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
97/*
98 * UML helper threads must not handle SIGWINCH/INT/TERM
99 */
100void os_fix_helper_signals(void)
101{
102	signal(SIGWINCH, SIG_IGN);
103	signal(SIGINT, SIG_DFL);
104	signal(SIGTERM, SIG_DFL);
105}
106
107void os_dump_core(void)
108{
109	int pid;
110
111	signal(SIGSEGV, SIG_DFL);
112
113	/*
114	 * We are about to SIGTERM this entire process group to ensure that
115	 * nothing is around to run after the kernel exits.  The
116	 * kernel wants to abort, not die through SIGTERM, so we
117	 * ignore it here.
118	 */
119
120	signal(SIGTERM, SIG_IGN);
121	kill(0, SIGTERM);
122	/*
123	 * Most of the other processes associated with this UML are
124	 * likely sTopped, so give them a SIGCONT so they see the
125	 * SIGTERM.
126	 */
127	kill(0, SIGCONT);
128
129	/*
130	 * Now, having sent signals to everyone but us, make sure they
131	 * die by ptrace.  Processes can survive what's been done to
132	 * them so far - the mechanism I understand is receiving a
133	 * SIGSEGV and segfaulting immediately upon return.  There is
134	 * always a SIGSEGV pending, and (I'm guessing) signals are
135	 * processed in numeric order so the SIGTERM (signal 15 vs
136	 * SIGSEGV being signal 11) is never handled.
137	 *
138	 * Run a waitpid loop until we get some kind of error.
139	 * Hopefully, it's ECHILD, but there's not a lot we can do if
140	 * it's something else.  Tell os_kill_ptraced_process not to
141	 * wait for the child to report its death because there's
142	 * nothing reasonable to do if that fails.
143	 */
144
145	while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
146		os_kill_ptraced_process(pid, 0);
147
148	uml_abort();
149}
150
151void um_early_printk(const char *s, unsigned int n)
152{
153	printf("%.*s", n, s);
154}
155