd_fd_error (fd, err);
217 errno = err;
218 return -1;
219}
220#endif
221
222/* Set up *FD to have PORT its server port, doing appropriate ctty magic.
223 Does no locking or unlocking. */
224
225extern void _hurd_port2fd (struct hurd_fd *fd, io_t port, int flags);
226
227/* Allocate a new file descriptor and install PORT in it (doing any
228 appropriate ctty magic); consumes a user reference on PORT. FLAGS are
229 as for `open'; only O_IGNORE_CTTY and O_CLOEXEC are meaningful, but all are
230 saved.
231
232 If the descriptor table is full, set errno, and return -1.
233 If DEALLOC is nonzero, deallocate PORT first. */
234
235extern int _hurd_intern_fd (io_t port, int flags, int dealloc);
236
237/* Allocate a new file descriptor in the table and return it, locked. The
238 new descriptor number will be no less than FIRST_FD. If the table is
239 full, set errno to EMFILE and return NULL. If FIRST_FD is negative or
240 bigger than the size of the table, set errno to EINVAL and return NULL. */
241
242extern struct hurd_fd *_hurd_alloc_fd (int *fd_ptr, int first_fd);
243
244/* Allocate a new file descriptor structure and initialize its port cells
245 with PORT and CTTY. (This does not affect the descriptor table.) */
246
247extern struct hurd_fd *_hurd_new_fd (io_t port, io_t ctty);
248
249/* Close a file descriptor, making it available for future reallocation. */
250
251extern error_t _hurd_fd_close (struct hurd_fd *fd);
252
253/* Read and write data from a file descriptor; just like `read' and `write'
254 if OFFSET is -1, or like `pread' and `pwrite' if OFFSET is not -1.
255 If successful, stores the amount actually read or written in *NBYTES. */
256
257extern error_t _hurd_fd_read (struct hurd_fd *fd,
258 void *buf, size_t *nbytes, __loff_t offset);
259extern error_t _hurd_fd_write (struct hurd_fd *fd,
260 const void *buf, size_t *nbytes, __loff_t offset);
261
262
263/* Call *RPC on PORT and/or CTTY; if a call on CTTY returns EBACKGROUND,
264 generate SIGTTIN/SIGTTOU or EIO as appropriate. */
265
266extern error_t _hurd_ctty_input (io_t port, io_t ctty, error_t (*rpc) (io_t));
267extern error_t _hurd_ctty_output (io_t port, io_t ctty, error_t (*rpc) (io_t));
268
269
270/* The guts of `select' and `poll'. Check the first NFDS descriptors
271 either in POLLFDS (if nonnull) or in each of READFDS, WRITEFDS,
272 EXCEPTFDS that is nonnull. If TIMEOUT is not NULL, time out after
273 waiting the interval specified therein. If SIGMASK is nonnull,
274 the set of blocked signals is temporarily set to that during this call.
275 Returns the number of ready descriptors, or -1 for errors. */
276struct pollfd;
277struct timespec;
278extern int _hurd_select (int nfds, struct pollfd *pollfds,
279 fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
280 const struct timespec *timeout,
281 const sigset_t *sigmask);
282
283/* Apply AT_FLAGS on FLAGS, in preparation for calling
284 __hurd_file_name_lookup. */
285
286#if defined __USE_EXTERN_INLINES && defined _LIBC
287# if IS_IN (libc)
288_HURD_FD_H_EXTERN_INLINE error_t
289__hurd_at_flags (int *at_flags, int *flags)
290{
291 if ((*at_flags & AT_SYMLINK_FOLLOW) && (*at_flags & AT_SYMLINK_NOFOLLOW))
292 return EINVAL;
293
294 *flags |= (*at_flags & AT_SYMLINK_NOFOLLOW) ? O_NOLINK : 0;
295 *at_flags &= ~AT_SYMLINK_NOFOLLOW;
296 if (*at_flags & AT_SYMLINK_FOLLOW)
297 *flags &= ~O_NOLINK;
298 *at_flags &= ~AT_SYMLINK_FOLLOW;
299 if (*at_flags != 0)
300 return EINVAL;
301
302 return 0;
303}
304# endif
305#endif
306
307/* Variant of file_name_lookup used in *at function implementations.
308 AT_FLAGS may only contain AT_SYMLINK_FOLLOW or AT_SYMLINK_NOFOLLOW,
309 which will remove and add O_NOLINK from FLAGS respectively.
310 Other bits cause EINVAL. */
311extern file_t __file_name_lookup_at (int fd, int at_flags,
312 const char *file_name,
313 int flags, mode_t mode);
314
315/* Variant of file_name_split used in *at function implementations. */
316extern file_t __file_name_split_at (int fd, const char *file_name,
317 char **name);
318
319/* Variant of directory_name_split used in *at function implementations. */
320extern file_t __directory_name_split_at (int fd, const char *directory_name,
321 char **name);
322
323
324
325#endif /* hurd/fd.h */
326

Warning: That file was not part of the compilation database. It may have many parsing errors.