proc.c revision 3fd099b71ae9e0c4fe9f48a239523e7037e4baf4 
1#include "config.h"
2
3#if defined(HAVE_LIBUNWIND)
4#include <libunwind.h>
5#include <libunwind-ptrace.h>
6#endif /* defined(HAVE_LIBUNWIND) */
7
8#include <sys/types.h>
9#include <string.h>
10#include <stdio.h>
11#include <errno.h>
12#include <stdlib.h>
13#include <assert.h>
14#include <error.h>
15
16#include "common.h"
17#include "breakpoint.h"
18#include "proc.h"
19#include "filter.h"
20
21static int
22process_bare_init(struct Process *proc, const char *filename, pid_t pid)
23{
24	fprintf(stderr, "process_bare_init %s %d\n", filename, pid);
25	memset(proc, 0, sizeof(*proc));
26
27	proc->filename = strdup(filename);
28	if (proc->filename == NULL) {
29	fail:
30		free(proc->filename);
31		if (proc->breakpoints != NULL)
32			dict_clear(proc->breakpoints);
33		return -1;
34	}
35
36	/* Add process so that we know who the leader is.  */
37	proc->pid = pid;
38	add_process(proc);
39	if (proc->leader == NULL)
40		goto fail;
41
42	if (proc->leader == proc) {
43		proc->breakpoints = dict_init(dict_key2hash_int,
44					      dict_key_cmp_int);
45		if (proc->breakpoints == NULL)
46			goto fail;
47	} else {
48		proc->breakpoints = NULL;
49	}
50
51#if defined(HAVE_LIBUNWIND)
52	proc->unwind_priv = _UPT_create(pid);
53	proc->unwind_as = unw_create_addr_space(&_UPT_accessors, 0);
54#endif /* defined(HAVE_LIBUNWIND) */
55
56	return 0;
57}
58
59static void
60process_bare_destroy(struct Process *proc)
61{
62	free(proc->filename);
63	dict_clear(proc->breakpoints);
64	remove_process(proc);
65}
66
67int
68process_init(struct Process *proc, const char *filename, pid_t pid, int enable)
69{
70	fprintf(stderr, "process_init %s %d enable=%d\n", filename, pid, enable);
71	if (process_bare_init(proc, filename, pid) < 0) {
72		error(0, errno, "init process %d", pid);
73		return -1;
74	}
75
76	if (proc->leader == proc && breakpoints_init(proc, enable) < 0) {
77		fprintf(stderr, "failed to init breakpoints %d\n",
78			proc->pid);
79		process_bare_destroy(proc);
80		return -1;
81	}
82
83	return 0;
84}
85
86struct Process *
87open_program(const char *filename, pid_t pid, int enable)
88{
89	fprintf(stderr, "open_program %s %d enable=%d\n",
90		filename, pid, enable);
91	assert(pid != 0);
92	struct Process *proc = malloc(sizeof(*proc));
93	if (proc == NULL
94	    || process_init(proc, filename, pid, enable) < 0) {
95		free(proc);
96		return NULL;
97	}
98	return proc;
99}
100
101struct clone_single_bp_data {
102	struct Process *old_proc;
103	struct Process *new_proc;
104	int error;
105};
106
107struct find_symbol_data {
108	struct library_symbol *old_libsym;
109	struct library_symbol *found_libsym;
110};
111
112static enum callback_status
113find_sym_in_lib(struct Process *proc, struct library *lib, void *u)
114{
115	struct find_symbol_data *fs = u;
116	fs->found_libsym
117		= library_each_symbol(lib, NULL, library_symbol_equal_cb,
118				      fs->old_libsym);
119	return fs->found_libsym != NULL ? CBS_STOP : CBS_CONT;
120}
121
122static void
123clone_single_bp(void *key, void *value, void *u)
124{
125	target_address_t addr = (target_address_t)key;
126	struct breakpoint *bp = value;
127	struct clone_single_bp_data *data = u;
128
129	/* Find library and symbol that this symbol was linked to.  */
130	struct library_symbol *libsym = bp->libsym;
131	struct library *lib = NULL;
