Doubt/problem using stat()

[indarkness]

Hi everybody!
I'm trying to make a function similar to "ls -l",but I have got a problem when I call my function,"Estadof" which tells me if a string is a directory or a file(if it's made). To do that,I use stat().Well,the problem is,when I use the function scandir() ,after call it, i give my function the name of the directory o file,and here is a problem,because I don't know why stat() gives an error.

What am I doing wrong?

Thanks!!



#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/dir.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>

int Estadof(char *f)
{
int n;
struct stat st;

n=0;

stat(f,&st);//informacion del fichero y la pasa a st que tiene la estructura

if(stat(f, &st)==0)
{
if(S_ISDIR(st.st_mode))
{
n=0;
printf("es un directorio \n");
}
if(S_ISREG(st.st_mode))
{
n=1;
printf("es un fichero regular \n");
}
}
else
{
perror("error en stat");//stat() ha fallado y ha devuelto -1
n=-1;
}

return n;
}

int Listdir(char *d)
{
int n=0;
int i;
int s=0;

struct dirent **archivos;

n=scandir(d,&archivos,0,alphasort);

if(n!=0)
{
for(i=0;i<n;i++)
{
if(strcmp(archivos[i]->d_name,".")!=0 && strcmp(archivos[i]->d_name,"..")!=0)
{
printf("%s \n",archivos[i]->d_name);

s=Estadof(archivos[i]->d_name);//HERE IS THE PROBLEM
//printf("%u \n",s);
}


}
}
else
perror("no hay directorios");


}
int main(int argc,char *argv[])
{
int i=0;

i=Listdir(argv[1]);
//Estadof(argv[1]);

return 0;
}

[Lux Perpetua]

Put your code in
tags, not
tags.

[psusi]

Some questions you should be asking yourself:

1) What is the error stat() is returning?

2) What is the file name you are passing stat() when it fails?

[gmargo]

I don't understand what problem you're having. Your code works for me. The only bug I see is how you check the return code for scandir - you should check for a -1 for error. And no need to call stat twice. And Estadof returns 0 for directory or unknown.

Update: the code worked for me because I only tested it on the current directory.

[indarkness]

Some questions you should be asking yourself:

1) What is the error stat() is returning?



First of all,thanks for answering me!!

The error which stat() returns,it's the element that I give the function,it is not a file or directory,and because that it returns this error




2) What is the file name you are passing stat() when it fails?



Here it's the problem, because I think I passing stat() a correct name. And to check that I use

printf("%s \n",archivos[i]->d_name);
And I see that the name i give stat() are correct,I mean,they are the names of the files or directories.

[indarkness]

I don't understand what problem you're having. Your code works for me. The only bug I see is how you check the return code for scandir - you should check for a -1 for error. And no need to call stat twice. And Estadof returns 0 for directory or unknown.

Thanks for replying! REally does the programs work for you? Well, let me show what I do to check the program:

THe directory where I work


javier@javier-desktop:~/LABSC$ ls -l
total 596
-rw-r--r-- 1 javier javier 354 2010-03-01 19:45 copy1.c
-rw-r--r-- 1 javier javier 19 2010-03-01 19:09 entrada
-rwxr-xr-x 1 javier javier 6917 2010-03-06 22:23 Estadof
-rwx------ 1 javier javier 681 2010-03-06 11:21 Estadof.c
-rwxr-xr-x 1 javier javier 7713 2010-03-06 22:25 Listdir
-rw-r--r-- 1 javier javier 1882 2010-03-06 22:25 Listdir.c
-rw-r--r-- 1 javier javier 1930 2010-03-06 22:23 Listdir.c~
-rw-r--r-- 1 javier javier 64 2010-03-01 19:55 ls1.c
-rw------- 1 javier javier 558646 2010-03-06 20:38 ProgUnix-Ficheros.pdf
drwxr-xr-x 3 javier javier 4096 2010-03-07 12:15 prueba
The directory with I want to check if my program works,it's called "prueba"


javier@javier-desktop:~/LABSC$ ls -l prueba
total 8
-rw-r--r-- 1 javier javier 0 2010-03-06 20:52 archivo nuevo~
-rw-r--r-- 1 javier javier 7 2010-03-06 22:13 archivo nuevo.c
drwxr-xr-x 2 javier javier 4096 2010-03-06 11:53 carpeta sin título

Running my program and what it shows


javier@javier-desktop:~/LABSC$ ./Listdir prueba
archivo nuevo.c
error en stat: No such file or directory
archivo nuevo~
error en stat: No such file or directory
carpeta sin título
error en stat: No such file or directory

[dwhitney67]

indarkness

When passing a file (or directory) name to stat(), the name needs to include the full path that leads to the file (or directory) if it is not in the current directory.

