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1 /*
2  * This file is part of ltrace.
3  * Copyright (C) 2011,2012,2013 Petr Machata, Red Hat Inc.
4  * Copyright (C) 2010 Arnaud Patard, Mandriva SA
5  * Copyright (C) 1998,2001,2002,2003,2004,2007,2008,2009 Juan Cespedes
6  * Copyright (C) 2008 Luis Machado, IBM Corporation
7  * Copyright (C) 2006 Ian Wienand
8  * Copyright (C) 2006 Paul Gilliam, IBM Corporation
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23  * 02110-1301 USA
24  */
25 
26 #include "config.h"
27 
28 #define _GNU_SOURCE
29 #include <assert.h>
30 #include <errno.h>
31 #include <signal.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <stdbool.h>
36 
37 #include "backend.h"
38 #include "breakpoint.h"
39 #include "common.h"
40 #include "fetch.h"
41 #include "library.h"
42 #include "proc.h"
43 #include "prototype.h"
44 #include "summary.h"
45 #include "value_dict.h"
46 
47 static void handle_signal(Event *event);
48 static void handle_exit(Event *event);
49 static void handle_exit_signal(Event *event);
50 static void handle_syscall(Event *event);
51 static void handle_arch_syscall(Event *event);
52 static void handle_sysret(Event *event);
53 static void handle_arch_sysret(Event *event);
54 static void handle_clone(Event *event);
55 static void handle_exec(Event *event);
56 static void handle_breakpoint(Event *event);
57 static void handle_new(Event *event);
58 
59 static void callstack_push_syscall(struct process *proc, int sysnum);
60 static void callstack_push_symfunc(struct process *proc, struct breakpoint *bp);
61 /* XXX Stack maintenance should be moved to a dedicated module, or to
62  * proc.c, and push/pop should be visible outside this module.  For
63  * now, because we need this in proc.c, this is non-static.  */
64 void callstack_pop(struct process *proc);
65 
66 static char *shortsignal(struct process *proc, int signum);
67 static char *sysname(struct process *proc, int sysnum);
68 static char *arch_sysname(struct process *proc, int sysnum);
69 
70 static Event *
call_handler(struct process * proc,Event * event)71 call_handler(struct process *proc, Event *event)
72 {
73 	assert(proc != NULL);
74 
75 	struct event_handler *handler = proc->event_handler;
76 	if (handler == NULL)
77 		return event;
78 
79 	return (*handler->on_event) (handler, event);
80 }
81 
82 void
handle_event(Event * event)83 handle_event(Event *event)
84 {
85 	if (exiting == 1) {
86 		debug(1, "ltrace about to exit");
87 		os_ltrace_exiting();
88 		exiting = 2;
89 	}
90 	debug(DEBUG_FUNCTION, "handle_event(pid=%d, type=%d)",
91 	      event->proc ? event->proc->pid : -1, event->type);
92 
93 	/* If the thread group or an individual task define an
94 	   overriding event handler, give them a chance to kick in.
