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Diffstat (limited to 'REORG.TODO/misc/pselect.c')
| -rw-r--r-- | REORG.TODO/misc/pselect.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/REORG.TODO/misc/pselect.c b/REORG.TODO/misc/pselect.c new file mode 100644 index 0000000000..2292219d3d --- /dev/null +++ b/REORG.TODO/misc/pselect.c @@ -0,0 +1,78 @@ +/* Copyright (C) 1996-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <signal.h> +#include <stddef.h> /* For NULL. */ +#include <sys/time.h> +#include <sys/select.h> +#include <sysdep-cancel.h> + + +/* Check the first NFDS descriptors each in READFDS (if not NULL) for read + readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS + (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out + after waiting the interval specified therein. Additionally set the sigmask + SIGMASK for this call. Returns the number of ready descriptors, or -1 for + errors. */ +int +__pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, + const struct timespec *timeout, const sigset_t *sigmask) +{ + struct timeval tval; + int retval; + sigset_t savemask; + + /* Change nanosecond number to microseconds. This might mean losing + precision and therefore the `pselect` should be available. But + for now it is hardly found. */ + if (timeout != NULL) + { + /* Catch bugs which would be hidden by the TIMESPEC_TO_TIMEVAL + computations. The division by 1000 truncates values. */ + if (__glibc_unlikely (timeout->tv_nsec < 0)) + { + __set_errno (EINVAL); + return -1; + } + + TIMESPEC_TO_TIMEVAL (&tval, timeout); + } + + /* The setting and restoring of the signal mask and the select call + should be an atomic operation. This can't be done without kernel + help. */ + if (sigmask != NULL) + __sigprocmask (SIG_SETMASK, sigmask, &savemask); + + /* Note the pselect() is a cancellation point. But since we call + select() which itself is a cancellation point we do not have + to do anything here. */ + retval = __select (nfds, readfds, writefds, exceptfds, + timeout != NULL ? &tval : NULL); + + if (sigmask != NULL) + __sigprocmask (SIG_SETMASK, &savemask, NULL); + + return retval; +} +#ifndef __pselect +weak_alias (__pselect, pselect) +/* __select handles cancellation. */ +LIBC_CANCEL_HANDLED (); +#endif |