cosmopolitan/third_party/musl/lockf.c
Justine Tunney 0c5dd7b342
Make improvements
- Improved async signal safety of read() particularly for longjmp()
- Started adding cancel cleanup handlers for locks / etc on Windows
- Make /dev/tty work better particularly for uses like `foo | less`
- Eagerly read console input into a linked list, so poll can signal
- Fix some libc definitional bugs, which configure scripts detected
2023-09-21 07:30:39 -07:00

72 lines
3.5 KiB
C

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
╚──────────────────────────────────────────────────────────────────────────────╝
│ │
│ Musl Libc │
│ Copyright © 2005-2014 Rich Felker, et al. │
│ │
│ Permission is hereby granted, free of charge, to any person obtaining │
│ a copy of this software and associated documentation files (the │
│ "Software"), to deal in the Software without restriction, including │
│ without limitation the rights to use, copy, modify, merge, publish, │
│ distribute, sublicense, and/or sell copies of the Software, and to │
│ permit persons to whom the Software is furnished to do so, subject to │
│ the following conditions: │
│ │
│ The above copyright notice and this permission notice shall be │
│ included in all copies or substantial portions of the Software. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
│ │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "third_party/musl/lockf.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/flock.h"
#include "libc/calls/weirdtypes.h"
#include "libc/errno.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/errfuns.h"
asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
// clang-format off
/**
* Locks file.
*
* @cancellationpoint when `op` is `F_LOCK`
*/
int lockf(int fd, int op, off_t size)
{
struct flock l = {
.l_type = F_WRLCK,
.l_whence = SEEK_CUR,
.l_len = size,
};
switch (op) {
case F_TEST:
l.l_type = F_RDLCK;
if (fcntl(fd, F_GETLK, &l) < 0)
return -1;
if (l.l_type == F_UNLCK || l.l_pid == getpid())
return 0;
return eacces();
case F_ULOCK:
l.l_type = F_UNLCK;
case F_TLOCK:
return fcntl(fd, F_SETLK, &l);
case F_LOCK:
return fcntl(fd, F_SETLKW, &l);
}
return einval();
}
__weak_reference(lockf, lockf64);