// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/personality.h>
#include <as-layout.h>
#include <init.h>
#include <kern_util.h>
#include <os.h>
#include <um_malloc.h>
#include "internal.h"
#define STACKSIZE (8 * 1024 * 1024)
long elf_aux_hwcap;
static void __init set_stklim(
void)
{
struct rlimit lim;
if (getrlimit(RLIMIT_STACK, &lim) < 0) {
perror(
"getrlimit");
exit(1);
}
if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) {
lim.rlim_cur = STACKSIZE;
if (setrlimit(RLIMIT_STACK, &lim) < 0) {
perror(
"setrlimit");
exit(1);
}
}
}
static void last_ditch_exit(
int sig)
{
uml_cleanup();
exit(1);
}
static void __init install_fatal_handler(
int sig)
{
struct sigaction action;
/* All signals are enabled in this handler ... */
sigemptyset(&action.sa_mask);
/*
* ... including the signal being handled, plus we want the
* handler reset to the default behavior, so that if an exit
* handler is hanging for some reason, the UML will just die
* after this signal is sent a second time.
*/
action.sa_flags = SA_RESETHAND | SA_NODEFER;
action.sa_restorer = NULL;
action.sa_handler = last_ditch_exit;
if (sigaction(sig, &action, NULL) < 0) {
os_warn(
"failed to install handler for signal %d "
"- errno = %d\n", sig, errno);
exit(1);
}
}
#define UML_LIB_PATH
":" OS_LIB_PATH
"/uml"
static void __init setup_env_path(
void)
{
char *new_path = NULL;
char *old_path = NULL;
int path_len = 0;
old_path = getenv(
"PATH");
/*
* if no PATH variable is set or it has an empty value
* just use the default + /usr/lib/uml
*/
if (!old_path || (path_len = strlen(old_path)) == 0) {
if (putenv(
"PATH=:/bin:/usr/bin/" UML_LIB_PATH))
perror(
"couldn't putenv");
return;
}
/* append /usr/lib/uml to the existing path */
path_len += strlen(
"PATH=" UML_LIB_PATH) + 1;
new_path = malloc(path_len);
if (!new_path) {
perror(
"couldn't malloc to set a new PATH");
return;
}
snprintf(new_path, path_len,
"PATH=%s" UML_LIB_PATH, old_path);
if (putenv(new_path)) {
perror(
"couldn't putenv to set a new PATH");
free(new_path);
}
}
int __init main(
int argc,
char **argv,
char **envp)
{
char **new_argv;
int ret, i, err;
/* Disable randomization and re-exec if it was changed successfully */
ret = personality(PER_LINUX | ADDR_NO_RANDOMIZE);
if (ret >= 0 && (ret & (PER_LINUX | ADDR_NO_RANDOMIZE)) !=
(PER_LINUX | ADDR_NO_RANDOMIZE)) {
char buf[4096] = {};
ssize_t ret;
ret = readlink(
"/proc/self/exe", buf,
sizeof(buf));
if (ret < 0 || ret >=
sizeof(buf)) {
perror(
"readlink failure");
exit(1);
}
execve(buf, argv, envp);
}
set_stklim();
setup_env_path();
setsid();
new_argv = malloc((argc + 1) *
sizeof(
char *));
if (new_argv == NULL) {
perror(
"Mallocing argv");
exit(1);
}
for (i = 0; i < argc; i++) {
new_argv[i] = strdup(argv[i]);
if (new_argv[i] == NULL) {
perror(
"Mallocing an arg");
exit(1);
}
}
new_argv[argc] = NULL;
/*
* Allow these signals to bring down a UML if all other
* methods of control fail.
*/
install_fatal_handler(SIGINT);
install_fatal_handler(SIGTERM);
#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
scan_elf_aux(envp);
#endif
change_sig(SIGPIPE, 0);
ret = linux_main(argc, argv, envp);
/*
* Disable SIGPROF - I have no idea why libc doesn't do this or turn
* off the profiling time, but UML dies with a SIGPROF just before
* exiting when profiling is active.
*/
change_sig(SIGPROF, 0);
/*
* This signal stuff used to be in the reboot case. However,
* sometimes a timer signal can come in when we're halting (reproducably
* when writing out gcov information, presumably because that takes
* some time) and cause a segfault.
*/
/* stop timers and set timer signal to be ignored */
os_timer_disable();
/* disable SIGIO for the fds and set SIGIO to be ignored */
err = deactivate_all_fds();
if (err)
os_warn(
"deactivate_all_fds failed, errno = %d\n", -err);
/*
* Let any pending signals fire now. This ensures
* that they won't be delivered after the exec, when
* they are definitely not expected.
*/
unblock_signals();
os_info(
"\n");
/* Reboot */
if (ret) {
execvp(new_argv[0], new_argv);
perror(
"Failed to exec kernel");
ret = 1;
}
return uml_exitcode;
}
extern void *__real_malloc(
int);
extern void __real_free(
void *);
/* workaround for -Wmissing-prototypes warnings */
void *__wrap_malloc(
int size);
void *__wrap_calloc(
int n,
int size);
void __wrap_free(
void *ptr);
void *__wrap_malloc(
int size)
{
void *ret;
if (!kmalloc_ok)
return __real_malloc(size);
else if (size <= UM_KERN_PAGE_SIZE)
/* finding contiguous pages can be hard*/
ret = uml_kmalloc(size, UM_GFP_KERNEL);
else ret = vmalloc(size);
/*
* glibc people insist that if malloc fails, errno should be
* set by malloc as well. So we do.
*/
if (ret == NULL)
errno = ENOMEM;
return ret;
}
void *__wrap_calloc(
int n,
int size)
{
void *ptr = __wrap_malloc(n * size);
if (ptr == NULL)
return NULL;
memset(ptr, 0, n * size);
return ptr;
}
void __wrap_free(
void *ptr)
{
unsigned long addr = (
unsigned long) ptr;
/*
* We need to know how the allocation happened, so it can be correctly
* freed. This is done by seeing what region of memory the pointer is
* in -
* physical memory - kmalloc/kfree
* kernel virtual memory - vmalloc/vfree
* anywhere else - malloc/free
* If kmalloc is not yet possible, then either high_physmem and/or
* end_vm are still 0 (as at startup), in which case we call free, or
* we have set them, but anyway addr has not been allocated from those
* areas. So, in both cases __real_free is called.
*
* CAN_KMALLOC is checked because it would be bad to free a buffer
* with kmalloc/vmalloc after they have been turned off during
* shutdown.
* XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so
* there is a possibility for memory leaks.
*/
if ((addr >= uml_physmem) && (addr < high_physmem)) {
if (kmalloc_ok)
kfree(ptr);
}
else if ((addr >= start_vm) && (addr < end_vm)) {
if (kmalloc_ok)
vfree(ptr);
}
else __real_free(ptr);
}