95 	   We will end up calling both handlers, if the first one
96 	   doesn't sink the event.  */
97 	if (event->proc != NULL) {
98 		event = call_handler(event->proc, event);
99 		if (event == NULL)
100 			/* It was handled.  */
101 			return;
102 
103 		/* Note: the previous handler has a chance to alter
104 		 * the event.  */
105 		if (event->proc != NULL
106 		    && event->proc->leader != NULL
107 		    && event->proc != event->proc->leader) {
108 			event = call_handler(event->proc->leader, event);
109 			if (event == NULL)
110 				return;
111 		}
112 	}
113 
114 	switch (event->type) {
115 	case EVENT_NONE:
116 		debug(1, "event: none");
117 		return;
118 
119 	case EVENT_SIGNAL:
120 		assert(event->proc != NULL);
121 		debug(1, "[%d] event: signal (%s [%d])",
122 		      event->proc->pid,
123 		      shortsignal(event->proc, event->e_un.signum),
124 		      event->e_un.signum);
125 		handle_signal(event);
126 		return;
127 
128 	case EVENT_EXIT:
129 		assert(event->proc != NULL);
130 		debug(1, "[%d] event: exit (%d)",
131 		      event->proc->pid,
132 		      event->e_un.ret_val);
133 		handle_exit(event);
134 		return;
135 
136 	case EVENT_EXIT_SIGNAL:
137 		assert(event->proc != NULL);
138 		debug(1, "[%d] event: exit signal (%s [%d])",
139 		      event->proc->pid,
140 		      shortsignal(event->proc, event->e_un.signum),
141 		      event->e_un.signum);
142 		handle_exit_signal(event);
143 		return;
144 
145 	case EVENT_SYSCALL:
146 		assert(event->proc != NULL);
147 		debug(1, "[%d] event: syscall (%s [%d])",
148 		      event->proc->pid,
149 		      sysname(event->proc, event->e_un.sysnum),
150 		      event->e_un.sysnum);
151 		handle_syscall(event);
152 		return;
153 
154 	case EVENT_SYSRET:
155 		assert(event->proc != NULL);
156 		debug(1, "[%d] event: sysret (%s [%d])",
157 		      event->proc->pid,
158 		      sysname(event->proc, event->e_un.sysnum),
159 		      event->e_un.sysnum);
160 		handle_sysret(event);
161 		return;
162 
163 	case EVENT_ARCH_SYSCALL:
164 		assert(event->proc != NULL);
165 		debug(1, "[%d] event: arch_syscall (%s [%d])",
166 		      event->proc->pid,
167 		      arch_sysname(event->proc, event->e_un.sysnum),
168 		      event->e_un.sysnum);
169 		handle_arch_syscall(event);
170 		return;
171 
172 	case EVENT_ARCH_SYSRET:
173 		assert(event->proc != NULL);
174 		debug(1, "[%d] event: arch_sysret (%s [%d])",
175 		      event->proc->pid,
176 		      arch_sysname(event->proc, event->e_un.sysnum),
177 		      event->e_un.sysnum);
178 		handle_arch_sysret(event);
179 		return;
180 
181 	case EVENT_CLONE:
182 	case EVENT_VFORK:
183 		assert(event->proc != NULL);
184 		debug(1, "[%d] event: clone (%u)",
185 		      event->proc->pid, event->e_un.newpid);
186 		handle_clone(event);
187 		return;
188 
189 	case EVENT_EXEC:
190 		assert(event->proc != NULL);
191 		debug(1, "[%d] event: exec()",
192 		      event->proc->pid);
193 		handle_exec(event);
194 		return;
195 
196 	case EVENT_BREAKPOINT:
197 		assert(event->proc != NULL);
198 		debug(1, "[%d] event: breakpoint %p",
199 		      event->proc->pid, event->e_un.brk_addr);
200 		handle_breakpoint(event);
201 		return;
202 
203 	case EVENT_NEW:
204 		debug(1, "[%d] event: new process",
205 		      event->e_un.newpid);
206 		handle_new(event);
207 		return;
208 	default:
209 		fprintf(stderr, "Error! unknown event?\n");
