/* *  sudo version 1.1 allows users to execute commands as root *  Copyright (C) 1991  The Root Group, Inc. * *  This program 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 1, or (at your option) *  any later version. * *  This program 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 this program; if not, write to the Free Software *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * *  If you make modifications to the source, we would be happy to have *  them to include in future releases.  Feel free to send them to: *      Jeff Nieusma                       nieusma@rootgroup.com *      3959 Arbol CT                      (303) 447-8093 *      Boulder, CO 80301-1752              * ******************************************************************* * *  This module contains the find_path() command that returns *  a pointer to a static area with the absolute path of the  *  command or NULL if the command is not found in the path * *  I also added the strdup() function in here after I found most *  systems don't have it... * *  Jeff Nieusma  Thu Mar 21 23:11:23 MST 1991 */#include <stdio.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/param.h>#include <string.h>#include <strings.h>extern char *malloc();extern char *getenv();extern char **Argv;char *find_path();static char *do_stat();static char *check_link();char *strdup();/******************************************************************* * * find_path() * * this function finds the full pathname for a command */char *find_path(file)char *file;{register char *n;char *path=NULL;char *cmd;if ( strlen ( file ) > MAXPATHLEN ) {    fprintf ( stderr, "%s:  path too long:  %s\n", Argv[0], file );    exit (1);    }    if ( *file == '.' && *(file+1) == '/' || *file == '/' )     return ( do_stat ( NULL, file ) );if ( ( path=getenv("PATH") ) == NULL ) return ( NULL ) ;if ( ( path=strdup(path) ) == NULL ) {    perror ( "find_path:  malloc" );    exit (1);    }while ( n = index ( path, ':' ) ) {    *n='\0';    if ( cmd = do_stat ( path, file ) ) return ( cmd );    path=n+1;    }if ( cmd = do_stat ( path, file ) )     return ( cmd );else    return ( NULL );	}/********************************************************************** *  * check_link() *  * this function makes sure the argument is not a symbolic link. * it returns the pathname of the binary or NULL */static char *check_link(path)char *path;{char buf1[MAXPATHLEN+1];    /* is the link */char *s, *buf;register int rtn;/* the recursive buck stops here */if ( path == NULL ) return NULL ;/* I'd rather play with pointers than arrays... */buf = buf1;/* If this is NOT a sym link, return */if ( ( rtn=readlink(path, buf, MAXPATHLEN)) < 0 )    return (path);/* if it is a sym link, NULL terminate the string */buf[rtn]='\0';/* if the link points to an absolute path, start again... */if ( *buf == '/' ) return ( do_stat( NULL, buf ) );/* if the link points to ./something or something/ we need to  * strip off the filename portion of the current path */if ( ( s=rindex(path,'/') ) == NULL ) {    fprintf( stderr, "check_link:  This path is very wierd: %s \n", path );    exit (1);    }else    *s='\0';/* as long as the link has ./ or ../ in it, get rid of it... */while ( *buf == '.' ) {    if ( strncmp(buf, "../", 3) == 0 ) {	if ( ( s=rindex(path, '/')) ) {            *s='\0';	    if ( *path == '\0' ) strcpy ( path, "/" );	    }	buf += 3; 	continue;	}    else if ( strncmp(buf, "./", 2) == 0 ) {	buf += 2;	continue;	}    else 	break;    }/* we have to copy the path buffer since do_stat() will bzero() it */if ( ( s = strdup ( path ) ) == NULL ) {    perror ( "check_link:  malloc" );    exit (1);    }return ( do_stat ( s, buf ) );}/****************************************************************** * *   do_stat() * *    This function takes a path and a file and stat()s the file *    If the file exists, the full path to that file is returned *    otherwise NULL is returned */static char *do_stat( path, file )char *path, *file;{static char buf[MAXPATHLEN+1];struct stat s;register char type;if ( *file == '.' && *(file+1) == '/' )     type=1;else  if ( *file == '/' )    type=2;else  if ( path == NULL )    type=2;else  if ( *path == '.' && *(path+1) == (char)NULL )    type=3;else    type=0;switch ( type ) {    case 1:        file += 2;    case 3:	if ( (path=(char *)malloc(MAXPATHLEN+1)) == NULL ) {	    perror ("do_stat:  malloc");	    exit (1);	    }	if ( ! getwd ( path ) ) {	    perror ("do_stat:  getwd");	    exit (1);	    }        break;    case 2:    default:        break;    }        if ( ( ( path? strlen(path) : 0 ) + strlen (file) ) > MAXPATHLEN - 1 ) {    fprintf ( stderr, "%s:  path too long:  %s/%s\n", Argv[0], path, file );    exit (1);    }bzero ( buf, MAXPATHLEN+1 );if ( path ) strcat ( buf, path );if ( *file != '/' && path [strlen(path)-1] != '/' ) strcat ( buf, "/" );strcat ( buf, file );if ( ! stat ( buf, &s ) )    return ( check_link ( buf ) );else    return ( NULL );}/****************************************************************** * *  strdup() * *  this function returns a pointer a string copied into  *  a malloc()ed buffer */char *strdup(s1)char *s1;{char *s;if ( ( s=(char *)malloc(strlen(s1)+1)) == NULL )    return (NULL);strcpy(s,s1);return (s);}