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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/param.h>
#include <sys/ucontext.h>
#include <string.h>
#include <errno.h>
#ifdef __linux__
#include <sys/prctl.h>
#ifndef PR_SET_PTRACER
#define PR_SET_PTRACER 0x59616d61
#endif
#elif defined (__APPLE__)
#include <signal.h>
#endif
static const char crash_switch[] = "--cc-handle-crash";
static const char fatal_err[] = "\n\n*** Fatal Error ***\n";
static const char pipe_err[] = "!!! Failed to create pipe\n";
static const char fork_err[] = "!!! Failed to fork debug process\n";
static const char exec_err[] = "!!! Failed to exec debug process\n";
static char argv0[PATH_MAX];
static char altstack[SIGSTKSZ];
static struct {
int signum;
pid_t pid;
int has_siginfo;
siginfo_t siginfo;
char buf[1024];
} crash_info;
static const struct {
const char *name;
int signum;
} signals[] = {
{ "Segmentation fault", SIGSEGV },
{ "Illegal instruction", SIGILL },
{ "FPU exception", SIGFPE },
{ "System BUS error", SIGBUS },
{ NULL, 0 }
};
static const struct {
int code;
const char *name;
} sigill_codes[] = {
#ifndef __FreeBSD__
{ ILL_ILLOPC, "Illegal opcode" },
{ ILL_ILLOPN, "Illegal operand" },
{ ILL_ILLADR, "Illegal addressing mode" },
{ ILL_ILLTRP, "Illegal trap" },
{ ILL_PRVOPC, "Privileged opcode" },
{ ILL_PRVREG, "Privileged register" },
{ ILL_COPROC, "Coprocessor error" },
{ ILL_BADSTK, "Internal stack error" },
#endif
{ 0, NULL }
};
static const struct {
int code;
const char *name;
} sigfpe_codes[] = {
{ FPE_INTDIV, "Integer divide by zero" },
{ FPE_INTOVF, "Integer overflow" },
{ FPE_FLTDIV, "Floating point divide by zero" },
{ FPE_FLTOVF, "Floating point overflow" },
{ FPE_FLTUND, "Floating point underflow" },
{ FPE_FLTRES, "Floating point inexact result" },
{ FPE_FLTINV, "Floating point invalid operation" },
{ FPE_FLTSUB, "Subscript out of range" },
{ 0, NULL }
};
static const struct {
int code;
const char *name;
} sigsegv_codes[] = {
#ifndef __FreeBSD__
{ SEGV_MAPERR, "Address not mapped to object" },
{ SEGV_ACCERR, "Invalid permissions for mapped object" },
#endif
{ 0, NULL }
};
static const struct {
int code;
const char *name;
} sigbus_codes[] = {
#ifndef __FreeBSD__
{ BUS_ADRALN, "Invalid address alignment" },
{ BUS_ADRERR, "Non-existent physical address" },
{ BUS_OBJERR, "Object specific hardware error" },
#endif
{ 0, NULL }
};
static int (*cc_user_info)(char*, char*);
static void gdb_info(pid_t pid)
{
char respfile[64];
char cmd_buf[128];
FILE *f;
int fd;
/* Create a temp file to put gdb commands into */
strcpy(respfile, "gdb-respfile-XXXXXX");
if((fd=mkstemp(respfile)) >= 0 && (f=fdopen(fd, "w")) != NULL)
{
fprintf(f, "attach %d\n"
"shell echo \"\"\n"
"shell echo \"* Loaded Libraries\"\n"
"info sharedlibrary\n"
"shell echo \"\"\n"
"shell echo \"* Threads\"\n"
"info threads\n"
"shell echo \"\"\n"
"shell echo \"* FPU Status\"\n"
"info float\n"
"shell echo \"\"\n"
"shell echo \"* Registers\"\n"
"info registers\n"
"shell echo \"\"\n"
"shell echo \"* Backtrace\"\n"
"thread apply all backtrace full\n"
"detach\n"
"quit\n", pid);
fclose(f);
/* Run gdb and print process info. */
snprintf(cmd_buf, sizeof(cmd_buf), "gdb --quiet --batch --command=%s", respfile);
printf("Executing: %s\n", cmd_buf);
fflush(stdout);
system(cmd_buf);
/* Clean up */
remove(respfile);
}
else
{
/* Error creating temp file */
if(fd >= 0)
{
close(fd);
remove(respfile);
}
printf("!!! Could not create gdb command file\n");
}
fflush(stdout);
}
static void sys_info(void)
{
#ifdef __unix__
system("echo \"System: `uname -a`\"");
putchar('\n');
fflush(stdout);
#endif
}
static size_t safe_write(int fd, const void *buf, size_t len)
{
size_t ret = 0;
while(ret < len)
{
ssize_t rem;
if((rem=write(fd, (const char*)buf+ret, len-ret)) == -1)
{
if(errno == EINTR)
continue;
break;
}
ret += rem;
}
return ret;
}
static void crash_catcher(int signum, siginfo_t *siginfo, void *context)
{
ucontext_t *ucontext = (ucontext_t*)context;
pid_t dbg_pid;
int fd[2];
/* Make sure the effective uid is the real uid */
if(getuid() != geteuid())
{
raise(signum);
return;
}
safe_write(STDERR_FILENO, fatal_err, sizeof(fatal_err)-1);
if(pipe(fd) == -1)
{
safe_write(STDERR_FILENO, pipe_err, sizeof(pipe_err)-1);
raise(signum);
return;
}
crash_info.signum = signum;
crash_info.pid = getpid();
crash_info.has_siginfo = !!siginfo;
if(siginfo)
crash_info.siginfo = *siginfo;
if(cc_user_info)