210 		exit(1);
211 	}
212 }
213 
214 typedef struct Pending_New Pending_New;
215 struct Pending_New {
216 	pid_t pid;
217 	Pending_New * next;
218 };
219 static Pending_New * pending_news = NULL;
220 
221 static int
pending_new(pid_t pid)222 pending_new(pid_t pid) {
223 	Pending_New * p;
224 
225 	debug(DEBUG_FUNCTION, "pending_new(%d)", pid);
226 
227 	p = pending_news;
228 	while (p) {
229 		if (p->pid == pid) {
230 			return 1;
231 		}
232 		p = p->next;
233 	}
234 	return 0;
235 }
236 
237 static void
pending_new_insert(pid_t pid)238 pending_new_insert(pid_t pid) {
239 	Pending_New * p;
240 
241 	debug(DEBUG_FUNCTION, "pending_new_insert(%d)", pid);
242 
243 	p = malloc(sizeof(Pending_New));
244 	if (!p) {
245 		perror("malloc()");
246 		exit(1);
247 	}
248 	p->pid = pid;
249 	p->next = pending_news;
250 	pending_news = p;
251 }
252 
253 static void
pending_new_remove(pid_t pid)254 pending_new_remove(pid_t pid)
255 {
256 	debug(DEBUG_FUNCTION, "pending_new_remove(%d)", pid);
257 
258 	Pending_New **pp;
259 	for (pp = &pending_news; *pp != NULL; pp = &(*pp)->next)
260 		if ((*pp)->pid == pid) {
261 			Pending_New *p = *pp;
262 			*pp = p->next;
263 			free(p);
264 			return;
265 		}
266 }
267 
268 static void
handle_clone(Event * event)269 handle_clone(Event *event)
270 {
271 	debug(DEBUG_FUNCTION, "handle_clone(pid=%d)", event->proc->pid);
272 
273 	struct process *proc = malloc(sizeof(*proc));
274 	pid_t newpid = event->e_un.newpid;
275 	if (proc == NULL
276 	    || process_clone(proc, event->proc, newpid) < 0) {
277 		free(proc);
278 		proc = NULL;
279 		fprintf(stderr,
280 			"Couldn't initialize tracing of process %d.\n",
281 			newpid);
282 
283 	} else {
284 		proc->parent = event->proc;
285 		/* We save register values to the arch pointer, and
286 		 * these need to be per-thread.  XXX arch_ptr should
287 		 * be retired in favor of fetch interface anyway.  */
288 		proc->arch_ptr = NULL;
289 	}
290 
291 	if (pending_new(newpid)) {
292 		pending_new_remove(newpid);
293 
294 		if (proc != NULL) {
295 			proc->event_handler = NULL;
296 			if (event->proc->state == STATE_ATTACHED
297 			    && options.follow)
298 				proc->state = STATE_ATTACHED;
299 			else
300 				proc->state = STATE_IGNORED;
301 		}
302 
303 		continue_process(newpid);
304 
305 	} else if (proc != NULL) {
306 		proc->state = STATE_BEING_CREATED;
307 	}
308 
309 	if (event->type != EVENT_VFORK)
310 		continue_process(event->proc->pid);
311 	else if (proc != NULL)
312 		continue_after_vfork(proc);
313 	else
314 		continue_process(newpid);
315 }
316 
317 static void
handle_new(Event * event)318 handle_new(Event *event)
319 {
320 	debug(DEBUG_FUNCTION, "handle_new(pid=%d)", event->e_un.newpid);
321 
322 	struct process *proc = pid2proc(event->e_un.newpid);
323 	if (!proc) {
324 		pending_new_insert(event->e_un.newpid);
325 	} else {
326 		assert(proc->state == STATE_BEING_CREATED);
327 		if (options.follow) {
328 			proc->state = STATE_ATTACHED;
329 		} else {
330 			proc->state = STATE_IGNORED;
331 		}
332 		continue_process(proc->pid);
333 	}
334 }
335 
336 static char *
shortsignal(struct process * proc,int signum)337 shortsignal(struct process *proc, int signum)
338 {
339 	static char *signalent0[] = {
340 #include "signalent.h"
341 	};
342 	static char *signalent1[] = {
343 #include "signalent1.h"
