| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1996-2016 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. |
| 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 | #include <errno.h> |
| 20 | #include <signal.h> |
| 21 | #include <stddef.h> /* For NULL. */ |
| 22 | #include <sys/time.h> |
| 23 | #include <sys/select.h> |
| 24 | #include <sysdep-cancel.h> |
| 25 | |
| 26 | |
| 27 | /* Check the first NFDS descriptors each in READFDS (if not NULL) for read |
| 28 | readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS |
| 29 | (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out |
| 30 | after waiting the interval specified therein. Additionally set the sigmask |
| 31 | SIGMASK for this call. Returns the number of ready descriptors, or -1 for |
| 32 | errors. */ |
| 33 | int |
| 34 | __pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, |
| 35 | const struct timespec *timeout, const sigset_t *sigmask) |
| 36 | { |
| 37 | struct timeval tval; |
| 38 | int retval; |
| 39 | sigset_t savemask; |
| 40 | |
| 41 | /* Change nanosecond number to microseconds. This might mean losing |
| 42 | precision and therefore the `pselect` should be available. But |
| 43 | for now it is hardly found. */ |
| 44 | if (timeout != NULL) |
| 45 | { |
| 46 | /* Catch bugs which would be hidden by the TIMESPEC_TO_TIMEVAL |
| 47 | computations. The division by 1000 truncates values. */ |
| 48 | if (__glibc_unlikely (timeout->tv_nsec < 0)) |
| 49 | { |
| 50 | __set_errno (EINVAL); |
| 51 | return -1; |
| 52 | } |
| 53 | |
| 54 | TIMESPEC_TO_TIMEVAL (&tval, timeout); |
| 55 | } |
| 56 | |
| 57 | /* The setting and restoring of the signal mask and the select call |
| 58 | should be an atomic operation. This can't be done without kernel |
| 59 | help. */ |
| 60 | if (sigmask != NULL) |
| 61 | __sigprocmask (SIG_SETMASK, sigmask, &savemask); |
| 62 | |
| 63 | /* Note the pselect() is a cancellation point. But since we call |
| 64 | select() which itself is a cancellation point we do not have |
| 65 | to do anything here. */ |
| 66 | retval = __select (nfds, readfds, writefds, exceptfds, |
| 67 | timeout != NULL ? &tval : NULL); |
| 68 | |
| 69 | if (sigmask != NULL) |
| 70 | __sigprocmask (SIG_SETMASK, &savemask, NULL); |
| 71 | |
| 72 | return retval; |
| 73 | } |
| 74 | #ifndef __pselect |
| 75 | weak_alias (__pselect, pselect) |
| 76 | /* __select handles cancellation. */ |
| 77 | LIBC_CANCEL_HANDLED (); |
| 78 | #endif |