swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: 69973b830859bc6529a7a0468ba0d80ee5117826 authored by Linus Torvalds on 11 December 2016, 19:17:54 UTC
Linux 4.9
Linux 4.9
Tip revision: 69973b8
process.c
/*
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#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/wait.h>
#include <asm/unistd.h>
#include <init.h>
#include <longjmp.h>
#include <os.h>
#define ARBITRARY_ADDR -1
#define FAILURE_PID -1
#define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
#define COMM_SCANF "%*[^)])"
unsigned long os_process_pc(int pid)
{
char proc_stat[STAT_PATH_LEN], buf[256];
unsigned long pc = ARBITRARY_ADDR;
int fd, err;
sprintf(proc_stat, "/proc/%d/stat", pid);
fd = open(proc_stat, O_RDONLY, 0);
if (fd < 0) {
printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
"errno = %d\n", proc_stat, errno);
goto out;
}
CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
if (err < 0) {
printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
"err = %d\n", proc_stat, errno);
goto out_close;
}
os_close_file(fd);
pc = ARBITRARY_ADDR;
if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
"%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
"%*d %*d %*d %*d %*d %lu", &pc) != 1)
printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
buf);
out_close:
close(fd);
out:
return pc;
}
int os_process_parent(int pid)
{
char stat[STAT_PATH_LEN];
char data[256];
int parent = FAILURE_PID, n, fd;
if (pid == -1)
return parent;
snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
fd = open(stat, O_RDONLY, 0);
if (fd < 0) {
printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat,
errno);
return parent;
}
CATCH_EINTR(n = read(fd, data, sizeof(data)));
close(fd);
if (n < 0) {
printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat,
errno);
return parent;
}
parent = FAILURE_PID;
n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
if (n != 1)
printk(UM_KERN_ERR "Failed to scan '%s'\n", data);
return parent;
}
void os_alarm_process(int pid)
{
kill(pid, SIGALRM);
}
void os_stop_process(int pid)
{
kill(pid, SIGSTOP);
}
void os_kill_process(int pid, int reap_child)
{
kill(pid, SIGKILL);
if (reap_child)
CATCH_EINTR(waitpid(pid, NULL, __WALL));
}
/* 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)
{
kill(pid, SIGKILL);
ptrace(PTRACE_KILL, pid);
ptrace(PTRACE_CONT, pid);
if (reap_child)
CATCH_EINTR(waitpid(pid, NULL, __WALL));
}
/* 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_getpgrp(void)
{
return getpgrp();
}
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;
}
static int os_page_mincore(void *addr)
{
char vec[2];
int ret;
ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
if (ret < 0) {
if (errno == ENOMEM || errno == EINVAL)
return 0;
else
return -errno;
}
return vec[0] & 1;
}
int os_mincore(void *addr, unsigned long len)
{
char *vec;
int ret, i;
if (len <= UM_KERN_PAGE_SIZE)
return os_page_mincore(addr);
vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE);
if (!vec)
return -ENOMEM;
ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
if (ret < 0) {
if (errno == ENOMEM || errno == EINVAL)
ret = 0;
else
ret = -errno;
goto out;
}
for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) {
if (!(vec[i] & 1)) {
ret = 0;
goto out;
}
}
ret = 1;
out:
free(vec);
return ret;
}
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);
signal(SIGWINCH, SIG_IGN);
}