Directories and files using dirent.h

I've the following code written in C and it displays files (name and size) and directories (<dir> if it encounters directory which is not hidden or not link) but it's not able to pass testing arguments test. I haven't done this test myself (it's just given to me to test my codes), that's why I don't know the reason for failing this test.

Code:

int main(int argc, char* argv[])
{
DIR *pdir;
struct dirent *pent;
struct stat statbuf;
if(argc>1)
{
    pdir=opendir(argv[1]);
} else {
    pdir=opendir(".");
}

//chdir(pdir);

if (!pdir){
    printf ("opendir() failure; terminating\n");
    exit(1);
}

while ((pent=readdir(pdir))!=NULL)
{
    stat(pent->d_name,&statbuf);
    if(strcmp(".", pent->d_name) == 0 || strcmp("..", pent->d_name) == 0)
        continue;
    if(S_ISDIR(statbuf.st_mode))
        printf("%s <dir>\n", pent->d_name);
    if(!(S_ISDIR(statbuf.st_mode)))
        printf("%s %d\n", pent->d_name, statbuf.st_size);
}
closedir(pdir);
return 0;
}

That's the test:

Code:

#!/bin/bash

LS_PY=./myls.py
LS_C=./myls

TMP1=~/lsout1
TMP2=~/lsout2
TMPERR=~/lserr

echo Testing files
$LS_PY > $TMP1
$LS_C > $TMP2
diff $TMP1 $TMP2 && echo OK || echo ERROR

echo Testing dirs
mkdir testdir
$LS_PY > $TMP1
$LS_C > $TMP2
diff $TMP1 $TMP2 && echo OK || echo ERROR
rmdir testdir

echo Testing arguments
$LS_PY / > $TMP1
$LS_C / > $TMP2
diff $TMP1 $TMP2 && echo OK || echo ERROR

echo Testing error-arguments - should see error below
$LS_C nonexistentdirectory > /dev/null && echo ERROR - RETURN ZERO || echo RETURN value OK

echo Testing error-arguments - should see error below
$LS_C tests.sh > /dev/null && echo ERROR - RETURN ZERO || echo RETURN value OK

Presumably the output of this program doesn't match the output of the python version. More than that I cannot say.

One candidate in the first test is that $TMP1 and $TMP2 are created by the respective calls to myls, which means that the second call to myls will see a different set of files than the first.

Other than that, diff will see differences if the file is not identical - even a space may be enough to make it think the content is different.

--
Mats

Numbers are the reason for error. I cannot locate the exact place where this error stems from. All I can say is that I have to change something in C code. Although at the moment this code seems to me fine and very logical. But it induces some random numbers instead of string "<dir>" when comparing names.
That's the error:

Code:

Testing arguments
1,15c1,15
< tmp <dir>
< usr <dir>
< sys <dir>
< opt <dir>
< nonexistent <dir>
< boot <dir>
< srv <dir>
< sbin <dir>
< bin <dir>
< lib <dir>
< etc <dir>
< proc <dir>
< media <dir>
< initrd <dir>
< mnt <dir>
---
> tmp -1078670360
> usr -1078670360
> sys -1078670360
> opt -1078670360
> nonexistent -1078670360
> boot -1078670360
> srv -1078670360
> sbin -1078670360
> bin -1078670360
> lib -1078670360
> etc -1078670360
> proc -1078670360
> media -1078670360
> initrd -1078670360
> mnt -1078670360
ERROR

Seems like your S_ISDIR isn't working right, as it appears that you are printing the size of a directory rather than the <dir> marker.

--
Mats

stat() returns a result.
Perhaps test for success before looking at st_mode for results.

Originally Posted by Salem

stat() returns a result.
Perhaps test for success before looking at st_mode for results.

Good point. The value -1078670360 is a stack-addres in Linux, so I would guess that stat is actually returning an error and your code isn't getting anything sensible back from stat().

One possible reason is that you are doing stat on the wrong file - I didn't look at it carefully, but if you are listing files in /, you may want to form a filename of /tmp for stat to give you valid values. Otherwise, it will be looking in the current directory for something called tmp - which I'd guess isn't there. Some work with strcat() would help here.

--
Mats