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 #ifndef PTRACE_EVENT_STOP
28 /* PTRACE_EVENT_STOP is defined in linux/ptrace.h, but this header
29 * collides with musl's sys/ptrace.h */
30 #define PTRACE_EVENT_STOP 128
33 #include <libubox/uloop.h>
34 #include <libubox/blobmsg.h>
35 #include <libubox/blobmsg_json.h>
37 #include "../syscall-names.h"
39 #define _offsetof(a, b) __builtin_offsetof(a,b)
40 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
43 #define reg_syscall_nr _offsetof(struct user, regs.orig_rax)
44 #elif defined(__i386__)
45 #define reg_syscall_nr _offsetof(struct user, regs.orig_eax)
50 #define reg_syscall_nr (EF_REG2 / 4)
51 #elif defined(__arm__)
52 #define reg_syscall_nr _offsetof(struct user, regs.uregs[7])
54 #error tracing is not supported on this architecture
57 #define INFO(fmt, ...) do { \
58 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
61 #define ERROR(fmt, ...) do { \
62 syslog(LOG_ERR, "utrace: "fmt, ## __VA_ARGS__); \
63 fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
67 struct uloop_process proc
;
71 static struct tracee tracer
;
72 static int *syscall_count
;
73 static struct blob_buf b
;
74 static int syscall_max
;
77 static int max_syscall
= ARRAY_SIZE(syscall_names
);
79 static void set_syscall(const char *name
, int val
)
83 for (i
= 0; i
< max_syscall
; i
++)
84 if (syscall_names
[i
] && !strcmp(syscall_names
[i
], name
)) {
85 syscall_count
[i
] = val
;
95 static int cmp_count(const void *a
, const void *b
)
97 return ((struct syscall
*)b
)->count
- ((struct syscall
*)a
)->count
;
100 static void print_syscalls(int policy
, const char *json
)
105 set_syscall("rt_sigaction", 1);
106 set_syscall("sigreturn", 1);
107 set_syscall("rt_sigreturn", 1);
108 set_syscall("exit_group", 1);
109 set_syscall("exit", 1);
111 struct syscall sorted
[ARRAY_SIZE(syscall_names
)];
113 for (i
= 0; i
< ARRAY_SIZE(syscall_names
); i
++) {
114 sorted
[i
].syscall
= i
;
115 sorted
[i
].count
= syscall_count
[i
];
118 qsort(sorted
, ARRAY_SIZE(syscall_names
), sizeof(sorted
[0]), cmp_count
);
120 blob_buf_init(&b
, 0);
121 c
= blobmsg_open_array(&b
, "whitelist");
123 for (i
= 0; i
< ARRAY_SIZE(syscall_names
); i
++) {
124 int sc
= sorted
[i
].syscall
;
125 if (!sorted
[i
].count
)
127 if (syscall_names
[sc
]) {
129 printf("syscall %d (%s) was called %d times\n",
130 sc
, syscall_names
[sc
], sorted
[i
].count
);
131 blobmsg_add_string(&b
, NULL
, syscall_names
[sc
]);
133 ERROR("no name found for syscall(%d)\n", sc
);
136 blobmsg_close_array(&b
, c
);
137 blobmsg_add_u32(&b
, "policy", policy
);
139 FILE *fp
= fopen(json
, "w");
141 fprintf(fp
, "%s", blobmsg_format_json_indent(b
.head
, true, 0));
143 INFO("saving syscall trace to %s\n", json
);
145 ERROR("failed to open %s\n", json
);
149 blobmsg_format_json_indent(b
.head
, true, 0));
154 static void tracer_cb(struct uloop_process
*c
, int ret
)
156 struct tracee
*tracee
= container_of(c
