File System (fs) Project
COP-3402

In the following cases, exit immediately with EXIT_FAILURE:

• If there are no arguments to the program
• If there are two arguments but the first is a not the "-l" flag.

In the following cases, skip printing the file

• The file or directory doesn't exist, lacks necessary permissions, or cannot be opened, read, and closed for any other reason

If a construct a new directory tree like this

mkdir contents
mkdir contents/subdir
touch contents/file1
echo -ne "1\n2\n3" > contents/file2
echo -ne "1\n2\n3\n4\n" > contents/subdir/file3

and then run myfind on it like this:

./myfind -l contents

I should see the following output:

contents
contents/subdir
contents/subdir/file3	4
contents/file2	2
contents/file1	0  

Where the space between the file name and the number of lines is a single tab character (\t).

See Grading for some automated test cases.

Be sure to print the entire path for each file, i.e., the given path argument joined with the path separator character ("/").

Do not use helper libraries or other simplified calls to achieve similar results as functions below. Just use the syscalls or library functions below for these aspects of the project.

• man is the command-line manual.
• LPI is The Linux Program Interface book.
• Knowledge of memory management and string processing is assumed.

These are a set of header files that is sufficient for completing the project:

#include <fcntl.h>         // O_RDONLY, O_WRONLY, O_CREAT, open
#include <errno.h>         // errno
#include <stdio.h>         // perror, fprintf
#include <dirent.h>        // opendir, readdir, DIR, struct dirent
#include <stdlib.h>        // exit
#include <sys/stat.h>      // stat
#include <assert.h>        // assert
#include <string.h>        // string.h
#include <unistd.h>        // read, write, close
#include <stdbool.h>       // bool

Be sure when concenating strings for the paths that you malloc enough space for the entire new string plus the additional path separator and plus the null terminator for the string, e.g.,

// len + separator + len + terminator
int concatlen = strlen(curpath) + 1 + strlen(curdir->d_name) + 1;
char *newpath = malloc(concatlen * sizeof(char));
if (NULL == newpath) {
  perror("malloc");
  exit(EXIT_FAILURE);
}
snprintf(newpath, concatlen, "%s/%s", curpath, curdir->d_name);

The grading tests will not put a path separator character at the end of the path, even if its a directory. In testing, if you do have a path separator, then joining by string concanetion may result in a double path separator, e.g., subdir//file, which should be harmless.

Be sure to complete the vc exercise before attempting this project.

Create a new local repository, following the directions in the vc exercise (including the git --set-upstream last step) and set the local and remote repository URLs to be the following locations:

See the hello project for instructions on cloning a project from the grading server.

Implement a file type filter option. This option will either limit the results to either only regular files or only directory files. The option will either be --type f to limit to only regular files or --type d to limit to only regular files. Without this option, there should be no filtering as in the non-bonus project requirements. Here is an example:

Take the following directory structure, where dir1 and dir2 are directory files while file1, file2, and file3 are regular files:

.
├── dir1
│   ├── file1
│   └── file2
├── dir2
└── file3

Running ./myfind --type f . should yield the following (in any order):

./file3
./dir1/file2
./dir1/file1

Running ./myfind --type d . should yield the following (in any order):

.
./dir2
./dir1

• These options will require allowing for up to three arguments by the tool without exiting with an error. This won't affect scoring, since this isn't tested.
• Be sure to allow any ordering of options, i.e., --type, and -l may appear in any order.
• Note that argv will have two separate array slots for the option name and the parameter to that name, e.g., -type and f may be argv[1] and argv[2] respectively. These indices may differ depending on the order of options given by the user on the command-line).
• You may use the getopt library if you want to make option processing easier.
• Bonus points will be graded mechanically, but test cases will not be released. Please develop your own test cases and use the examples given above.
• The file type is not its extension. Where can we see whether the file is a regular file or a directory file?
• The non-bonus requirements for recursively traverses subdirectories and using -l still apply.