/* Utilities to execute a program in a subprocess (possibly linked by pipes
   with other subprocesses), and wait for it.
   Copyright (C) 1996, 1997 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* This file exports two functions: pexecute and pwait.  */

/* This file lives in at least two places: libiberty and gcc.
   Don't change one without the other.  */

#include <stdio.h>
#include <errno.h>

#ifdef IN_GCC
#include "config.h"
#include "gansidecl.h"
/* ??? Need to find a suitable header file.  */
#define PEXECUTE_FIRST   1
#define PEXECUTE_LAST    2
#define PEXECUTE_ONE     (PEXECUTE_FIRST + PEXECUTE_LAST)
#define PEXECUTE_SEARCH  4
#define PEXECUTE_VERBOSE 8
#else
#include "libiberty.h"
#endif

/* stdin file number.  */
#define STDIN_FILE_NO 0

/* stdout file number.  */
#define STDOUT_FILE_NO 1

/* value of `pipe': port index for reading.  */
#define READ_PORT 0

/* value of `pipe': port index for writing.  */
#define WRITE_PORT 1

static char *install_error_msg = "installation problem, cannot exec `%s'";

/* pexecute: execute a program.

   PROGRAM and ARGV are the arguments to execv/execvp.

   THIS_PNAME is name of the calling program (i.e. argv[0]).

   TEMP_BASE is the path name, sans suffix, of a temporary file to use
   if needed.  This is currently only needed for MSDOS ports that don't use
   GO32 (do any still exist?).  Ports that don't need it can pass NULL.

   (FLAGS & PEXECUTE_SEARCH) is non-zero if $PATH should be searched
   (??? It's not clear that GCC passes this flag correctly).
   (FLAGS & PEXECUTE_FIRST) is nonzero for the first process in chain.
   (FLAGS & PEXECUTE_FIRST) is nonzero for the last process in chain.
   FIRST_LAST could be simplified to only mark the last of a chain of processes
   but that requires the caller to always mark the last one (and not give up
   early if some error occurs).  It's more robust to require the caller to
   mark both ends of the chain.

   The result is the pid on systems like Unix where we fork/exec and on systems
   like WIN32 and OS2 where we use spawn.  It is up to the caller to wait for
   the child.

   The result is the WEXITSTATUS on systems like MSDOS where we spawn and wait
   for the child here.

   Upon failure, ERRMSG_FMT and ERRMSG_ARG are set to the text of the error
   message with an optional argument (if not needed, ERRMSG_ARG is set to
   NULL), and -1 is returned.  `errno' is available to the caller to use.

   pwait: cover function for wait.

   PID is the process id of the task to wait for.
   STATUS is the `status' argument to wait.
   FLAGS is currently unused (allows future enhancement without breaking
   upward compatibility).  Pass 0 for now.

   The result is the pid of the child reaped,
   or -1 for failure (errno says why).

   On systems that don't support waiting for a particular child, PID is
   ignored.  On systems like MSDOS that don't really multitask pwait
   is just a mechanism to provide a consistent interface for the caller.

   pfinish: finish generation of script

   pfinish is necessary for systems like MPW where a script is generated that
   runs the requested programs.
*/

#ifdef __MSDOS__

/* MSDOS doesn't multitask, but for the sake of a consistent interface
   the code behaves like it does.  pexecute runs the program, tucks the
   exit code away, and returns a "pid".  pwait must be called to fetch the
   exit code.  */

#include <process.h>

/* For communicating information from pexecute to pwait.  */
static int last_pid = 0;
static int last_status = 0;
static int last_reaped = 0;

int
pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
     const char *program;
     char * const *argv;
     const char *this_pname;
     const char *temp_base;
     char **errmsg_fmt, **errmsg_arg;
     int flags;
{
  int rc;

  last_pid++;
  if (last_pid < 0)
    last_pid = 1;

  if ((flags & PEXECUTE_ONE) != PEXECUTE_ONE)
    abort ();

