escape.c

Gcomm is a serial communications program similar to seyon, but more modern, and easier to use. Works

#ifndef lint
static const char sccsid[] = "@(#)escape.c 1.1 96/11/02 Edward Falk" ;
#endif

/**********
 *
 *
 *	@@@@@   @@@@   @@@    @@@   @@@@   @@@@@  
 *	@      @      @      @   @  @   @  @      
 *	@@@     @@@   @      @@@@@  @@@@   @@@    
 *	@          @  @      @   @  @      @      
 *	@@@@@  @@@@    @@@   @   @  @      @@@@@  
 *
 *	ESCAPE - filename completion
 *
 *	int
 *	filenam_escape(name,maxlen)	filename completion.
 *		char	*name ;			pathname
 *		int	maxlen ;		maximum length of pathname
 *
 *	This routine takes a pathname and completes it as far as possible.
 *	escape returns the number of matches, or -1 on error.  If the number
 *	of matches is not exactly 1, we probably don't have a complete path
 *	and the application should ring the bell.
 *
 *	This function also completes user names in "~user" form.  This can
 *	be very slow if there are a lot of password entries.
 *
 *	Note: escape optimizes the case where no expansion at all can be
 *	performed.  When this happens, the returned number of matches will
 *	be short (but greater than 1)
 *
 *
 *	int
 *	filename_expand(name)		'~' expansion.
 *		char	*name ;
 *
 *	This function expands a filename with a leading '~', in place.
 *	'name' must point to a buffer long enough to hold the complete
 *	path.  If the form is "~user" and the password entry for the
 *	user cannot be found, an error occurs.  This function returns 0
 *	on success, nonzero on failure.
 *
 *
 *
 *
 *	Edward A. Falk
 *	Sun Microsystems
 *
 *	September, 1990
 *
 *
 *
 **********/

#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/param.h>		/* defines MAXPATHLEN */
#include <pwd.h>


extern	char	*getenv() ;


/* return values from parse() function */

static	int	unamecomp ;	/* username completion? */
static	DIR	*dir ;		/* directory to search, if any */
static	char	*namestr ;	/* part of name where results will go */
static	int	matchlen ;	/* length of namestr */


/* cute optimization */

#define	STRCMP(a,b)	( *(a)!=*(b)  ||  strcmp((a),(b)) )
#define	STRNCMP(a,b,l)	( *(a)!=*(b)  ||  strncmp((a),(b),(l)) )


#ifdef	STANDALONE
main()
{
	test("a") ;
	test("f") ;
	test("e") ;
	test("et") ;
	test("n") ;
	test("~/Es") ;
	test("~/Escape/f") ;
	test("~/Escape/et") ;
	test("/vm") ;
	test("~falk/") ;
	test("~moose/") ;
	test("~fal") ;
	test("~jput") ;
	test("~jp") ;
	test("~") ;
	test2("~falk/los") ;
	test2("~falk") ;
	test2("~moose/") ;
	exit(0) ;
}


test(str)
	char	*str ;
{
	char	path[MAXPATHLEN] ;
	int	i ;

	strcpy(path, str) ;
	i = escape(path, MAXPATHLEN) ;
	printf("# matches = %d, path=%s\n", i, path) ;
}


test2(str)
	char	*str ;
{
	char	path[MAXPATHLEN] ;
	int	i ;

	strcpy(path, str) ;
	i = expand_user(path) ;
	printf("path=%s\n", path) ;
}
#endif	/* STANDALONE */


static	int
parse(name,maxlen)
	char	*name ;		/* file to match */
	int	maxlen ;
{
	char		dirname[MAXPATHLEN] ;
	char		*homedir ;
	char		*dirstr ;
	struct passwd	*passent ;

	/* cases:
	 *  "~"		username matching
	 *  "~/		get home directory
	 *  "~xx	username matching
	 *  "~xx/	get username
	 *  "/		root
	 *  anything	"."
	 */

	unamecomp = 0 ;
	dir = NULL ;


	if( name[0] == '~' )
	{
	  if( name[1] == '/' )
	  {
	    homedir = getenv("HOME") ;
	    if( homedir == NULL )
	      return -1 ;

	    strcpy(dirname, homedir) ;
	    strcat(dirname, name+1) ;
	    namestr = strrchr(name, '/') + 1 ;
	    *strrchr(dirname, '/') = '\0' ;
	    dir = opendir(dirname) ;
	  }
	  else
	  {
	    dirstr = strchr(name, '/') ;
	    if( dirstr == NULL )		/* username matching */
	    {
	      unamecomp = 1 ;
	      namestr = name+1 ;
	      matchlen = strlen(namestr) ;
	      return 0 ;
	    }
	    else
	    {
	      *dirstr = '\0' ;
	      passent = getpwnam(name+1) ;
	      *dirstr = '/' ;
	      if( passent == NULL )
		return -1 ;

