mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 15:03:34 +00:00
997ce29ddc
- SQLite file locking now works on Windows - SQLite will now use fdatasync() on non-Apple platforms - Fix Ctrl-C handler on Windows to not crash with TLS - Signals now work in multithreaded apps on Windows - fcntl() will now accurately report EINVAL errors - fcntl() now has excellent --strace logging - Token bucket replenish now go 100x faster - *NSYNC cancellations now work on Windows - Support closefrom() on NetBSD
155 lines
7.3 KiB
C
155 lines
7.3 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/struct/flock.h"
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#include "libc/calls/struct/flock.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/describeflags.internal.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/consts/f.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, which let independent
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* processes (and on Windows, threads too!) read/write lock byte ranges
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* of files. See `test/libc/calls/lock_test.c` for an example.
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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 fd is the file descriptor
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* @param cmd can be one of:
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* - `F_GETFD` gets `FD_CLOEXEC` status of `fd
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* - `F_SETFD` sets `FD_CLOEXEC` status of `arg` file descriptor
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* - `F_GETFL` returns file descriptor status flags
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* - `F_SETFL` sets file descriptor status flags
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* - `F_DUPFD` is like dup() but `arg` is a minimum result, e.g. 3
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* - `F_DUPFD_CLOEXEC` ditto but sets `O_CLOEXEC` on returned fd
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* - `F_SETLK` for record locking where `arg` is `struct flock`
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* - `F_SETLKW` ditto but waits (i.e. blocks) for lock
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* - `F_GETLK` to retrieve information about a record lock
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* - `F_OFD_SETLK` for better locks on Linux and XNU
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* - `F_OFD_SETLKW` for better locks on Linux and XNU
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* - `F_OFD_GETLK` for better locks on Linux and XNU
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* - `F_FULLFSYNC` on MacOS for fsync() with release barrier
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* - `F_BARRIERFSYNC` on MacOS for fsync() with even more barriers
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* - `F_SETNOSIGPIPE` on MacOS and NetBSD to control `SIGPIPE`
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* - `F_GETNOSIGPIPE` on MacOS and NetBSD to control `SIGPIPE`
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* - `F_GETPATH` on MacOS and NetBSD where arg is `char[PATH_MAX]`
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* - `F_MAXFD` on NetBSD to get max open file descriptor
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* - `F_NOCACHE` on MacOS to toggle data caching
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* - `F_GETPIPE_SZ` on Linux to get pipe size
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* - `F_SETPIPE_SZ` on Linux to set pipe size
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* - `F_NOTIFY` raise `SIGIO` upon `fd` events in `arg` on Linux
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* - `DN_ACCESS` for file access
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* - `DN_MODIFY` for file modifications
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* - `DN_CREATE` for file creations
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* - `DN_DELETE` for file deletions
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* - `DN_RENAME` for file renames
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* - `DN_ATTRIB` for file attribute changes
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* - `DN_MULTISHOT` bitwise or for realtime signals (non-coalesced)
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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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* @raise EBADF if `fd` isn't a valid open file descriptor
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* @raise EINVAL if `cmd` is unknown or unsupported by os
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* @raise EINVAL if `cmd` is invalid or unsupported by os
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* @raise EPERM if pledge() is in play w/o `stdio` or `flock` promise
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* @raise ENOLCK if `F_SETLKW` would have exceeded `RLIMIT_LOCKS`
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* @raise EPERM if `cmd` is `F_SETOWN` and we weren't authorized
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* @raise ESRCH if `cmd` is `F_SETOWN` and process group not found
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* @raise EDEADLK if `cmd` was `F_SETLKW` and waiting would deadlock
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* @raise EMFILE if `cmd` is `F_DUPFD` or `F_DUPFD_CLOEXEC` and
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* `RLIMIT_NOFILE` would be exceeded
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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 (cmd >= 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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} else {
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rc = ebadf();
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}
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#ifdef SYSDEBUG
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if (cmd == F_GETFD || //
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cmd == F_GETOWN || //
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cmd == F_FULLFSYNC || //
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cmd == F_BARRIERFSYNC || //
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cmd == F_MAXFD) {
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STRACE("fcntl(%d, %s) → %d% m", fd, DescribeFcntlCmd(cmd), rc);
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} else if (cmd == F_GETFL) {
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STRACE("fcntl(%d, %s) → %s% m", fd, DescribeFcntlCmd(cmd),
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DescribeOpenFlags(rc));
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} else if (cmd == F_SETLK || //
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cmd == F_SETLKW || //
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cmd == F_GETLK || //
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((SupportsLinux() || SupportsXnu()) && //
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cmd != -1 && //
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(cmd == F_OFD_SETLK || //
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cmd == F_OFD_SETLKW || //
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cmd == F_OFD_GETLK))) {
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STRACE("fcntl(%d, %s, %s) → %d% m", fd, DescribeFcntlCmd(cmd),
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DescribeFlock(cmd, (struct flock *)arg), rc);
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} else if ((SupportsNetbsd() || SupportsXnu()) && cmd != -1 &&
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cmd == F_GETPATH) {
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STRACE("fcntl(%d, %s, [%s]) → %d% m", fd, DescribeFcntlCmd(cmd),
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!rc ? (const char *)arg : "n/a", rc);
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} else if (SupportsLinux() && cmd != -1 && cmd == F_NOTIFY) {
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STRACE("fcntl(%d, %s, %s) → %d% m", fd, DescribeFcntlCmd(cmd),
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DescribeDnotifyFlags(arg), rc);
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} else {
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STRACE("fcntl(%d, %s, %ld) → %#x% m", fd, DescribeFcntlCmd(cmd), arg, rc);
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}
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#endif
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return rc;
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}
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