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)
46 #error tracing is not supported on this architecture
49 #define INFO(fmt, ...) do { \
50 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
53 #define ERROR(fmt, ...) do { \
54 syslog(0, "utrace: "fmt, ## __VA_ARGS__); \
55 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
58 static struct uloop_process tracer;
59 static int *syscall_count;
60 static struct blob_buf b;
61 static int syscall_max;
62 static int in_syscall;
65 static int max_syscall = ARRAY_SIZE(syscall_names);
67 static void set_syscall(const char *name, int val)
71 for (i = 0; i < max_syscall; i++)
72 if (syscall_names[i] && !strcmp(syscall_names[i], name)) {
73 syscall_count[i] = val;
78 static void print_syscalls(int policy, const char *json)
83 set_syscall("rt_sigaction", 1);
84 set_syscall("sigreturn", 1);
85 set_syscall("rt_sigreturn", 1);
86 set_syscall("exit_group", 1);
87 set_syscall("exit", 1);
90 c = blobmsg_open_array(&b, "whitelist");
92 for (i = 0; i < ARRAY_SIZE(syscall_names); i++) {
93 if (!syscall_count[i])
95 if (syscall_names[i]) {
97 printf("syscall %d (%s) was called %d times\n",
98 i, syscall_names[i], syscall_count[i]);
99 blobmsg_add_string(&b, NULL, syscall_names[i]);
101 ERROR("no name found for syscall(%d)\n", i);
104 blobmsg_close_array(&b, c);
105 blobmsg_add_u32(&b, "policy", policy);
107 FILE *fp = fopen(json, "w");
109 fprintf(fp, "%s", blobmsg_format_json_indent(b.head, true, 0));
111 INFO("saving syscall trace to %s\n", json);
113 ERROR("failed to open %s\n", json);
117 blobmsg_format_json_indent(b.head, true, 0));
122 static void tracer_cb(struct uloop_process *c, int ret)
124 if (WIFSTOPPED(ret) && WSTOPSIG(ret) & 0x80) {
126 int syscall = ptrace(PTRACE_PEEKUSER, c->pid, reg_syscall_nr);
128 if (syscall < syscall_max) {
129 syscall_count[syscall]++;
131 fprintf(stderr, "%s()\n", syscall_names[syscall]);
133 fprintf(stderr, "syscal(%d)\n", syscall);
136 in_syscall = !in_syscall;
137 } else if (WIFEXITED(ret)) {
141 ptrace(PTRACE_SYSCALL, c->pid, 0, 0);
142 uloop_process_add(&tracer);
145 int main(int argc, char **argv, char **envp)
148 int status, ch, policy = EPERM;
151 while ((ch = getopt(argc, argv, "f:p:")) != -1) {
157 policy = atoi(optarg);
168 if (getenv("TRACE_DEBUG"))
170 unsetenv("TRACE_DEBUG");
175 char **_argv = calloc(argc + 1, sizeof(char *));
177 char preload[] = "LD_PRELOAD=/lib/libpreload-trace.so";
181 memcpy(_argv, argv, argc * sizeof(char *));
186 _envp = calloc(envc, sizeof(char *));
187 memcpy(&_envp[1], _envp, envc * sizeof(char *));
190 ret = execve(_argv[0], _argv, envp);
191 ERROR("failed to exec %s: %s\n", _argv[0], strerror(errno));
198 syscall_max = ARRAY_SIZE(syscall_names);
199 syscall_count = calloc(syscall_max, sizeof(int));
200 waitpid(child, &status, 0);
201 if (!WIFSTOPPED(status)) {
202 ERROR("failed to start %s\n", *argv);
206 ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD);
207 ptrace(PTRACE_SYSCALL, child, 0, 0);
211 tracer.cb = tracer_cb;
212 uloop_process_add(&tracer);
217 if (asprintf(&json, "/tmp/%s.%u.json", basename(*argv), child) < 0)
218 ERROR("failed to allocate output path: %s\n", strerror(errno));
220 print_syscalls(policy, json);