deb-mbse/lib/expipe.c

/*****************************************************************************
 *
 * File ..................: expipe.c
 * Purpose ...............: MBSE BBS Execute pipe
 * Last modification date : 22-Apr-2001
 *
 *****************************************************************************
 * Copyright (C) 1997-2001
 *   
 * Michiel Broek		FIDO:		2:280/2802
 * Beekmansbos 10
 * 1971 BV IJmuiden
 * the Netherlands
 *
 * This file is part of MBSE BBS.
 *
 * This BBS is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * MBSE BBS 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 MBSE BBS; see the file COPYING.  If not, write to the Free
 * Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *****************************************************************************/

#include "libs.h"
#include "structs.h"
#include "records.h"
#include "clcomm.h"
#include "common.h"



static struct _fppid {
	FILE	*fp;
	int	pid;
} fppid[] = {
	{NULL, 0}, {NULL, 0}, {NULL, 0}
};

#define maxfppid 2



FILE *expipe(char *cmd, char *from, char *to)
{
	char	buf[256], *buflimit;
	char	*vector[16];
	int	i, rc;
	char	*p, *q, *f=from, *t=to;
	int	pipedes[2];
	FILE	*fp;
	int	pid, slot;

	buflimit = buf + sizeof(buf) -1 - (f&&t&&(strlen(f)>strlen(t))?strlen(f):t?strlen(t):0);

	for (slot = 0; slot <= maxfppid; slot++) {
		if (fppid[slot].fp == NULL) 
			break;
	}
	if (slot > maxfppid) {
		WriteError("Attempt to pipe more than %d processes", maxfppid + 1);
		return NULL;
	}

	for (p = cmd, q = buf; (*p); p++) {
		if (q > buflimit) {
			WriteError("Attempt to pipe too long command");
			return NULL;
		}
		switch (*p) {
		case '$':	switch (*(++p)) {
				case 'f':
				case 'F': 	if ((f)) 
							while (*f) 
								*(q++) = *(f++);
						f=from; 
						break;
				case 't':
				case 'T': 	if ((t)) 
							while (*t) 
								*(q++) = *(t++);
						t=to; 
						break;
				default: 	*(q++)='$'; 
						*(q++)=*p; 
						break;
				}
				break;
		case '\\':	*(q++) = *(++p); 
				break;
		default: 	*(q++) = *p; 
				break;
		}
	}

	*q = '\0';
	Syslog('+', "Expipe: %s",buf);
	i = 0;
	vector[i++] = strtok(buf," \t\n");
	while ((vector[i++] = strtok(NULL," \t\n")) && (i<16));
	vector[15] = NULL;
	fflush(stdout);
	fflush(stderr);
	if (pipe(pipedes) != 0) {
		WriteError("$Pipe failed for command \"%s\"", MBSE_SS(vector[0]));
		return NULL;
	}

	Syslog('e', "pipe() returned read=%d, write=%d", pipedes[0], pipedes[1]);
	if ((pid = fork()) == 0) {
		close(pipedes[1]);
		close(0);
		if (dup(pipedes[0]) != 0) {
			WriteError("$Reopen of stdin for command %s failed", MBSE_SS(vector[0]));
			exit(-1);
		}
		rc = execv(vector[0],vector);
		WriteError("$Exec \"%s\" returned %d", MBSE_SS(vector[0]), rc);
		exit(-1);
	}

	close(pipedes[0]);

	if ((fp = fdopen(pipedes[1],"w")) == NULL) {
		WriteError("$fdopen failed for pipe to command \"%s\"", MBSE_SS(vector[0]));
	}

	fppid[slot].fp = fp;
	fppid[slot].pid = pid;
	return fp;
}



int exclose(FILE *fp)
{
	int	status, rc;
	int	pid, slot, sverr;

	for (slot = 0; slot <= maxfppid; slot++) {
		if (fppid[slot].fp == fp) 
			break;
	}
	if (slot > maxfppid) {
		WriteError("Attempt to close unopened pipe");
		return -1;
	}
	pid = fppid[slot].pid;
	fppid[slot].fp = NULL;
	fppid[slot].pid = 0;

	Syslog('e', "Closing pipe to the child process %d",pid);
	if ((rc = fclose(fp)) != 0) {
		WriteError("$Error closing pipe to transport (rc=%d)", rc);
		if ((rc = kill(pid,SIGKILL)) != 0)
			WriteError("$kill for pid %d returned %d",pid,rc);
	}
	Syslog('e', "Waiting for process %d to finish",pid);
	do {
		rc = wait(&status);
		sverr = errno;
		if (status)
			Syslog('e', "$Wait returned %d, status %d,%d", rc, status >> 8, status & 0xff);
	} while (((rc > 0) && (rc != pid)) || ((rc == -1) && (sverr == EINTR)));

	switch (rc) {
	case -1:WriteError("$Wait returned %d, status %d,%d", rc, status >> 8, status & 0xff);
		return -1;
	case 0:	return 0;
	default:
		if (WIFEXITED(status)) {
			rc = WEXITSTATUS(status);
			if (rc) {
				WriteError("Expipe: returned error %d", rc);
				return rc;
			}
		}
		if (WIFSIGNALED(status)) {
			rc = WTERMSIG(status);
			WriteError("Wait stopped on signal %d", rc);
			return rc;
		}
		if (rc)
			WriteError("Wait stopped unknown, rc=%d", rc);
		return rc;
	}
	return 0;
}