/* * Do file name expansion with "native" shell.  Using the native shell * (as described in the SHELL environmental variable) allows for csh or * ksh abbreviations that sh doesn't recognize.  Returns a pointer to * a static area. */#define EXPAND_BUF	2048#include <stdio.h>#include <signal.h>#include <fcntl.h>#include "config.h"#ifdef BSD#include <sys/file.h>#endif /* BSD */char *expand(input)char *input;{	extern char *null_ptr;	FILE *pfp, *n_popen();	int last;	char buf[1024], *strpbrk(), *strcpy();	static char ans[EXPAND_BUF];					/* same rules as str_dup() */	if (input == NULL)		return(NULL);	if (*input == '\0')		return(null_ptr);					/* any thing to expand? */	if (!strpbrk(input, "$*{}[]\\?~")) {		strcpy(ans, input);		return(ans);	}					/* popen an echo */	sprintf(buf, "echo %s", input);	pfp = n_popen(buf, "r");	fgets(ans, EXPAND_BUF, pfp);	n_pclose(pfp);	if (!strlen(ans)) {		strcpy(ans, input);		return(ans);	}	/*	 * A horrible kludge...  if the last character is not a line	 * feed, then the csh has returned an error message.  Otherwise	 * zap the line feed.	 */	last = strlen(ans) -1;	if (ans[last] != '\n') {		strcpy(ans, input);		return(ans);	}	else		ans[last] = '\0';	return(ans);}#define	tst(a,b) (*mode == 'r'? (b) : (a))#define	RDR	0#define	WTR	1static int popen_pid[20];FILE *n_popen(cmd, mode)char *cmd, *mode;{	int myside, hisside, ppid, p[2];	char *shellpath, *shell, *flags, *getenv(), *strrchr();	void _exit();	if (pipe(p) < 0)		return NULL;	myside = tst(p[WTR], p[RDR]);	hisside = tst(p[RDR], p[WTR]);					/* get the environmental variable */	shellpath = getenv("SHELL");	if (shellpath == NULL || *shellpath == '\0')		shellpath = "/bin/sh";	if (shell = strrchr(shellpath, '/'))		shell++;	else {		shellpath = "/bin/sh";		shell = "sh";	}					/* fix up the flags */	if (!strcmp(shell, "csh"))		flags = "-fc";	else		flags = "-c";		/* Korn shell too */	if (!(ppid = fork())) {		int stdio;					/* no error messages please */		close(2);		open("/dev/null", O_WRONLY);		setgid(getgid());		setuid(getuid());		stdio = tst(0, 1);		close(myside);		close(stdio);		fcntl(hisside, F_DUPFD, stdio);		close(hisside);		execl(shellpath, shell, flags, cmd, (char *) 0);		_exit(1);	}	if (ppid == -1) {		close(myside);		close(hisside);		return NULL;	}	popen_pid[myside] = ppid;	close(hisside);	return(fdopen(myside, mode));}n_pclose(ptr)FILE *ptr;{	SIG_TYPE (*hstat)(), (*istat)(), (*qstat)();	int f, r, sig_status;	f = fileno(ptr);	fclose(ptr);	istat = signal(SIGINT, SIG_IGN);	qstat = signal(SIGQUIT, SIG_IGN);	hstat = signal(SIGHUP, SIG_IGN);	while ((r = wait(&sig_status)) != popen_pid[f] && r != -1)		;	if (r == -1)		sig_status = -1;	signal(SIGINT, istat);	signal(SIGQUIT, qstat);	signal(SIGHUP, hstat);	return(sig_status);}