proc.c revision 69a03e6f8c15fb0272089e387a658acad887fb9c 
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	continue_process(pid);
67	proc->breakpoints_enabled = 1;
68}
69
70void
71open_pid(pid_t pid)
72{
73	debug(DEBUG_PROCESS, "open_pid(pid=%d)", pid);
74	pid_t *tasks;
75	size_t ntasks;
76	int should_free = 1;
77	if (process_tasks(pid, &tasks, &ntasks) < 0) {
78		fprintf(stderr, "Cannot obtain tasks of pid %u: %s\n", pid,
79			strerror(errno));
80
81		// Attach at least this one.
82		tasks = &pid;
83		ntasks = 1;
84		should_free = 0;
85	}
86
87	size_t i;
88	for (i = 0; i < ntasks; ++i)
89		open_one_pid(tasks[i]);
90
91	if (should_free)
92		free(tasks);
93}
94
95static enum pcb_status
96find_proc(Process * proc, void * data)
97{
98	pid_t pid = (pid_t)(uintptr_t)data;
99	return proc->pid == pid ? pcb_stop : pcb_cont;
100}
101
102Process *
103pid2proc(pid_t pid) {
104	return each_process(NULL, &find_proc, (void *)(uintptr_t)pid);
105}
106
107
108static Process * list_of_processes = NULL;
109
110Process *
111each_process(Process * proc,
112	     enum pcb_status (* cb)(Process * proc, void * data),
113	     void * data)
114{
115	Process * it = proc ?: list_of_processes;
116	for (; it != NULL; ) {
117		/* Callback might call remove_process.  */
118		Process * next = it->next;
119		if ((*cb) (it, data) == pcb_stop)
120			return it;
121		it = next;
122	}
123	return NULL;
124}
125
126Process *
127each_task(Process * it, enum pcb_status (* cb)(Process * proc, void * data),
128	  void * data)
129{
130	if (it != NULL) {
131		Process * leader = it->leader;
132		for (; it != NULL && it->leader == leader; ) {
133			/* Callback might call remove_process.  */
134			Process * next = it->next;
135			if ((*cb) (it, data) == pcb_stop)
136				return it;
137			it = next;
138		}
139	}
140	return NULL;
141}
142
143void
144add_process(Process * proc)
145{
146	Process ** leaderp = &list_of_processes;
147	if (proc->pid) {
148		pid_t tgid = process_leader(proc->pid);
149		if (tgid == proc->pid)
150			proc->leader = proc;
151		else {
152			Process * leader = pid2proc(tgid);
153			proc->leader = leader;
154			if (leader != NULL)
155				// NULL: sub-task added before leader?
156				leaderp = &leader->next;
157		}
158	}
159	proc->next = *leaderp;
160	*leaderp = proc;
161}
162
163static enum pcb_status
164clear_leader(Process * proc, void * data)
165{
166	debug(DEBUG_FUNCTION, "detach_task %d from leader %d",
167	      proc->pid, proc->leader->pid);
168	proc->leader = NULL;
169	return pcb_cont;
170}
171
172static enum ecb_status
173event_for_proc(Event * event, void * data)
174{
175	if (event->proc == data)
176		return ecb_deque;
177	else
178		return ecb_cont;
179}
180
181static void
182delete_events_for(Process * proc)
183{
184	Event * event;
185	while ((event = each_qd_event(&event_for_proc, proc)) != NULL)
186		free(event);
187}
188
189void
190remove_process(Process *proc)
191{
192	Process *tmp, *tmp2;
193
194	debug(DEBUG_FUNCTION, "remove_proc(pid=%d)", proc->pid);
195
196	if (proc->leader == proc)
197		each_task(proc, &clear_leader, NULL);
198
199	if (list_of_processes == proc) {
200		tmp = list_of_processes;
201		list_of_processes = list_of_processes->next;
202		delete_events_for(tmp);
203		free(tmp);
204		return;
205	}
206	tmp = list_of_processes;
207	while (tmp->next) {
208		if (tmp->next == proc) {
209			tmp2 = tmp->next;
210			tmp->next = tmp->next->next;
211			delete_events_for(tmp2);
212			free(tmp2);
213			return;
214		}
215		tmp = tmp->next;
216	}
217}
218