libltrace.c revision cc0e1e4b83d69441cc5f61ea87eda5458ee9fae3 
1#include "config.h"
2
3#include <sys/param.h>
4#include <sys/wait.h>
5#include <errno.h>
6#include <signal.h>
7#include <stdio.h>
8#include <stdlib.h>
9#include <string.h>
10#include <unistd.h>
11
12#include "common.h"
13#include "proc.h"
14
15char *command = NULL;
16
17int exiting = 0;		/* =1 if a SIGINT or SIGTERM has been received */
18
19static enum callback_status
20stop_non_p_processes(Process *proc, void *data)
21{
22	int stop = 1;
23
24	struct opt_p_t *it;
25	for (it = opt_p; it != NULL; it = it->next) {
26		Process * p_proc = pid2proc(it->pid);
27		if (p_proc == NULL) {
28			printf("stop_non_p_processes: %d terminated?\n", it->pid);
29			continue;
30		}
31		if (p_proc == proc || p_proc->leader == proc->leader) {
32			stop = 0;
33			break;
34		}
35	}
36
37	if (stop) {
38		debug(2, "Sending SIGSTOP to process %u", proc->pid);
39		kill(proc->pid, SIGSTOP);
40	}
41
42	return CBS_CONT;
43}
44
45static void
46signal_alarm(int sig) {
47	signal(SIGALRM, SIG_DFL);
48	each_process(NULL, &stop_non_p_processes, NULL);
49}
50
51static void
52signal_exit(int sig)
53{
54	debug(1, "Received interrupt signal; exiting...");
55	if (exiting != 0)
56		return;
57
58	exiting = 1 + !!os_ltrace_exiting_sighandler();
59
60	signal(SIGINT, SIG_IGN);
61	signal(SIGTERM, SIG_IGN);
62	signal(SIGALRM, signal_alarm);
63	//alarm(1);
64}
65
66static void
67normal_exit(void) {
68	output_line(0, 0);
69	if (options.summary) {
70		show_summary();
71	}
72	if (options.output) {
73		fclose(options.output);
74		options.output = NULL;
75	}
76}
77
78void
79ltrace_init(int argc, char **argv) {
80	struct opt_p_t *opt_p_tmp;
81
82	atexit(normal_exit);
83	signal(SIGINT, signal_exit);	/* Detach processes when interrupted */
84	signal(SIGTERM, signal_exit);	/*  ... or killed */
85
86	argv = process_options(argc, argv);
87	while (opt_F) {
88		/* If filename begins with ~, expand it to the user's home */
89		/* directory. This does not correctly handle ~yoda, but that */
90		/* isn't as bad as it seems because the shell will normally */
91		/* be doing the expansion for us; only the hardcoded */
92		/* ~/.ltrace.conf should ever use this code. */
93		if (opt_F->filename[0] == '~') {
94			char path[PATH_MAX];
95			char *home_dir = getenv("HOME");
96			if (home_dir) {
97				strncpy(path, home_dir, PATH_MAX - 1);
98				path[PATH_MAX - 1] = '\0';
99				strncat(path, opt_F->filename + 1,
100						PATH_MAX - strlen(path) - 1);
101				read_config_file(path);
102			}
103		} else {
104			read_config_file(opt_F->filename);
105		}
106		opt_F = opt_F->next;
107	}
108	if (command) {
109		/* Check that the binary ABI is supported before
110		 * calling execute_program.  */
111		struct ltelf lte = {};
112		open_elf(&lte, command);
113
114		pid_t pid = execute_program(command, argv);
115		struct Process *proc = open_program(command, pid);
116		if (proc == NULL) {
117			fprintf(stderr, "couldn't open program '%s': %s\n",
118				command, strerror(errno));
119			exit(EXIT_FAILURE);
120		}
121
122		trace_set_options(proc);
123		continue_process(pid);
124	}
125	opt_p_tmp = opt_p;
126	while (opt_p_tmp) {
127		open_pid(opt_p_tmp->pid);
128		opt_p_tmp = opt_p_tmp->next;
129	}
130}
131
132static int num_ltrace_callbacks[EVENT_MAX];
133static callback_func * ltrace_callbacks[EVENT_MAX];
134
135void
136ltrace_add_callback(callback_func func, Event_type type) {
137	ltrace_callbacks[type] = realloc(ltrace_callbacks[type], (num_ltrace_callbacks[type]+1)*sizeof(callback_func));
138	ltrace_callbacks[type][num_ltrace_callbacks[type]++] = func;
139}
140
141static void
142dispatch_callbacks(Event * ev) {
143	int i;
144	/* Ignoring case 1: signal into a dying tracer */
145	if (ev->type==EVENT_SIGNAL &&
146			exiting && ev->e_un.signum == SIGSTOP) {
147		return;
148	}
149	/* Ignoring case 2: process being born before a clone event */
150	if (ev->proc && ev->proc->state == STATE_IGNORED) {
151		return;
152	}
153	for (i=0; i<num_ltrace_callbacks[ev->type]; i++) {
154		ltrace_callbacks[ev->type][i](ev);
155	}
156}
157
158void
159ltrace_main(void) {
160	Event * ev;
161	while (1) {
162		ev = next_event();
163		dispatch_callbacks(ev);
164		handle_event(ev);
165	}
166}
167