/*

  Copyright (C) 2000, 2001 Silicon Graphics, Inc.  All Rights Reserved.

   Path64 is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation version 2.1

   Path64 is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
   License for more details.

   You should have received a copy of the GNU General Public License
   along with Path64; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

   Special thanks goes to SGI for their continued support to open source

*/


#pragma ident "@(#) libf/pxf/pxfexecve.c	92.1	06/29/99 11:36:06"

#include <errno.h>
#include <liberrno.h>
#include <fortran.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

extern char *_fc_acopy(_fcd f);

/*
 *  PXFEXECVE  -- execute a new process image file using new environment
 *                variables
 *  (section 3.1.2 of Posix 1003.9-1992)
 *
 *  Synopsis:
 *     SUBROUTINE PXFEXECVE (PATH,LENPATH,ARGV,LENARGV,IARGC,
 *   +   ENV,LENENV,IENVC,IERROR)
 *     INTEGER LENPATH,IARGC,LENARGV(0:IARGC-1),LENENV,IENVC,IERROR
 *     CHARACTER*(*) PATH,ARGV(0:IARGC-1),ENV(IENVC)
 *
 *  Function description:
 *  The routine PXFEXECVE uses the execve(2) system call to replace the
 *  current process image with a new process image. The environment
 *  variables are not inherited from the calling process image.
 *  The environment variables for the new process image are specified by
 *  the ENV argument.
 *
 *  Description of arguments:
 *  PATH     is an input character variable or array element containing
 *           the pathname of the new process image file.
 *
 *  LENPATH  is an input integer variable for the length of PATH. If
 *           LENPATH is zero, trailing blanks are removed.
 *
 *  ARGV     is an input array of character strings. ARGV contains the
 *           arguments to be passed to the new process image.
 *
 *  LENARGV  is an input array of intergers. Each element in LENARGV
 *           contains the length of the corresponding character
 *           string in ARGV. If an element in LENARGV is zero, the
 *           corresponding element in ARGV will have all trailing
 *           blanks stripped.
 *
 *  IARGC    is an input integer variable. IARGC contains the number of
 *           arguments to pass to the new process image.
 *
 *  ENV      is an input array of character strings. ENV contains the
 *           environment variables for the new process image.
 *
 *  LENENV   is an input array of integers. Each element in LENENV
 *           contains the length of the corresponding character
 *           string in ENV. IF an element in LENENV is zero, the
 *           corresponding element in ENV will have all trailing
 *           blanks stripped.
 *
 *  IENVC    is an input integer variable. IENVC contains the number of
 *           environment variables for the new process image.
 *
 *  IERROR   is an output integer variable that will contain
 *           the status:
 *
 *            zero    - PXFEXECVE was unsuccessful.
 *
 *            nonzero - PXFEXECVE was not successful.
 *
 *           PXFEXECVE may return any of the following error
 *           values:
 *
 *           EACCES       If the new process file is not a regular file,
 *                        the new process image file mode denies execution
 *                        permission, or search permission is denied for
 *                        a directory listed in the new process image
 *                        file's path prefix.
 *
 *           ENOENT       If one or more components of the new process
 *                        image file's path name do not exist.
 *
 *           ENOEXEC      If the new process image file has the
 *                        appropriate access permission but an invalid
 *                        magic number in its header.
 *
 *           ENOMEM       If the memory needed to create structures used
 *                        by PXFEXECVE could not be allocated.
 *
 *           EINVAL       If LENPATH < 0 or LENPATH > LEN(PATH), any
 *                        element of LENARGV, or any element of LENENV is
 *                        less than zero or greater than the length of the
 *                        corresponding element in ARGV.
 *
 *           UNICOS 9 only errors:
 *
 *           E2BIG        If the number of bytes in ARGV is greater than
 *                        the system-imposed limit of ARG_MAX found in
 *                        <limits.h>.
 *
 *           EDMOFF       If the process image file is offline, and
 *                        the data migration facility is not configured
 *                        in the system.
 *
 *           EFAULT       If the new process image file is not as long as
 *                        indicated by the size values in it header.
 *
 *           ENOMEM       If the new process requires more memory than is
 *                        allowed by the system-imposed maximum MAXMEM.
 *
 *           EOFFLIN      If the process image file is offline, and
 *                        automatic file retrieval is disabled.
 *
 *           EOFLNDD      If the file is offline, and the data management
 *                        daemon is not currently executing.
 * 
 *           EOFLNNR      If the file is offline, and it is currently
 *                        unretrievable.
 *
 *           IRIX 6.2 only errors:
 *
 *           E2BIG        If the number of bytes in the new process's argument
 *                        list is greater than the system-imposed limit
 *                        {ARG_MAX} [see sysconf(2), intro(2), and limits.h].
 *                        The argument list limit is the sum of the size of
 *                        the argument list plus the size of the environment's
 *                        exported shell variables.
 *
 *           E2BIG        If the number of bytes in the first line of an
 *                        interpreter file is greater than 256 bytes.
 *
 *           EAGAIN       If there is not enough memory.
 *
 *           ELIBACC      If the required shared library does not have
 *                        execute permission.
 *
 *           ELIBEXEC     If PATH points to a shared library.
 *
 *           ELIBMAX      If the required number of shared libraries
 *                        exceeds the system imposed maximum {SHLIB_MAX)
 *                        [see intro(2)].
 *
 *           ELOOP        If too many symbolic links were encountered in
 *                        translating PATH.
 *
 *           ENAMETOOLONG If the length of PATH exceeds PATH_MAX found
 *                        in <limits.h>, or the length of a path
 *                        component exceeds NAME_MAX found in <limits.h>
 *                        while POSIX_NO_TRUNC is in effect.
 *
 *           ENOEXEC      If the executable process image file has badly
 *                        formed header information or the requested
 *                        virtual addresses are not available.
 *
 *           ENOMEM       If the new process image requires more virtual
 *                        space than is allowed either by the
 *                        system-imposed maximum or the process imposed
 *                        maximum PROCSIZE_MAX [see getrlimit(2) and
 *                        intro(2)].
 *
 *           EPERM        If a non-superuser tries to execute a setuid
 *                        file which belongs to some other user and the
 *                        file system in which then file resides has
 *                        been mounted with the nosuid option [see
 *                        fstab(4)], or if a non-superuser attempts to
 *                        execute a setuid or setgid shell script with
 *                        a uid or gid which is different than the user's
 *                        effective uid/gid, and the configured value for
 *                        nosuidshells is non-zero (the default) [see
 *                        intro(2) and lboot(1M)].
 *
 */

