1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
#include "wrapper.h"
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/mman.h>
#include "verbose.h"
#include <pthread.h>
void
verbose_log(const char *fmt, ...)
{
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_lock(&mutex);
fprintf(stderr, "%lu: ", pthread_self());
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fputc('\n', stderr);
pthread_mutex_unlock(&mutex);
}
#ifdef VERBOSE_FUNCTIONS
# ifdef ANDROID_X86_LINKER
__asm__(
"wrapper_start: nop\n"
"wrapper_symbol: pushl $0xFAFBFCFD\n"
"wrapper_trace: movl $0xFAFBFCFD, %eax\ncall *%eax\npop %eax\n"
"wrapper_call: movl $0xFAFBFCFD, %eax\njmp *%eax\n"
"wrapper_end: nop\n"
);
# define WRAPPER_TRACE
# else
# warning "no wrapper asm for this platform, function tracing is not available"
# endif
#endif
#ifdef WRAPPER_TRACE
extern char wrapper_start, wrapper_symbol, wrapper_trace, wrapper_call, wrapper_end;
static union {
void *ptr;
char* (*fun)(const char *mangled_name, char *output_buffer, size_t *length, int *status);
} __cxa_demangle;
static void
trace(const char *const symbol)
{
assert(symbol);
if (__cxa_demangle.ptr) {
int status;
char *demangled;
static __thread char *data;
static __thread size_t size;
static __thread bool skip_trace;
if (skip_trace)
return;
skip_trace = true;
if ((demangled = __cxa_demangle.fun(symbol, data, &size, &status))) {
data = (data != demangled ? demangled : data);
verbose("trace: %s", demangled);
return;
}
skip_trace = false;
}
verbose("trace: %s", symbol);
}
#endif
void
wrapper_set_cpp_demangler(void *function)
{
#ifdef WRAPPER_TRACE
__cxa_demangle.ptr = function;
#endif
}
void*
wrapper_create(const char *const symbol, void *function)
{
assert(symbol);
if (!function) {
verbose_log("FIXME: unimplemented symbol: %s", symbol);
return NULL;
}
#ifdef WRAPPER_TRACE
const size_t sz = &wrapper_end - &wrapper_start;
unsigned char *fun = mmap(NULL, sz, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
assert(fun != MAP_FAILED);
memcpy(fun, &wrapper_start, sz);
#ifdef ANDROID_X86_LINKER
memcpy(fun + (&wrapper_symbol - &wrapper_start) + 1, &symbol, sizeof(symbol));
memcpy(fun + (&wrapper_trace - &wrapper_start) + 1, (uintptr_t[]){ (uintptr_t)trace }, sizeof(uintptr_t));
memcpy(fun + (&wrapper_call - &wrapper_start) + 1, &function, sizeof(function));
#else
# error "you forgot to implement the pointer setups for your asm platform"
#endif
mprotect(fun, sz, PROT_READ | PROT_EXEC);
return fun;
#else
return function;
#endif
}
|