344 	};
345 	static char **signalents[] = { signalent0, signalent1 };
346 	int nsignals[] = { sizeof signalent0 / sizeof signalent0[0],
347 		sizeof signalent1 / sizeof signalent1[0]
348 	};
349 
350 	debug(DEBUG_FUNCTION, "shortsignal(pid=%d, signum=%d)", proc->pid, signum);
351 
352 	assert(proc->personality < sizeof signalents / sizeof signalents[0]);
353 	if (signum < 0 || signum >= nsignals[proc->personality]) {
354 		return "UNKNOWN_SIGNAL";
355 	} else {
356 		return signalents[proc->personality][signum];
357 	}
358 }
359 
360 static char *
sysname(struct process * proc,int sysnum)361 sysname(struct process *proc, int sysnum)
362 {
363 	static char result[128];
364 	static char *syscallent0[] = {
365 #include "syscallent.h"
366 	};
367 	static char *syscallent1[] = {
368 #include "syscallent1.h"
369 	};
370 	static char **syscallents[] = { syscallent0, syscallent1 };
371 	int nsyscalls[] = {
372 		sizeof syscallent0 / sizeof syscallent0[0],
373 		sizeof syscallent1 / sizeof syscallent1[0],
374 	};
375 
376 	debug(DEBUG_FUNCTION, "sysname(pid=%d, sysnum=%d)", proc->pid, sysnum);
377 
378 	assert(proc->personality < sizeof syscallents / sizeof syscallents[0]);
379 	if (sysnum < 0 || sysnum >= nsyscalls[proc->personality]) {
380 		sprintf(result, "SYS_%d", sysnum);
381 		return result;
382 	} else {
383 		return syscallents[proc->personality][sysnum];
384 	}
385 }
386 
387 static char *
arch_sysname(struct process * proc,int sysnum)388 arch_sysname(struct process *proc, int sysnum)
389 {
390 	static char result[128];
391 	static char *arch_syscallent[] = {
392 #include "arch_syscallent.h"
393 	};
394 	int nsyscalls = sizeof arch_syscallent / sizeof arch_syscallent[0];
395 
396 	debug(DEBUG_FUNCTION, "arch_sysname(pid=%d, sysnum=%d)", proc->pid, sysnum);
397 
398 	if (sysnum < 0 || sysnum >= nsyscalls) {
399 		sprintf(result, "ARCH_%d", sysnum);
400 		return result;
401 	} else {
402 		sprintf(result, "ARCH_%s", arch_syscallent[sysnum]);
403 		return result;
404 	}
405 }
406 
407 #ifndef HAVE_STRSIGNAL
408 # define strsignal(SIGNUM) "???"
409 #endif
410 
411 static void
handle_signal(Event * event)412 handle_signal(Event *event) {
413 	debug(DEBUG_FUNCTION, "handle_signal(pid=%d, signum=%d)", event->proc->pid, event->e_un.signum);
414 	if (event->proc->state != STATE_IGNORED && !options.no_signals) {
415 		output_line(event->proc, "--- %s (%s) ---",
416 				shortsignal(event->proc, event->e_un.signum),
417 				strsignal(event->e_un.signum));
418 	}
419 	continue_after_signal(event->proc->pid, event->e_un.signum);
420 }
421 
422 static int
init_syscall_symbol(struct library_symbol * libsym,const char * name)423 init_syscall_symbol(struct library_symbol *libsym, const char *name)
424 {
425 	static struct library syscall_lib;
426 
427 	if (syscall_lib.protolib == NULL) {
428 		struct protolib *protolib
429 			= protolib_cache_load(&g_protocache, "syscalls", 0, 1);
430 		if (protolib == NULL) {
431 			fprintf(stderr, "Couldn't load system call prototypes:"
432 				" %s.\n", strerror(errno));
433 
434 			/* Instead, get a fake one just so we can
435 			 * carry on, limping.  */
436 			protolib = malloc(sizeof *protolib);
437 			if (protolib == NULL) {
438 				fprintf(stderr, "Couldn't even allocate a fake "
439 					"prototype library: %s.\n",
440 					strerror(errno));
