Current working directory

问题

I am currently building some code that traverses through directorys listing all files and paths and file sizes. I am now stuck with the final part of the traverse process which is the if statement to make the code go into any encountered directories.

do {
    char *filename = entry->d_name;
    stat(filename,&buffer);
    if (S_ISDIR(buffer.st_mode)) {
        name = entry->d_name;
        chdir(name);
        if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
            continue;
        listdir(name);     //THIS IS THE NAME OF THE FUNCTION THAT THIS SNIPPET IT FROM!
        chdir("..");
    }
    else
        printf("%s\t%d\n", entry->d_name,buffer.st_size);

Am so confused by trying to get it to cd into the directory that it encounters! ARGH!

回答1:

The problem, when I executed, was stat() was failing.

This worked for me:

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

void listdir(const char* const name);

int main(void)
{
    listdir(getenv("PWD"));
    return 0;
}

void listdir(const char* const name)
{
    DIR *dir;
    struct dirent *entry;
    struct stat buffer;
    char* path = 0;

    if (!(dir = opendir(name)))
        return;
    if (!(entry = readdir(dir)))
        return;

    do {
        path =
            malloc((strlen(name) + strlen(entry->d_name) + 2) * sizeof(char));
        sprintf(path, "%s/%s", name, entry->d_name);

        if (-1 == stat(path,&buffer))
        {
            fprintf(stderr, "stat(%s) failed: %s\n",
                path, strerror(errno));
            exit(1);
        }
        else if (S_ISDIR(buffer.st_mode))
        {
            if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0)
            {
                listdir(path);
            }
        }
        else
        {
            printf("%s\t%d\n", path, buffer.st_size);
        }
        free(path);
    } while (entry = readdir(dir));
    closedir(dir);
}

EDIT:

Removed call to chdir() as realised it was superfluous. This does provide listing but does not do it using chdir().

回答2:

First, you should use lstat. Second, with your chdir(name) call, you actually do go up into parent direectories (when name=".."), but never go back down.

回答3:

The problems lie in this code:

if (S_ISDIR(buffer.st_mode)) {
    name = entry->d_name;
    chdir(name);
    if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
        continue;
    listdir(name);     //THIS IS THE NAME OF THE FUNCTION THAT THIS SNIPPET IT FROM!
    chdir("..");
}

This is embedded in a do-while loop, but you don't show us how the directory entry is read.

The strcmp() conditions should be applied to the current directory before doing a chdir(); that is a 'dangerous' operation. When you're sure that you need to process the directory, then you can do chdir(), open a new directory stream, and process entries from the new stream - which is probably a recursive call, and then chdir() back again. Your jump after you've done chdir(..) (because you didn't check for .. before doing the chdir(name)) is going to wreak havoc on things.

You should look up fchdir() which might be better for the purpose of getting back to where you started.

来源：https://stackoverflow.com/questions/8460166/current-working-directory

标签

traversal