By default, both scandir() and stat() only examine the current directory. If the file you want to examine is in a different directory, then you need to be explicit.

In your code, change it to do the following:


...

int Listdir(const char *dir)
{
struct dirent** archivos;

int n = scandir(dir, &archivos, 0, alphasort);

if (n > 0)
{
for (int i = 0; i < n; ++i)
{
if (strcmp(archivos[i]->d_name, ".") != 0 &&
strcmp(archivos[i]->d_name, "..") != 0)
{
char fullPath[1024] = {0};

snprintf(fullPath, sizeof(fullPath) - 1, "%s/%s", dir, archivos[i]->d_name);

printf("%s\n",fullPath);

Estadof(fullPath);
}
}
}
else
{
perror("no hay directorios");
}
}

...


P.S. If you want to recursively delve into sub-directories, then you would be better served using opendir() and readdir(), versus using scandir(). (EDIT: Actually, scandir() could be made to work).

[psusi]

First of all,thanks for answering me!!

The error which stat() returns,it's the element that I give the function,it is not a file or directory,and because that it returns this error

I can't understand this sentence. stat() returns an error code telling you WHY it failed. Your code does not check that. You should check that to get a better idea of what is going wrong.

[indarkness]

I can't understand this sentence. stat() returns an error code telling you WHY it failed. Your code does not check that. You should check that to get a better idea of what is going wrong.
ok,I meant,I know what error is giving stat(),but I couldn't understand why it's giving it.Beacuse I think I pass a correct argument.

[dwhitney67]

... Beacuse I think I pass a correct argument.

You're not passing the correct argument; please read my earlier post.

[indarkness]

indarkness

When passing a file (or directory) name to stat(), the name needs to include the full path that leads to the file (or directory) if it is not in the current directory.

By default, both scandir() and stat() only examine the current directory. If the file you want to examine is in a different directory, then you need to be explicit.

In your code, change it to do the following:


...

int Listdir(const char *dir)
{
struct dirent** archivos;

int n = scandir(dir, &archivos, 0, alphasort);

if (n > 0)
{
for (int i = 0; i < n; ++i)
{
if (strcmp(archivos[i]->d_name, ".") != 0 &&
strcmp(archivos[i]->d_name, "..") != 0)
{
char fullPath[1024] = {0};

snprintf(fullPath, sizeof(fullPath) - 1, "%s/%s", dir, archivos[i]->d_name);

printf("%s\n",fullPath);

Estadof(fullPath);
}
}
}
else
{
perror("no hay directorios");
}
}

...
P.S. If you want to recursively delve into sub-directories, then you would be better served using opendir() and readdir(), versus using scandir(). (EDIT: Actually, scandir() could be made to work).

Thank yo very much! So my problem was,I was trying to examine other directory,not the current,wasn't I?
Watching the directories I replied to gmargo,how should I invoke the function to it works correctly?


EDIT: I read your post,but I forgot to send the reply.

[indarkness]

P.S. If you want to recursively delve into sub-directories, then you would be better served using opendir() and readdir(), versus using scandir(). (EDIT: Actually, scandir() could be made to work).
wow how do you know my next step is that?

[psusi]

ok,I meant,I know what error is giving stat(),but I couldn't understand why it's giving it.Beacuse I think I pass a correct argument.

You never said what the error code is and the code you posted does not check it.

[indarkness]

You never said what the error code is and the code you posted does not check it.
Sorry for my bad explanation:icon_frown:

[indarkness]

P.S. If you want to recursively delve into sub-directories, then you would be better served using opendir() and readdir(), versus using scandir(). (EDIT: Actually, scandir() could be made to work).

How could I o it recursively?? I'v tried whit oppendir an readdir, but I can't get it.

[dwhitney67]

Something like:


void dirContents(const char* dirname)
{
DIR* dir = opendir(dirname);

if (dir)
{
struct dirent* entry = 0;

while ((entry = readdir(dir)) != 0)
{
if (strcmp(entry->d_name, ".") == 0 ||
strcmp(entry->d_name, "..") == 0))
{
/* skips the '.' and '..' dirs
continue;
}

if (entry->d_type == DT_DIR)
{
/* found a directory; need to do something 'special'

/* alloc space for the dirname, a slash char, the entry name, and a null-char */
char* newdir = malloc(strlen(dirname) + 1 + strlen(entry->d_name) + 1);

/* build full path for the new entry found */
sprintf(newdir, "%s/%s", dirname, entry->d_name);

/* recursively call dirContents() with the new path
dirContents(newdir);

/* if here, clean up */
free(newdir);
}
else
{
switch (entry->d_type)
{
case DT_REG:
printf("%s: regular file\n", entry->d_name);
break;

/* cases for other DT types */

case DT_UNKNOWN:
default:
printf("%s: unknown type\n", entry->d_name);
break;
}
}
}
}
}