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
|
//===-- sanitizer_tls_get_addr.cc -----------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Handle the __tls_get_addr call.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_tls_get_addr.h"
#include "sanitizer_flags.h"
#include "sanitizer_platform_interceptors.h"
namespace __sanitizer {
#if SANITIZER_INTERCEPT_TLS_GET_ADDR
// The actual parameter that comes to __tls_get_addr
// is a pointer to a struct with two words in it:
struct TlsGetAddrParam {
uptr dso_id;
uptr offset;
};
// Glibc starting from 2.19 allocates tls using __signal_safe_memalign,
// which has such header.
struct Glibc_2_19_tls_header {
uptr size;
uptr start;
};
// This must be static TLS
__attribute__((tls_model("initial-exec")))
static __thread DTLS dtls;
// Make sure we properly destroy the DTLS objects:
// this counter should never get too large.
static atomic_uintptr_t number_of_live_dtls;
static const uptr kDestroyedThread = -1;
static inline void DTLS_Resize(uptr new_size) {
if (dtls.dtv_size >= new_size) return;
new_size = RoundUpToPowerOfTwo(new_size);
new_size = Max(new_size, 4096UL / sizeof(DTLS::DTV));
DTLS::DTV *new_dtv =
(DTLS::DTV *)MmapOrDie(new_size * sizeof(DTLS::DTV), "DTLS_Resize");
CHECK_LT(atomic_fetch_add(&number_of_live_dtls, 1, memory_order_relaxed),
1 << 20);
if (dtls.dtv_size)
internal_memcpy(new_dtv, dtls.dtv, dtls.dtv_size * sizeof(DTLS::DTV));
DTLS_Destroy();
dtls.dtv = new_dtv;
dtls.dtv_size = new_size;
}
void DTLS_Destroy() {
if (!dtls.dtv_size) return;
uptr s = dtls.dtv_size;
dtls.dtv_size = kDestroyedThread; // Do this before unmap for AS-safety.
UnmapOrDie(dtls.dtv, s * sizeof(DTLS::DTV));
atomic_fetch_sub(&number_of_live_dtls, 1, memory_order_relaxed);
}
void DTLS_on_tls_get_addr(void *arg_void, void *res) {
TlsGetAddrParam *arg = reinterpret_cast<TlsGetAddrParam *>(arg_void);
uptr dso_id = arg->dso_id;
if (dtls.dtv_size == kDestroyedThread) return;
DTLS_Resize(dso_id + 1);
if (dtls.dtv[dso_id].beg)
return;
uptr tls_size = 0;
uptr tls_beg = reinterpret_cast<uptr>(res) - arg->offset;
VPrintf(2, "__tls_get_addr: %p {%p,%p} => %p; tls_beg: %p; sp: %p\n", arg,
arg->dso_id, arg->offset, res, tls_beg, &tls_beg);
if (dtls.last_memalign_ptr == tls_beg) {
tls_size = dtls.last_memalign_size;
VPrintf(2, "__tls_get_addr: glibc <=2.18 suspected; tls={%p,%p}\n", tls_beg,
tls_size);
} else if ((tls_beg % 4096) == sizeof(Glibc_2_19_tls_header)) {
// We may want to check gnu_get_libc_version().
Glibc_2_19_tls_header *header = (Glibc_2_19_tls_header *)tls_beg - 1;
tls_size = header->size;
tls_beg = header->start;
VPrintf(2, "__tls_get_addr: glibc >=2.19 suspected; tls={%p %p}\n", tls_beg,
tls_size);
} else {
VPrintf(2, "__tls_get_addr: Can't guess glibc version\n");
// This may happen inside the DTOR of main thread, so just ignore it.
tls_size = 0;
}
dtls.dtv[dso_id].beg = tls_beg;
dtls.dtv[dso_id].size = tls_size;
}
void DTLS_on_libc_memalign(void *ptr, uptr size) {
VPrintf(2, "DTLS_on_libc_memalign: %p %p\n", ptr, size);
dtls.last_memalign_ptr = reinterpret_cast<uptr>(ptr);
dtls.last_memalign_size = size;
}
DTLS *DTLS_Get() { return &dtls; }
#else
void DTLS_on_libc_memalign(void *ptr, uptr size) {}
void DTLS_on_tls_get_addr(void *arg, void *res) {}
DTLS *DTLS_Get() { return 0; }
void DTLS_Destroy() {}
#endif // SANITIZER_INTERCEPT_TLS_GET_ADDR
} // namespace __sanitizer
|
