/* $RCSfile: popen.c,v $$Revision: 4.0.1.1 $$Date: 91/06/07 11:22:52 $ * *    (C) Copyright 1988, 1990 Diomidis Spinellis. * *    You may distribute under the terms of either the GNU General Public *    License or the Artistic License, as specified in the README file. * * $Log:	popen.c,v $ * Revision 4.0.1.1  91/06/07  11:22:52  lwall * patch4: new copyright notice *  * Revision 4.0  91/03/20  01:34:50  lwall * 4.0 baseline. *  * Revision 3.0.1.2  90/08/09  04:04:42  lwall * patch19: various MSDOS and OS/2 patches folded in *  * Revision 3.0.1.1  90/03/27  16:11:57  lwall * patch16: MSDOS support *  * Revision 1.1  90/03/18  20:32:20  dds * Initial revision * *//* * Popen and pclose for MS-DOS */#include <stdlib.h>#include <stdio.h>#include <process.h>/* * Possible actions on an popened file */enum action {	delete, 			/* Used for "r". Delete the tmp file */	execute				/* Used for "w". Execute the command. */};/* * Linked list of things to do at the end of the program execution. */static struct todo {	FILE *f;			/* File we are working on (to fclose) */	const char *name;		/* Name of the file (to unlink) */	const char *command;		/* Command to execute */	enum action what;		/* What to do (execute or delete) */	struct todo *next;		/* Next structure */} *todolist;/* Clean up function */static int close_pipes(void);/* * Add a file f running the command command on file name to the list * of actions to be done at the end.  The action is specified in what. * Return -1 on failure, 0 if ok. */static intadd(FILE *f, const char *command, const char *name, enum action what){	struct todo    *p;	if ((p = (struct todo *) malloc(sizeof(struct todo))) == NULL)		return -1;	p->f = f;	p->command = command;	p->name = name;	p->what = what;	p->next = todolist;	todolist = p;	return 0;}FILE *mypopen(const char *command, const char *t){	char buff[256];	char *name;	FILE *f;	static init = 0;	if (!init)		if (onexit(close_pipes) == NULL)			return NULL;		else			init++;	if ((name = tempnam((char*)NULL, "pp")) == NULL)		return NULL;	switch (*t) {	case 'r':		sprintf(buff, "%s >%s", command, name);		if (system(buff) || (f = fopen(name, "r")) == NULL) {			free(name);			return NULL;		}		if (add(f, command, name, delete)) {			(void)fclose(f);			(void)unlink(name);			free(name);			return NULL;		}		return f;	case 'w':		if ((f = fopen(name, "w")) == NULL) {			free(name);			return NULL;		}		if (add(f, command, name, execute)) {			(void)fclose(f);			(void)unlink(name);			free(name);			return NULL;		}		return f;	default:		free(name);		return NULL;	}}intmypclose(FILE *f){	struct todo *p, **prev;	char buff[256];	const char *name;	int status;	for (p = todolist, prev = &todolist; p; prev = &(p->next), p = p->next)		if (p->f == f) {			*prev = p->next;			name = p->name;			switch (p->what) {			case delete:				free(p);				if (fclose(f) == EOF) {					(void)unlink(name);					status = EOF;				} else if (unlink(name) < 0)					status = EOF;				else					status = 0;				free((void*)name);				return status;			case execute:				(void)sprintf(buff, "%s <%s", p->command, p->name);				free(p);				if (fclose(f) == EOF) {					(void)unlink(name);					status = EOF;				} else if (system(buff)) {					(void)unlink(name);					status = EOF;				} else if (unlink(name) < 0)					status = EOF;				else					status = 0;				free((void*)name);				return status;			default:				return EOF;			}		}	return EOF;}/* * Clean up at the end.  Called by the onexit handler. */static intclose_pipes(void){	struct todo    *p;	for (p = todolist; p; p = p->next)		(void)mypclose(p->f);	return 0;}