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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/utsname.h>
#include <sys/random.h>
#include <init.h>
#include <os.h>
void stack_protections(unsigned long address)
{
if (mprotect((void *) address, UM_THREAD_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC) < 0)
panic("protecting stack failed, errno = %d", errno);
}
int raw(int fd)
{
struct termios tt;
int err;
CATCH_EINTR(err = tcgetattr(fd, &tt));
if (err < 0)
return -errno;
cfmakeraw(&tt);
CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));
if (err < 0)
return -errno;
/*
* XXX tcsetattr could have applied only some changes
* (and cfmakeraw() is a set of changes)
*/
return 0;
}
void setup_machinename(char *machine_out)
{
struct utsname host;
uname(&host);
#ifdef UML_CONFIG_UML_X86
# ifndef UML_CONFIG_64BIT
if (!strcmp(host.machine, "x86_64")) {
strcpy(machine_out, "i686");
return;
}
# else
if (!strcmp(host.machine, "i686")) {
strcpy(machine_out, "x86_64");
return;
}
# endif
#endif
strcpy(machine_out, host.machine);
}
void setup_hostinfo(char *buf, int len)
{
struct utsname host;
uname(&host);
snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,
host.release, host.version, host.machine);
}
/*
* We cannot use glibc's abort(). It makes use of tgkill() which
* has no effect within UML's kernel threads.
* After that glibc would execute an invalid instruction to kill
* the calling process and UML crashes with SIGSEGV.
*/
static inline void __attribute__ ((noreturn)) uml_abort(void)
{
sigset_t sig;
fflush(NULL);
if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))
sigprocmask(SIG_UNBLOCK, &sig, 0);
for (;;)
if (kill(getpid(), SIGABRT) < 0)
exit(127);
}
ssize_t os_getrandom(void *buf, size_t len, unsigned int flags)
{
return getrandom(buf, len, flags);
}
/*
* UML helper threads must not handle SIGWINCH/INT/TERM
*/
void os_fix_helper_signals(void)
{
signal(SIGWINCH, SIG_IGN);
signal(SIGINT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
}
void os_dump_core(void)
{
int pid;
signal(SIGSEGV, SIG_DFL);
/*
* We are about to SIGTERM this entire process group to ensure that
* nothing is around to run after the kernel exits. The
* kernel wants to abort, not die through SIGTERM, so we
* ignore it here.
*/
signal(SIGTERM, SIG_IGN);
kill(0, SIGTERM);
/*
* Most of the other processes associated with this UML are
* likely sTopped, so give them a SIGCONT so they see the
* SIGTERM.
*/
kill(0, SIGCONT);
/*
* Now, having sent signals to everyone but us, make sure they
* die by ptrace. Processes can survive what's been done to
* them so far - the mechanism I understand is receiving a
* SIGSEGV and segfaulting immediately upon return. There is
* always a SIGSEGV pending, and (I'm guessing) signals are
* processed in numeric order so the SIGTERM (signal 15 vs
* SIGSEGV being signal 11) is never handled.
*
* Run a waitpid loop until we get some kind of error.
* Hopefully, it's ECHILD, but there's not a lot we can do if
* it's something else. Tell os_kill_ptraced_process not to
* wait for the child to report its death because there's
* nothing reasonable to do if that fails.
*/
while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
os_kill_ptraced_process(pid, 0);
uml_abort();
}
void um_early_printk(const char *s, unsigned int n)
{
printf("%.*s", n, s);
}
static int quiet_info;
static int __init quiet_cmd_param(char *str, int *add)
{
quiet_info = 1;
return 0;
}
__uml_setup("quiet", quiet_cmd_param,
"quiet\n"
" Turns off information messages during boot.\n\n");
/*
* The os_info/os_warn functions will be called by helper threads. These
* have a very limited stack size and using the libc formatting functions
* may overflow the stack.
* So pull in the kernel vscnprintf and use that instead with a fixed
* on-stack buffer.
*/
int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
void os_info(const char *fmt, ...)
{
char buf[256];
va_list list;
int len;
if (quiet_info)
return;
va_start(list, fmt);
len = vscnprintf(buf, sizeof(buf), fmt, list);
fwrite(buf, len, 1, stderr);
va_end(list);
}
void os_warn(const char *fmt, ...)
{
char buf[256];
va_list list;
int len;
va_start(list, fmt);
len = vscnprintf(buf, sizeof(buf), fmt, list);
fwrite(buf, len, 1, stderr);
va_end(list);
}
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