441 				abort();
442 			}
443 			protolib_init(protolib);
444 		}
445 
446 		assert(protolib != NULL);
447 		if (library_init(&syscall_lib, LT_LIBTYPE_SYSCALL) < 0) {
448 			fprintf(stderr, "Couldn't initialize system call "
449 				"library: %s.\n", strerror(errno));
450 			abort();
451 		}
452 
453 		library_set_soname(&syscall_lib, "SYS", 0);
454 		syscall_lib.protolib = protolib;
455 	}
456 
457 	if (library_symbol_init(libsym, 0, name, 0, LS_TOPLT_NONE) < 0)
458 		return -1;
459 
460 	libsym->lib = &syscall_lib;
461 	return 0;
462 }
463 
464 /* Account the unfinished functions on the call stack.  */
465 static void
account_current_callstack(struct process * proc)466 account_current_callstack(struct process *proc)
467 {
468 	if (! options.summary)
469 		return;
470 
471 	struct timedelta spent[proc->callstack_depth];
472 
473 	size_t i;
474 	for (i = 0; i < proc->callstack_depth; ++i) {
475 		struct callstack_element *elem = &proc->callstack[i];
476 		spent[i] = calc_time_spent(elem->enter_time);
477 	}
478 
479 	for (i = 0; i < proc->callstack_depth; ++i) {
480 		struct callstack_element *elem = &proc->callstack[i];
481 		struct library_symbol syscall, *libsym = NULL;
482 		if (elem->is_syscall) {
483 			const char *name = sysname(proc, elem->c_un.syscall);
484 			if (init_syscall_symbol(&syscall, name) >= 0)
485 				libsym = &syscall;
486 
487 		} else {
488 			libsym = elem->c_un.libfunc;
489 		}
490 
491 		if (libsym != NULL) {
492 			summary_account_call(libsym, spent[i]);
493 
494 			if (elem->is_syscall)
495 				library_symbol_destroy(&syscall);
496 		}
497 	}
498 }
499 
500 static void
handle_exit(Event * event)501 handle_exit(Event *event) {
502 	debug(DEBUG_FUNCTION, "handle_exit(pid=%d, status=%d)", event->proc->pid, event->e_un.ret_val);
503 	if (event->proc->state != STATE_IGNORED) {
504 		output_line(event->proc, "+++ exited (status %d) +++",
505 				event->e_un.ret_val);
506 	}
507 
508 	account_current_callstack(event->proc);
509 	remove_process(event->proc);
510 }
511 
512 static void
handle_exit_signal(Event * event)513 handle_exit_signal(Event *event) {
514 	debug(DEBUG_FUNCTION, "handle_exit_signal(pid=%d, signum=%d)", event->proc->pid, event->e_un.signum);
515 	if (event->proc->state != STATE_IGNORED) {
516 		output_line(event->proc, "+++ killed by %s +++",
517 				shortsignal(event->proc, event->e_un.signum));
518 	}
519 
520 	account_current_callstack(event->proc);
521 	remove_process(event->proc);
522 }
523 
524 static void
output_syscall(struct process * proc,const char * name,enum tof tof,bool left,struct timedelta * spent)525 output_syscall(struct process *proc, const char *name, enum tof tof,
526 	       bool left, struct timedelta *spent)
527 {
528 	if (left)
529 		assert(spent == NULL);
530 
531 	struct library_symbol syscall;
532 	if (init_syscall_symbol(&syscall, name) >= 0) {
533 		if (left) {
534 			if (! options.summary)
535 				output_left(tof, proc, &syscall);
536 		} else if (options.summary) {
537 			summary_account_call(&syscall, *spent);
538 		} else {
539 			output_right(tof, proc, &syscall, spent);
540 		}
541 
542 		library_symbol_destroy(&syscall);
543 	}
544 }
545 
546 static void
output_syscall_left(struct process * proc,const char * name)547 output_syscall_left(struct process *proc, const char *name)
548 {
549 	output_syscall(proc, name, LT_TOF_SYSCALL, true, NULL);