#ifdef __GO32__
  /* ??? What are the possible return values from spawnv?  */
  rc = (flags & PEXECUTE_SEARCH ? spawnvp : spawnv) (1, program, argv);
#else
  char *scmd, *rf;
  FILE *argfile;
  int i, el = flags & PEXECUTE_SEARCH ? 4 : 0;

  scmd = (char *) xmalloc (strlen (program) + strlen (temp_base) + 6 + el);
  rf = scmd + strlen(program) + 2 + el;
  sprintf (scmd, "%s%s @%s.gp", program,
	   (flags & PEXECUTE_SEARCH ? ".exe" : ""), temp_base);
  argfile = fopen (rf, "w");
  if (argfile == 0)
    {
      int errno_save = errno;
      free (scmd);
      errno = errno_save;
      *errmsg_fmt = "cannot open `%s.gp'";
      *errmsg_arg = temp_base;
      return -1;
    }

  for (i=1; argv[i]; i++)
    {
      char *cp;
      for (cp = argv[i]; *cp; cp++)
	{
	  if (*cp == '"' || *cp == '\'' || *cp == '\\' || isspace (*cp))
	    fputc ('\\', argfile);
	  fputc (*cp, argfile);
	}
      fputc ('\n', argfile);
    }
  fclose (argfile);

  rc = system (scmd);

  {
    int errno_save = errno;
    remove (rf);
    free (scmd);
    errno = errno_save;
  }
#endif

  if (rc == -1)
    {
      *errmsg_fmt = install_error_msg;
      *errmsg_arg = program;
      return -1;
    }

  /* Tuck the status away for pwait, and return a "pid".  */
  last_status = rc << 8;
  return last_pid;
}

int
pwait (pid, status, flags)
     int pid;
     int *status;
     int flags;
{
  /* On MSDOS each pexecute must be followed by it's associated pwait.  */
  if (pid != last_pid
      /* Called twice for the same child?  */
      || pid == last_reaped)
    {
      /* ??? ECHILD would be a better choice.  Can we use it here?  */
      errno = EINVAL;
      return -1;
    }
  /* ??? Here's an opportunity to canonicalize the values in STATUS.
     Needed?  */
  *status = last_status;
  last_reaped = last_pid;
  return last_pid;
}

#endif /* MSDOS */

#if defined (_WIN32)

#include <process.h>
extern int _spawnv ();
extern int _spawnvp ();

int
pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
     const char *program;
     char * const *argv;
     const char *this_pname;
     const char *temp_base;
     char **errmsg_fmt, **errmsg_arg;
     int flags;
{
  int pid;

  if ((flags & PEXECUTE_ONE) != PEXECUTE_ONE)
    abort ();
  pid = (flags & PEXECUTE_SEARCH ? _spawnvp : _spawnv) (_P_NOWAIT, program, argv);
  if (pid == -1)
    {
      *errmsg_fmt = install_error_msg;
      *errmsg_arg = program;
      return -1;
    }
  return pid;
}

int
pwait (pid, status, flags)
     int pid;
     int *status;
     int flags;
{
  /* ??? Here's an opportunity to canonicalize the values in STATUS.
     Needed?  */
  return cwait (status, pid, WAIT_CHILD);
}

#endif /* _WIN32 */

#ifdef OS2

/* ??? Does OS2 have process.h?  */
extern int spawnv ();
extern int spawnvp ();

int
pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
     const char *program;
     char * const *argv;
     const char *this_pname;
     const char *temp_base;
     char **errmsg_fmt, **errmsg_arg;
     int flags;
{
  int pid;

  if ((flags & PEXECUTE_ONE) != PEXECUTE_ONE)
    abort ();
  /* ??? Presumably 1 == _P_NOWAIT.  */
  pid = (flags & PEXECUTE_SEARCH ? spawnvp : spawnv) (1, program, argv);
  if (pid == -1)
    {
      *errmsg_fmt = install_error_msg;
      *errmsg_arg = program;
      return -1;
    }
  return pid;
}

int
pwait (pid, status, flags)
     int pid;
     int *status;
     int flags;
{
  /* ??? Here's an opportunity to canonicalize the values in STATUS.
     Needed?  */
  int pid = wait (status);
  return pid;
}

#endif /* OS2 */

#ifdef MPW

/* MPW pexecute doesn't actually run anything; instead, it writes out
   script commands that, when run, will do the actual executing.

