1: /* Initial program startup for running under the GNU Hurd.
    2:    Copyright (C) 1991,92,93,94,95,96,97,98,2002 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 Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the 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:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    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 "hurdstartup.h"
   32: #include <argz.h>
   33: 
   34: mach_port_t *_hurd_init_dtable;
   35: mach_msg_type_number_t _hurd_init_dtablesize;
   36: 
   37: extern void __mach_init (void);
   38: 
   39: /* Entry point.  This is the first thing in the text segment.
   40: 
   41:    The exec server started the initial thread in our task with this spot the
   42:    PC, and a stack that is presumably big enough.  We do basic Mach
   43:    initialization so mig-generated stubs work, and then do an exec_startup
   44:    RPC on our bootstrap port, to which the exec server responds with the
   45:    information passed in the exec call, as well as our original bootstrap
   46:    port, and the base address and size of the preallocated stack.
   47: 
   48:    If using cthreads, we are given a new stack by cthreads initialization and
   49:    deallocate the stack set up by the exec server.  On the new stack we call
   50:    `start1' (above) to do the rest of the startup work.  Since the stack may
   51:    disappear out from under us in a machine-dependent way, we use a pile of
   52:    static variables to communicate the information from exec_startup to start1.
   53:    This is unfortunate but preferable to machine-dependent frobnication to copy
   54:    the state from the old stack to the new one.  */
   55: 
   56: 
   57: void
   58: _hurd_startup (void **argptr, void (*main) (intptr_t *data))
   59: {
   60:   error_t err;
   61:   mach_port_t in_bootstrap;
   62:   char *args, *env;
   63:   mach_msg_type_number_t argslen, envlen;
   64:   struct hurd_startup_data data;
   65:   char **argv, **envp;
   66:   int argc, envc;
   67:   intptr_t *argcptr;
   68:   vm_address_t addr;
   69: 
   70:   /* Attempt to map page zero redzoned before we receive any RPC
   71:      data that might get allocated there.  We can ignore errors.  */
   72:   addr = 0;
   73:   __vm_map (__mach_task_self (),
   74:             &addr, __vm_page_size, 0, 0, MACH_PORT_NULL, 0, 1,
   75:             VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_COPY);
   76: 
   77:   if (err = __task_get_special_port (__mach_task_self (), TASK_BOOTSTRAP_PORT,
   78:                                      &in_bootstrap))
   79:     LOSE;
   80: 
   81:   if (in_bootstrap != MACH_PORT_NULL)
   82:     {
   83:       /* Call the exec server on our bootstrap port and
   84:          get all our standard information from it.  */
   85: 
   86:       argslen = envlen = 0;
   87:       data.dtablesize = data.portarraysize = data.intarraysize = 0;
   88: 
   89:       err = __exec_startup_get_info (in_bootstrap,
   90:                                      &data.user_entry,
   91:                                      &data.phdr, &data.phdrsz,
   92:                                      &data.stack_base, &data.stack_size,
   93:                                      &data.flags,
   94:                                      &args, &argslen,
   95:                                      &env, &envlen,
   96:                                      &data.dtable, &data.dtablesize,
   97:                                      &data.portarray, &data.portarraysize,
   98:                                      &data.intarray, &data.intarraysize);
   99:       __mach_port_deallocate (__mach_task_self (), in_bootstrap);
  100:     }
  101: 
  102:   if (err || in_bootstrap == MACH_PORT_NULL || (data.flags & EXEC_STACK_ARGS))
  103:     {
  104:       /* Either we have no bootstrap port, or the RPC to the exec server
  105:          failed, or whoever started us up passed the flag saying args are
  106:          on the stack.  Try to snarf the args in the canonical Mach way.
  107:          Hopefully either they will be on the stack as expected, or the
  108:          stack will be zeros so we don't crash.  */
  109: 
  110:       argcptr = (intptr_t *) argptr;
  111:       argc = argcptr[0];
  112:       argv = (char **) &argcptr[1];
  113:       envp = &argv[argc + 1];
  114:       envc = 0;
  115:       while (envp[envc])
  116:         ++envc;
  117:     }
  118:   else
  119:     {
  120:       /* Turn the block of null-separated strings we were passed for the
  121:          arguments and environment into vectors of pointers to strings.  */
  122: 
  123:       /* Count up the arguments so we can allocate ARGV.  */
  124:       argc = __argz_count (args, argslen);
  125:       /* Count up the environment variables so we can allocate ENVP.  */
  126:       envc = __argz_count (env, envlen);
  127: 
  128:       /* There were some arguments.  Allocate space for the vectors of
  129:          pointers and fill them in.  We allocate the space for the
  130:          environment pointers immediately after the argv pointers because
  131:          the ELF ABI will expect it.  */
  132:       argcptr = __alloca (sizeof (intptr_t) +
  133:                           (argc + 1 + envc + 1) * sizeof (char *) +
  134:                           sizeof (struct hurd_startup_data));
  135:       *argcptr = argc;
  136:       argv = (void *) (argcptr + 1);
  137:       __argz_extract (args, argslen, argv);
  138: 
  139:       /* There was some environment.  */
  140:       envp = &argv[argc + 1];
  141:       __argz_extract (env, envlen, envp);
  142:     }
  143: 
  144:   if (err || in_bootstrap == MACH_PORT_NULL)
  145:     {
  146:       /* Either we have no bootstrap port, or the RPC to the exec server
  147:          failed.  Set all our other variables to have empty information.  */
  148: 
  149:       data.flags = 0;
  150:       args = env = NULL;
  151:       argslen = envlen = 0;
  152:       data.dtable = NULL;
  153:       data.dtablesize = 0;
  154:       data.portarray = NULL;
  155:       data.portarraysize = 0;
  156:       data.intarray = NULL;
  157:       data.intarraysize = 0;
  158:     }
  159:   else if ((void *) &envp[envc + 1] == argv[0])
  160:     {
  161:       /* The arguments arrived on the stack from the kernel, but our
  162:          protocol requires some space after them for a `struct
  163:          hurd_startup_data'.  Move them.  */
  164:       struct
  165:         {
  166:           intptr_t count;
  167:           char *argv[argc + 1];
  168:           char *envp[envc + 1];
  169:           struct hurd_startup_data data;
  170:         } *args = alloca (sizeof *args);
  171:       if ((void *) &args[1] == (void *) argcptr)
  172:         args = alloca (-((char *) &args->data - (char *) args));
  173:       memmove (args, argcptr, (char *) &args->data - (char *) args);
  174:       argcptr = (void *) args;
  175:       argv = args->argv;
  176:       envp = args->envp;
  177:     }
  178: 
  179:   {
  180:     struct hurd_startup_data *d = (void *) &envp[envc + 1];
  181: 
  182:     if ((void *) d != argv[0])
  183:       {
  184:         *d = data;
  185:         _hurd_init_dtable = d->dtable;
  186:         _hurd_init_dtablesize = d->dtablesize;
  187:       }
  188: 
  189:     (*main) (argcptr);
  190:   }
  191: 
  192:   /* Should never get here.  */
  193:   LOSE;
  194:   abort ();
  195: }