cosmopolitan/libc/calls/write.c
2022-10-07 03:41:50 -07:00

88 lines
4.7 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 2020 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/internal.h"
#include "libc/calls/struct/iovec.h"
#include "libc/calls/struct/iovec.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/sock/sock.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.internal.h"
/**
* Writes data to file descriptor.
*
* This function changes the current file position. For documentation
* on file position behaviors and gotchas, see the lseek() function.
* This function may be used on socket file descriptors, including on
* Windows.
*
* @param fd is open file descriptor
* @param buf is copied from, cf. copy_file_range(), sendfile(), etc.
* @return [1..size] bytes on success, or -1 w/ errno; noting zero is
* impossible unless size was passed as zero to do an error check
* @raise EBADF if `fd` is negative or not an open file descriptor
* @raise EBADF if `fd` wasn't opened with `O_WRONLY` or `O_RDWR`
* @raise EPIPE if `fd` is a pipe whose other reader end was closed,
* after the `SIGPIPE` signal was delivered, blocked, or ignored
* @raise EFBIG if `RLIMIT_FSIZE` soft limit was exceeded, after the
* `SIGXFSZ` signal was either delivered, blocked, or ignored
* @raise EFAULT if `size` is nonzero and `buf` points to bad memory
* @raise EPERM if pledge() is in play without the stdio promise
* @raise ENOSPC if device containing `fd` is full
* @raise EIO if low-level i/o error happened
* @raise EINTR if signal was delivered instead
* @raise EAGAIN if `O_NONBLOCK` is in play and write needs to block
* @raise ENOBUFS if kernel lacked internal resources; which FreeBSD
* and XNU say could happen with sockets, and OpenBSD documents it
* as a general possibility; whereas other system don't specify it
* @raise ENXIO is specified only by POSIX and XNU when a request is
* made of a nonexistent device or outside device capabilities
* @asyncsignalsafe
* @restartable
* @vforksafe
*/
ssize_t write(int fd, const void *buf, size_t size) {
ssize_t rc;
if (fd >= 0) {
if ((!buf && size) || (IsAsan() && !__asan_is_valid(buf, size))) {
rc = efault();
} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
rc = _weaken(__zipos_write)(
(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle,
&(struct iovec){buf, size}, 1, -1);
} else if (!IsWindows() && !IsMetal()) {
rc = sys_write(fd, buf, size);
} else if (fd >= g_fds.n) {
rc = ebadf();
} else if (IsMetal()) {
rc = sys_writev_metal(g_fds.p + fd, &(struct iovec){buf, size}, 1);
} else {
rc = sys_writev_nt(fd, &(struct iovec){buf, size}, 1);
}
} else {
rc = ebadf();
}
DATATRACE("write(%d, %#.*hhs%s, %'zu) → %'zd% m", fd, MAX(0, MIN(40, rc)),
buf, rc > 40 ? "..." : "", size, rc);
return rc;
}