mirror of
https://github.com/jart/cosmopolitan.git
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6f7d0cb1c3
This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
75 lines
3.5 KiB
C
75 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/syscall-nt.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/zipos/zipos.internal.h"
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/**
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* Does things with file descriptor, via re-imagined hourglass api, e.g.
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*
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* CHECK_NE(-1, fcntl(fd, F_SETFD, FD_CLOEXEC));
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*
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* This function lets you duplicate file descriptors without running
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* into an edge case where they take over stdio handles:
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*
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* CHECK_GE((newfd = fcntl(oldfd, F_DUPFD, 3)), 3);
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* CHECK_GE((newfd = fcntl(oldfd, F_DUPFD_CLOEXEC, 3)), 3);
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*
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* This function implements POSIX Advisory Locks, e.g.
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*
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* CHECK_NE(-1, fcntl(zfd, F_SETLKW, &(struct flock){F_WRLCK}));
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* // ...
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* CHECK_NE(-1, fcntl(zfd, F_SETLK, &(struct flock){F_UNLCK}));
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*
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* Please be warned that locks currently do nothing on Windows since
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* figuring out how to polyfill them correctly is a work in progress.
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*
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* @param cmd can be F_{GET,SET}{FD,FL}, etc.
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* @param arg can be FD_CLOEXEC, etc. depending
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* @return 0 on success, or -1 w/ errno
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* @asyncsignalsafe
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* @restartable
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*/
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int fcntl(int fd, int cmd, ...) {
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int rc;
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va_list va;
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uintptr_t arg;
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va_start(va, cmd);
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arg = va_arg(va, uintptr_t);
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va_end(va);
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if (fd >= 0) {
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if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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rc = _weaken(__zipos_fcntl)(fd, cmd, arg);
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} else if (!IsWindows()) {
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rc = sys_fcntl(fd, cmd, arg);
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} else {
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rc = sys_fcntl_nt(fd, cmd, arg);
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}
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} else {
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rc = einval();
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}
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STRACE("fcntl(%d, %d, %p) → %#x% m", fd, cmd, arg, rc);
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return rc;
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}
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