Segmentation fault when trying to read hidden files linux - c

Question

My program reads the content of a directory specified at command line. It reads the directory recursively i.e. if we are reading contents of directory "test" and inside it we have another directory "inside", then it will also read the content of the directory named "inside". The issue is it works fine if i do not read hidden directories i.e. directories that start with "." . But in case i read hidden directories too it says Segmentation fault.
The code is as below:
The main file:
#include "helper.h"
/*
* Display's content of String array passed to it,
* that should conatin full path to files.
*/
void display(char **);
/*
* Free's the memory utilized by the program
*/
void cleanup(char **);
int main(int argc, char *argv[])
{
// ensure proper usage
if (argc != 2)
{
printf("Usage: %s [dir]\n\n", argv[0]);
return 1;
}
char **files = calloc(1, sizeof(char *));
// get files from the directory specified
getFiles(&files, argv[1]);
// display files
display(files);
// free memory utilized by files array
cleanup(files);
// that's all folks
return 0;
}
/*
* Display's content of String array passed to it,
* that should conatin full path to files.
*/
void display(char **files)
{
// Color Red
// printf("[0;31;40m");
// display files
for (int i = 0; files[i]; i++)
{
printf("%s\n", files[i]);
}
// turn off color
// printf("[0;37;40m");
}
/*
* Free's the memory utilized by the program
*/
void cleanup(char **files)
{
// free memory utilized by files array
for (int i = 0; files[i]; i++)
free(files[i]);
free(files);
}
The getFiles function is defined in helpers.c file which contain the following code as below:
#include "helper.h"
#include <dirent.h>
#include <stdlib.h>
#include <sys/types.h>
/*
* Stores the list of files present in direectory pointed by 'dir'
* in array of strings pointed by 'files'
*/
void getFiles(char ***files, const char* dir)
{
static int i;
// ensure directory is valid
if (dir == NULL)
{
printf("Error: Invalid Directory\n\n");
exit(1);
}
// declare and initialize directory handler
DIR *dd = opendir(dir);
if (dd == NULL)
{
printf("Error: Directory Not Found\n\n");
exit(2);
}
// structure that store file attributes read
struct dirent *content;
// read directory until all files are scanned
while ((content = readdir(dd)) != NULL)
{
// ignore '.' and '..' directories
if (strcmp(content->d_name, ".") == 0 ||
strcmp(content->d_name, "..") == 0)
continue;
/*if (content->d_name[0] == '.')
continue;*/
//store full file path from current directory
char temp[1024] = {0};
// make full path
makepath(temp, dir, content->d_name);
// recall itself if another directory found
if (isdir(temp))
{
// read this new directory found
getFiles(files, temp);
continue;
}
// allocate memory to store locations of char *
*files = realloc(*files, (i + 2)*(sizeof(char *)));
// allocate heap memory and store location
*(*(files + 0) + i) = (char *)strdup(temp);
// move to next location
i++;
}
// free directory handler
closedir(dd);
// set NULL after last file name
*(*(files + 0) + i) = '\0';
}
/*
* returns true if 'dir' refers to a directory, false otherwise
*/
bool isdir(const char * dir)
{
DIR *temp;
temp = opendir(dir);
if (temp != NULL)
{
closedir(temp);
return true;
}
return false;
}
/*
* appends dir and file/directory name to src,
* thus makes a full file/directory path, from current directory
*/
void makepath(char src[], const char *dir, const char *file)
{
// prepend directory name
strcat(src, dir);
strcat(src, "/");
// append file/directory name
strcat(src, file);
}
Necessary header files are included by me in helper.h file.
Also i wanted to know am i making mistake in memory allocation. (In realloc in getFiles Function).
Ignore hidden files line is commented by me at this time.
/*if (content->d_name[0] == '.')
continue;*/
If i uncomment the above line then program works fine.
If you are thinking why i am storing file names as read by readdir function, because those names are necessary for me later so that is why i am not right away displaying the file names.
Any suggestion how i can better implement this program and also how to fix the issue that occurs when i read hidden directories.

Answer 1

I don't know if that's the problem but here:
// set NULL after last file name
*(*(files + 0) + i) == '\0';
^ you are not setting to NULL, you are comparing