cc_user_info(crash_info.buf, crash_info.buf+sizeof(crash_info.buf));
/* Fork off to start a crash handler */
switch((dbg_pid=fork()))
{
/* Error */
case -1:
safe_write(STDERR_FILENO, fork_err, sizeof(fork_err)-1);
raise(signum);
return;
case 0:
dup2(fd[0], STDIN_FILENO);
close(fd[0]);
close(fd[1]);
execl(argv0, argv0, crash_switch, NULL);
safe_write(STDERR_FILENO, exec_err, sizeof(exec_err)-1);
_exit(1);
default:
#ifdef __linux__
prctl(PR_SET_PTRACER, dbg_pid, 0, 0, 0);
#endif
safe_write(fd[1], &crash_info, sizeof(crash_info));
close(fd[0]);
close(fd[1]);
/* Wait; we'll be killed when gdb is done */
do {
int status;
if(waitpid(dbg_pid, &status, 0) == dbg_pid &&
(WIFEXITED(status) || WIFSIGNALED(status)))
{
/* The debug process died before it could kill us */
raise(signum);
break;
}
} while(1);
}
}
static void crash_handler(const char *logfile)
{
const char *sigdesc = "";
int i;
if(fread(&crash_info, sizeof(crash_info), 1, stdin) != 1)
{
fprintf(stderr, "!!! Failed to retrieve info from crashed process\n");
exit(1);
}
/* Get the signal description */
for(i = 0;signals[i].name;++i)
{
if(signals[i].signum == crash_info.signum)
{
sigdesc = signals[i].name;
break;
}
}
if(crash_info.has_siginfo)
{
switch(crash_info.signum)
{
case SIGSEGV:
for(i = 0;sigsegv_codes[i].name;++i)
{
if(sigsegv_codes[i].code == crash_info.siginfo.si_code)
{
sigdesc = sigsegv_codes[i].name;
break;
}
}
break;
case SIGFPE:
for(i = 0;sigfpe_codes[i].name;++i)
{
if(sigfpe_codes[i].code == crash_info.siginfo.si_code)
{
sigdesc = sigfpe_codes[i].name;
break;
}
}
break;
case SIGILL:
for(i = 0;sigill_codes[i].name;++i)
{
if(sigill_codes[i].code == crash_info.siginfo.si_code)
{
sigdesc = sigill_codes[i].name;
break;
}
}
break;
case SIGBUS:
for(i = 0;sigbus_codes[i].name;++i)
{
if(sigbus_codes[i].code == crash_info.siginfo.si_code)
{
sigdesc = sigbus_codes[i].name;
break;
}
}
break;
}
}
fprintf(stderr, "%s (signal %i)\n", sigdesc, crash_info.signum);
if(crash_info.has_siginfo)
fprintf(stderr, "Address: %p\n", crash_info.siginfo.si_addr);
fputc('\n', stderr);
if(logfile)
{
/* Create crash log file and redirect shell output to it */
if(freopen(logfile, "wa", stdout) != stdout)
{
fprintf(stderr, "!!! Could not create %s following signal\n", logfile);
exit(1);
}
fprintf(stderr, "Generating %s and killing process %d, please wait... ", logfile, crash_info.pid);
printf("*** Fatal Error ***\n"
"%s (signal %i)\n", sigdesc, crash_info.signum);
if(crash_info.has_siginfo)
printf("Address: %p\n", crash_info.siginfo.si_addr);
fputc('\n', stdout);
fflush(stdout);
}
sys_info();
crash_info.buf[sizeof(crash_info.buf)-1] = '\0';
printf("%s\n", crash_info.buf);
fflush(stdout);
if(crash_info.pid > 0)
{
gdb_info(crash_info.pid);
kill(crash_info.pid, SIGKILL);
}
if(logfile)
{
const char *str;
char buf[512];
if((str=getenv("KDE_FULL_SESSION")) && strcmp(str, "true") == 0)
snprintf(buf, sizeof(buf), "kdialog --title \"Very Fatal Error\" --textbox \"%s\" 800 600", logfile);
else if((str=getenv("GNOME_DESKTOP_SESSION_ID")) && str[0] != '\0')
snprintf(buf, sizeof(buf), "gxmessage -buttons \"Okay:0\" -geometry 800x600 -title \"Very Fatal Error\" -center -file \"%s\"", logfile);
else
snprintf(buf, sizeof(buf), "xmessage -buttons \"Okay:0\" -center -file \"%s\"", logfile);
system(buf);
}
exit(0);
}
int cc_install_handlers(int argc, char **argv, int num_signals, int *signals, const char *logfile, int (*user_info)(char*, char*))
{
struct sigaction sa;
stack_t altss;
int retval;
if(argc == 2 && strcmp(argv[1], crash_switch) == 0)
crash_handler(logfile);
cc_user_info = user_info;
if(argv[0][0] == '/')
snprintf(argv0, sizeof(argv0), "%s", argv[0]);
else
{
getcwd(argv0, sizeof(argv0));
retval = strlen(argv0);
snprintf(argv0+retval, sizeof(argv0)-retval, "/%s", argv[0]);
}
/* Set an alternate signal stack so SIGSEGVs caused by stack overflows
* still run */
altss.ss_sp = altstack;
altss.ss_flags = 0;
altss.ss_size = sizeof(altstack);
sigaltstack(&altss, NULL);
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = crash_catcher;
sa.sa_flags = SA_RESETHAND | SA_NODEFER | SA_SIGINFO | SA_ONSTACK;
sigemptyset(&sa.sa_mask);
retval = 0;
while(num_signals--)
{
if((*signals != SIGSEGV && *signals != SIGILL && *signals != SIGFPE &&
*signals != SIGBUS) || sigaction(*signals, &sa, NULL) == -1)
{
*signals = 0;
retval = -1;
}
++signals;
}
return retval;
}
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