1/*
  2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <stdio.h>
  7#include <stdlib.h>
  8#include <unistd.h>
  9#include <errno.h>
 10#include <signal.h>
 11#include <string.h>
 12#include <termios.h>
 13#include <wait.h>
 14#include <sys/mman.h>
 15#include <sys/utsname.h>
 16#include "os.h"
 17
 18void stack_protections(unsigned long address)
 19{
 20	if (mprotect((void *) address, UM_THREAD_SIZE,
 21		    PROT_READ | PROT_WRITE | PROT_EXEC) < 0)
 22		panic("protecting stack failed, errno = %d", errno);
 23}
 24
 25int raw(int fd)
 26{
 27	struct termios tt;
 28	int err;
 29
 30	CATCH_EINTR(err = tcgetattr(fd, &tt));
 31	if (err < 0)
 32		return -errno;
 33
 34	cfmakeraw(&tt);
 35
 36	CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));
 37	if (err < 0)
 38		return -errno;
 39
 40	/*
 41	 * XXX tcsetattr could have applied only some changes
 42	 * (and cfmakeraw() is a set of changes)
 43	 */
 44	return 0;
 45}
 46
 47void setup_machinename(char *machine_out)
 48{
 49	struct utsname host;
 50
 51	uname(&host);
 52#ifdef UML_CONFIG_UML_X86
 53# ifndef UML_CONFIG_64BIT
 54	if (!strcmp(host.machine, "x86_64")) {
 55		strcpy(machine_out, "i686");
 56		return;
 57	}
 58# else
 59	if (!strcmp(host.machine, "i686")) {
 60		strcpy(machine_out, "x86_64");
 61		return;
 62	}
 63# endif
 64#endif
 65	strcpy(machine_out, host.machine);
 66}
 67
 68void setup_hostinfo(char *buf, int len)
 69{
 70	struct utsname host;
 71
 72	uname(&host);
 73	snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,
 74		 host.release, host.version, host.machine);
 75}
 76
 77/*
 78 * We cannot use glibc's abort(). It makes use of tgkill() which
 79 * has no effect within UML's kernel threads.
 80 * After that glibc would execute an invalid instruction to kill
 81 * the calling process and UML crashes with SIGSEGV.
 82 */
 83static inline void __attribute__ ((noreturn)) uml_abort(void)
 84{
 85	sigset_t sig;
 86
 87	fflush(NULL);
 88
 89	if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))
 90		sigprocmask(SIG_UNBLOCK, &sig, 0);
 91
 92	for (;;)
 93		if (kill(getpid(), SIGABRT) < 0)
 94			exit(127);
 95}
 96
 97void os_dump_core(void)
 98{
 99	int pid;
100
101	signal(SIGSEGV, SIG_DFL);
102
103	/*
104	 * We are about to SIGTERM this entire process group to ensure that
105	 * nothing is around to run after the kernel exits.  The
106	 * kernel wants to abort, not die through SIGTERM, so we
107	 * ignore it here.
108	 */
109
110	signal(SIGTERM, SIG_IGN);
111	kill(0, SIGTERM);
112	/*
113	 * Most of the other processes associated with this UML are
114	 * likely sTopped, so give them a SIGCONT so they see the
115	 * SIGTERM.
116	 */
117	kill(0, SIGCONT);
118
119	/*
120	 * Now, having sent signals to everyone but us, make sure they
121	 * die by ptrace.  Processes can survive what's been done to
122	 * them so far - the mechanism I understand is receiving a
123	 * SIGSEGV and segfaulting immediately upon return.  There is
124	 * always a SIGSEGV pending, and (I'm guessing) signals are
125	 * processed in numeric order so the SIGTERM (signal 15 vs
126	 * SIGSEGV being signal 11) is never handled.
127	 *
128	 * Run a waitpid loop until we get some kind of error.
129	 * Hopefully, it's ECHILD, but there's not a lot we can do if
130	 * it's something else.  Tell os_kill_ptraced_process not to
131	 * wait for the child to report its death because there's
132	 * nothing reasonable to do if that fails.
133	 */
134
135	while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
136		os_kill_ptraced_process(pid, 0);
137
138	uml_abort();
139}
140
141void um_early_printk(const char *s, unsigned int n)
142{
143	printf("%.*s", n, s);
144}