Question

Hey everyone. I need to write a POSIX program to search through an entire file system for a specified file starting at the top directory. I’ve got some code which isn’t done at all, but when I run it, and check to see if a particular file is a directory, it’s saying this file which is not at all a directory is a directory and is trying to move into it, causing an error. I’m not sure how I can tell it that this type of file isn’t a directory.

Here’s my code. I know it’s not perfect and I could probably do some things differently in the way of getting the directory names and passing them into the function. Either way, I’m pretty sure I have to do this recursively.

The file in question is /dev/dri/card0 and I’m running this from a Debian virtual machine.

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <time.h>
#include <stdint.h>
#include <locale.h>
#include <langinfo.h>
#include <fcntl.h>
#include <iostream>
#include <stdio.h>
#include <string>
using namespace std; 

void SearchDirectory(string file_Name, string directory){
    string new_Directory = directory; 
    DIR *dirp; 
    dirp = opendir(directory.c_str()); 
    struct dirent *dptr; 
    struct stat statStruct; 

    while(dptr = readdir(dirp)){
        stat(dptr->d_name, &statStruct); 
        if( S_ISDIR(statStruct.st_mode) ){

            string check = dptr->d_name; 
            if ( check.compare(".") == 0 || check.compare("..") == 0 ){
                continue; 
            }
            else{
                cout << dptr->d_name << " is is a directory" << endl; 
                new_Directory.append("/");
                new_Directory.append(dptr->d_name);  
                SearchDirectory(file_Name, new_Directory); 
            }
        }
        else if( S_ISREG(statStruct.st_mode)){
            string check = dptr->d_name; 
            if( check.compare(file_Name) == 0){
                cout << "Found " << file_Name << " in " << directory << "/" << endl; 
            }
        }
    }
}

int main(int argc, char *argv[]){

    if(argc < 2 || argc > 2){
        cerr << "This program will find the specified file." << endl; 
        cerr << "Usage: mysearch <filename>" << endl; 
        return 1; 
    }

    string file_Name = argv[1]; 
    SearchDirectory(file_Name, "/"); 

    return 0; 

}

Answer 1

->d_name returns just the name of the file, not the path to the file. You need to stat (not yet constructed) new_Directory instead of dptr->d_name.

You also have a problem if a directory contains more than one subdirectories. Your construction of new_Directory is incorrect for each subdirectory after the first.

You never closedir your directory handle, so you run out of resources. You should also consider loading the entire directory into an array before recursing to avoid running out of handles.

void SearchDirectory(string directory, string target_File_Name){
    DIR *dirp = opendir(directory.c_str());
    if (!dirp) {
        perror(("opendir " + directory).c_str());
        return;
    }

    struct dirent *dptr;
    while(dptr = readdir(dirp)){
        string file_Name = dptr->d_name;
        string file_Path = directory + "/" + file_Name;

        struct stat statStruct; 
        stat(file_Path.c_str(), &statStruct); 
        if( S_ISDIR(statStruct.st_mode) ){
            if ( file_Name.compare(".") == 0 || file_Name.compare("..") == 0 ){
                continue; 
            }

            SearchDirectory(file_Path, target_File_Name);
        }
        else if( S_ISREG(statStruct.st_mode)){
            if( file_Name.compare(target_File_Name) == 0){
                cout << file_Path << endl;
            }
        }
    }

    closedir(dirp);
}

Update: Added second problem.

Update: Added third problem.

Update: Added code.