550 }
551 
552 static void
output_syscall_right(struct process * proc,const char * name,struct timedelta * spent)553 output_syscall_right(struct process *proc, const char *name,
554 		     struct timedelta *spent)
555 {
556 	output_syscall(proc, name, LT_TOF_SYSCALLR, false, spent);
557 }
558 
559 static void
handle_syscall(Event * event)560 handle_syscall(Event *event)
561 {
562 	debug(DEBUG_FUNCTION, "handle_syscall(pid=%d, sysnum=%d)", event->proc->pid, event->e_un.sysnum);
563 	if (event->proc->state != STATE_IGNORED) {
564 		callstack_push_syscall(event->proc, event->e_un.sysnum);
565 		if (options.syscalls)
566 			output_syscall_left(event->proc,
567 					    sysname(event->proc,
568 						    event->e_un.sysnum));
569 	}
570 	continue_after_syscall(event->proc, event->e_un.sysnum, 0);
571 }
572 
573 static void
handle_exec(Event * event)574 handle_exec(Event *event)
575 {
576 	struct process *proc = event->proc;
577 
578 	/* Save the PID so that we can use it after unsuccessful
579 	 * process_exec.  */
580 	pid_t pid = proc->pid;
581 
582 	debug(DEBUG_FUNCTION, "handle_exec(pid=%d)", proc->pid);
583 	if (proc->state == STATE_IGNORED) {
584 	untrace:
585 		untrace_pid(pid);
586 		remove_process(proc);
587 		return;
588 	}
589 	output_line(proc, "--- Called exec() ---");
590 
591 	account_current_callstack(proc);
592 
593 	if (process_exec(proc) < 0) {
594 		fprintf(stderr,
595 			"couldn't reinitialize process %d after exec\n", pid);
596 		goto untrace;
597 	}
598 
599 	continue_after_exec(proc);
600 }
601 
602 static void
handle_arch_syscall(Event * event)603 handle_arch_syscall(Event *event) {
604 	debug(DEBUG_FUNCTION, "handle_arch_syscall(pid=%d, sysnum=%d)", event->proc->pid, event->e_un.sysnum);
605 	if (event->proc->state != STATE_IGNORED) {
606 		callstack_push_syscall(event->proc, 0xf0000 + event->e_un.sysnum);
607 		if (options.syscalls) {
608 			output_syscall_left(event->proc,
609 					    arch_sysname(event->proc,
610 							 event->e_un.sysnum));
611 		}
612 	}
613 	continue_process(event->proc->pid);
614 }
615 
616 static void
handle_x_sysret(Event * event,char * (* name_cb)(struct process *,int))617 handle_x_sysret(Event *event, char *(*name_cb)(struct process *, int))
618 {
619 	debug(DEBUG_FUNCTION, "handle_x_sysret(pid=%d, sysnum=%d)",
620 	      event->proc->pid, event->e_un.sysnum);
621 
622 	unsigned d = event->proc->callstack_depth;
623 	assert(d > 0);
624 	struct callstack_element *elem = &event->proc->callstack[d - 1];
625 	assert(elem->is_syscall);
626 
627 	if (event->proc->state != STATE_IGNORED) {
628 		struct timedelta spent = calc_time_spent(elem->enter_time);
629 		if (options.syscalls)
630 			output_syscall_right(event->proc,
631 					     name_cb(event->proc,
632 						     event->e_un.sysnum),
633 					     &spent);
634 
635 		callstack_pop(event->proc);
636 	}
637 	continue_after_syscall(event->proc, event->e_un.sysnum, 1);
638 }
639 
640 static void
handle_sysret(Event * event)641 handle_sysret(Event *event)
642 {
643 	handle_x_sysret(event, &sysname);
644 }
645 
646 static void
handle_arch_sysret(Event * event)647 handle_arch_sysret(Event *event)
648 {
649 	handle_x_sysret(event, &arch_sysname);
650 }
651 
652 static void
output_right_tos(struct process * proc)653 output_right_tos(struct process *proc)
654 {
