Go Premium for a chance to win a PS4. Enter to Win

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 587
  • Last Modified:

NEED HELP READING DIRECTORY CONTENTS RECURSIVELY

Hi everyone!

This is my problem:
I'm trying to read the contents of a directory recursively and below is my code so far... I'm sure I have a lot of mistakes but could anyone help me? When I run this program I get Segmentation fault ! What should I do???


DIR* directory;
struct dirent* pdirent;
struct stat  Stat;

void perform( char* A )
{

        if(stat(A , &Stat) < 0)
        {
                printf("Error !!!!");
                return;
        }

        directory = opendir(A);
        while( (pdirent = readdir(directory)) != NULL)
        {

                if((pdirent -> d_name != ".") && (pdirent->d_name != ".."))
                {
                        printf("%s \n" , pdirent -> d_name);

                        if(S_ISDIR(Stat.st_mode))
                        {
                                perform(pdirent-> d_name);

                        }
                 }
        }

        closedir(directory);

}


In main I call perform( argv[1] )



I'd appreciate any help !!!
0
akiskal
Asked:
akiskal
2 Solutions
 
ravenscr98Commented:
First, make your variables local to the function.  Each directory needs its own DIR* pointer, otherwise when you backtrack from the recursive call the variable directory has changed its value.

Also, when you test to see if the current file name is a directory in order to recursively descend, you are testing Stat for the current directory you are in, not for the file name you have just read.

Look at those two issues.  If you still get a seg fault, figure out where it is and I'm sure one of the experts here can help.
0
 
Karl Heinz KremerCommented:
THere are a few more problems: You cannot compare strings with != - you need to use strcmp(), also, when you call perform() recursively, you are only passing in the subdirectory, and not the whole directory (consisting of the base dirctory (A) plus the subdir.
0
 
Karl Heinz KremerCommented:
Try this:

#include <sys/stat.h>
#include <sys/types.h>
#include <stdio.h>
#include <dirent.h>
#include <linux/limits.h>

void
perform (char *A)
{
  DIR *directory;
  struct dirent *pdirent;
  struct stat Stat;
  directory = opendir (A);
  while ((pdirent = readdir (directory)) != NULL)
    {
      if (strcmp (pdirent->d_name, ".") && strcmp (pdirent->d_name, ".."))
        {
          printf ("%s \n", pdirent->d_name);
          char newpath[PATH_MAX];
          sprintf (newpath, "%s/%s", A, pdirent->d_name);
          if (stat (newpath, &Stat) < 0)
            {
              printf ("Error !!!!\n");
              return;
            }
          if (S_ISDIR (Stat.st_mode))
            {
              perform (newpath);
            }
        }
    }
  closedir (directory);
}

int
main (int argc, char *argv[])
{
  perform (argv[1]);
}

But keep in mind that I'm not doing any error checking. As soon as you try to e.g. traverse into a directory that you cannot read, it will segfault. But other than that it does work correctly. There was another problem with the call to stat(): You only called it for the directory, but not for any of the directory entries you read.
0
What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

 
Alf666Commented:
The following will work. But you have a lot to learn. I suggest you examine line by line...

#include <sys/types.h>
#include <dirent.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>

void perform( char* A )
{
  DIR *directory;
  struct dirent *pdirent;
  struct stat Stat;
  struct stat fileStat ;
  char fileName[FILENAME_MAX] ;

  if(stat(A , &Stat) < 0) {
    perror(A);
    return;
  }

  directory = opendir(A);

  while ((pdirent = readdir(directory)) != NULL) {

    if (strncmp(pdirent->d_name, ".", 1)
      && strncmp(pdirent->d_name, "..", 2)) {

      if (snprintf(fileName, FILENAME_MAX, "%s/%s", A, pdirent->d_name)
        >= FILENAME_MAX) {
      fprintf(stderr, "File name too long : %s", fileName) ;
      return ;
      }

      if(stat(fileName , &fileStat) < 0) {
      perror(fileName);
      continue ;
      }
      printf("%s \n" , fileName);
     
      if(S_ISDIR(fileStat.st_mode)) {
      printf("doing : %s\n" , fileName);
      perform(fileName);
      }

    }
  }
  closedir(directory);
}


main(int argc, char **argv) {

  perform( argv[1] ) ;
}
0
 
akiskalAuthor Commented:
Thanks very much guys I really appreciate your help!!!!  

khkremer I made a mistake when I accepted tha last answer and I didn't give you any points!!! I'm really sorry but I really thank you for your help!

Everything worked fine with Alf666 's code and now I can go on with my work! Thanks again guys!
0
 
Karl Heinz KremerCommented:
You can post a request in the Support area (see the link at the top of the page) and have them re-open this question (happens all the time). This will allow you to accept the correct answer(s) again.  
0

Featured Post

NEW Veeam Backup for Microsoft Office 365 1.5

With Office 365, it’s your data and your responsibility to protect it. NEW Veeam Backup for Microsoft Office 365 eliminates the risk of losing access to your Office 365 data.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now