libltrace.c revision cebb88491e68bdf4d466b03970c9ca77f65615f8 
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) {
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	if (opt_p) {
58		struct opt_p_t *tmp = opt_p;
59		while (tmp) {
60			debug(2, "Sending SIGSTOP to process %u\n", tmp->pid);
61			kill(tmp->pid, SIGSTOP);
62			tmp = tmp->next;
63		}
64	}
65	alarm(1);
66}
67
68static void
69normal_exit(void) {
70	output_line(0, 0);
71	if (options.summary) {
72		show_summary();
73	}
74	if (options.output) {
75		fclose(options.output);
76		options.output = NULL;
77	}
78}
79
80void
81ltrace_init(int argc, char **argv) {
82	struct opt_p_t *opt_p_tmp;
83
84	atexit(normal_exit);
85	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
86	signal(SIGTERM, signal_exit);	/*  ... or killed */
87
88	argv = process_options(argc, argv);
89	while (opt_F) {
90		/* If filename begins with ~, expand it to the user's home */
91		/* directory. This does not correctly handle ~yoda, but that */
92		/* isn't as bad as it seems because the shell will normally */
93		/* be doing the expansion for us; only the hardcoded */
94		/* ~/.ltrace.conf should ever use this code. */
95		if (opt_F->filename[0] == '~') {
96			char path[PATH_MAX];
97			char *home_dir = getenv("HOME");
98			if (home_dir) {
99				strncpy(path, home_dir, PATH_MAX - 1);
100				path[PATH_MAX - 1] = '\0';
101				strncat(path, opt_F->filename + 1,
102						PATH_MAX - strlen(path) - 1);
103				read_config_file(path);
104			}
105		} else {
106			read_config_file(opt_F->filename);
107		}
108		opt_F = opt_F->next;
109	}
110	if (opt_e) {
111		struct opt_e_t *tmp = opt_e;
112		while (tmp) {
113			debug(1, "Option -e: %s\n", tmp->name);
114			tmp = tmp->next;
115		}
116	}
117	if (command) {
118		open_program(command, execute_program(command, argv), 0);
119	}
120	opt_p_tmp = opt_p;
121	while (opt_p_tmp) {
122		open_pid(opt_p_tmp->pid);
123		opt_p_tmp = opt_p_tmp->next;
124	}
125}
126
127static int num_ltrace_callbacks[EVENT_MAX];
128static callback_func * ltrace_callbacks[EVENT_MAX];
129
130void
131ltrace_add_callback(callback_func func, Event_type type) {
132	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
133	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
134}
135
136static void
137dispatch_callbacks(Event * ev) {
138	int i;
139	/* Ignoring case 1: signal into a dying tracer */
140	if (ev->type==EVENT_SIGNAL &&
141			exiting && ev->e_un.signum == SIGSTOP) {
142		return;
143	}
144	/* Ignoring case 2: process being born before a clone event */
145	if (ev->proc && ev->proc->state == STATE_IGNORED) {
146		return;
147	}
148	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
149		ltrace_callbacks[ev->type][i](ev);
150	}
151}
152
153void
154ltrace_main(void) {
155	Event * ev;
156	while (1) {
157		ev = next_event();
158		dispatch_callbacks(ev);
159		handle_event(ev);
160	}
161}
162