655 	size_t d = proc->callstack_depth;
656 	assert(d > 0);
657 	struct callstack_element *elem = &proc->callstack[d - 1];
658 	assert(! elem->is_syscall);
659 
660 	if (proc->state != STATE_IGNORED) {
661 		struct timedelta spent = calc_time_spent(elem->enter_time);
662 		if (options.summary)
663 			summary_account_call(elem->c_un.libfunc, spent);
664 		else
665 			output_right(LT_TOF_FUNCTIONR, proc, elem->c_un.libfunc,
666 				     &spent);
667 	}
668 }
669 
670 #ifndef ARCH_HAVE_SYMBOL_RET
arch_symbol_ret(struct process * proc,struct library_symbol * libsym)671 void arch_symbol_ret(struct process *proc, struct library_symbol *libsym)
672 {
673 }
674 #endif
675 
676 static void
handle_breakpoint(Event * event)677 handle_breakpoint(Event *event)
678 {
679 	int i, j;
680 	struct breakpoint *sbp;
681 	struct process *leader = event->proc->leader;
682 	void *brk_addr = event->e_un.brk_addr;
683 
684 	/* The leader has terminated.  */
685 	if (leader == NULL) {
686 		continue_process(event->proc->pid);
687 		return;
688 	}
689 
690 	debug(DEBUG_FUNCTION, "handle_breakpoint(pid=%d, addr=%p)",
691 	      event->proc->pid, brk_addr);
692 	debug(2, "event: breakpoint (%p)", brk_addr);
693 
694 	for (i = event->proc->callstack_depth - 1; i >= 0; i--) {
695 		if (brk_addr == event->proc->callstack[i].return_addr) {
696 			for (j = event->proc->callstack_depth - 1; j > i; j--)
697 				callstack_pop(event->proc);
698 
699 			struct library_symbol *libsym =
700 			    event->proc->callstack[i].c_un.libfunc;
701 
702 			arch_symbol_ret(event->proc, libsym);
703 			output_right_tos(event->proc);
704 			callstack_pop(event->proc);
705 
706 			/* Pop also any other entries that seem like
707 			 * they are linked to the current one: they
708 			 * have the same return address, but were made
709 			 * for different symbols.  This should only
710 			 * happen for entry point tracing, i.e. for -x
711 			 * everywhere, or -x and -e on MIPS.  */
712 			while (event->proc->callstack_depth > 0) {
713 				struct callstack_element *prev;
714 				size_t d = event->proc->callstack_depth;
715 				prev = &event->proc->callstack[d - 1];
716 
717 				if (prev->c_un.libfunc == libsym
718 				    || prev->return_addr != brk_addr)
719 					break;
720 
721 				arch_symbol_ret(event->proc,
722 						prev->c_un.libfunc);
723 				output_right_tos(event->proc);
724 				callstack_pop(event->proc);
725 			}
726 
727 			/* Maybe the previous callstack_pop's got rid
728 			 * of the breakpoint, but if we are in a
729 			 * recursive call, it's still enabled.  In
730 			 * that case we need to skip it properly.  */
731 			if ((sbp = address2bpstruct(leader, brk_addr)) != NULL) {
732 				continue_after_breakpoint(event->proc, sbp);
733 			} else {
734 				set_instruction_pointer(event->proc, brk_addr);
735 				continue_process(event->proc->pid);
736 			}
737 			return;
738 		}
739 	}
740 
741 	if ((sbp = address2bpstruct(leader, brk_addr)) != NULL)
742 		breakpoint_on_hit(sbp, event->proc);
743 	else if (event->proc->state != STATE_IGNORED)
744 		output_line(event->proc,
745 			    "unexpected breakpoint at %p", brk_addr);
746 
747 	/* breakpoint_on_hit may delete its own breakpoint, so we have
748 	 * to look it up again.  */
749 	if ((sbp = address2bpstruct(leader, brk_addr)) != NULL) {
750 
751 		if (event->proc->state != STATE_IGNORED
