int
mdb_signal_sethandler(int sig, mdb_signal_f *handler, void *data)
{
struct sigaction act;
int status;
ASSERT(sig > 0 && sig < NSIG && sig != SIGKILL && sig != SIGSTOP);
sig_handlers[sig] = handler;
sig_data[sig] = data;
if (handler == SIG_DFL || handler == SIG_IGN) {
act.sa_handler = handler;
act.sa_flags = SA_RESTART;
} else {
act.sa_handler = sig_stub;
act.sa_flags = SA_SIGINFO | SA_RESTART | SA_ONSTACK;
}
(void) sigemptyset(&act.sa_mask);
if (sig == SIGWINCH || sig == SIGTSTP) {
(void) sigaddset(&act.sa_mask, SIGWINCH);
(void) sigaddset(&act.sa_mask, SIGTSTP);
(void) sigaddset(&act.sa_mask, SIGHUP);
(void) sigaddset(&act.sa_mask, SIGTERM);
}
if ((status = sigaction(sig, &act, NULL)) == 0)
(void) mdb_signal_unblock(sig);
return (status);
}
void
vfail(const char *format, va_list alist)
{
extern const char *volatile _mdb_abort_str;
static char buf[256];
static int nfail;
if (_mdb_abort_str == NULL) {
_mdb_abort_str = buf; /* Do this first so we don't recurse */
(void) mdb_iob_vsnprintf(buf, sizeof (buf), format, alist);
nfail = 1;
}
/*
* We'll try to print failure messages twice. Any more than that,
* and we're probably hitting an assertion or some other problem in
* the printing routines, and will recurse until we run out of stack.
*/
if (nfail++ < 3) {
mdb_iob_printf(mdb.m_err, "%s ABORT: ", mdb.m_pname);
mdb_iob_vprintf(mdb.m_err, format, alist);
mdb_iob_flush(mdb.m_err);
(void) mdb_signal_blockall();
(void) mdb_signal_raise(SIGABRT);
(void) mdb_signal_unblock(SIGABRT);
}
exit(1);
}
/*
* The real main loop of the debugger: create a new execution frame on the
* debugger stack, and while we have input available, call into the parser.
*/
int
mdb_run(void)
{
volatile int err;
mdb_frame_t f;
mdb_intr_disable();
mdb_frame_push(&f);
/*
* This is a fresh mdb context, so ignore any pipe command we may have
* inherited from the previous frame.
*/
f.f_pcmd = NULL;
if ((err = setjmp(f.f_pcb)) != 0) {
int pop = (mdb.m_in != NULL &&
(mdb_iob_isapipe(mdb.m_in) || mdb_iob_isastr(mdb.m_in)));
int fromcmd = (f.f_cp != NULL);
mdb_dprintf(MDB_DBG_DSTK, "frame <%u> caught event %s\n",
f.f_id, mdb_err2str(err));
/*
* If a syntax error or other failure has occurred, pop all
* input buffers pushed by commands executed in this frame.
*/
while (mdb_iob_stack_size(&f.f_istk) != 0) {
if (mdb.m_in != NULL)
mdb_iob_destroy(mdb.m_in);
mdb.m_in = mdb_iob_stack_pop(&f.f_istk);
yylineno = mdb_iob_lineno(mdb.m_in);
}
/*
* Reset standard output and the current frame to a known,
* clean state, so we can continue execution.
*/
mdb_iob_margin(mdb.m_out, MDB_IOB_DEFMARGIN);
mdb_iob_clrflags(mdb.m_out, MDB_IOB_INDENT);
mdb_iob_discard(mdb.m_out);
mdb_frame_reset(&f);
/*
* If there was an error writing to output, display a warning
* message if this is the topmost frame.
*/
if (err == MDB_ERR_OUTPUT && mdb.m_depth == 1 && errno != EPIPE)
mdb_warn("write failed");
/*
* If an interrupt or quit signal is reported, we may have been
* in the middle of typing or processing the command line:
* print a newline and discard everything in the parser's iob.
* Note that we do this after m_out has been reset, otherwise
* we could trigger a pipe context switch or cause a write
* to a broken pipe (in the case of a shell command) when
* writing the newline.
*/
if (err == MDB_ERR_SIGINT || err == MDB_ERR_QUIT) {
mdb_iob_nl(mdb.m_out);
yydiscard();
}
/*
* If we quit or abort using the output pager, reset the
* line count on standard output back to zero.
*/
if (err == MDB_ERR_PAGER || MDB_ERR_IS_FATAL(err))
mdb_iob_clearlines(mdb.m_out);
/*
* If the user requested the debugger quit or abort back to
* the top, or if standard input is a pipe or mdb_eval("..."),
* then propagate the error up the debugger stack.
*/
if (MDB_ERR_IS_FATAL(err) || pop != 0 ||
(err == MDB_ERR_PAGER && mdb.m_fmark != &f) ||
(err == MDB_ERR_NOMEM && !fromcmd)) {
mdb_frame_pop(&f, err);
return (err);
}
/*
* If we've returned here from a context where signals were
* blocked (e.g. a signal handler), we can now unblock them.
*/
if (err == MDB_ERR_SIGINT)
(void) mdb_signal_unblock(SIGINT);
} else
mdb_intr_enable();
for (;;) {
while (mdb.m_in != NULL && (mdb_iob_getflags(mdb.m_in) &
(MDB_IOB_ERR | MDB_IOB_EOF)) == 0) {
if (mdb.m_depth == 1 &&
mdb_iob_stack_size(&f.f_istk) == 0) {
mdb_iob_clearlines(mdb.m_out);
mdb_tgt_periodic(mdb.m_target);
}
(void) yyparse();
}
if (mdb.m_in != NULL) {
if (mdb_iob_err(mdb.m_in)) {
warn("error reading input stream %s\n",
mdb_iob_name(mdb.m_in));
}
mdb_iob_destroy(mdb.m_in);
mdb.m_in = NULL;
}
if (mdb_iob_stack_size(&f.f_istk) == 0)
break; /* return when we're out of input */
mdb.m_in = mdb_iob_stack_pop(&f.f_istk);
yylineno = mdb_iob_lineno(mdb.m_in);
}
mdb_frame_pop(&f, 0);
/*
* The value of '.' is a per-frame attribute, to preserve it properly
* when switching frames. But in the case of calling mdb_run()
* explicitly (such as through mdb_eval), we want to propagate the value
* of '.' to the parent.
*/
mdb_nv_set_value(mdb.m_dot, f.f_dot);
return (0);
}
