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author | Ulrich Drepper <drepper@redhat.com> | 2005-12-14 15:06:39 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 2005-12-14 15:06:39 +0000 |
commit | 9d13fb2413921c713f83efe331e8e4d219c62c6b (patch) | |
tree | 2d44d7ac45ab2d147eb8361bbff880c365aa8ad5 /io/lockf.c | |
parent | b6ab06cef4670e02756bcdd4d2c33a49369a4346 (diff) | |
download | glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.zip glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.tar.gz glibc-9d13fb2413921c713f83efe331e8e4d219c62c6b.tar.bz2 |
Moved to csu/errno-loc.c.
Diffstat (limited to 'io/lockf.c')
-rw-r--r-- | io/lockf.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/io/lockf.c b/io/lockf.c new file mode 100644 index 0000000..7b23f66 --- /dev/null +++ b/io/lockf.c @@ -0,0 +1,74 @@ +/* Copyright (C) 1994,1996,1997,1998,2000,2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sys/types.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> +#include <string.h> + +/* lockf is a simplified interface to fcntl's locking facilities. */ + +int +lockf (int fd, int cmd, off_t len) +{ + struct flock fl; + + memset ((char *) &fl, '\0', sizeof (fl)); + + /* lockf is always relative to the current file position. */ + fl.l_whence = SEEK_CUR; + fl.l_start = 0; + fl.l_len = len; + + switch (cmd) + { + case F_TEST: + /* Test the lock: return 0 if FD is unlocked or locked by this process; + return -1, set errno to EACCES, if another process holds the lock. */ + fl.l_type = F_RDLCK; + if (__fcntl (fd, F_GETLK, &fl) < 0) + return -1; + if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ()) + return 0; + __set_errno (EACCES); + return -1; + + case F_ULOCK: + fl.l_type = F_UNLCK; + cmd = F_SETLK; + break; + case F_LOCK: + fl.l_type = F_WRLCK; + cmd = F_SETLKW; + break; + case F_TLOCK: + fl.l_type = F_WRLCK; + cmd = F_SETLK; + break; + + default: + __set_errno (EINVAL); + return -1; + } + + /* lockf() is a cancellation point but so is fcntl() if F_SETLKW is + used. Therefore we don't have to care about cancellation here, + the fcntl() function will take care of it. */ + return __fcntl (fd, cmd, &fl); +} |