132	if (libsym != NULL) {
133		struct find_symbol_data f_data = {
134			.old_libsym = libsym,
135		};
136		lib = proc_each_library(data->old_proc, NULL,
137					find_sym_in_lib, &f_data);
138		assert(lib != NULL);
139		libsym = f_data.found_libsym;
140	}
141
142	/* LIB and LIBSYM now hold the new library and symbol that
143	 * correspond to the original breakpoint.  Now we can do the
144	 * clone itself.  */
145	struct breakpoint *clone = malloc(sizeof(*clone));
146	if (clone == NULL
147	    || breakpoint_init(clone, data->new_proc, addr, libsym) < 0) {
148		data->error = -1;
149		return;
150	}
151	breakpoint_set_callbacks(clone, bp->cbs);
152}
153
154int
155process_clone(struct Process *retp, struct Process *proc, pid_t pid)
156{
157	if (process_bare_init(retp, proc->filename, pid) < 0) {
158	fail:
159		error(0, errno, "clone process %d->%d", proc->pid, pid);
160		return -1;
161	}
162
163	/* For non-leader processes, that's all we need to do.  */
164	if (proc->leader != proc)
165		return 0;
166
167	/* Clone symbols first so that we can clone and relink
168	 * breakpoints.  */
169	struct library *lib;
170	struct library **nlibp = &retp->libraries;
171	for (lib = proc->libraries; lib != NULL; lib = lib->next) {
172		*nlibp = malloc(sizeof(**nlibp));
173		if (*nlibp == NULL
174		    || library_clone(*nlibp, lib) < 0) {
175		fail2:
176			process_bare_destroy(retp);
177
178			/* Error when cloning.  Unroll what was done.  */
179			for (lib = retp->libraries; lib != NULL; ) {
180				struct library *next = lib->next;
181				library_destroy(lib);
182				free(lib);
183				lib = next;
184			}
185			goto fail;
186		}
187
188		nlibp = &(*nlibp)->next;
189	}
190
191	/* Now clone breakpoints.  Symbol relinking is done in
192	 * clone_single_bp.  */
193	struct clone_single_bp_data data = {
194		.old_proc = proc,
195		.new_proc = retp,
196		.error = 0,
197	};
198	dict_apply_to_all(proc->breakpoints, &clone_single_bp, &data);
199
200	if (data.error < 0)
201		goto fail2;
202
203	return 0;
204}
205
206static int
207open_one_pid(pid_t pid)
208{
209	Process *proc;
210	char *filename;
211	debug(DEBUG_PROCESS, "open_one_pid(pid=%d)", pid);
212
213	/* Get the filename first.  Should the trace_pid fail, we can
214	 * easily free it, untracing is more work.  */
215	if ((filename = pid2name(pid)) == NULL
216	    || trace_pid(pid) < 0) {
217		free(filename);
218		return -1;
219	}
220
221	proc = open_program(filename, pid, 0);
222	if (proc == NULL)
223		return -1;
224	trace_set_options(proc, pid);
225
226	return 0;
227}
228
229static enum callback_status
230start_one_pid(Process * proc, void * data)
231{
232	continue_process(proc->pid);
233	return CBS_CONT;
234}
235
236void
237open_pid(pid_t pid)
238{
239	debug(DEBUG_PROCESS, "open_pid(pid=%d)", pid);
240	/* If we are already tracing this guy, we should be seeing all
241	 * his children via normal tracing route.  */
242	if (pid2proc(pid) != NULL)
243		return;
244
245	/* First, see if we can attach the requested PID itself.  */
246	if (open_one_pid(pid)) {
247		fprintf(stderr, "Cannot attach to pid %u: %s\n",
248			pid, strerror(errno));
249		trace_fail_warning(pid);
250		return;
251	}
252
253	/* Now attach to all tasks that belong to that PID.  There's a
254	 * race between process_tasks and open_one_pid.  So when we
255	 * fail in open_one_pid below, we just do another round.
