generic-library/bionic
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Log signal info at time of receipt

Browse Source 
When a fatal signal is received, we now write a message to the log
that looks like this:

  F/libc    ( 1540): Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1)

This is useful for debugging fatal signals that turn out not to be
fatal.  This also changes the signal reset from SIG_IGN to SIG_DFL,
so that future non-fatal fatal signals are fatal.

The code that blocked SIGUSR1 to avoid being interrupted by the GC
has been removed.

Also, fix minor issues in format_buffer().

Bug 5035703

Change-Id: I8940af47297b5dcf3cf33537e3483ca5334ed565
This commit is contained in:
Andy McFadden 2011-07-29 12:46:34 -07:00
parent 3a5d668e01
commit ec92af8fe5
2 changed files with 70 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
linker/debugger.c
View File

@ -87,13 +87,49 @@ static int socket_abstract_client(const char *name, int type)
return s;
}
void debugger_signal_handler(int n)
#include "linker_format.h"
#include <../libc/private/logd.h>
/*
* Writes a summary of the signal to the log file.
*
* We could be here as a result of native heap corruption, or while a
* mutex is being held, so we don't want to use any libc functions that
* could allocate memory or hold a lock.
*/
static void logSignalSummary(int signum, const siginfo_t* info)
{
char buffer[128];
char* signame;
switch (signum) {
case SIGILL: signame = "SIGILL"; break;
case SIGABRT: signame = "SIGABRT"; break;
case SIGBUS: signame = "SIGBUS"; break;
case SIGFPE: signame = "SIGFPE"; break;
case SIGSEGV: signame = "SIGSEGV"; break;
case SIGSTKFLT: signame = "SIGSTKFLT"; break;
case SIGPIPE: signame = "SIGPIPE"; break;
default: signame = "???"; break;
}
format_buffer(buffer, sizeof(buffer),
"Fatal signal %d (%s) at 0x%08x (code=%d)",
signum, signame, info->si_addr, info->si_code);
__libc_android_log_write(ANDROID_LOG_FATAL, "libc", buffer);
}
/*
* Catches fatal signals so we can ask debuggerd to ptrace us before
* we crash.
*/
void debugger_signal_handler(int n, siginfo_t* info, void* unused)
{
unsigned tid;
int s;
/* avoid picking up GC interrupts */
signal(SIGUSR1, SIG_IGN);
logSignalSummary(n, info);
tid = gettid();
s = socket_abstract_client("android:debuggerd", SOCK_STREAM);
@ -117,16 +153,22 @@ void debugger_signal_handler(int n)
}
/* remove our net so we fault for real when we return */
signal(n, SIG_IGN);
signal(n, SIG_DFL);
}
void debugger_init()
{
signal(SIGILL, debugger_signal_handler);
signal(SIGABRT, debugger_signal_handler);
signal(SIGBUS, debugger_signal_handler);
signal(SIGFPE, debugger_signal_handler);
signal(SIGSEGV, debugger_signal_handler);
signal(SIGSTKFLT, debugger_signal_handler);
signal(SIGPIPE, debugger_signal_handler);
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_sigaction = debugger_signal_handler;
act.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&act.sa_mask);
sigaction(SIGILL, &act, NULL);
sigaction(SIGABRT, &act, NULL);
sigaction(SIGBUS, &act, NULL);
sigaction(SIGFPE, &act, NULL);
sigaction(SIGSEGV, &act, NULL);
sigaction(SIGSTKFLT, &act, NULL);
sigaction(SIGPIPE, &act, NULL);
}

32
linker/linker_format.c
View File

@ -427,18 +427,20 @@ format_hex(char *buffer, size_t buffsize, uint64_t value, int isCap)
static void
out_vformat(Out *o, const char *format, va_list args)
{
int nn = 0, mm;
int padZero = 0;
int padLeft = 0;
char sign = '\0';
int width = -1;
int prec = -1;
size_t bytelen = sizeof(int);
const char* str;
int slen;
char buffer[32]; /* temporary buffer used to format numbers */
int nn = 0;
for (;;) {
int mm;
int padZero = 0;
int padLeft = 0;
char sign = '\0';
int width = -1;
int prec = -1;
size_t bytelen = sizeof(int);
const char* str;
int slen;
char buffer[32]; /* temporary buffer used to format numbers */
char c;
/* first, find all characters that are not 0 or '%' */
@ -525,9 +527,6 @@ out_vformat(Out *o, const char *format, va_list args)
bytelen = sizeof(ptrdiff_t);
c = format[nn++];
break;
case 'p':
bytelen = sizeof(void*);
c = format[nn++];
default:
;
}
@ -543,7 +542,7 @@ out_vformat(Out *o, const char *format, va_list args)
buffer[1] = '\0';
str = buffer;
} else if (c == 'p') {
uint64_t value = (uint64_t)(ptrdiff_t) va_arg(args, void*);
uint64_t value = (uintptr_t) va_arg(args, void*);
buffer[0] = '0';
buffer[1] = 'x';
format_hex(buffer + 2, sizeof buffer-2, value, 0);
@ -684,7 +683,7 @@ int main(void)
utest_expect("-8123", "%d", -8123);
utest_expect("16", "%hd", 0x7fff0010);
utest_expect("16", "%hhd", 0x7fffff10);
utest_expect("68719476736", "%lld", 0x1000000000);
utest_expect("68719476736", "%lld", 0x1000000000LL);
utest_expect("70000", "%ld", 70000);
utest_expect("0xb0001234", "%p", (void*)0xb0001234);
utest_expect("12ab", "%x", 0x12ab);
@ -697,6 +696,9 @@ int main(void)
utest_expect("1234 ", "%-8d", 1234);
utest_expect("abcdef ", "%-11s", "abcdef");
utest_expect("something:1234", "%s:%d", "something", 1234);
utest_expect("005:5:05", "%03d:%d:%02d", 5, 5, 5);
utest_expect("5,0x0", "%d,%p", 5, NULL);
utest_expect("68719476736,6,7,8", "%lld,%d,%d,%d", 0x1000000000LL, 6, 7, 8);
return gFails != 0;
}