libltrace.c revision 673ff510953b65b844a58478aa434120f457c014 
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 <limits.h>
25#include <sys/param.h>
26#include <sys/wait.h>
27#include <errno.h>
28#include <signal.h>
29#include <stdio.h>
30#include <stdlib.h>
31#include <string.h>
32#include <unistd.h>
33
34#include "common.h"
35#include "proc.h"
36#include "read_config_file.h"
37#include "backend.h"
38#include "prototype.h"
39
40char *command = NULL;
41
42int exiting = 0;		/* =1 if a SIGINT or SIGTERM has been received */
43
44static enum callback_status
45stop_non_p_processes(struct process *proc, void *data)
46{
47	int stop = 1;
48
49	struct opt_p_t *it;
50	for (it = opt_p; it != NULL; it = it->next) {
51		struct process *p_proc = pid2proc(it->pid);
52		if (p_proc == NULL) {
53			printf("stop_non_p_processes: %d terminated?\n", it->pid);
54			continue;
55		}
56		if (p_proc == proc || p_proc->leader == proc->leader) {
57			stop = 0;
58			break;
59		}
60	}
61
62	if (stop) {
63		debug(2, "Sending SIGSTOP to process %u", proc->pid);
64		kill(proc->pid, SIGSTOP);
65	}
66
67	return CBS_CONT;
68}
69
70static void
71signal_alarm(int sig) {
72	signal(SIGALRM, SIG_DFL);
73	each_process(NULL, &stop_non_p_processes, NULL);
74}
75
76static void
77signal_exit(int sig)
78{
79	if (exiting != 0)
80		return;
81
82	exiting = 1 + !!os_ltrace_exiting_sighandler();
83
84	signal(SIGINT, SIG_IGN);
85	signal(SIGTERM, SIG_IGN);
86	signal(SIGALRM, signal_alarm);
87	//alarm(1);
88}
89
90static void
91normal_exit(void)
92{
93	if (options.summary)
94		show_summary();
95	if (options.output) {
96		fclose(options.output);
97		options.output = NULL;
98	}
99}
100
101void
102ltrace_init(int argc, char **argv) {
103	struct opt_p_t *opt_p_tmp;
104
105	atexit(normal_exit);
106	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
107	signal(SIGTERM, signal_exit);	/*  ... or killed */
108
109	argv = process_options(argc, argv);
110	init_global_config();
111
112	if (command) {
113		/* Check that the binary ABI is supported before
114		 * calling execute_program.  */
115		struct ltelf lte;
116		ltelf_init(&lte, command);
117		ltelf_destroy(&lte);
118
119		pid_t pid = execute_program(command, argv);
120		struct process *proc = open_program(command, pid);
121		if (proc == NULL) {
122			fprintf(stderr, "couldn't open program '%s': %s\n",
123				command, strerror(errno));
124			exit(EXIT_FAILURE);
125		}
126
127		trace_set_options(proc);
128		continue_process(pid);
129	}
130	opt_p_tmp = opt_p;
131	while (opt_p_tmp) {
132		open_pid(opt_p_tmp->pid);
133		opt_p_tmp = opt_p_tmp->next;
134	}
135}
136
137static int num_ltrace_callbacks[EVENT_MAX];
138static callback_func * ltrace_callbacks[EVENT_MAX];
139
140void
141ltrace_add_callback(callback_func func, Event_type type) {
142	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
143	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
144}
145
146static void
147dispatch_callbacks(Event * ev) {
148	int i;
149	/* Ignoring case 1: signal into a dying tracer */
150	if (ev->type==EVENT_SIGNAL &&
151			exiting && ev->e_un.signum == SIGSTOP) {
152		return;
153	}
154	/* Ignoring case 2: process being born before a clone event */
155	if (ev->proc && ev->proc->state == STATE_IGNORED) {
156		return;
157	}
158	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
159		ltrace_callbacks[ev->type][i](ev);
160	}
161}
162
163void
164ltrace_main(void) {
165	Event * ev;
166	while (1) {
167		ev = next_event();
168		dispatch_callbacks(ev);
169		handle_event(ev);
170	}
171}
172