libltrace.c revision 8a730f3e5844b86386032e93f91aa3df814ad9c3 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2011,2012,2013 Petr Machata, Red Hat Inc.
4 * Copyright (C) 2009 Juan Cespedes
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21
22#include "config.h"
23
24#include <sys/param.h>
25#include <sys/wait.h>
26#include <errno.h>
27#include <limits.h>
28#include <locale.h>
29#include <signal.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <string.h>
33#include <unistd.h>
34
35#include "backend.h"
36#include "common.h"
37#include "proc.h"
38#include "prototype.h"
39#include "read_config_file.h"
40#include "summary.h"
41
42char *command = NULL;
43
44int exiting = 0;		/* =1 if a SIGINT or SIGTERM has been received */
45
46static enum callback_status
47stop_non_p_processes(struct process *proc, void *data)
48{
49	int stop = 1;
50
51	struct opt_p_t *it;
52	for (it = opt_p; it != NULL; it = it->next) {
53		struct process *p_proc = pid2proc(it->pid);
54		if (p_proc == NULL) {
55			printf("stop_non_p_processes: %d terminated?\n", it->pid);
56			continue;
57		}
58		if (p_proc == proc || p_proc->leader == proc->leader) {
59			stop = 0;
60			break;
61		}
62	}
63
64	if (stop) {
65		debug(2, "Sending SIGSTOP to process %u", proc->pid);
66		kill(proc->pid, SIGSTOP);
67	}
68
69	return CBS_CONT;
70}
71
72static void
73signal_alarm(int sig) {
74	signal(SIGALRM, SIG_DFL);
75	each_process(NULL, &stop_non_p_processes, NULL);
76}
77
78static void
79signal_exit(int sig)
80{
81	if (exiting != 0)
82		return;
83
84	exiting = 1 + !!os_ltrace_exiting_sighandler();
85
86	signal(SIGINT, SIG_IGN);
87	signal(SIGTERM, SIG_IGN);
88	signal(SIGALRM, signal_alarm);
89	//alarm(1);
90}
91
92static void
93normal_exit(void)
94{
95	if (options.summary)
96		show_summary();
97	if (options.output) {
98		fclose(options.output);
99		options.output = NULL;
100	}
101}
102
103void
104ltrace_init(int argc, char **argv)
105{
106	setlocale(LC_ALL, "");
107
108	struct opt_p_t *opt_p_tmp;
109
110	atexit(normal_exit);
111	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
112	signal(SIGTERM, signal_exit);	/*  ... or killed */
113
114	argv = process_options(argc, argv);
115	init_global_config();
116
117	if (command) {
118		/* Check that the binary ABI is supported before
119		 * calling execute_program.  */
120		{
121			struct ltelf lte;
122			if (ltelf_init(&lte, command) == 0)
123				ltelf_destroy(&lte);
124			else
125				exit(EXIT_FAILURE);
126		}
127
128		pid_t pid = execute_program(command, argv);
129		struct process *proc = open_program(command, pid);
130		if (proc == NULL) {
131			fprintf(stderr, "couldn't open program '%s': %s\n",
132				command, strerror(errno));
133			exit(EXIT_FAILURE);
134		}
135
136		trace_set_options(proc);
137		continue_process(pid);
138	}
139	opt_p_tmp = opt_p;
140	while (opt_p_tmp) {
141		open_pid(opt_p_tmp->pid);
142		opt_p_tmp = opt_p_tmp->next;
143	}
144}
145
146static int num_ltrace_callbacks[EVENT_MAX];
147static callback_func * ltrace_callbacks[EVENT_MAX];
148
149void
150ltrace_add_callback(callback_func func, Event_type type) {
151	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
152	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
153}
154
155static void
156dispatch_callbacks(Event * ev) {
157	int i;
158	/* Ignoring case 1: signal into a dying tracer */
159	if (ev->type==EVENT_SIGNAL &&
160			exiting && ev->e_un.signum == SIGSTOP) {
161		return;
162	}
163	/* Ignoring case 2: process being born before a clone event */
164	if (ev->proc && ev->proc->state == STATE_IGNORED) {
165		return;
166	}
167	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
168		ltrace_callbacks[ev->type][i](ev);
169	}
170}
171
172void
173ltrace_main(void) {
174	Event * ev;
175	while (1) {
176		ev = next_event();
177		dispatch_callbacks(ev);
178		handle_event(ev);
179	}
180}
181