Text file src/pkg/runtime/cgo/gcc_darwin_arm64.c
1 // Copyright 2014 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 <limits.h>
6 #include <pthread.h>
7 #include <signal.h>
8 #include <string.h> /* for strerror */
9 #include <sys/param.h>
10 #include <unistd.h>
11 #include <stdlib.h>
12
13 #include <CoreFoundation/CFBundle.h>
14 #include <CoreFoundation/CFString.h>
15
16 #include "libcgo.h"
17 #include "libcgo_unix.h"
18
19 #define magic (0xc476c475c47957UL)
20
21 // inittls allocates a thread-local storage slot for g.
22 //
23 // It finds the first available slot using pthread_key_create and uses
24 // it as the offset value for runtime.tlsg.
25 static void
26 inittls(void **tlsg, void **tlsbase)
27 {
28 pthread_key_t k;
29 int i, err;
30
31 err = pthread_key_create(&k, nil);
32 if(err != 0) {
33 fprintf(stderr, "runtime/cgo: pthread_key_create failed: %d\n", err);
34 abort();
35 }
36 //fprintf(stderr, "runtime/cgo: k = %d, tlsbase = %p\n", (int)k, tlsbase); // debug
37 pthread_setspecific(k, (void*)magic);
38 // The first key should be at 257.
39 for (i=0; i<PTHREAD_KEYS_MAX; i++) {
40 if (*(tlsbase+i) == (void*)magic) {
41 *tlsg = (void*)(i*sizeof(void *));
42 pthread_setspecific(k, 0);
43 return;
44 }
45 }
46 fprintf(stderr, "runtime/cgo: could not find pthread key.\n");
47 abort();
48 }
49
50 static void *threadentry(void*);
51 static void (*setg_gcc)(void*);
52
53 void
54 _cgo_sys_thread_start(ThreadStart *ts)
55 {
56 pthread_attr_t attr;
57 sigset_t ign, oset;
58 pthread_t p;
59 size_t size;
60 int err;
61
62 //fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
63 sigfillset(&ign);
64 pthread_sigmask(SIG_SETMASK, &ign, &oset);
65
66 pthread_attr_init(&attr);
67 size = 0;
68 pthread_attr_getstacksize(&attr, &size);
69 // Leave stacklo=0 and set stackhi=size; mstart will do the rest.
70 ts->g->stackhi = size;
71 err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
72
73 pthread_sigmask(SIG_SETMASK, &oset, nil);
74
75 if (err != 0) {
76 fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
77 abort();
78 }
79 }
80
81 extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
82 static void*
83 threadentry(void *v)
84 {
85 ThreadStart ts;
86
87 ts = *(ThreadStart*)v;
88 free(v);
89
90 darwin_arm_init_thread_exception_port();
91
92 crosscall1(ts.fn, setg_gcc, (void*)ts.g);
93 return nil;
94 }
95
96 // init_working_dir sets the current working directory to the app root.
97 // By default darwin/arm processes start in "/".
98 static void
99 init_working_dir()
100 {
101 CFBundleRef bundle = CFBundleGetMainBundle();
102 if (bundle == NULL) {
103 fprintf(stderr, "runtime/cgo: no main bundle\n");
104 return;
105 }
106 CFURLRef url_ref = CFBundleCopyResourceURL(bundle, CFSTR("Info"), CFSTR("plist"), NULL);
107 if (url_ref == NULL) {
108 // No Info.plist found. It can happen on Corellium virtual devices.
109 return;
110 }
111 CFStringRef url_str_ref = CFURLGetString(url_ref);
112 char buf[MAXPATHLEN];
113 Boolean res = CFStringGetCString(url_str_ref, buf, sizeof(buf), kCFStringEncodingUTF8);
114 CFRelease(url_ref);
115 if (!res) {
116 fprintf(stderr, "runtime/cgo: cannot get URL string\n");
117 return;
118 }
119
120 // url is of the form "file:///path/to/Info.plist".
121 // strip it down to the working directory "/path/to".
122 int url_len = strlen(buf);
123 if (url_len < sizeof("file://")+sizeof("/Info.plist")) {
124 fprintf(stderr, "runtime/cgo: bad URL: %s\n", buf);
125 return;
126 }
127 buf[url_len-sizeof("/Info.plist")+1] = 0;
128 char *dir = &buf[0] + sizeof("file://")-1;
129
130 if (chdir(dir) != 0) {
131 fprintf(stderr, "runtime/cgo: chdir(%s) failed\n", dir);
132 }
133
134 // The test harness in go_darwin_arm_exec passes the relative working directory
135 // in the GoExecWrapperWorkingDirectory property of the app bundle.
136 CFStringRef wd_ref = CFBundleGetValueForInfoDictionaryKey(bundle, CFSTR("GoExecWrapperWorkingDirectory"));
137 if (wd_ref != NULL) {
138 if (!CFStringGetCString(wd_ref, buf, sizeof(buf), kCFStringEncodingUTF8)) {
139 fprintf(stderr, "runtime/cgo: cannot get GoExecWrapperWorkingDirectory string\n");
140 return;
141 }
142 if (chdir(buf) != 0) {
143 fprintf(stderr, "runtime/cgo: chdir(%s) failed\n", buf);
144 }
145 }
146 }
147
148 void
149 x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
150 {
151 pthread_attr_t attr;
152 size_t size;
153
154 //fprintf(stderr, "x_cgo_init = %p\n", &x_cgo_init); // aid debugging in presence of ASLR
155 setg_gcc = setg;
156 pthread_attr_init(&attr);
157 pthread_attr_getstacksize(&attr, &size);
158 g->stacklo = (uintptr)&attr - size + 4096;
159 pthread_attr_destroy(&attr);
160
161 // yes, tlsbase from mrs might not be correctly aligned.
162 inittls(tlsg, (void**)((uintptr)tlsbase & ~7));
163
164 darwin_arm_init_mach_exception_handler();
165 darwin_arm_init_thread_exception_port();
166
167 init_working_dir();
168 }
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