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1998-08-31 15:56 Ulrich Drepper <drepper@cygnus.com> * db2/db_int.h: Use <db.h> instead of "db.h" to find header in include. * include/stdio.h: Add __vsscanf. * libio/stdio.h: Make vfscanf, scanf, and vsscanf available if __USE_ISOC9X. Remove __vsscanf declaration. Always declare fgetpos and fsetpos. * math/math.h: Define isinf as macro. * math/bits/mathcalls.h: Change to declare __isinf all the time. Don't declare scalb for ISO C 9x. * math/tgmath.h: Define fma. Rewrite the underlying macros. * stdlib/stdlib.h: Declare strtof and strtold is __USE_ISOC9X. * sysdeps/unix/sysv/linux/bits/sigcontext.h: Allow inclusion from sys/ucontext.h. * sysdeps/wordsize-32/inttypes.h: Define missing PRI* and SCN* macros. 1998-08-31 Andreas Jaeger <aj@arthur.rhein-neckar.de> * sysdeps/standalone/bits/errno.h (ENOMSG): Remove duplicate. Reported by jreising@frequentis.com [PR libc/767]. 1998-08-31 Andreas Jaeger <aj@arthur.rhein-neckar.de> * io/lockf.c (lockf): Move initilisation of fl.l_whence and fl.l_start at beginning of function. Patch by Geoff. Dash <geoffd@zeta.org.au> [PR libc/769].
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* Copyright (C) 1994, 1996, 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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/* lockf is a simplified interface to fcntl's locking facilities. */
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int
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lockf (int fd, int cmd, off_t len)
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{
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struct flock fl;
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memset ((char *) &fl, '\0', sizeof (fl));
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/* lockf is always relative to the current file position. */
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fl.l_whence = SEEK_CUR;
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fl.l_start = 0;
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fl.l_len = len;
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switch (cmd)
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{
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case F_TEST:
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/* Test the lock: return 0 if FD is unlocked or locked by this process;
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return -1, set errno to EACCES, if another process holds the lock. */
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if (__fcntl (fd, F_GETLK, &fl) < 0)
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return -1;
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if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ())
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return 0;
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__set_errno (EACCES);
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return -1;
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case F_ULOCK:
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fl.l_type = F_UNLCK;
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cmd = F_SETLK;
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break;
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case F_LOCK:
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fl.l_type = F_WRLCK;
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cmd = F_SETLKW;
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break;
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case F_TLOCK:
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fl.l_type = F_WRLCK;
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cmd = F_SETLK;
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break;
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default:
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__set_errno (EINVAL);
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return -1;
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}
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return __fcntl (fd, cmd, &fl);
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}
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