1 #include <errno.h>
2 #include <linux/unistd.h>
3
4 #include <sys/ptrace.h>
5 #include <sys/syscall.h>
6 #include <unistd.h>
7
8 #include "sysdep/tls.h"
9
10 #ifndef PTRACE_GET_THREAD_AREA
11 #define PTRACE_GET_THREAD_AREA 25
12 #endif
13
14 #ifndef PTRACE_SET_THREAD_AREA
15 #define PTRACE_SET_THREAD_AREA 26
16 #endif
17
18 /* Checks whether host supports TLS, and sets *tls_min according to the value
19 * valid on the host.
20 * i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
check_host_supports_tls(int * supports_tls,int * tls_min)21 void check_host_supports_tls(int *supports_tls, int *tls_min)
22 {
23 /* Values for x86 and x86_64.*/
24 int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
25 int i;
26
27 for (i = 0; i < ARRAY_SIZE(val); i++) {
28 user_desc_t info;
29 info.entry_number = val[i];
30
31 if (syscall(__NR_get_thread_area, &info) == 0) {
32 *tls_min = val[i];
33 *supports_tls = 1;
34 return;
35 } else {
36 if (errno == EINVAL)
37 continue;
38 else if (errno == ENOSYS)
39 *supports_tls = 0;
40 return;
41 }
42 }
43
44 *supports_tls = 0;
45 }
46
os_set_thread_area(user_desc_t * info,int pid)47 int os_set_thread_area(user_desc_t *info, int pid)
48 {
49 int ret;
50
51 ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
52 (unsigned long) info);
53 if (ret < 0)
54 ret = -errno;
55 return ret;
56 }
57
os_get_thread_area(user_desc_t * info,int pid)58 int os_get_thread_area(user_desc_t *info, int pid)
59 {
60 int ret;
61
62 ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
63 (unsigned long) info);
64 if (ret < 0)
65 ret = -errno;
66 return ret;
67 }
68