#ifdef _UNICOS
void
PXFEXECVE(
#else
void
_PXFEXECVE(
#endif
	  _fcd PATH,
	  _f_int *LENPATH,
	  _fcd ARGV,       /* packed array of fortran strings */
	  _f_int *LENARGV,
	  _f_int *IARGC,
	  _fcd ENV,        /* packed array of fortran strings */
	  _f_int *LENENV,
	  _f_int *IENVC,
	  _f_int *IERROR
)
{
  char **arg,        /* vector of argument strings for execve */
    **env,           /* vector of environment strings for execve */
    *cpath,          /* file path for executable */
    *cstring_ARGV,   /* the C-style string for the ARGV fortran character
			descriptor */
    *cstring_ENV;    /* the C-style string for the ENV fortran character
			descriptor */
  int clenpath,      /* equal to *LENPATH, the user defined length of PATH */
    i,j,             /* loop counters */
    position,        /* current position in the string cstring_ARGV */
    ciargc,          /* equal to *IARGC, the number of arguments for execve */
    cienvc,          /* equal to *IENVC, the number of environement variables
			for execve */
    cstring_lenargv, /* the length of the FCD ARGV. Note: This is the length of
		        an individual FCD in the array ARGV. */
    cstring_lenenv,  /* the length of the FCD ENV. Note: This is the length of
		        an individual FCD in the array ENV. */
    len;             /* length of string to copy from cstring_ARGV or
			cstring_ENV to a string in the arg vector of strings
			or env vector of strings, respectively. */

  clenpath = *LENPATH;
  cstring_lenargv = _fcdlen(ARGV);
  ciargc = *IARGC;
  cstring_lenenv = _fcdlen(ENV);
  cienvc = *IENVC;


  /* check for valid path length passed in by user */
  if (clenpath < 0 || clenpath > _fcdlen(PATH)) {
    *IERROR = EINVAL;
    return;
  } else {
    if (clenpath == 0) {
      /*
       * If length is zero, user wants trailing blanks stripped.
       * Otherwise, malloc memory and copy the string adding a
       * NULL terminator.
       */
      cpath = _fc_acopy(PATH);

