argproc.c

/*
*   $Id$
*
*   Copyright (c) 1989, Mark Pizzolato (mark@infopiz.uucp)
*
*   This source code is released for free distribution under the terms of the
*   GNU General Public License.
*
*   Provided by Stephen P. Wall <swall@redcom.com>
*   Extracted from the VMS port of GNU patch-2.1.
*
*   This module provides redirection support for the VAX DECC port of
*   Exuberant Ctags.
*/
/*
 * @(#)argproc.c 1.0 89/02/01			Mark Pizzolato (mark@infopiz.uucp)
 */

#ifndef lint
char argproc_version [] = "@(#)argproc.c VMS uucp Version infopiz-1.0";
#endif

#include <ctype.h>
#include <descrip.h>
#include <dvidef.h>
#include <errno.h>
#include <iodef.h>
#include <lib$routines.h>
#include <starlet.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syidef.h>				/* System Information Definitions		*/

#define EXIT_OK 1				/* image exit code */
#define EXIT_ERR 0x10000000		/* image exit code */

/*
 * getredirection() is intended to aid in porting C programs
 * to VMS (Vax-11 C) which does not support '>' and '<'
 * I/O redirection, along with a command line pipe mechanism
 * using the '|' AND background command execution '&'.
 * The piping mechanism will probably work with almost any 'filter' type
 * of program.  With suitable modification, it may useful for other
 * portability problems as well.
 *
 * Author:  Mark Pizzolato		mark@infopiz.UUCP
 * Mods:    Steve Wall			Don't return a full path unless the
 *								original filename included a path.
 */
struct list_item
	{
	struct list_item *next;
	char *value;
	};

static expand_wild_cards ();
static char *pipe_and_fork ();

int
getredirection (ac, av)
int				*ac;
char			***av;
/*
 * Process vms redirection arg's.  Exit if any error is seen.
 * If getredirection() processes an argument, it is erased
 * from the vector.  getredirection () returns a new argc and argv value.
 * In the event that a background command is requested (by a trailing "&"),
 * this routine creates a background subprocess, and simply exits the program.
 *
 * Warning: do not try to simplify the code for vms.  The code
 * presupposes that getredirection() is called before any data is
 * read from stdin or written to stdout.
 *
 * Normal usage is as follows:
 *
 *		main (argc, argv)
 *		int				argc;
 *		char			*argv [];
 *		{
 *				getredirection (&argc, &argv);
 *		}
 */
{
	int					argc = *ac;		/* Argument Count		  */
	char				**argv = *av;	/* Argument Vector		  */
	char				*ap;			/* Argument pointer		  */
	int					j;				/* argv [] index				  */
	extern int			errno;			/* Last vms i/o error	  */
	int					item_count = 0;	/* Count of Items in List */
	struct list_item	*list_head = 0;	/* First Item in List		*/
	struct list_item	*list_tail;		/* Last Item in List		*/
	char				*in = NULL;		/* Input File Name			*/
	char				*out = NULL;	/* Output File Name			*/
	char				*outmode = "w";	/* Mode to Open Output File */
	int					cmargc = 0;		/* Piped Command Arg Count  */
	char				**cmargv = NULL;/* Piped Command Arg Vector */

	/*
	 * First handle the case where the last thing on the line ends with
	 * a '&'.  This indicates the desire for the command to be run in a
	 * subprocess, so we satisfy that desire.
	 */
	{
	extern background_process ();
	ap = argv [argc-1];
	if (0 == strcmp ("&", ap))
		exit (background_process (--argc, argv));
	if ('&' == ap [strlen (ap)-1])
		{
		ap [strlen (ap)-1] = '\0';
		exit (background_process (argc, argv));
		}
	}
	/*
	 * Now we handle the general redirection cases that involve '>', '>>',
	 * '<', and pipes '|'.
	 */
	for (j = 0; j < argc; ++j)
		{
		if (0 == strcmp ("<", argv [j]))
			{
			if (j+1 >= argc)
				{
				errno = EINVAL;
				perror ("No input file");
				exit (EXIT_ERR);
				}
			in = argv [++j];
			continue;
			}
		if ('<' == *(ap = argv [j]))
			{
			in = 1 + ap;
			continue;
			}
		if (0 == strcmp (">", ap))
			{
			if (j+1 >= argc)
				{
				errno = EINVAL;
				perror ("No output file");
				exit (EXIT_ERR);
				}
			out = argv [++j];
			continue;
			}
		if ('>' == *ap)
			{
			if ('>' == ap [1])
				{
				outmode = "a";
				if ('\0' == ap [2])
					out = argv [++j];
				else
					out = 2 + ap;
				}
			else
				out = 1 + ap;
			continue;
			}
		if (0 == strcmp ("|", argv [j]))
			{
			if (j+1 >= argc)
				{
				errno = EPIPE;
				perror ("No command to Pipe to");
				exit (EXIT_ERR);
				}
			cmargc = argc- (j+1);
			cmargv = &argv [j+1];
			argc = j;
			continue;
			}
		if ('|' == *(ap = argv [j]))
			{
			++argv [j];
			cmargc = argc-j;
			cmargv = &argv [j];
			argc = j;
			continue;
			}
		expand_wild_cards (ap, &list_head, &list_tail, &item_count);
		}
	/*
	 * Allocate and fill in the new argument vector, Some Unix's terminate
	 * the list with an extra null pointer.
	 */
	argv = *av = calloc (item_count+1, sizeof (char *));
	for (j = 0; j < item_count; ++j, list_head = list_head->next)
		argv [j] = list_head->value;
	*ac = item_count;
	if (cmargv != NULL)
		{
		char subcmd [1024];

