Thread: Unable to List Files Attributes on EXT2

The code is well commented, the compiler isn't pointing anything really great, so I'm kinda lost, it is an exercise on a book I'm reading...

Code:

/*check flags.c - display info on ext2 extended attributes*/

/* For each file name on the command line, display information on that 
file's ext2 attributes */

#include<errno.h>
#include<fcntl.h>
#include<linux/ext2_fs.h>
#include<stdio.h>
#include<sys/ioctl.h>
#include<unistd.h>

int main(int argc, char **argv){
	
	char **filename = argv + 1;
	int fd;
	int flags;
	
/*Iterate over each file name on the command line. The last pointer in argv[]
	is NULL, so this while() loop is legal*/
	while (*filename){

/*Unlike normal attributes, ext2 attributes can only be queried if 
we have a file descriptor (a file name is not sufficient). We 
dont need write acces to query the ext2 attributes, so O_RDONLY is ok*/
		
		fd = open(*filename, O_RDONLY);
			if (fd < 0) {
				fprintf(stderr,"cannot open %s: %s\n", *filename, 
						strerror(errno));
				return 1;
			}
/*This gets the attributes, and puts them into flags*/
				
			if (ioctl(fd, EXT2_IOC_GETFLAGS, &flags)){
				fprintf(stderr,"ioctl failed on %s: %s\n", *filename, 
						strerror(errno));
				return 1;
			}
			
			printf("%s:", *filename++);

/*Check for each attribute, and display a message for each one wich is returned 
on*/
			if (flags & EXT2_APPEND_FL) printf("Append");
			if (flags & EXT2_IMMUTABLE_FL) printf("Immutable");
			if (flags & EXT2_SYNC_FL) printf("Sync");
			if (flags & EXT2_NODUMP_FL) printf("No dump");
			
			printf("\n");
			close(fd);			
	}
	
	return 0;
}

The problem is simple, the program does nothing...

Originally Posted by itsme86

Are you supplying any filenames on the command line (i.e.: flags file1 file2 file3)?

yes, but I now I thing I might be doing it wrong in Anjuta (the IDE I'm using) could you plase give an example of call to the program to check one file? I would be very gratefull!

EXECUTING:
/home/imanewbie/Projects/Junk Code/checkflags checkflags.c
----------------------------------------------
checkflags.c:

----------------------------------------------
Program exited successfully with errcode (0)
Press the Enter key to close this terminal ...


Suggestions?

Originally Posted by Hammer

>>Program exited successfully
What's the problem exactly?

The program exited (didn't crash) but also did'nt displayed the info I was waiting for:

Code:

/*check flags.c - display info on ext2 extended attributes*/

/* For each file name on the command line, display information on that 
file's ext2 attributes */

#include<errno.h>
#include<fcntl.h>
#include<linux/ext2_fs.h>
#include<stdio.h>
#include<sys/ioctl.h>
#include<unistd.h>

int main(int argc, char **argv){
	
	char **filename = argv + 1;
	int fd;
	int flags;
	
/*Iterate over each file name on the command line. The last pointer in argv[]
	is NULL, so this while() loop is legal*/
	while (*filename){

/*Unlike normal attributes, ext2 attributes can only be queried if 
we have a file descriptor (a file name is not sufficient). We 
dont need write acces to query the ext2 attributes, so O_RDONLY is ok*/
		
		fd = open(*filename, O_RDONLY);
			if (fd < 0) {
				fprintf(stderr,"cannot open %s: %s\n", *filename, 
						strerror(errno));
				return 1;
			}
/*This gets the attributes, and puts them into flags*/
				
			if (ioctl(fd, EXT2_IOC_GETFLAGS, &flags)){
				fprintf(stderr,"ioctl failed on %s: %s\n", *filename, 
						strerror(errno));
				return 1;
			}
			
			printf("%s:", *filename++);

/*Check for each attribute, and display a message for each one wich is returned 
on*/
			if (flags & EXT2_APPEND_FL) printf("Append");
			if (flags & EXT2_IMMUTABLE_FL) printf("Immutable");
			if (flags & EXT2_SYNC_FL) printf("Sync");
			if (flags & EXT2_NODUMP_FL) printf("No dump");
			
			printf("\n");
			close(fd);			
	}
	
	return 0;
}

Originally Posted by Hammer

Did you pass it any parameters?

I think this piece of code should do it:

Code:

/*This gets the attributes, and puts them into flags*/
				
			if (ioctl(fd, EXT2_IOC_GETFLAGS, &flags)){
				fprintf(stderr,"ioctl failed on %s: %s\n", *filename, 
						strerror(errno));
				return 1;
			}

Well I added you piece of code to check for the parameters but it goes trought without printing the error advices... But still not working.

Originally Posted by Salem

Depends what you mean by not working.
The code you posted a couple of posts ago works just fine - it prints a list of filenames passed on the command line.
As for printing the flags, well that really depends on finding files with those attributes set.

Salem, I've read on Google about passing the parameters on command line, but the code didn't worked the way they told me to call it, could you please, just type the way I must call it on shell?

MyUser@blah:~here follows the call that I don't know how to do?
Thx a lot by the attention.