, struct tracee
, proc
);
157 int inject_signal
= 0;
159 /* We explicitely check for events in upper 16 bits, because
160 * musl (as opposed to glibc) does not report
161 * PTRACE_EVENT_STOP as WIFSTOPPED */
162 if (WIFSTOPPED(ret
) || (ret
>> 16)) {
163 if (WSTOPSIG(ret
) & 0x80) {
164 if (!tracee
->in_syscall
) {
165 int syscall
= ptrace(PTRACE_PEEKUSER
, c
->pid
, reg_syscall_nr
);
167 if (syscall
< syscall_max
) {
168 syscall_count
[syscall
]++;
170 fprintf(stderr
, "%s()\n", syscall_names
[syscall
]);
172 fprintf(stderr
, "syscal(%d)\n", syscall
);
175 tracee
->in_syscall
= !tracee
->in_syscall
;
176 } else if ((ret
>> 8) == (SIGTRAP
| (PTRACE_EVENT_FORK
<< 8)) ||
177 (ret
>> 8) == (SIGTRAP
| (PTRACE_EVENT_VFORK
<< 8)) ||
178 (ret
>> 8) == (SIGTRAP
| (PTRACE_EVENT_CLONE
<< 8))) {
179 struct tracee
*child
= calloc(1, sizeof(struct tracee
));
181 ptrace(PTRACE_GETEVENTMSG
, c
->pid
, 0, &child
->proc
.pid
);
182 child
->proc
.cb
= tracer_cb
;
183 ptrace(PTRACE_SYSCALL
, child
->proc
.pid
, 0, 0);
184 uloop_process_add(&child
->proc
);
186 fprintf(stderr
, "Tracing new child %d\n", child
->proc
.pid
);
187 } else if ((ret
>> 16) == PTRACE_EVENT_STOP
) {
188 /* Nothing special to do here */
190 inject_signal
= WSTOPSIG(ret
);
192 fprintf(stderr
, "Injecting signal %d into pid %d\n",
193 inject_signal
, tracee
->proc
.pid
);
195 } else if (WIFEXITED(ret
) || (WIFSIGNALED(ret
) && WTERMSIG(ret
))) {
196 if (tracee
== &tracer
) {
197 uloop_end(); /* Main process exit */
200 fprintf(stderr
, "Child %d exited\n", tracee
->proc
.pid
);
206 ptrace(PTRACE_SYSCALL
, c
->pid
, 0, inject_signal
);
207 uloop_process_add(c
);
210 int main(int argc
, char **argv
, char **envp
)
213 int status
, ch
, policy
= EPERM
;
216 while ((ch
= getopt(argc
, argv
, "f:p:")) != -1) {
222 policy
= atoi(optarg
);
233 if (getenv("TRACE_DEBUG"))
235 unsetenv("TRACE_DEBUG");
240 char **_argv
= calloc(argc
+ 1, sizeof(char *));
242 char *preload
= "LD_PRELOAD=/lib/libpreload-trace.so";
246 memcpy(_argv
, argv
, argc
* sizeof(char *));
251 _envp
= calloc(envc
+ 1, sizeof(char *));
252 memcpy(&_envp
[1], envp
, envc
* sizeof(char *));
255 ret
= execve(_argv
[0], _argv
, _envp
);
256 ERROR("failed to exec %s: %s\n", _argv
[0], strerror(errno
));
266 syscall_max
= ARRAY_SIZE(syscall_names
);
267 syscall_count
= calloc(syscall_max
, sizeof(int));
268 waitpid(child
, &status
, WUNTRACED
);
269 if (!WIFSTOPPED(status
)) {
270 ERROR("failed to start %s\n", *argv
);
274 ptrace(PTRACE_SEIZE
, child
, 0,
275 PTRACE_O_TRACESYSGOOD
|
277 PTRACE_O_TRACEVFORK
|
278 PTRACE_O_TRACECLONE
);
279 ptrace(PTRACE_SYSCALL
, child
, 0, SIGCONT
);
282 tracer
.proc
.pid
= child
;
283 tracer
.proc
.cb
= tracer_cb
;
284 uloop_process_add(&tracer
.proc
);
289 if (asprintf(&json
, "/tmp/%s.%u.json", basename(*argv
), child
) < 0)
290 ERROR("failed to allocate output path: %s\n", strerror(errno
));
292 print_syscalls(policy
, json
);