   For example, in GCC's case, GCC will write out several script commands:

   cpp ...
   cc1 ...
   as ...
   ld ...

   and then exit.  None of the above programs will have run yet.  The task
   that called GCC will then execute the script and cause cpp,etc. to run.
   The caller must invoke pfinish before calling exit.  This adds
   the finishing touches to the generated script.  */

static int first_time = 1;

int
pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
     const char *program;
     char * const *argv;
     const char *this_pname;
     const char *temp_base;
     char **errmsg_fmt, **errmsg_arg;
     int flags;
{
  char tmpprogram[255];
  char *cp, *tmpname;
  int i;

  mpwify_filename (program, tmpprogram);
  if (first_time)
    {
      printf ("Set Failed 0\n");
      first_time = 0;
    }

  fputs ("If {Failed} == 0\n", stdout);
  /* If being verbose, output a copy of the command.  It should be
     accurate enough and escaped enough to be "clickable".  */
  if (flags & PEXECUTE_VERBOSE)
    {
      fputs ("\tEcho ", stdout);
      fputc ('\'', stdout);
      fputs (tmpprogram, stdout);
      fputc ('\'', stdout);
      fputc (' ', stdout);
      for (i=1; argv[i]; i++)
	{
	  fputc ('\'', stdout);
	  /* See if we have an argument that needs fixing.  */
	  if (strchr(argv[i], '/'))
	    {
	      tmpname = xmalloc (256);
	      mpwify_filename (argv[i], tmpname);
	      argv[i] = tmpname;
	    }
	  for (cp = argv[i]; *cp; cp++)
	    {
	      /* Write an Option-d escape char in front of special chars.  */
	      if (strchr("'+", *cp))
		fputc ('\266', stdout);
	      fputc (*cp, stdout);
	    }
	  fputc ('\'', stdout);
	  fputc (' ', stdout);
	}
      fputs ("\n", stdout);
    }
  fputs ("\t", stdout);
  fputs (tmpprogram, stdout);
  fputc (' ', stdout);

  for (i=1; argv[i]; i++)
    {
      /* See if we have an argument that needs fixing.  */
      if (strchr(argv[i], '/'))
	{
	  tmpname = xmalloc (256);
	  mpwify_filename (argv[i], tmpname);
	  argv[i] = tmpname;
	}
      if (strchr (argv[i], ' '))
	fputc ('\'', stdout);
      for (cp = argv[i]; *cp; cp++)
	{
	  /* Write an Option-d escape char in front of special chars.  */
	  if (strchr("'+", *cp))
	    fputc ('\266', stdout);
	  fputc (*cp, stdout);
	}
      if (strchr (argv[i], ' '))
	fputc ('\'', stdout);
      fputc (' ', stdout);
    }

  fputs ("\n", stdout);

  /* Output commands that arrange to clean up and exit if a failure occurs.
     We have to be careful to collect the status from the program that was
     run, rather than some other script command.  Also, we don't exit
     immediately, since necessary cleanups are at the end of the script.  */
  fputs ("\tSet TmpStatus {Status}\n", stdout);
  fputs ("\tIf {TmpStatus} != 0\n", stdout);
  fputs ("\t\tSet Failed {TmpStatus}\n", stdout);
  fputs ("\tEnd\n", stdout);
  fputs ("End\n", stdout);

  /* We're just composing a script, can't fail here.  */
  return 0;
}

int
pwait (pid, status, flags)
     int pid;
     int *status;
     int flags;
{
  *status = 0;
  return 0;
}

/* Write out commands that will exit with the correct error code
   if something in the script failed.  */

void
pfinish ()
{
  printf ("\tExit \"{Failed}\"\n");
}

#endif /* MPW */

/* include for Unix-like environments but not for Dos-like environments */
#if ! defined (__MSDOS__) && ! defined (OS2) && ! defined (MPW) \
    && ! defined (_WIN32)

