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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <asm/unistd.h>
#include <init.h>
#include <longjmp.h>
#include <os.h>
#include <skas/skas.h>
void os_alarm_process(int pid)
{
if (pid <= 0)
return;
kill(pid, SIGALRM);
}
void os_kill_process(int pid, int reap_child)
{
if (pid <= 0)
return;
/* Block signals until child is reaped */
block_signals();
kill(pid, SIGKILL);
if (reap_child)
CATCH_EINTR(waitpid(pid, NULL, __WALL));
unblock_signals();
}
/* Kill off a ptraced child by all means available. kill it normally first,
* then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
* which it can't exit directly.
*/
void os_kill_ptraced_process(int pid, int reap_child)
{
if (pid <= 0)
return;
/* Block signals until child is reaped */
block_signals();
kill(pid, SIGKILL);
ptrace(PTRACE_KILL, pid);
ptrace(PTRACE_CONT, pid);
if (reap_child)
CATCH_EINTR(waitpid(pid, NULL, __WALL));
unblock_signals();
}
pid_t os_reap_child(void)
{
int status;
/* Try to reap a child */
return waitpid(-1, &status, WNOHANG);
}
/* Don't use the glibc version, which caches the result in TLS. It misses some
* syscalls, and also breaks with clone(), which does not unshare the TLS.
*/
int os_getpid(void)
{
return syscall(__NR_getpid);
}
int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
int r, int w, int x)
{
void *loc;
int prot;
prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
(x ? PROT_EXEC : 0);
loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
fd, off);
if (loc == MAP_FAILED)
return -errno;
return 0;
}
int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
{
int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
(x ? PROT_EXEC : 0));
if (mprotect(addr, len, prot) < 0)
return -errno;
return 0;
}
int os_unmap_memory(void *addr, int len)
{
int err;
err = munmap(addr, len);
if (err < 0)
return -errno;
return 0;
}
#ifndef MADV_REMOVE
#define MADV_REMOVE KERNEL_MADV_REMOVE
#endif
int os_drop_memory(void *addr, int length)
{
int err;
err = madvise(addr, length, MADV_REMOVE);
if (err < 0)
err = -errno;
return err;
}
int __init can_drop_memory(void)
{
void *addr;
int fd, ok = 0;
printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
fd = create_mem_file(UM_KERN_PAGE_SIZE);
if (fd < 0) {
printk(UM_KERN_ERR "Creating test memory file failed, "
"err = %d\n", -fd);
goto out;
}
addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
if (addr == MAP_FAILED) {
printk(UM_KERN_ERR "Mapping test memory file failed, "
"err = %d\n", -errno);
goto out_close;
}
if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
goto out_unmap;
}
printk(UM_KERN_CONT "OK\n");
ok = 1;
out_unmap:
munmap(addr, UM_KERN_PAGE_SIZE);
out_close:
close(fd);
out:
return ok;
}
void init_new_thread_signals(void)
{
set_handler(SIGSEGV);
set_handler(SIGTRAP);
set_handler(SIGFPE);
set_handler(SIGILL);
set_handler(SIGBUS);
signal(SIGHUP, SIG_IGN);
set_handler(SIGIO);
/* We (currently) only use the child reaper IRQ in seccomp mode */
if (using_seccomp)
set_handler(SIGCHLD);
signal(SIGWINCH, SIG_IGN);
}
void os_set_pdeathsig(void)
{
prctl(PR_SET_PDEATHSIG, SIGKILL);
}
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