1 // Copyright 2015 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 #include <pthread.h>
6 #include <string.h>
7 #include <signal.h>
8 #include <ucontext.h>
9 #include "libcgo.h"
10 #include "libcgo_unix.h"
11
12 static void* threadentry(void*);
13 static void (*setg_gcc)(void*);
14
15 void
x_cgo_init(G * g,void (* setg)(void *))16 x_cgo_init(G *g, void (*setg)(void*))
17 {
18 ucontext_t ctx;
19
20 setg_gcc = setg;
21 if (getcontext(&ctx) != 0)
22 perror("runtime/cgo: getcontext failed");
23 g->stacklo = (uintptr_t)ctx.uc_stack.ss_sp;
24
25 // Solaris processes report a tiny stack when run with "ulimit -s unlimited".
26 // Correct that as best we can: assume it's at least 1 MB.
27 // See golang.org/issue/12210.
28 if(ctx.uc_stack.ss_size < 1024*1024)
29 g->stacklo -= 1024*1024 - ctx.uc_stack.ss_size;
30
31 // Sanity check the results now, rather than getting a
32 // morestack on g0 crash.
33 if (g->stacklo >= g->stackhi) {
34 fatalf("bad stack bounds: lo=%p hi=%p", (void*)(g->stacklo), (void*)(g->stackhi));
35 }
36 }
37
38 void
_cgo_sys_thread_start(ThreadStart * ts)39 _cgo_sys_thread_start(ThreadStart *ts)
40 {
41 pthread_attr_t attr;
42 sigset_t ign, oset;
43 pthread_t p;
44 void *base;
45 size_t size;
46 int err;
47
48 sigfillset(&ign);
49 pthread_sigmask(SIG_SETMASK, &ign, &oset);
50
51 pthread_attr_init(&attr);
52
53 if (pthread_attr_getstack(&attr, &base, &size) != 0)
54 perror("runtime/cgo: pthread_attr_getstack failed");
55 if (size == 0) {
56 ts->g->stackhi = 2 << 20;
57 if (pthread_attr_setstack(&attr, NULL, ts->g->stackhi) != 0)
58 perror("runtime/cgo: pthread_attr_setstack failed");
59 } else {
60 ts->g->stackhi = size;
61 }
62 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
63 err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
64
65 pthread_sigmask(SIG_SETMASK, &oset, nil);
66
67 if (err != 0) {
68 fatalf("pthread_create failed: %s", strerror(err));
69 }
70 }
71
72 extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
73 static void*
threadentry(void * v)74 threadentry(void *v)
75 {
76 ThreadStart ts;
77
78 ts = *(ThreadStart*)v;
79 free(v);
80
81 crosscall1(ts.fn, setg_gcc, (void*)ts.g);
82 return nil;
83 }
84