#ifdef VMS
#define vfork() (decc$$alloc_vfork_blocks() >= 0 ? \
               lib$get_current_invo_context(decc$$get_vfork_jmpbuf()) : -1)
#else
#ifdef USG
#define vfork fork
#endif
#endif

extern int execv ();
extern int execvp ();

int
pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
     const char *program;
     char * const *argv;
     const char *this_pname;
     const char *temp_base;
     char **errmsg_fmt, **errmsg_arg;
     int flags;
{
  int (*func)() = (flags & PEXECUTE_SEARCH ? execvp : execv);
  int pid;
  int pdes[2];
  int input_desc, output_desc;
  int retries, sleep_interval;
  /* Pipe waiting from last process, to be used as input for the next one.
     Value is STDIN_FILE_NO if no pipe is waiting
     (i.e. the next command is the first of a group).  */
  static int last_pipe_input;

  /* If this is the first process, initialize.  */
  if (flags & PEXECUTE_FIRST)
    last_pipe_input = STDIN_FILE_NO;

  input_desc = last_pipe_input;

  /* If this isn't the last process, make a pipe for its output,
     and record it as waiting to be the input to the next process.  */
  if (! (flags & PEXECUTE_LAST))
    {
      if (pipe (pdes) < 0)
	{
	  *errmsg_fmt = "pipe";
	  *errmsg_arg = NULL;
	  return -1;
	}
      output_desc = pdes[WRITE_PORT];
      last_pipe_input = pdes[READ_PORT];
    }
  else
    {
      /* Last process.  */
      output_desc = STDOUT_FILE_NO;
      last_pipe_input = STDIN_FILE_NO;
    }

  /* Fork a subprocess; wait and retry if it fails.  */
  sleep_interval = 1;
  for (retries = 0; retries < 4; retries++)
    {
      pid = vfork ();
      if (pid >= 0)
	break;
      sleep (sleep_interval);
      sleep_interval *= 2;
    }

  switch (pid)
    {
    case -1:
      {
#ifdef vfork
	*errmsg_fmt = "fork";
#else
	*errmsg_fmt = "vfork";
#endif
	*errmsg_arg = NULL;
	return -1;
      }

    case 0: /* child */
      /* Move the input and output pipes into place, if necessary.  */
      if (input_desc != STDIN_FILE_NO)
	{
	  close (STDIN_FILE_NO);
	  dup (input_desc);
	  close (input_desc);
	}
      if (output_desc != STDOUT_FILE_NO)
	{
	  close (STDOUT_FILE_NO);
	  dup (output_desc);
	  close (output_desc);
	}

      /* Close the parent's descs that aren't wanted here.  */
      if (last_pipe_input != STDIN_FILE_NO)
	close (last_pipe_input);

      /* Exec the program.  */
      (*func) (program, argv);

      /* Note: Calling fprintf and exit here doesn't seem right for vfork.  */
      fprintf (stderr, "%s: ", this_pname);
      fprintf (stderr, install_error_msg, program);
#ifdef IN_GCC
      fprintf (stderr, ": %s\n", my_strerror (errno));
#else
      fprintf (stderr, ": %s\n", xstrerror (errno));
#endif
      exit (-1);
      /* NOTREACHED */
      return 0;

    default:
      /* In the parent, after forking.
	 Close the descriptors that we made for this child.  */
      if (input_desc != STDIN_FILE_NO)
	close (input_desc);
      if (output_desc != STDOUT_FILE_NO)
	close (output_desc);

      /* Return child's process number.  */
      return pid;
    }
}

int
pwait (pid, status, flags)
     int pid;
     int *status;
     int flags;
{
  /* ??? Here's an opportunity to canonicalize the values in STATUS.
     Needed?  */
#ifdef VMS
  pid = waitpid (-1, status, 0);
#else
  pid = wait (status);
#endif
  return pid;
}

#endif /* ! __MSDOS__ && ! OS2 && ! MPW && ! _WIN32 */