	      strcpy(dirname, passent->pw_dir) ;
	      strcat(dirname, dirstr) ;
	      namestr = strrchr(name,'/') + 1 ;
	      *strrchr(dirname, '/') = '\0' ;
	      dir = opendir(dirname) ;
	    }
	  }
	}
	else
	{
	  strcpy(dirname, name) ;
	  namestr = strrchr(name, '/') ;
	  if( namestr == NULL )			/* no path */
	  {
	    namestr = name ;
	    dir = opendir(".") ;
	  }
	  else if( namestr == name )		/* absolute path */
	  {
	    ++namestr ;
	    dir = opendir("/") ;
	  }
	  else					/* relative path */
	  {
	    ++namestr ;
	    *strrchr(dirname, '/') = '\0' ;
	    dir = opendir(dirname) ;
	  }
	}

	matchlen = strlen(namestr) ;
	return dir == NULL ;
}


int
filename_escape(name,maxlen)
	char	*name ;		/* file to match */
	int	maxlen ;
{
	int		nummatch = 0 ;
	struct dirent	*entry ;
	struct passwd	*passent ;
	int		copout = 0 ;	/* unable to expand at all */

	if( parse(name,maxlen) )
	  return 0 ;

	if( matchlen == 0 )
	  return 2 ;


	if( !unamecomp )
	{
	  /* now to search the directory for matches */

	  while( !copout  &&  (entry = readdir(dir)) != NULL )
	  {
	    if( STRCMP(entry->d_name, ".") != 0  &&
		STRCMP(entry->d_name, "..") != 0  &&
		STRNCMP(namestr, entry->d_name, matchlen) == 0 )
	    {
	      if( ++nummatch == 1 )	/* first match */
		strcpy(namestr, entry->d_name) ;
	      else			/* ambiguity! */
	      {
		char *ptr1=namestr+matchlen, *ptr2=entry->d_name+matchlen ;
		while( *ptr1 == *ptr2 )
		  ++ptr1, ++ptr2 ;
		*ptr1 = '\0' ;
		copout = ptr1 == namestr+matchlen ;
	      }
	    }
	  }
	  closedir(dir) ;
	}
	else
	{
	  setpwent() ;
	  while( !copout  &&  (passent = getpwent()) != NULL )
	  {
	    if( STRNCMP(namestr, passent->pw_name, matchlen) == 0 )
	    {
	      if( nummatch == 0 )	/* first match */
	      {
		strcpy(namestr, passent->pw_name) ;
		nummatch = 1 ;
	      }
	      else			/* ambiguity! */
	      {
		char *ptr1=namestr+matchlen, *ptr2=passent->pw_name+matchlen ;
		while( *ptr1 != '\0'  &&  *ptr1 == *ptr2 )
		  ++ptr1, ++ptr2 ;
		if( *ptr1 != *ptr2 )
		{
		  *ptr1 = '\0' ;
		  ++nummatch ;
		  copout = ptr1 == namestr+matchlen ;
		}
	      }
	    }
	  }
	}

	return nummatch ;
}




int
filename_expand(name)
	char	*name ;		/* file to match */
{
	char		dirname[MAXPATHLEN] ;
	char		*homedir ;
	char		*dirstr ;
	struct passwd	*passent ;

	if( name[0] != '~' )
	  return 0 ;			/* that was easy */

	/* cases:
	 *  "~"		fail
	 *  "~/		get home directory
	 *  "~xx	username matching
	 */

	if( name[1] == '/' )
	{
	  homedir = getenv("HOME") ;
	  if( homedir == NULL )
	    return -1 ;

	  strcpy(dirname, homedir) ;
	  strcat(dirname, name+1) ;
	  strcpy(name,dirname) ;
	}
	else
	{
	  dirstr = strchr(name, '/') ;
	  if( dirstr != NULL )
	    *dirstr = '\0' ;
	  passent = getpwnam(name+1) ;
	  if( dirstr != NULL )
	    *dirstr = '/' ;
	  if( passent == NULL )
	    return -1 ;

	  strcpy(dirname, passent->pw_dir) ;
	  if( dirstr != NULL )
	    strcat(dirname, dirstr) ;
	  strcpy(name,dirname) ;
	}
	return 0 ;
}