1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <ctype.h>
33 #include <signal.h>
34 #include <sys/mman.h>
35 #include <errno.h>
36
37 #include "linker.h"
38
39 #include <sys/socket.h>
40 #include <sys/un.h>
41
42 void notify_gdb_of_libraries();
43
44 #define RETRY_ON_EINTR(ret,cond) \
45 do { \
46 ret = (cond); \
47 } while (ret < 0 && errno == EINTR)
48
49
socket_abstract_client(const char * name,int type)50 static int socket_abstract_client(const char *name, int type)
51 {
52 struct sockaddr_un addr;
53 size_t namelen;
54 socklen_t alen;
55 int s, err;
56
57 namelen = strlen(name);
58
59 // Test with length +1 for the *initial* '\0'.
60 if ((namelen + 1) > sizeof(addr.sun_path)) {
61 errno = EINVAL;
62 return -1;
63 }
64
65 /* This is used for abstract socket namespace, we need
66 * an initial '\0' at the start of the Unix socket path.
67 *
68 * Note: The path in this case is *not* supposed to be
69 * '\0'-terminated. ("man 7 unix" for the gory details.)
70 */
71 memset (&addr, 0, sizeof addr);
72 addr.sun_family = AF_LOCAL;
73 addr.sun_path[0] = 0;
74 memcpy(addr.sun_path + 1, name, namelen);
75
76 alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
77
78 s = socket(AF_LOCAL, type, 0);
79 if(s < 0) return -1;
80
81 RETRY_ON_EINTR(err,connect(s, (struct sockaddr *) &addr, alen));
82 if (err < 0) {
83 close(s);
84 s = -1;
85 }
86
87 return s;
88 }
89
90 #include "linker_format.h"
91 #include <../libc/private/logd.h>
92
93 /*
94 * Writes a summary of the signal to the log file.
95 *
96 * We could be here as a result of native heap corruption, or while a
97 * mutex is being held, so we don't want to use any libc functions that
98 * could allocate memory or hold a lock.
99 */
logSignalSummary(int signum,const siginfo_t * info)100 static void logSignalSummary(int signum, const siginfo_t* info)
101 {
102 char buffer[128];
103
104 char* signame;
105 switch (signum) {
106 case SIGILL: signame = "SIGILL"; break;
107 case SIGABRT: signame = "SIGABRT"; break;
108 case SIGBUS: signame = "SIGBUS"; break;
109 case SIGFPE: signame = "SIGFPE"; break;
110 case SIGSEGV: signame = "SIGSEGV"; break;
111 case SIGSTKFLT: signame = "SIGSTKFLT"; break;
112 case SIGPIPE: signame = "SIGPIPE"; break;
113 default: signame = "???"; break;
114 }
115
116 format_buffer(buffer, sizeof(buffer),
117 "Fatal signal %d (%s) at 0x%08x (code=%d)",
118 signum, signame, info->si_addr, info->si_code);
119
120 __libc_android_log_write(ANDROID_LOG_FATAL, "libc", buffer);
121 }
122
123 /*
124 * Catches fatal signals so we can ask debuggerd to ptrace us before
125 * we crash.
126 */
debugger_signal_handler(int n,siginfo_t * info,void * unused)127 void debugger_signal_handler(int n, siginfo_t* info, void* unused)
128 {
129 unsigned tid;
130 int s;
131
132 logSignalSummary(n, info);
133
134 tid = gettid();
135 s = socket_abstract_client("android:debuggerd", SOCK_STREAM);
136
137 if(s >= 0) {
138 /* debugger knows our pid from the credentials on the
139 * local socket but we need to tell it our tid. It
140 * is paranoid and will verify that we are giving a tid
141 * that's actually in our process
142 */
143 int ret;
144
145 RETRY_ON_EINTR(ret, write(s, &tid, sizeof(unsigned)));
146 if (ret == sizeof(unsigned)) {
147 /* if the write failed, there is no point to read on
148 * the file descriptor. */
149 RETRY_ON_EINTR(ret, read(s, &tid, 1));
150 notify_gdb_of_libraries();
151 }
152 close(s);
153 }
154
155 /* remove our net so we fault for real when we return */
156 signal(n, SIG_DFL);
157 }
158
debugger_init()159 void debugger_init()
160 {
161 struct sigaction act;
162 memset(&act, 0, sizeof(act));
163 act.sa_sigaction = debugger_signal_handler;
164 act.sa_flags = SA_RESTART | SA_SIGINFO;
165 sigemptyset(&act.sa_mask);
166
167 sigaction(SIGILL, &act, NULL);
168 sigaction(SIGABRT, &act, NULL);
169 sigaction(SIGBUS, &act, NULL);
170 sigaction(SIGFPE, &act, NULL);
171 sigaction(SIGSEGV, &act, NULL);
172 sigaction(SIGSTKFLT, &act, NULL);
173 sigaction(SIGPIPE, &act, NULL);
174 }
175