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/* WhereAmI
*
* A category of Application that provides methods for finding the
* application executable and executable directory.
*
* Copyright 1991, 1992 Scott Hess. This source code may be
* redistributed and modified without restriction. Well, one
* restriction - do not claim that you wrote it.
*
* Scott Hess
* 12901 Upton Avenue South, #326
* Burnsville, MN 55337
* (612) 895-1208
* scott@gac.edu
* shess@ssesco.com
*/
#import "WhereAmI.h"
#import <appkit/defaults.h>
#import <sys/param.h>
#import <libc.h>
#import <strings.h>
@implementation Application (WhereAmI)
int whereAmIReference=0;
-(NXAtom)whoAmI
{
static NXAtom whoAmI=NULL;
static BOOL beenHere;
if( !beenHere) {
char buf[ MAXPATHLEN+1]="";
char linkbuf[ MAXPATHLEN+1];
int len, links;
/* First, trace the file that is in NXArgv[ 0].
* If it starts with '/', it's an absolute pathname and thus truth.
* Else, check to see if it is relative to the working directory.
* Else, look on the path for it.
*/
if( NXArgv[ 0][ 0]=='/') {
strcpy( buf, NXArgv[ 0]);
} else if( access( NXArgv[ 0], F_OK)==0) {
if( getwd( buf)) {
strcat( buf, "/");
strcat( buf, NXArgv[ 0]);
}
} else {
const char *pathList=getenv( "PATH");
if( pathList) {
while( *pathList) {
const char *colon=index( pathList, ':');
if( colon) {
strncpy( buf, pathList, colon-pathList);
buf[ colon-pathList]=0;
pathList=colon+1;
} else {
strcpy( buf, pathList);
pathList+=strlen( pathList);
}
strcat( buf, "/");
strcat( buf, NXArgv[ 0]);
if( access( buf, F_OK)==0) {
break;
}
}
}
if( !pathList || *pathList==0) {
buf[ 0]='\0';
}
}
/* Now, trace the file through symbolic links to where it _really_ is.
* Note that symbolic links can be multiple.
* Give up after tracing through 8 links (assume a cycle).
*/
for( links=0; links<8 && (len=readlink( buf, linkbuf, MAXPATHLEN))!=-1; links++) {
linkbuf[ len]='\0';
if( linkbuf[ 0]=='/') {
strcpy( buf, linkbuf);
} else {
char *p=linkbuf;
for( ;;) {
char *s=rindex( buf, '/');
if( s) {
*s='\0';
}
if( strncmp( p, "../", 3)) {
break;
}
p+=3;
}
strcat( buf, "/");
strcat( buf, p);
}
}
if( links==8) {
buf[ 0]='\0';
}
if( !access( buf, X_OK)) {
whoAmI=NXUniqueString( buf);
}
beenHere=YES;
}
return whoAmI;
}
-(NXAtom)whereAmI
{
static NXAtom whereAmI=NULL;
static BOOL beenHere=NO;
if( !beenHere) {
/* Just get the executable path, and then strip off the
* executable's name.
*/
NXAtom who=[self whoAmI];
if( who) {
char buf[ MAXPATHLEN+1]="";
char *i;
strcpy( buf, who);
i=rindex( buf, '/');
if( i) {
*i='\0';
}
if( buf[ 0]) {
whereAmI=NXUniqueString( buf);
} else {
whereAmI="";
}
}
beenHere=YES;
}
return whereAmI;
}
-(const char *)whereIs:(const char *)file path:(char *)result
{
/* Get the directory the application resides in.
* Append the file part.
* Attempt to verify the file's existance.
*/
if( result) {
NXAtom where=[self whereAmI];
if( where) {
strcpy( result, where);
strcat( result, "/");
if( file) {
strcat( result, file);
}
if( !access( result, F_OK)) {
return result;
}
return NULL;
}
}
*result='\0';
return NULL;
}
@end
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