256	 * Chances are that by then that PID will have gone away, and
257	 * that's why we have seen the failure.  The processes that we
258	 * manage to open_one_pid are stopped, so we should eventually
259	 * reach a point where process_tasks doesn't give any new
260	 * processes (because there's nobody left to produce
261	 * them).  */
262	size_t old_ntasks = 0;
263	int have_all;
264	while (1) {
265		pid_t *tasks;
266		size_t ntasks;
267		size_t i;
268
269		if (process_tasks(pid, &tasks, &ntasks) < 0) {
270			fprintf(stderr, "Cannot obtain tasks of pid %u: %s\n",
271				pid, strerror(errno));
272			break;
273		}
274
275		have_all = 1;
276		for (i = 0; i < ntasks; ++i)
277			if (pid2proc(tasks[i]) == NULL
278			    && open_one_pid(tasks[i]))
279				have_all = 0;
280
281		free(tasks);
282
283		if (have_all && old_ntasks == ntasks)
284			break;
285		old_ntasks = ntasks;
286	}
287
288	/* Done.  Now initialize breakpoints and then continue
289	 * everyone.  */
290	Process * leader;
291	leader = pid2proc(pid)->leader;
292	enable_all_breakpoints(leader);
293
294	each_task(pid2proc(pid)->leader, NULL, start_one_pid, NULL);
295}
296
297static enum callback_status
298find_proc(Process * proc, void * data)
299{
300	pid_t pid = (pid_t)(uintptr_t)data;
301	return proc->pid == pid ? CBS_STOP : CBS_CONT;
302}
303
304Process *
305pid2proc(pid_t pid) {
306	return each_process(NULL, &find_proc, (void *)(uintptr_t)pid);
307}
308
309static Process * list_of_processes = NULL;
310
311static void
312unlist_process(Process * proc)
313{
314	Process *tmp;
315
316	if (list_of_processes == proc) {
317		list_of_processes = list_of_processes->next;
318		return;
319	}
320
321	for (tmp = list_of_processes; ; tmp = tmp->next) {
322		/* If the following assert fails, the process wasn't
323		 * in the list.  */
324		assert(tmp->next != NULL);
325
326		if (tmp->next == proc) {
327			tmp->next = tmp->next->next;
328			return;
329		}
330	}
331}
332
333struct Process *
334each_process(struct Process *start_after,
335	     enum callback_status(*cb)(struct Process *proc, void *data),
336	     void *data)
337{
338	struct Process *it = start_after == NULL ? list_of_processes
339		: start_after->next;
340
341	while (it != NULL) {
342		/* Callback might call remove_process.  */
343		struct Process *next = it->next;
344		switch ((*cb)(it, data)) {
345		case CBS_FAIL:
346			/* XXX handle me */
347		case CBS_STOP:
348			return it;
349		case CBS_CONT:
350			break;
351		}
352		it = next;
353	}
354	return NULL;
355}
356
357Process *
358each_task(struct Process *proc, struct Process *start_after,
359	  enum callback_status(*cb)(struct Process *proc, void *data),
360	  void *data)
361{
362	assert(proc != NULL);
363	struct Process *it = start_after == NULL ? proc->leader
364		: start_after->next;
365
366	if (it != NULL) {
367		struct Process *leader = it->leader;
368		while (it != NULL && it->leader == leader) {
369			/* Callback might call remove_process.  */
370			struct Process *next = it->next;
371			switch ((*cb)(it, data)) {
372			case CBS_FAIL:
373				/* XXX handle me */
374			case CBS_STOP:
375				return it;
376			case CBS_CONT:
377				break;
378			}
379			it = next;
380		}
381	}
382	return NULL;
383}
384
385void
386add_process(Process * proc)
387{
388	fprintf(stderr, "add_process %d\n", proc->pid);
389	Process ** leaderp = &list_of_processes;
390	if (proc->pid) {
391		pid_t tgid = process_leader(proc->pid);
392		fprintf(stderr, " + leader is %d\n", tgid);
393		if (tgid == 0)
394			/* Must have been terminated before we managed
395			 * to fully attach.  */
396			return;
397		if (tgid == proc->pid)
398			proc->leader = proc;
399		else {
400			Process * leader = pid2proc(tgid);
401			proc->leader = leader;
402			if (leader != NULL)
403				leaderp = &leader->next;
404		}
405	}
406	proc->next = *leaderp;
407	*leaderp = proc;
408}
409
410void
411change_process_leader(Process * proc, Process * leader)
412{
413	Process ** leaderp = &list_of_processes;
414	if (proc->leader == leader)
415		return;
416
417	assert(leader != NULL);
418	unlist_process(proc);
419	if (proc != leader)
420		leaderp = &leader->next;
421
422	proc->leader = leader;
423	proc->next = *leaderp;
424	*leaderp = proc;
425}
426
427static enum callback_status
428clear_leader(struct Process *proc, void *data)
429{
