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GeezerVison is showing github.com — libstacktrace/stacktrace.c at main · cppcoffee/libstacktrace

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#define _GNU_SOURCE
#include <execinfo.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <signal.h>
#include <unistd.h>
#include "symbol_table.h"
// The max number of levels in the stack trace
#define STACK_TRACE_MAX_LEVELS 100
#define BUFFER_LENGTH 4096
typedef void (*signal_handler_t)(int signo, siginfo_t *info, void *ctx);
static void register_crash_handlers();
static int backtrace_symbol_write(int fd, const char *text, void *addr);
// store process full path.
static char program_path[PATH_MAX];
// the current program binary symbol table.
static symbol_table_t symtab;
// initialize stacktrace library.
int init_stacktrace()
{
int n;
n = readlink("/proc/self/exe", program_path, PATH_MAX);
if (n < 0 || n >= PATH_MAX) {
return -1;
}
program_path[n] = '\0';
if (symbol_table_build(program_path, &symtab) != 0) {
return -2;
}
register_crash_handlers();
return 0;
}
static void
stack_trace_dump()
{
int i, btl;
char **strings;
void *stack[STACK_TRACE_MAX_LEVELS + 1];
const char *msg = " - STACK TRACE: \n";
if (write(STDERR_FILENO, program_path, strlen(program_path)) == -1) {
return;
}
if (write(STDERR_FILENO, msg, strlen(msg)) == -1) {
return;
}
memset(stack, 0, sizeof(stack));
if ((btl = backtrace(stack, STACK_TRACE_MAX_LEVELS)) > 2) {
strings = backtrace_symbols(stack, btl);
if (strings != NULL) {
for (i = 2; i < btl; i++) {
backtrace_symbol_write(STDERR_FILENO, strings[i], stack[i]);
}
free(strings);
} else {
backtrace_symbols_fd(stack + 2, btl - 2, STDERR_FILENO);
}
}
}
// Reset a signal handler to the default handler.
static void
signal_reset_default(int signo)
{
struct sigaction act;
act.sa_handler = SIG_DFL;
act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
sigemptyset(&(act.sa_mask));
assert(sigaction(signo, &act, NULL) == 0);
}
static void
signal_crash_handler(int signo, siginfo_t *siginfo, void *data)
{
stack_trace_dump();
signal_reset_default(signo);
// throw signal to default handler.
raise(signo);
}
static void
set_signal(int signo, signal_handler_t handler)
{
struct sigaction act;
act.sa_handler = NULL;
act.sa_sigaction = handler;
act.sa_flags = SA_SIGINFO;
sigemptyset(&(act.sa_mask));
assert(sigaction(signo, &act, NULL) == 0);
}
static void
register_crash_handlers()
{
set_signal(SIGBUS, signal_crash_handler);
set_signal(SIGSEGV, signal_crash_handler);
set_signal(SIGILL, signal_crash_handler);
set_signal(SIGTRAP, signal_crash_handler);
set_signal(SIGFPE, signal_crash_handler);
set_signal(SIGABRT, signal_crash_handler);
}
static int
backtrace_symbol_format(char *buf, size_t len, const char *prefix, frame_record_t fr)
{
int n;
char *p = buf;
// file name
if (fr.filename != NULL) {
n = snprintf(p, len, "%s %s", prefix, fr.filename);
} else {
n = snprintf(p, len, "%s ??", prefix);
}
p += n;
len -= n;
// function name
if (fr.functionname != NULL && *fr.functionname != '\0') {
n = snprintf(p, len, " %s()", fr.functionname);
} else {
n = snprintf(p, len, " ??");
}
p += n;
len -= n;
// line
if (fr.line != 0) {
n = snprintf(p, len, ":%u", fr.line);
p += n;
len -= n;
}
// discriminator
if (fr.discriminator != 0) {
n = snprintf(p, len, " (discriminator %u)\n", fr.discriminator);
} else {
n = snprintf(p, len, "\n");
}
p += n;
len -= n;
return p - buf;
}
static int
backtrace_symbol_write(int fd, const char *text, void *addr)
{
frame_record_t fr;
int n;
char buf[BUFFER_LENGTH + 1];
if (symbol_table_find(&symtab, addr, &fr)) {
n = backtrace_symbol_format(buf, BUFFER_LENGTH, text, fr);
} else {
n = snprintf(buf, BUFFER_LENGTH, "%s\n", text);
}
buf[n] = '\0';
if (write(fd, buf, strlen(buf)) == -1) {
return -1;
}
return 0;
}
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