cosmopolitan/libc/calls/shm_open.c
2023-10-31 23:57:52 -07:00

45 lines
2.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/blockcancel.internal.h"
#include "libc/calls/calls.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/errfuns.h"
/**
* Opens POSIX named memory object.
*
* @param name should begin with a `/` and shouldn't contain subsequent
* slash characters, and furthermore shouldn't exceed NAME_MAX, for
* maximum portability; POSIX defines it as opening a multi-process
* object and leaves all other names implementation defined; and we
* choose (in this implementation) to define those names as meaning
* the same thing while not imposing any length limit; cosmo always
* feeds your name through BLAKE2B to create a `.sem` file existing
* under `/dev/shm` if available, otherwise it will go under `/tmp`
* @return open file descriptor, or -1 w/ errno
*/
int shm_open(const char *name, int oflag, unsigned mode) {
int fd;
char path[78];
shm_path_np(name, path);
BLOCK_CANCELATION;
fd = openat(AT_FDCWD, path, oflag, mode);
ALLOW_CANCELATION;
return fd;
}