		if (out != NULL)
			{
			errno = EINVAL;
			perror ("Invalid '|' and '>' specified");
			exit (EXIT_ERR);
			}
		strcpy (subcmd, cmargv [0]);
		for (j = 1; j < cmargc; ++j)
			{
			strcat (subcmd, " \"");
			strcat (subcmd, cmargv [j]);
			strcat (subcmd, "\"");
			}
		out = pipe_and_fork (subcmd);
		}
	if ((in != NULL) && (NULL == freopen (in, "r", stdin, "mbc=32", "mbf=2")))
		{
		perror (in);			/* Can't find file				*/
		exit (EXIT_ERR);				/* Is a fatal error				*/
		}
	if ((out != NULL) && (NULL == freopen (out, outmode, stdout, "mbc=32", "mbf=2")))
		{
		perror (ap);			/* Error, can't write or append	*/
		exit (EXIT_ERR);				/* Is a fatal error				*/
		}
#ifdef DEBUG
	fprintf (stderr, "Arglist:\n");
	for (j = 0; j < *ac;  ++j)
		fprintf (stderr, "argv[%d] = '%s'\n", j, argv [j]);
#endif
	return 0;
}

static add_item (head, tail, value, count)
struct list_item **head;
struct list_item **tail;
char *value;
int *count;
{
	if (*head == 0)
		{
		if (NULL == (*head = calloc (1, sizeof (**head))))
			{
			errno = ENOMEM;
			perror ("");
			exit (EXIT_ERR);
			}
		*tail = *head;
		}
	else
		if (NULL == ((*tail)->next = calloc (1, sizeof (**head))))
			{
			errno = ENOMEM;
			perror ("");
			exit (EXIT_ERR);
			}
		else
			*tail = (*tail)->next;
	(*tail)->value = value;
	++ (*count);
}

static expand_wild_cards (item, head, tail, count)
char *item;
struct list_item **head;
struct list_item **tail;
int *count;
{
int expcount = 0;
int context = 0;
int status;
int status_value;
char *had_version;
int had_path;
$DESCRIPTOR (filespec, item);
/*$DESCRIPTOR (defaultspec, "SYS$DISK:[]*.*;");*/
$DESCRIPTOR (defaultspec, "");
$DESCRIPTOR (resultspec, "");

	if (strcspn (item, "*%") == strlen (item))
		{
		add_item (head, tail, item, count);
		return;
		}
	resultspec.dsc$b_dtype = DSC$K_DTYPE_T;
	resultspec.dsc$b_class = DSC$K_CLASS_D;
	resultspec.dsc$a_pointer = NULL;
	filespec.dsc$w_length = strlen (item);
	/*
	 * Only return version specs, if the caller specified a version
	 */
	had_version = strchr (item, ';');
	/*
	 * Only return full path if the caller specified a path
	 */
	had_path = (strchr (item, ']') || strchr (item, ':'));
	while (1 == (1&lib$find_file (&filespec, &resultspec, &context,
								 &defaultspec, 0, &status_value, &0)))
		{
		char *string;
		char *c;

		if (NULL == (string = calloc (1, resultspec.dsc$w_length+1)))
			{
			errno = ENOMEM;
			perror ("");
			exit (EXIT_ERR);
			}
		strncpy (string, resultspec.dsc$a_pointer, resultspec.dsc$w_length);
		string [resultspec.dsc$w_length] = '\0';
		if (NULL == had_version)
			*((char *) strrchr (string, ';')) = '\0';
		if (!had_path) {
			char *s = strrchr (string, ']');
			if ( s == NULL ) s = strrchr (string, ':');
			if ( s != NULL ) strcpy (string, s+1);
		}
		/*
		 * Be consistent with what the C RTL has already done to the rest of
		 * the argv items and lowercase all of these names.
		 */
		for (c = string; *c; ++c)
			if (isupper (*c))
				*c = tolower (*c);
		add_item (head, tail, string, count);
		++expcount;
		}
	if (expcount == 0)
		add_item (head, tail, item, count);
	lib$sfree1_dd (&resultspec);
	lib$find_file_end (&context);
}

static int child_st [2];		/* Event Flag set when child process completes	*/

static short child_chan;/* I/O Channel for Pipe Mailbox					*/

static exit_handler (status)
int *status;
{
short iosb [4];

