libltrace.c revision 3ed2a4227d5f2a8d44f3c6ffd704a9d2e867c591 
1#include "config.h"
2
3#include <sys/param.h>
4#include <sys/wait.h>
5#include <errno.h>
6#include <error.h>
7#include <signal.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11#include <unistd.h>
12
13#include "common.h"
14#include "proc.h"
15
16char *command = NULL;
17
18int exiting = 0;		/* =1 if a SIGINT or SIGTERM has been received */
19
20static enum callback_status
21stop_non_p_processes(Process *proc, void *data)
22{
23	int stop = 1;
24
25	struct opt_p_t *it;
26	for (it = opt_p; it != NULL; it = it->next) {
27		Process * p_proc = pid2proc(it->pid);
28		if (p_proc == NULL) {
29			printf("stop_non_p_processes: %d terminated?\n", it->pid);
30			continue;
31		}
32		if (p_proc == proc || p_proc->leader == proc->leader) {
33			stop = 0;
34			break;
35		}
36	}
37
38	if (stop) {
39		debug(2, "Sending SIGSTOP to process %u", proc->pid);
40		kill(proc->pid, SIGSTOP);
41	}
42
43	return CBS_CONT;
44}
45
46static void
47signal_alarm(int sig) {
48	signal(SIGALRM, SIG_DFL);
49	each_process(NULL, &stop_non_p_processes, NULL);
50}
51
52static void
53signal_exit(int sig)
54{
55	debug(1, "Received interrupt signal; exiting...");
56	if (exiting != 0)
57		return;
58
59	exiting = 1 + !!os_ltrace_exiting_sighandler();
60
61	signal(SIGINT, SIG_IGN);
62	signal(SIGTERM, SIG_IGN);
63	signal(SIGALRM, signal_alarm);
64	//alarm(1);
65}
66
67static void
68normal_exit(void) {
69	output_line(0, 0);
70	if (options.summary) {
71		show_summary();
72	}
73	if (options.output) {
74		fclose(options.output);
75		options.output = NULL;
76	}
77}
78
79void
80ltrace_init(int argc, char **argv) {
81	struct opt_p_t *opt_p_tmp;
82
83	atexit(normal_exit);
84	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
85	signal(SIGTERM, signal_exit);	/*  ... or killed */
86
87	argv = process_options(argc, argv);
88	while (opt_F) {
89		/* If filename begins with ~, expand it to the user's home */
90		/* directory. This does not correctly handle ~yoda, but that */
91		/* isn't as bad as it seems because the shell will normally */
92		/* be doing the expansion for us; only the hardcoded */
93		/* ~/.ltrace.conf should ever use this code. */
94		if (opt_F->filename[0] == '~') {
95			char path[PATH_MAX];
96			char *home_dir = getenv("HOME");
97			if (home_dir) {
98				strncpy(path, home_dir, PATH_MAX - 1);
99				path[PATH_MAX - 1] = '\0';
100				strncat(path, opt_F->filename + 1,
101						PATH_MAX - strlen(path) - 1);
102				read_config_file(path);
103			}
104		} else {
105			read_config_file(opt_F->filename);
106		}
107		opt_F = opt_F->next;
108	}
109	if (command) {
110		/* Check that the binary ABI is supported before
111		 * calling execute_program.  */
112		struct ltelf lte = {};
113		open_elf(&lte, command);
114
115		pid_t pid = execute_program(command, argv);
116		struct Process *proc = open_program(command, pid, 0);
117		if (proc == NULL)
118			error(EXIT_FAILURE, errno,
119			      "couldn't open program '%s'", command);
120		continue_process(pid);
121	}
122	opt_p_tmp = opt_p;
123	while (opt_p_tmp) {
124		open_pid(opt_p_tmp->pid);
125		opt_p_tmp = opt_p_tmp->next;
126	}
127}
128
129static int num_ltrace_callbacks[EVENT_MAX];
130static callback_func * ltrace_callbacks[EVENT_MAX];
131
132void
133ltrace_add_callback(callback_func func, Event_type type) {
134	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
135	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
136}
137
138static void
139dispatch_callbacks(Event * ev) {
140	int i;
141	/* Ignoring case 1: signal into a dying tracer */
142	if (ev->type==EVENT_SIGNAL &&
143			exiting && ev->e_un.signum == SIGSTOP) {
144		return;
145	}
146	/* Ignoring case 2: process being born before a clone event */
147	if (ev->proc && ev->proc->state == STATE_IGNORED) {
148		return;
149	}
150	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
151		ltrace_callbacks[ev->type][i](ev);
152	}
153}
154
155void
156ltrace_main(void) {
157	Event * ev;
158	while (1) {
159		ev = next_event();
160		dispatch_callbacks(ev);
161		handle_event(ev);
162	}
163}
164