cosmopolitan/libc/calls/prctl.c
2022-08-13 13:11:56 -07:00

67 lines
3 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 2022 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/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/sysv/consts/pr.h"
#include "libc/sysv/errfuns.h"
/**
* Tunes process on Linux.
*
* @raise ENOSYS on non-Linux
*/
privileged int prctl(int operation, ...) {
int rc;
va_list va;
intptr_t a, b, c, d;
va_start(va, operation);
a = va_arg(va, intptr_t);
b = va_arg(va, intptr_t);
c = va_arg(va, intptr_t);
d = va_arg(va, intptr_t);
va_end(va);
if (IsLinux()) {
asm volatile("mov\t%5,%%r10\n\t"
"mov\t%6,%%r8\n\t"
"syscall"
: "=a"(rc)
: "0"(157), "D"(operation), "S"(a), "d"(b), "g"(c), "g"(d)
: "rcx", "r8", "r10", "r11", "memory");
if (rc > -4096u) errno = -rc, rc = -1;
} else {
rc = enosys();
}
#ifdef SYSDEBUG
if (operation == PR_CAPBSET_READ || operation == PR_CAPBSET_DROP) {
STRACE("prctl(%s, %s) → %d% m", DescribePrctlOperation(operation),
DescribeCapability(a), rc);
} else {
STRACE("prctl(%s, %p, %p, %p, %p) → %d% m",
DescribePrctlOperation(operation), a, b, c, d, rc);
}
#endif
return rc;
}