mirror of
https://github.com/jart/cosmopolitan.git
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1d8937d528
This change reduces the memory requirements of your APE Loader by 10x, in terms of virtual memory size, thanks to the help of alloca(). We're also now creating argument blocks with the same layout across systems.
100 lines
5 KiB
C
100 lines
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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/rlimit.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.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/macros.internal.h"
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#include "libc/sysv/consts/rlimit.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Sets resource limit for current process.
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*
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* The following resources are recommended:
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*
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* - `RLIMIT_STACK` controls how much stack memory is available to the
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* main thread. This setting is inherited across fork() and execve()
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* Please note it's only safe for Cosmopolitan programs, to set this
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* value to at least `PTHREAD_STACK_MIN * 2`. On Windows this cannot
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* be used to extend the stack, which is currently hard-coded.
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*
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* - `RLIMIT_AS` limits the size of the virtual address space. This will
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* work on all platforms except WSL. It is emulated on XNU and Windows
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* which means it won't propagate across execve() currently.
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*
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* - `RLIMIT_CPU` causes `SIGXCPU` to be sent to the process when the
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* soft limit on CPU time is exceeded, and the process is destroyed
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* when the hard limit is exceeded. It works everywhere but Windows
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* where it should be possible to poll getrusage() with setitimer()
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*
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* - `RLIMIT_FSIZE` causes `SIGXFSZ` to sent to the process when the
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* soft limit on file size is exceeded and the process is destroyed
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* when the hard limit is exceeded. It works everywhere but Windows
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* and it also causes `EFBIG` to be returned by i/o functions after
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* the `SIGXFSZ` signal is delivered or ignored
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*
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* - `RLIMIT_NPROC` limits the number of simultaneous processes and it
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* should work on all platforms except Windows. Please be advised it
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* limits the process, with respect to the activities of the user id
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* as a whole.
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*
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* - `RLIMIT_NOFILE` limits the number of open file descriptors and it
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* should work on all platforms except Windows (TODO)
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*
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* The rlimit magnums differ for each platform but occupy the interval
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* zero through `RLIM_NLIMITS`. Usually they're set to `RLIM_INFINITY`
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* which is `-1` on Linux/Windows, and `LONG_MAX` on BSDs. In any case
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* they're both very large numbers under the Cosmopolitan unsigned ABI
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* because struct rlimit uses uint64_t. The special magnum 127 is used
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* for constant values that aren't supported by the host platform.
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*
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* @param rlim specifies new resource limit
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* @return 0 on success or -1 w/ errno
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* @see libc/sysv/consts.sh
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* @vforksafe
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*/
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int setrlimit(int resource, const struct rlimit *rlim) {
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int rc;
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if (resource == 127) {
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rc = einval();
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} else if (!rlim || (IsAsan() && !__asan_is_valid(rlim, sizeof(*rlim)))) {
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rc = efault();
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} else if (!IsWindows()) {
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rc = sys_setrlimit(resource, rlim);
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if (IsXnu() && !rc && resource == RLIMIT_AS) {
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// TODO(jart): What's up with XNU and NetBSD?
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__virtualmax = rlim->rlim_cur;
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}
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} else if (resource == RLIMIT_STACK) {
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rc = enotsup();
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} else if (resource == RLIMIT_AS) {
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__virtualmax = rlim->rlim_cur;
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rc = 0;
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} else {
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rc = einval();
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}
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STRACE("setrlimit(%s, %s) → %d% m", DescribeRlimitName(resource),
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DescribeRlimit(0, rlim), rc);
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return rc;
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}
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