	if (0 == child_st [0])
		{
#ifdef DEBUG
		fprintf (stderr, "Waiting for Child Process to Finnish . . .\n");
#endif
		sys$qiow (0, child_chan, IO$_WRITEOF, iosb, 0, 0, 0, 0, 0, 0, 0, 0);
		sys$dassgn (child_chan);
		fclose (stdout);
		sys$synch (0, child_st);
		}
}


static sig_child (chan)
int chan;
{
#ifdef DEBUG
	fprintf (stderr, "Child Completion AST\n");
#endif
	if (child_st [0] == 0)
		child_st [0] = 1;
}

static struct exit_control_block
	{
	struct exit_control_block *flink;
	int	(*exit_routine) ();
	int arg_count;
	int *status_address;
	int exit_status;
	} exit_block =
	{
	0,
	exit_handler,
	1,
	&exit_block.exit_status,
	0
	};

static char *pipe_and_fork (cmd)
char *cmd;
{
	$DESCRIPTOR (cmddsc, cmd);
	static char mbxname [64];
	$DESCRIPTOR (mbxdsc, mbxname);
	short iosb [4];
	int status;
	int pid;
	struct
		{
		short dna_buflen;
		short dna_itmcod;
		char *dna_buffer;
		unsigned short *dna_retlen;
		int listend;
		} itmlst =
		{
		sizeof (mbxname),
		DVI$_DEVNAM,
		mbxname,
		&mbxdsc.dsc$w_length,
		0
		};
	int mbxsize;
	struct
		{
		short mbf_buflen;
		short mbf_itmcod;
		int *mbf_maxbuf;
		unsigned short *mbf_retlen;
		int listend;
		} syiitmlst =
		{
		sizeof (mbxsize),
		SYI$_MAXBUF,
		&mbxsize,
		0,
		0
		};

	cmddsc.dsc$w_length = strlen (cmd);
	/*
	 * Get the SYSGEN parameter MAXBUF, and the smaller of it and 2048 as
	 * the size of the 'pipe' mailbox.
	 */
	if (1 == (1& (vaxc$errno = sys$getsyiw (0, 0, 0, &syiitmlst, iosb, 0, 0, 0))))
		vaxc$errno = iosb [0];
	if (0 == (1&vaxc$errno))
		{
		errno = EVMSERR;
		perror ("Can't get SYSGEN parameter value for MAXBUF");
		exit (EXIT_ERR);
		}
	if (mbxsize > 2048)
		mbxsize = 2048;
	if (0 == (1& (vaxc$errno = sys$crembx (0, &child_chan, mbxsize, mbxsize, 0, 0, 0))))
		{
		errno = EVMSERR;
		perror ("Can't create pipe mailbox");
		exit (EXIT_ERR);
		}
	if (1 == (1& (vaxc$errno = sys$getdviw (0, child_chan, 0, &itmlst, iosb,
										  0, 0, 0))))
		vaxc$errno = iosb [0];
	if (0 == (1&vaxc$errno))
		{
		errno = EVMSERR;
		perror ("Can't get pipe mailbox device name");
		exit (EXIT_ERR);
		}
	mbxname [mbxdsc.dsc$w_length] = '\0';
#ifdef DEBUG
	fprintf (stderr, "Pipe Mailbox Name = '%s'\n", mbxname);
#endif
	if (0 == (1& (vaxc$errno = lib$spawn (&cmddsc, &mbxdsc, 0, &1,
										0, &pid, child_st, &0, sig_child,
										&child_chan))))
		{
		errno = EVMSERR;
		perror ("Can't spawn subprocess");
		exit (EXIT_ERR);
		}
#ifdef DEBUG
	fprintf (stderr, "Subprocess's Pid = %08X\n", pid);
#endif
	sys$dclexh (&exit_block);
	return (mbxname);
}

background_process (argc, argv)
int argc;
char **argv;
{
char command [2048] = "$";
$DESCRIPTOR (value, command);
$DESCRIPTOR (cmd, "BACKGROUND$COMMAND");
$DESCRIPTOR (null, "NLA0:");
int pid;

	strcat (command, argv [0]);
	while (--argc)
		{
		strcat (command, " \"");
		strcat (command, *(++argv));
		strcat (command, "\"");
		}
	value.dsc$w_length = strlen (command);
	if (0 == (1& (vaxc$errno = lib$set_symbol (&cmd, &value))))
		{
		errno = EVMSERR;
		perror ("Can't create symbol for subprocess command");
		exit (EXIT_ERR);
		}
	if (0 == (1& (vaxc$errno = lib$spawn (&cmd, &null, 0, &17, 0, &pid))))
		{
		errno = EVMSERR;
		perror ("Can't spawn subprocess");
		exit (EXIT_ERR);
		}
#ifdef DEBUG
	fprintf (stderr, "%s\n", command);
#endif
	fprintf (stderr, "%08X\n", pid);
	return (EXIT_OK);
}

/* vi:set tabstop=4 shiftwidth=4: */