752 		    && sbp->libsym != NULL) {
753 			event->proc->stack_pointer = get_stack_pointer(event->proc);
754 			callstack_push_symfunc(event->proc, sbp);
755 			if (! options.summary)
756 				output_left(LT_TOF_FUNCTION, event->proc,
757 					    sbp->libsym);
758 		}
759 
760 		breakpoint_on_continue(sbp, event->proc);
761 		return;
762 	} else {
763 		set_instruction_pointer(event->proc, brk_addr);
764 	}
765 
766 	continue_process(event->proc->pid);
767 }
768 
769 static void
callstack_push_syscall(struct process * proc,int sysnum)770 callstack_push_syscall(struct process *proc, int sysnum)
771 {
772 	struct callstack_element *elem;
773 
774 	debug(DEBUG_FUNCTION, "callstack_push_syscall(pid=%d, sysnum=%d)", proc->pid, sysnum);
775 	/* FIXME: not good -- should use dynamic allocation. 19990703 mortene. */
776 	if (proc->callstack_depth == MAX_CALLDEPTH - 1) {
777 		fprintf(stderr, "%s: Error: call nesting too deep!\n", __func__);
778 		abort();
779 		return;
780 	}
781 
782 	elem = &proc->callstack[proc->callstack_depth];
783 	*elem = (struct callstack_element){};
784 	elem->is_syscall = 1;
785 	elem->c_un.syscall = sysnum;
786 	elem->return_addr = NULL;
787 
788 	proc->callstack_depth++;
789 	if (opt_T || options.summary) {
790 		struct timezone tz;
791 		gettimeofday(&elem->enter_time, &tz);
792 	}
793 }
794 
795 static void
callstack_push_symfunc(struct process * proc,struct breakpoint * bp)796 callstack_push_symfunc(struct process *proc, struct breakpoint *bp)
797 {
798 	struct callstack_element *elem;
799 
800 	debug(DEBUG_FUNCTION, "callstack_push_symfunc(pid=%d, symbol=%s)",
801 	      proc->pid, bp->libsym->name);
802 	/* FIXME: not good -- should use dynamic allocation. 19990703 mortene. */
803 	if (proc->callstack_depth == MAX_CALLDEPTH - 1) {
804 		fprintf(stderr, "%s: Error: call nesting too deep!\n", __func__);
805 		abort();
806 		return;
807 	}
808 
809 	elem = &proc->callstack[proc->callstack_depth++];
810 	*elem = (struct callstack_element){};
811 	elem->is_syscall = 0;
812 	elem->c_un.libfunc = bp->libsym;
813 
814 	struct breakpoint *rbp = NULL;
815 	if (breakpoint_get_return_bp(&rbp, bp, proc) == 0
816 	    && rbp != NULL) {
817 		struct breakpoint *ext_rbp = insert_breakpoint(proc, rbp);
818 		if (ext_rbp != rbp) {
819 			breakpoint_destroy(rbp);
820 			free(rbp);
821 			rbp = ext_rbp;
822 		}
823 	}
824 
825 	elem->return_addr = rbp != NULL ? rbp->addr : 0;
826 
827 	if (opt_T || options.summary) {
828 		struct timezone tz;
829 		gettimeofday(&elem->enter_time, &tz);
830 	}
831 }
832 
833 void
callstack_pop(struct process * proc)834 callstack_pop(struct process *proc)
835 {
836 	struct callstack_element *elem;
837 	assert(proc->callstack_depth > 0);
838 
839 	debug(DEBUG_FUNCTION, "callstack_pop(pid=%d)", proc->pid);
840 	elem = &proc->callstack[proc->callstack_depth - 1];
841 	if (!elem->is_syscall && elem->return_addr) {
842 		struct breakpoint *bp
843 			= address2bpstruct(proc->leader, elem->return_addr);
844 		if (bp != NULL) {
845 			breakpoint_on_hit(bp, proc);
846 			delete_breakpoint(proc, bp);
847 		}
848 	}
849 
850 	if (elem->fetch_context != NULL)
851 		fetch_arg_done(elem->fetch_context);
852 
853 	if (elem->arguments != NULL) {
854 		val_dict_destroy(elem->arguments);
855 		free(elem->arguments);
856 	}
857 
858 	proc->callstack_depth--;
859 }
860