Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Using [uw]tmp

On Dec 13, 2005, at 7:38 AM, Graham J Lee wrote:
I want to get login information for users (basically my goal is a Bonjour-enabled equivalent to the old GNU or ICSI distributed finger server[*], where any systems on the local network register themselves with the server so I can find out if a user has logged in anywhere on the local network) and as neither of the distributed fingers come anywhere near close to compiling on Darwin (8.3.0) have tried to start from scratch. Having observed that /var/run/ utmpx is empty, and that there's no getutent on Darwin, I'm doing it the same way that programs like w(1) do and reading struct utmps from the appropriate file. However, what I get back doesn't seem consistent with the idea that utmp(5) [or indeed wtmp(5)] is just a bunch of struct utmps stored back to back. Here's my code: 

Graham,

It looks like your problem is that you're using sizeof on a pointer, which is going to be 4, rather than the correct size, so you're looking at the file four bytes at a time.

If you change to use sizeof(struct utmp) then this works as expected.

-Jason

#import <Foundation/Foundation.h>
#import <utmp.h>
#import <stdlib.h>
#import <stdio.h>

extern int errno;
int main (int argc, const char * argv[]) {
	NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
	FILE *utmp_file;
	struct utmp *utmp_store;

errno=0;
if((utmp_file=fopen(_PATH_UTMP,"rb"))==NULL)
{
perror("csalutd: couldn't open utmp");
exit(EXIT_FAILURE);
}
if((utmp_store=(struct utmp *)malloc(sizeof(utmp_store)))==NULL)
{
perror("csalutd: couldn't malloc struct");
exit(EXIT_FAILURE);
}
while(fread(utmp_store,sizeof(utmp_store),1,utmp_file)==1)
{
printf("That fool %s, over %s way, was responsible.\nIt was at % d on %s.\n",utmp_store->ut_name,utmp_store->ut_host,utmp_store- >ut_time,utmp_store->ut_line);
}
fclose(utmp_file);

[pool release];
return 0;
} 


_______________________________________________
Do not post admin requests to the list. They will be ignored.
Darwin-dev mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/darwin-dev/email@hidden

This email sent to email@hidden
References: 
 >Using [uw]tmp (From: Graham J Lee <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.