proc.c revision 75dcf7d73b6c19f7aeb932e4cb5e251b316a6c69 
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
15#include "common.h"
16
17Process *
18open_program(char *filename, pid_t pid, int enable) {
19	Process *proc;
20	assert(pid != 0);
21	proc = calloc(sizeof(Process), 1);
22	if (!proc) {
23		perror("malloc");
24		exit(1);
25	}
26	proc->filename = strdup(filename);
27	proc->breakpoints_enabled = -1;
28	proc->pid = pid;
29#if defined(HAVE_LIBUNWIND)
30	proc->unwind_priv = _UPT_create(pid);
31	proc->unwind_as = unw_create_addr_space(&_UPT_accessors, 0);
32#endif /* defined(HAVE_LIBUNWIND) */
33
34	add_process(proc);
35	assert(proc->leader != NULL);
36
37	if (proc->leader == proc)
38		breakpoints_init(proc, enable);
39
40	return proc;
41}
42
43static void
44open_one_pid(pid_t pid)
45{
46	Process *proc;
47	char *filename;
48	debug(DEBUG_PROCESS, "open_one_pid(pid=%d)", pid);
49
50
51	if (trace_pid(pid) < 0) {
52		fprintf(stderr, "Cannot attach to pid %u: %s\n", pid,
53			strerror(errno));
54		return;
55	}
56
57	filename = pid2name(pid);
58
59	if (!filename) {
60		fprintf(stderr, "Cannot trace pid %u: %s\n", pid,
61				strerror(errno));
62		return;
63	}
64
65	proc = open_program(filename, pid, 1);
66	trace_set_options(proc, pid);
67	continue_process(pid);
68	proc->breakpoints_enabled = 1;
69}
70
71void
72open_pid(pid_t pid)
73{
74	debug(DEBUG_PROCESS, "open_pid(pid=%d)", pid);
75	pid_t *tasks;
76	size_t ntasks;
77	int should_free = 1;
78	if (process_tasks(pid, &tasks, &ntasks) < 0) {
79		fprintf(stderr, "Cannot obtain tasks of pid %u: %s\n", pid,
80			strerror(errno));
81
82		// Attach at least this one.
83		tasks = &pid;
84		ntasks = 1;
85		should_free = 0;
86	}
87
88	size_t i;
89	for (i = 0; i < ntasks; ++i)
90		open_one_pid(tasks[i]);
91
92	if (should_free)
93		free(tasks);
94}
95
96static enum pcb_status
97find_proc(Process * proc, void * data)
98{
99	pid_t pid = (pid_t)(uintptr_t)data;
100	return proc->pid == pid ? pcb_stop : pcb_cont;
101}
102
103Process *
104pid2proc(pid_t pid) {
105	return each_process(NULL, &find_proc, (void *)(uintptr_t)pid);
106}
107
108
109static Process * list_of_processes = NULL;
110
111Process *
112each_process(Process * proc,
113	     enum pcb_status (* cb)(Process * proc, void * data),
114	     void * data)
115{
116	Process * it = proc ?: list_of_processes;
117	for (; it != NULL; ) {
118		/* Callback might call remove_process.  */
119		Process * next = it->next;
120		if ((*cb) (it, data) == pcb_stop)
121			return it;
122		it = next;
123	}
124	return NULL;
125}
126
127Process *
128each_task(Process * it, enum pcb_status (* cb)(Process * proc, void * data),
129	  void * data)
130{
131	if (it != NULL) {
132		Process * leader = it->leader;
133		for (; it != NULL && it->leader == leader; ) {
134			/* Callback might call remove_process.  */
135			Process * next = it->next;
136			if ((*cb) (it, data) == pcb_stop)
137				return it;
138			it = next;
139		}
140	}
141	return NULL;
142}
143
144void
145add_process(Process * proc)
146{
147	Process ** leaderp = &list_of_processes;
148	if (proc->pid) {
149		pid_t tgid = process_leader(proc->pid);
150		if (tgid == proc->pid)
151			proc->leader = proc;
152		else {
153			Process * leader = pid2proc(tgid);
154			proc->leader = leader;
155			if (leader != NULL)
156				// NULL: sub-task added before leader?
157				leaderp = &leader->next;
158		}
159	}
160	proc->next = *leaderp;
161	*leaderp = proc;
162}
163
164static enum pcb_status
165clear_leader(Process * proc, void * data)
166{
167	debug(DEBUG_FUNCTION, "detach_task %d from leader %d",
168	      proc->pid, proc->leader->pid);
169	proc->leader = NULL;
170	return pcb_cont;
171}
172
173static enum ecb_status
174event_for_proc(Event * event, void * data)
175{
176	if (event->proc == data)
177		return ecb_deque;
178	else
179		return ecb_cont;
180}
181
182static void
183delete_events_for(Process * proc)
184{
185	Event * event;
186	while ((event = each_qd_event(&event_for_proc, proc)) != NULL)
187		free(event);
188}
189
190void
191remove_process(Process *proc)
192{
193	Process *tmp, *tmp2;
194
195	debug(DEBUG_FUNCTION, "remove_proc(pid=%d)", proc->pid);
196
197	if (proc->leader == proc)
198		each_task(proc, &clear_leader, NULL);
199
200	if (list_of_processes == proc) {
201		tmp = list_of_processes;
202		list_of_processes = list_of_processes->next;
203		delete_events_for(tmp);
204		free(tmp);
205		return;
206	}
207	tmp = list_of_processes;
208	while (tmp->next) {
209		if (tmp->next == proc) {
210			tmp2 = tmp->next;
211			tmp->next = tmp->next->next;
212			delete_events_for(tmp2);
213			free(tmp2);
214			return;
215		}
216		tmp = tmp->next;
217	}
218}
219
220void
221install_event_handler(Process * proc, Event_Handler * handler)
222{
223	debug(DEBUG_FUNCTION, "install_event_handler(pid=%d, %p)", proc->pid, handler);
224	assert(proc->event_handler == NULL);
225	proc->event_handler = handler;
226}
227
228void
229destroy_event_handler(Process * proc)
230{
231	Event_Handler * handler = proc->event_handler;
232	debug(DEBUG_FUNCTION, "destroy_event_handler(pid=%d, %p)", proc->pid, handler);
233	assert(handler != NULL);
234	handler->destroy(handler);
235	free(handler);
236	proc->event_handler = NULL;
237}
238