2 * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU Lesser General Public License version 2.1
6 * as published by the Free Software Foundation
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
16 #include <sys/ptrace.h>
17 #include <sys/types.h>
27 #include <libubox/uloop.h>
28 #include <libubox/blobmsg.h>
29 #include <libubox/blobmsg_json.h>
31 #include "../syscall-names.h"
33 #define _offsetof(a, b) __builtin_offsetof(a,b)
34 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
37 #define reg_syscall_nr _offsetof(struct user, regs.orig_rax)
38 #elif defined(__i386__)
39 #define reg_syscall_nr _offsetof(struct user, regs.orig_eax)
44 #define reg_syscall_nr (EF_REG2 / 4)
45 #elif defined(__arm__)
46 #define reg_syscall_nr _offsetof(struct user, regs.uregs[7])
48 #error tracing is not supported on this architecture
51 #define INFO(fmt, ...) do { \
52 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
55 #define ERROR(fmt, ...) do { \
56 syslog(LOG_ERR, "utrace: "fmt, ## __VA_ARGS__); \
57 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
61 struct uloop_process proc;
65 static struct tracee tracer;
66 static int *syscall_count;
67 static struct blob_buf b;
68 static int syscall_max;
71 static int max_syscall = ARRAY_SIZE(syscall_names);
73 static void set_syscall(const char *name, int val)
77 for (i = 0; i < max_syscall; i++)
78 if (syscall_names[i] && !strcmp(syscall_names[i], name)) {
79 syscall_count[i] = val;
89 static int cmp_count(const void *a, const void *b)
91 return ((struct syscall*)b)->count - ((struct syscall*)a)->count;
94 static void print_syscalls(int policy, const char *json)
99 set_syscall("rt_sigaction", 1);
100 set_syscall("sigreturn", 1);
101 set_syscall("rt_sigreturn", 1);
102 set_syscall("exit_group", 1);
103 set_syscall("exit", 1);
105 struct syscall sorted[ARRAY_SIZE(syscall_names)];
107 for (i = 0; i < ARRAY_SIZE(syscall_names); i++) {
108 sorted[i].syscall = i;
109 sorted[i].count = syscall_count[i];
112 qsort(sorted, ARRAY_SIZE(syscall_names), sizeof(sorted[0]), cmp_count);
114 blob_buf_init(&b, 0);
115 c = blobmsg_open_array(&b, "whitelist");
117 for (i = 0; i < ARRAY_SIZE(syscall_names); i++) {
118 int sc = sorted[i].syscall;
119 if (!sorted[i].count)
121 if (syscall_names[sc]) {
123 printf("syscall %d (%s) was called %d times\n",
124 sc, syscall_names[sc], sorted[i].count);
125 blobmsg_add_string(&b, NULL, syscall_names[sc]);
127 ERROR("no name found for syscall(%d)\n", sc);
130 blobmsg_close_array(&b, c);
131 blobmsg_add_u32(&b, "policy", policy);
133 FILE *fp = fopen(json, "w");
135 fprintf(fp, "%s", blobmsg_format_json_indent(b.head, true, 0));
137 INFO("saving syscall trace to %s\n", json);
139 ERROR("failed to open %s\n", json);
143 blobmsg_format_json_indent(b.head, true, 0));
148 static void tracer_cb(struct uloop_process *c, int ret)
150 struct tracee *tracee = container_of(c, struct tracee, proc);
151 int inject_signal = 0;
153 if (WIFSTOPPED(ret)) {
154 if (WSTOPSIG(ret) & 0x80) {
155 if (!tracee->in_syscall) {
156 int syscall = ptrace(PTRACE_PEEKUSER, c->pid, reg_syscall_nr);
158 if (syscall < syscall_max) {
159 syscall_count[syscall]++;
161 fprintf(stderr, "%s()\n", syscall_names[syscall]);
163 fprintf(stderr, "syscal(%d)\n", syscall);
166 tracee->in_syscall = !tracee->in_syscall;
167 } else if ((ret >> 8) == (SIGTRAP | (PTRACE_EVENT_FORK << 8)) ||
168 (ret >> 8) == (SIGTRAP | (PTRACE_EVENT_VFORK << 8)) ||
169 (ret >> 8) == (SIGTRAP | (PTRACE_EVENT_CLONE << 8))) {
170 struct tracee *child = calloc(1, sizeof(struct tracee));
172 ptrace(PTRACE_GETEVENTMSG, c->pid, 0, &child->proc.pid);
173 child->proc.cb = tracer_cb;
174 ptrace(PTRACE_SYSCALL, child->proc.pid, 0, 0);
175 uloop_process_add(&child->proc);
177 fprintf(stderr, "Tracing new child %d\n", child->proc.pid);
179 inject_signal = WSTOPSIG(ret);
181 fprintf(stderr, "Injecting signal %d into pid %d\n",
182 inject_signal, tracee->proc.pid);
184 } else if (WIFEXITED(ret) || (WIFSIGNALED(ret) && WTERMSIG(ret))) {
185 if (tracee == &tracer) {
186 uloop_end(); /* Main process exit */
189 fprintf(stderr, "Child %d exited\n", tracee->proc.pid);
195 ptrace(PTRACE_SYSCALL, c->pid, 0, inject_signal);
196 uloop_process_add(c);
199 int main(int argc, char **argv, char **envp)
202 int status, ch, policy = EPERM;
205 while ((ch = getopt(argc, argv, "f:p:")) != -1) {
211 policy = atoi(optarg);
222 if (getenv("TRACE_DEBUG"))
224 unsetenv("TRACE_DEBUG");
229 char **_argv = calloc(argc + 1, sizeof(char *));
231 char *preload = "LD_PRELOAD=/lib/libpreload-trace.so";
235 memcpy(_argv, argv, argc * sizeof(char *));
240 _envp = calloc(envc + 1, sizeof(char *));
241 memcpy(&_envp[1], envp, envc * sizeof(char *));
244 ret = execve(_argv[0], _argv, _envp);
245 ERROR("failed to exec %s: %s\n", _argv[0], strerror(errno));
255 syscall_max = ARRAY_SIZE(syscall_names);
256 syscall_count = calloc(syscall_max, sizeof(int));
257 waitpid(child, &status, 0);
258 if (!WIFSTOPPED(status)) {
259 ERROR("failed to start %s\n", *argv);
263 ptrace(PTRACE_SETOPTIONS, child, 0,
264 PTRACE_O_TRACESYSGOOD |
266 PTRACE_O_TRACEVFORK |
267 PTRACE_O_TRACECLONE);
268 ptrace(PTRACE_SYSCALL, child, 0, 0);
271 tracer.proc.pid = child;
272 tracer.proc.cb = tracer_cb;
273 uloop_process_add(&tracer.proc);
278 if (asprintf(&json, "/tmp/%s.%u.json", basename(*argv), child) < 0)
279 ERROR("failed to allocate output path: %s\n", strerror(errno));
281 print_syscalls(policy, json);