libgo/runtime/go-libmain.c

   1 /* go-libmain.c -- the startup function for a Go library.
   2
   3    Copyright 2015 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include "config.h"
   8
   9 #include <errno.h>
  10 #include <pthread.h>
  11 #include <stdlib.h>
  12 #include <time.h>
  13 #include <unistd.h>
  14
  15 #include "runtime.h"
  16 #include "array.h"
  17 #include "arch.h"
  18
  19 /* This is used when building a standalone Go library using the Go
  20    command's -buildmode=c-archive or -buildmode=c-shared option.  It
  21    starts up the Go code as a global constructor but does not take any
  22    other action.  The main program is written in some other language
  23    and calls exported Go functions as needed.  */
  24
  25 static void die (const char *, int);
  26 /* .init_array section does not exist in AIX XCOFF.
  27    -Wl,-binitfini:__go_init option will be required to build go
  28    libraries and make sure __go_init is called when the library is
  29    loaded. This requires __go_init to be exported.  */
  30
  31 void __go_init (int, char **, char **);
  32 static void *gostart (void *);
  33
  34 /* Used to pass arguments to the thread that runs the Go startup.  */
  35
  36 struct args {
  37   int argc;
  38   char **argv;
  39 };
  40
  41 #ifndef _AIX
  42 /* We use .init_array so that we can get the command line arguments.
  43    This obviously assumes .init_array support; different systems may
  44    require other approaches.  */
  45
  46 typedef void (*initarrayfn) (int, char **, char **);
  47
  48 static initarrayfn initarray[1]
  49 __attribute__ ((section (".init_array"), used)) =
  50   { __go_init };
  51 #endif
  52
  53 /* This function is called at program startup time.  It starts a new
  54    thread to do the actual Go startup, so that program startup is not
  55    paused waiting for the Go initialization functions.  Exported cgo
  56    functions will wait for initialization to complete if
  57    necessary.  */
  58
  59 void
  60 __go_init (int argc, char **argv, char** env __attribute__ ((unused)))
  61 {
  62   int err;
  63   pthread_attr_t attr;
  64   struct args *a;
  65   pthread_t tid;
  66
  67   runtime_isarchive = true;
  68
  69   setIsCgo ();
  70   runtime_cpuinit ();
  71   runtime_initsig(true);
  72
  73   a = (struct args *) malloc (sizeof *a);
  74   if (a == NULL)
  75     die ("malloc", errno);
  76   a->argc = argc;
  77   a->argv = argv;
  78
  79   err = pthread_attr_init (&attr);
  80   if (err != 0)
  81     die ("pthread_attr_init", err);
  82   err = pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  83   if (err != 0)
  84     die ("pthread_attr_setdetachstate", err);
  85
  86   err = pthread_create (&tid, &attr, gostart, (void *) a);
  87   if (err != 0)
  88     die ("pthread_create", err);
  89
  90   err = pthread_attr_destroy (&attr);
  91   if (err != 0)
  92     die ("pthread_attr_destroy", err);
  93 }
  94
  95 /* Start up the Go runtime.  */
  96
  97 static void *
  98 gostart (void *arg)
  99 {
 100   struct args *a = (struct args *) arg;
 101
 102   if (runtime_isstarted)
 103     return NULL;
 104   runtime_isstarted = true;
 105
 106   runtime_check ();
 107   runtime_args (a->argc, (byte **) a->argv);
 108   setncpu (getproccount ());
 109   setpagesize (getpagesize ());
 110   runtime_sched = runtime_getsched();
 111   runtime_schedinit ();
 112   __go_go (runtime_main, NULL);
 113   runtime_mstart (runtime_m ());
 114   abort ();
 115 }
 116
 117 /* If something goes wrong during program startup, crash.  There is no
 118    way to report failure and nobody to whom to report it.  */
 119
 120 static void
 121 die (const char *fn, int err)
 122 {
 123   fprintf (stderr, "%s: %d\n", fn, err);
 124   exit (EXIT_FAILURE);
 125 }