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