    } else {
      
      cpath = (char *)malloc(clenpath + 1);
      if (cpath != NULL) {
	memcpy(cpath, _fcdtocp(PATH), clenpath);
	cpath[clenpath] = '\0';
      } else {
	*IERROR = ENOMEM;
	return;
      }

    }
  }



  /* check the LENARGV array for proper values before copying ARGV strings */
  i = 0;
  while (i < ciargc) {
    len = LENARGV[i];
    if (len < 0 || len > cstring_lenargv) {
      *IERROR = EINVAL;
      free(cpath);
      return;
    }
    i++;
  }

  /* check the LENENV array for proper values before copying ENV strings */
  i = 0;
  while (i < cienvc) {
    len = LENENV[i];
    if (len < 0 || len > cstring_lenenv) {
      *IERROR = EINVAL;
      free(cpath);
      return;
    }
    i++;
  }


  /* attempt to copy all argument strings from ARGV */

  arg = (char **)calloc(ciargc + 1,sizeof(char *));
  if (arg == NULL) {
    *IERROR = ENOMEM;
    free(cpath);
    return;
  }

  cstring_ARGV = _fcdtocp(ARGV);
  
  /* malloc the memory for all the strings copy each Fortran string
   * into a C-style string */
  for (i = 0, position = 0; i < ciargc; position += cstring_lenargv, i++) {
    len = LENARGV[i];
    /* strip off trailing blanks */
    if (len == 0) {
      len = cstring_lenargv - 1;
      while ((len > 0) &&
	     cstring_ARGV[(i * cstring_lenargv) + len] == ' ') {
	len--;
      }
      len++;
    }
    if ((arg[i] = (char *)malloc((len+1)*sizeof(char))) == NULL) {
      for (; i >= 0; i--) {
	free(arg[i]);
      }
      free(arg);
      free(cpath);
      *IERROR = ENOMEM;
      return;
    }
    
    strncpy(arg[i], &cstring_ARGV[position], len);
    arg[i][len] = '\0';
  }


  /* attempt to copy all environment strings from ENV */

  env = (char **)calloc(cienvc + 1,sizeof(char *));
  if (env == NULL) {
    *IERROR = ENOMEM;
    for (; i >= 0; i--) {
      free(arg[i]);
    }
    free(arg);
    free(env);
    free(cpath);
    return;
  }

  cstring_ENV = _fcdtocp(ARGV);
  
  /* malloc the memory for all the strings copy each Fortran string
   * into a C-style string */
  for (j = 0, position = 0; j < cienvc; position += cstring_lenenv, j++) {
    len = LENENV[j];
    /* strip off trailing blanks */
    if (len == 0) {
      len = cstring_lenenv - 1;
      while ((len > 0) &&
	     cstring_ENV[(j * cstring_lenenv) + len] == ' ') {
	len--;
      }
      len++;
    }
    if ((env[j] = (char *)malloc((len+1)*sizeof(char))) == NULL) {
      for (; i >= 0; i--) {
	free(arg[i]);
      }
      free(arg);
      for (; j >= 0; j--) {
	free(env[j]);
      }
      free(env);
      free(cpath);
      *IERROR = ENOMEM;
      return;
    }
    
    strncpy(env[j], &cstring_ENV[position], len);
    env[j][len] = '\0';
  }


  if (execve(cpath, arg, env) == -1) {
    for (i--; i >= 0; i--) {
      free(arg[i]);
    }
    free(arg);
    for (; j >= 0; j--) {
      free(env[j]);
    }
    free(env);
    free(cpath);
    *IERROR = errno;
    return;
  }

  *IERROR = 0;
}

#ifndef _UNICOS
void
pxfexecve_(
	  char *PATH,
	  _f_int *LENPATH,
	  char *ARGV,
	  _f_int *LENARGV,
	  _f_int *IARGC,
	  char  *ENV,
	  _f_int *LENENV,
	  _f_int *IENVC,
	  _f_int *IERROR,
	  _f_int pathlen,
	  _f_int argvlen,
	  _f_int envlen
)
{
  _PXFEXECVE( _cptofcd(PATH,pathlen), LENPATH, _cptofcd(ARGV,argvlen),
	      LENARGV, IARGC, _cptofcd(ENV,envlen), LENENV, IENVC, IERROR);
}
#endif