430	debug(DEBUG_FUNCTION, "detach_task %d from leader %d",
431	      proc->pid, proc->leader->pid);
432	proc->leader = NULL;
433	return CBS_CONT;
434}
435
436static enum ecb_status
437event_for_proc(Event * event, void * data)
438{
439	if (event->proc == data)
440		return ecb_deque;
441	else
442		return ecb_cont;
443}
444
445static void
446delete_events_for(Process * proc)
447{
448	Event * event;
449	while ((event = each_qd_event(&event_for_proc, proc)) != NULL)
450		free(event);
451}
452
453void
454remove_process(Process *proc)
455{
456	debug(DEBUG_FUNCTION, "remove_proc(pid=%d)", proc->pid);
457
458	if (proc->leader == proc)
459		each_task(proc, NULL, &clear_leader, NULL);
460
461	unlist_process(proc);
462	delete_events_for(proc);
463}
464
465void
466install_event_handler(Process *proc, struct event_handler *handler)
467{
468	debug(DEBUG_FUNCTION, "install_event_handler(pid=%d, %p)", proc->pid, handler);
469	assert(proc->event_handler == NULL);
470	proc->event_handler = handler;
471}
472
473void
474destroy_event_handler(Process * proc)
475{
476	struct event_handler *handler = proc->event_handler;
477	debug(DEBUG_FUNCTION, "destroy_event_handler(pid=%d, %p)", proc->pid, handler);
478	assert(handler != NULL);
479	if (handler->destroy != NULL)
480		handler->destroy(handler);
481	free(handler);
482	proc->event_handler = NULL;
483}
484
485static enum callback_status
486breakpoint_for_symbol(struct library_symbol *libsym, void *data)
487{
488	struct Process *proc = data;
489
490	if (!filter_matches_symbol(options.filter, libsym))
491		return CBS_CONT;
492
493	struct breakpoint *bp = malloc(sizeof(*bp));
494	if (bp == NULL
495	    || breakpoint_init(bp, proc, libsym->enter_addr, libsym) < 0) {
496	fail:
497		free(bp);
498		return CBS_FAIL;
499	}
500	if (proc_add_breakpoint(proc, bp) < 0) {
501		breakpoint_destroy(bp);
502		goto fail;
503	}
504
505	return CBS_CONT;
506}
507
508void
509proc_add_library(struct Process *proc, struct library *lib)
510{
511	assert(lib->next == NULL);
512	lib->next = proc->libraries;
513	proc->libraries = lib;
514	fprintf(stderr, "=== Added library %s@%p (%s) to %d:\n",
515		lib->soname, lib->base, lib->pathname, proc->pid);
516
517	if (!filter_matches_library(options.filter, lib))
518		return;
519
520	struct library_symbol *libsym = NULL;
521	while ((libsym = library_each_symbol(lib, libsym, breakpoint_for_symbol,
522					     proc)) != NULL)
523		error(0, errno, "insert breakpoint for %s", libsym->name);
524}
525
526int
527proc_remove_library(struct Process *proc, struct library *lib)
528{
529	struct library **libp;
530	for (libp = &proc->libraries; *libp != NULL; libp = &(*libp)->next)
531		if (*libp == lib) {
532			*libp = lib->next;
533			return 0;
534		}
535	return -1;
536}
537
538struct library *
539proc_each_library(struct Process *proc, struct library *it,
540		  enum callback_status (*cb)(struct Process *proc,
541					     struct library *lib, void *data),
542		  void *data)
543{
544	if (it == NULL)
545		it = proc->libraries;
546
547	while (it != NULL) {
548		struct library *next = it->next;
549
550		switch (cb(proc, it, data)) {
551		case CBS_FAIL:
552			/* XXX handle me */
553		case CBS_STOP:
554			return it;
555		case CBS_CONT:
556			break;
557		}
558
559		it = next;
560	}
561
562	return NULL;
563}
564
565int
566proc_add_breakpoint(struct Process *proc, struct breakpoint *bp)
567{
568	struct Process *leader = proc->leader;
569
570	/* Only the group leader should be getting the breakpoints and
571	 * thus have ->breakpoint initialized.  */
572	assert(leader != NULL);
573	assert(leader->breakpoints != NULL);
574
575	/* Make sure it wasn't inserted yet.  */
576	assert(bp->proc == NULL);
577
578	debug(DEBUG_FUNCTION, "proc_insert_breakpoint(pid=%d, %s@%p)",
579	      proc->pid, breakpoint_name(bp), bp->addr);
580
581	assert(dict_find_entry(leader->breakpoints, bp->addr) == NULL);
582	if (dict_enter(leader->breakpoints, bp->addr, bp) < 0) {
583		error(0, errno, "couldn't enter breakpoint %s@%p to dictionary",
584		      breakpoint_name(bp), bp->addr);
585		return -1;
586	}
587
588	bp->proc = proc;
589	return 0;
590}
591
592int
593proc_remove_breakpoint(struct Process *proc, struct breakpoint *bp)
594{
595	/* XXX We can't, really.  We are missing dict_remove.  */
596	assert(!"Not yet implemented!");
597	abort();
598}
599