events.c revision 8f6d1ecd5f4301f899927a553572c5089fd29bcf 
1#if HAVE_CONFIG_H
2#include "config.h"
3#endif
4
5#define	_GNU_SOURCE	1
6#include <stdlib.h>
7#include <sys/types.h>
8#include <sys/wait.h>
9#include <errno.h>
10#include <signal.h>
11#include <string.h>
12#include <sys/ptrace.h>
13
14#include "ltrace.h"
15#include "options.h"
16#include "output.h"
17#include "debug.h"
18
19static Event event;
20
21Event *
22next_event(void) {
23	pid_t pid;
24	int status;
25	int tmp;
26	int stop_signal;
27
28	if (!list_of_processes) {
29		debug(1, "No more children");
30		exit(0);
31	}
32	pid = wait(&status);
33	if (pid == -1) {
34		if (errno == ECHILD) {
35			debug(1, "No more children");
36			exit(0);
37		} else if (errno == EINTR) {
38			debug(1, "wait received EINTR ?");
39			event.type = EVENT_NONE;
40			return &event;
41		}
42		perror("wait");
43		exit(1);
44	}
45	event.proc = pid2proc(pid);
46	if (!event.proc) {
47		event.type = EVENT_NEW;
48		return &event;
49	}
50	get_arch_dep(event.proc);
51	event.proc->instruction_pointer = NULL;
52	debug(3, "event from pid %u", pid);
53	if (event.proc->breakpoints_enabled == -1) {
54		enable_all_breakpoints(event.proc);
55		event.type = EVENT_NONE;
56		trace_set_options(event.proc, event.proc->pid);
57		continue_process(event.proc->pid);
58		return &event;
59	}
60	if (opt_i) {
61		event.proc->instruction_pointer =
62		    get_instruction_pointer(event.proc);
63	}
64	switch (syscall_p(event.proc, status, &tmp)) {
65		case 1:
66			event.type = EVENT_SYSCALL;
67			event.e_un.sysnum = tmp;
68			return &event;
69		case 2:
70			event.type = EVENT_SYSRET;
71			event.e_un.sysnum = tmp;
72			return &event;
73		case 3:
74			event.type = EVENT_ARCH_SYSCALL;
75			event.e_un.sysnum = tmp;
76			return &event;
77		case 4:
78			event.type = EVENT_ARCH_SYSRET;
79			event.e_un.sysnum = tmp;
80			return &event;
81		case -1:
82			event.type = EVENT_NONE;
83			continue_process(event.proc->pid);
84			return &event;
85	}
86	if (WIFSTOPPED(status) && ((status>>16 == PTRACE_EVENT_FORK) || (status>>16 == PTRACE_EVENT_VFORK) || (status>>16 == PTRACE_EVENT_CLONE))) {
87		unsigned long data;
88		ptrace(PTRACE_GETEVENTMSG, pid, NULL, &data);
89		event.type = EVENT_CLONE;
90		event.e_un.newpid = data;
91		return &event;
92	}
93	if (WIFSTOPPED(status) && (status>>16 == PTRACE_EVENT_EXEC)) {
94		event.type = EVENT_EXEC;
95		return &event;
96	}
97	if (WIFEXITED(status)) {
98		event.type = EVENT_EXIT;
99		event.e_un.ret_val = WEXITSTATUS(status);
100		return &event;
101	}
102	if (WIFSIGNALED(status)) {
103		event.type = EVENT_EXIT_SIGNAL;
104		event.e_un.signum = WTERMSIG(status);
105		return &event;
106	}
107	if (!WIFSTOPPED(status)) {
108		event.type = EVENT_NONE;
109		return &event;
110	}
111
112	stop_signal = WSTOPSIG(status);
113
114	/* On some targets, breakpoints are signalled not using
115	   SIGTRAP, but also with SIGILL, SIGSEGV or SIGEMT.  Check
116	   for these. */
117	if (stop_signal == SIGSEGV
118	    || stop_signal == SIGILL
119#ifdef SIGEMT
120	    || stop_signal == SIGEMT
121#endif
122	    ) {
123		// If we didn't need to know IP so far, get it now.
124		void * addr = opt_i
125		  ? event.proc->instruction_pointer
126		  : (event.proc->instruction_pointer = get_instruction_pointer (event.proc));
127
128		if (address2bpstruct(event.proc, addr))
129			stop_signal = SIGTRAP;
130	}
131
132	if (stop_signal != (SIGTRAP | event.proc->tracesysgood)
133	    && stop_signal != SIGTRAP) {
134		event.type = EVENT_SIGNAL;
135		event.e_un.signum = stop_signal;
136		return &event;
137	}
138
139	if (was_exec(event.proc, status)) {
140		pid_t saved_pid;
141
142		event.type = EVENT_NONE;
143		event.e_un.signum = WSTOPSIG(status);
144		debug(1, "Placing breakpoints for the new program");
145		event.proc->mask_32bit = 0;
146		event.proc->personality = 0;
147		event.proc->arch_ptr = NULL;
148		event.proc->filename = pid2name(event.proc->pid);
149		saved_pid = event.proc->pid;
150		event.proc->pid = 0;
151		breakpoints_init(event.proc);
152		event.proc->pid = saved_pid;
153		continue_process(event.proc->pid);
154		return &event;
155	}
156
157	event.type = EVENT_BREAKPOINT;
158	if (!event.proc->instruction_pointer) {
159		event.proc->instruction_pointer =
160		    get_instruction_pointer(event.proc);
161	}
162	event.e_un.brk_addr =
163	    event.proc->instruction_pointer - DECR_PC_AFTER_BREAK;
164	return &event;
165}
166