hurd/hurdstartup.c

   1 /* Initial program startup for running under the GNU Hurd.
   2    Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <hurd.h>
  25 #include <hurd/exec_startup.h>
  26 #include <sysdep.h>
  27 #include <hurd/threadvar.h>
  28 #include <unistd.h>
  29 #include <elf.h>
  30 #include "set-hooks.h"
  31 #include "hurdmalloc.h"         /* XXX */
  32 #include "hurdstartup.h"
  33 #include <argz.h>
  34
  35 mach_port_t *_hurd_init_dtable;
  36 mach_msg_type_number_t _hurd_init_dtablesize;
  37
  38 extern void __mach_init (void);
  39
  40 /* Entry point.  This is the first thing in the text segment.
  41
  42    The exec server started the initial thread in our task with this spot the
  43    PC, and a stack that is presumably big enough.  We do basic Mach
  44    initialization so mig-generated stubs work, and then do an exec_startup
  45    RPC on our bootstrap port, to which the exec server responds with the
  46    information passed in the exec call, as well as our original bootstrap
  47    port, and the base address and size of the preallocated stack.
  48
  49    If using cthreads, we are given a new stack by cthreads initialization and
  50    deallocate the stack set up by the exec server.  On the new stack we call
  51    `start1' (above) to do the rest of the startup work.  Since the stack may
  52    disappear out from under us in a machine-dependent way, we use a pile of
  53    static variables to communicate the information from exec_startup to start1.
  54    This is unfortunate but preferable to machine-dependent frobnication to copy
  55    the state from the old stack to the new one.  */
  56
  57
  58 void
  59 _hurd_startup (void **argptr, void (*main) (int *data))
  60 {
  61   error_t err;
  62   mach_port_t in_bootstrap;
  63   char *args, *env;
  64   mach_msg_type_number_t argslen, envlen;
  65   struct hurd_startup_data data;
  66   char **argv, **envp;
  67   int argc, envc;
  68   int *argcptr;
  69   vm_address_t addr;
  70
  71   /* Attempt to map page zero redzoned before we receive any RPC
  72      data that might get allocated there.  We can ignore errors.  */
  73   addr = 0;
  74   __vm_map (__mach_task_self (),
  75             &addr, __vm_page_size, 0, 0, MACH_PORT_NULL, 0, 1,
  76             VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_COPY);
  77
  78   if (err = __task_get_special_port (__mach_task_self (), TASK_BOOTSTRAP_PORT,
  79                                      &in_bootstrap))
  80     LOSE;
  81
  82   if (in_bootstrap != MACH_PORT_NULL)
  83     {
  84       /* Call the exec server on our bootstrap port and
  85          get all our standard information from it.  */
  86
  87       argslen = envlen = 0;
  88       data.dtablesize = data.portarraysize = data.intarraysize = 0;
  89
  90       err = __exec_startup_get_info (in_bootstrap,
  91                                      &data.user_entry,
  92                                      &data.phdr, &data.phdrsz,
  93                                      &data.stack_base, &data.stack_size,
  94                                      &data.flags,
  95                                      &args, &argslen,
  96                                      &env, &envlen,
  97                                      &data.dtable, &data.dtablesize,
  98                                      &data.portarray, &data.portarraysize,
  99                                      &data.intarray, &data.intarraysize);
 100       __mach_port_deallocate (__mach_task_self (), in_bootstrap);
 101     }
 102
 103   if (err || in_bootstrap == MACH_PORT_NULL || (data.flags & EXEC_STACK_ARGS))
 104     {
 105       /* Either we have no bootstrap port, or the RPC to the exec server
 106          failed, or whoever started us up passed the flag saying args are
 107          on the stack.  Try to snarf the args in the canonical Mach way.
 108          Hopefully either they will be on the stack as expected, or the
 109          stack will be zeros so we don't crash.  */
 110
 111       argcptr = (int *) argptr;
 112       argc = argcptr[0];
 113       argv = (char **) &argcptr[1];
 114       envp = &argv[argc + 1];
 115       envc = 0;
 116       while (envp[envc])
 117         ++envc;
 118     }
 119   else
 120     {
 121       /* Turn the block of null-separated strings we were passed for the
 122          arguments and environment into vectors of pointers to strings.  */
 123
 124       /* Count up the arguments so we can allocate ARGV.  */
 125       argc = __argz_count (args, argslen);
 126       /* Count up the environment variables so we can allocate ENVP.  */
 127       envc = __argz_count (env, envlen);
 128
 129       /* There were some arguments.  Allocate space for the vectors of
 130          pointers and fill them in.  We allocate the space for the
 131          environment pointers immediately after the argv pointers because
 132          the ELF ABI will expect it.  */
 133       argcptr = __alloca (sizeof (int) +
 134                           (argc + 1 + envc + 1) * sizeof (char *) +
 135                           sizeof (struct hurd_startup_data));
 136       *argcptr = argc;
 137       argv = (void *) (argcptr + 1);
 138       __argz_extract (args, argslen, argv);
 139
 140       /* There was some environment.  */
 141       envp = &argv[argc + 1];
 142       __argz_extract (env, envlen, envp);
 143     }
 144
 145   if (err || in_bootstrap == MACH_PORT_NULL)
 146     {
 147       /* Either we have no bootstrap port, or the RPC to the exec server
 148          failed.  Set all our other variables to have empty information.  */
 149
 150       data.flags = 0;
 151       args = env = NULL;
 152       argslen = envlen = 0;
 153       data.dtable = NULL;
 154       data.dtablesize = 0;
 155       data.portarray = NULL;
 156       data.portarraysize = 0;
 157       data.intarray = NULL;
 158       data.intarraysize = 0;
 159     }
 160   else if ((void *) &envp[envc + 1] == argv[0])
 161     {
 162       /* The arguments arrived on the stack from the kernel, but our
 163          protocol requires some space after them for a `struct
 164          hurd_startup_data'.  Move them.  */
 165       struct
 166         {
 167           int count;
 168           char *argv[argc + 1];
 169           char *envp[envc + 1];
 170           struct hurd_startup_data data;
 171         } *args = alloca (sizeof *args);
 172       if ((void *) &args[1] == (void *) argcptr)
 173         args = alloca (-((char *) &args->data - (char *) args));
 174       memmove (args, argcptr, (char *) &args->data - (char *) args);
 175       argcptr = (void *) args;
 176       argv = args->argv;
 177       envp = args->envp;
 178     }
 179
 180   {
 181     struct hurd_startup_data *d = (void *) &envp[envc + 1];
 182
 183     if ((void *) d != argv[0])
 184       {
 185         *d = data;
 186         _hurd_init_dtable = d->dtable;
 187         _hurd_init_dtablesize = d->dtablesize;
 188       }
 189
 190     (*main) (argcptr);
 191   }
 192
 193   /* Should never get here.  */
 194   LOSE;
 195   abort ();
 196 }