libltrace.c revision 02bd9eca0b439b6950ab72ba64b67181e5bf0fbd 
1#include "config.h"
2
3#include <stdio.h>
4#include <stdlib.h>
5#include <unistd.h>
6#include <string.h>
7#include <errno.h>
8#include <sys/param.h>
9#include <signal.h>
10#include <sys/wait.h>
11
12#include "common.h"
13
14char *command = NULL;
15
16int exiting = 0;		/* =1 if a SIGINT or SIGTERM has been received */
17
18static enum pcb_status
19stop_non_p_processes (Process * proc, void * data)
20{
21	int stop = 1;
22
23	struct opt_p_t *it;
24	for (it = opt_p; it != NULL; it = it->next) {
25		Process * p_proc = pid2proc(it->pid);
26		if (p_proc == NULL) {
27			printf("stop_non_p_processes: %d terminated?\n", it->pid);
28			continue;
29		}
30		if (p_proc == proc || p_proc->leader == proc->leader) {
31			stop = 0;
32			break;
33		}
34	}
35
36	if (stop) {
37		debug(2, "Sending SIGSTOP to process %u", proc->pid);
38		kill(proc->pid, SIGSTOP);
39	}
40
41	return pcb_cont;
42}
43
44static void
45signal_alarm(int sig) {
46	signal(SIGALRM, SIG_DFL);
47	each_process(NULL, &stop_non_p_processes, NULL);
48}
49
50static void
51signal_exit(int sig) {
52	exiting = 1;
53	debug(1, "Received interrupt signal; exiting...");
54	signal(SIGINT, SIG_IGN);
55	signal(SIGTERM, SIG_IGN);
56	signal(SIGALRM, signal_alarm);
57	//alarm(1);
58}
59
60static void
61normal_exit(void) {
62	output_line(0, 0);
63	if (options.summary) {
64		show_summary();
65	}
66	if (options.output) {
67		fclose(options.output);
68		options.output = NULL;
69	}
70}
71
72void
73ltrace_init(int argc, char **argv) {
74	struct opt_p_t *opt_p_tmp;
75
76	atexit(normal_exit);
77	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
78	signal(SIGTERM, signal_exit);	/*  ... or killed */
79
80	argv = process_options(argc, argv);
81	while (opt_F) {
82		/* If filename begins with ~, expand it to the user's home */
83		/* directory. This does not correctly handle ~yoda, but that */
84		/* isn't as bad as it seems because the shell will normally */
85		/* be doing the expansion for us; only the hardcoded */
86		/* ~/.ltrace.conf should ever use this code. */
87		if (opt_F->filename[0] == '~') {
88			char path[PATH_MAX];
89			char *home_dir = getenv("HOME");
90			if (home_dir) {
91				strncpy(path, home_dir, PATH_MAX - 1);
92				path[PATH_MAX - 1] = '\0';
93				strncat(path, opt_F->filename + 1,
94						PATH_MAX - strlen(path) - 1);
95				read_config_file(path);
96			}
97		} else {
98			read_config_file(opt_F->filename);
99		}
100		opt_F = opt_F->next;
101	}
102	if (opt_e) {
103		struct opt_e_t *tmp = opt_e;
104		while (tmp) {
105			debug(1, "Option -e: %s\n", tmp->name);
106			tmp = tmp->next;
107		}
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		open_program(command, execute_program(command, argv), 0);
116	}
117	opt_p_tmp = opt_p;
118	while (opt_p_tmp) {
119		open_pid(opt_p_tmp->pid);
120		opt_p_tmp = opt_p_tmp->next;
121	}
122}
123
124static int num_ltrace_callbacks[EVENT_MAX];
125static callback_func * ltrace_callbacks[EVENT_MAX];
126
127void
128ltrace_add_callback(callback_func func, Event_type type) {
129	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
130	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
131}
132
133static void
134dispatch_callbacks(Event * ev) {
135	int i;
136	/* Ignoring case 1: signal into a dying tracer */
137	if (ev->type==EVENT_SIGNAL &&
138			exiting && ev->e_un.signum == SIGSTOP) {
139		return;
140	}
141	/* Ignoring case 2: process being born before a clone event */
142	if (ev->proc && ev->proc->state == STATE_IGNORED) {
143		return;
144	}
145	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
146		ltrace_callbacks[ev->type][i](ev);
147	}
148}
149
150void
151ltrace_main(void) {
152	Event * ev;
153	while (1) {
154		ev = next_event();
155		dispatch_callbacks(ev);
156		handle_event(ev);
157	}
158}
159