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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}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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 <init.h>
17#include <os.h>
18
19void stack_protections(unsigned long address)
20{
21 if (mprotect((void *) address, UM_THREAD_SIZE,
22 PROT_READ | PROT_WRITE | PROT_EXEC) < 0)
23 panic("protecting stack failed, errno = %d", errno);
24}
25
26int raw(int fd)
27{
28 struct termios tt;
29 int err;
30
31 CATCH_EINTR(err = tcgetattr(fd, &tt));
32 if (err < 0)
33 return -errno;
34
35 cfmakeraw(&tt);
36
37 CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));
38 if (err < 0)
39 return -errno;
40
41 /*
42 * XXX tcsetattr could have applied only some changes
43 * (and cfmakeraw() is a set of changes)
44 */
45 return 0;
46}
47
48void setup_machinename(char *machine_out)
49{
50 struct utsname host;
51
52 uname(&host);
53#ifdef UML_CONFIG_UML_X86
54# ifndef UML_CONFIG_64BIT
55 if (!strcmp(host.machine, "x86_64")) {
56 strcpy(machine_out, "i686");
57 return;
58 }
59# else
60 if (!strcmp(host.machine, "i686")) {
61 strcpy(machine_out, "x86_64");
62 return;
63 }
64# endif
65#endif
66 strcpy(machine_out, host.machine);
67}
68
69void setup_hostinfo(char *buf, int len)
70{
71 struct utsname host;
72
73 uname(&host);
74 snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,
75 host.release, host.version, host.machine);
76}
77
78/*
79 * We cannot use glibc's abort(). It makes use of tgkill() which
80 * has no effect within UML's kernel threads.
81 * After that glibc would execute an invalid instruction to kill
82 * the calling process and UML crashes with SIGSEGV.
83 */
84static inline void __attribute__ ((noreturn)) uml_abort(void)
85{
86 sigset_t sig;
87
88 fflush(NULL);
89
90 if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))
91 sigprocmask(SIG_UNBLOCK, &sig, 0);
92
93 for (;;)
94 if (kill(getpid(), SIGABRT) < 0)
95 exit(127);
96}
97
98/*
99 * UML helper threads must not handle SIGWINCH/INT/TERM
100 */
101void os_fix_helper_signals(void)
102{
103 signal(SIGWINCH, SIG_IGN);
104 signal(SIGINT, SIG_DFL);
105 signal(SIGTERM, SIG_DFL);
106}
107
108void os_dump_core(void)
109{
110 int pid;
111
112 signal(SIGSEGV, SIG_DFL);
113
114 /*
115 * We are about to SIGTERM this entire process group to ensure that
116 * nothing is around to run after the kernel exits. The
117 * kernel wants to abort, not die through SIGTERM, so we
118 * ignore it here.
119 */
120
121 signal(SIGTERM, SIG_IGN);
122 kill(0, SIGTERM);
123 /*
124 * Most of the other processes associated with this UML are
125 * likely sTopped, so give them a SIGCONT so they see the
126 * SIGTERM.
127 */
128 kill(0, SIGCONT);
129
130 /*
131 * Now, having sent signals to everyone but us, make sure they
132 * die by ptrace. Processes can survive what's been done to
133 * them so far - the mechanism I understand is receiving a
134 * SIGSEGV and segfaulting immediately upon return. There is
135 * always a SIGSEGV pending, and (I'm guessing) signals are
136 * processed in numeric order so the SIGTERM (signal 15 vs
137 * SIGSEGV being signal 11) is never handled.
138 *
139 * Run a waitpid loop until we get some kind of error.
140 * Hopefully, it's ECHILD, but there's not a lot we can do if
141 * it's something else. Tell os_kill_ptraced_process not to
142 * wait for the child to report its death because there's
143 * nothing reasonable to do if that fails.
144 */
145
146 while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
147 os_kill_ptraced_process(pid, 0);
148
149 uml_abort();
150}
151
152void um_early_printk(const char *s, unsigned int n)
153{
154 printf("%.*s", n, s);
155}
156
157static int quiet_info;
158
159static int __init quiet_cmd_param(char *str, int *add)
160{
161 quiet_info = 1;
162 return 0;
163}
164
165__uml_setup("quiet", quiet_cmd_param,
166"quiet\n"
167" Turns off information messages during boot.\n\n");
168
169void os_info(const char *fmt, ...)
170{
171 va_list list;
172
173 if (quiet_info)
174 return;
175
176 va_start(list, fmt);
177 vfprintf(stderr, fmt, list);
178 va_end(list);
179}
180
181void os_warn(const char *fmt, ...)
182{
183 va_list list;
184
185 va_start(list, fmt);
186 vfprintf(stderr, fmt, list);
187 va_end(list);
188}