Linked list of leaf files and directories in a dir tree using C - linked-list

Question

I'm using nftw(file tree walk) for traversing a dir(which has sub-directories and files). I've passed a directory using CLI function. Now I need to store the leaf files and dirs(empty dirs) into a linked list and print them out. I've create a function for nftw called as disp & passed it to nftw so that it'll print out some info about the files. The linked list stores the info of file produced by stat & for printing the linked Linked list printll function is used.
For files I can check that typeflag == FTW_F and then enter the following but how do I check empty directories in nftw and add them to the linked list?
I've tried the following
#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <ftw.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
typedef struct node{
long ino; //Inode number
long f_size; //file size
long a_tm; //Access time
long m_tm; //Modify time
long c_tm; //change time
struct node *next;
}node;
node *tmp = NULL;
static node *head = NULL;
void printll(node *head);
//display function
static int disp(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw);
//Function to create linked list
static int linked(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw);
/* ------------------Main---------------------*/
int main(int argc, char *argv[]){
int flags = 0;
if(argc > 2 && strchr(argv[2], 'd') != NULL)
flags |= FTW_DEPTH;
printf("File_type\tF_size\t\tPath\t\t\t\t\t\t\tInode\n");
if(nftw((argc < 2) ? "." : argv[1], disp, 20, flags) == -1) {
perror("nftw");
return -1;
}
printf("\n");
// nftw((argc < 2) ? "." : argv[1], linked, 20, flags);
printll(tmp);
exit(EXIT_SUCCESS);
}
static int disp(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw){
printf("%-3s\t\t%7jd\t\t%-40s\t\t%ld\n",
(typeflag == FTW_D) ? "d" : (typeflag == FTW_F) ? "f": "???",
s->st_size, fpath, s->st_ino);
struct dirent *r;
if(typeflag == FTW_F){ //How to check empty dirs here?
if(head == NULL){
head = malloc(sizeof(node));
head->ino = s->st_ino;
head->f_size = s->st_size;
head->a_tm = s->st_atime;
head->m_tm = s->st_mtime;
head->c_tm = s->st_ctime;
head->next = NULL;
tmp = head;
} else if(head != NULL) {
if(tmp != NULL){
node *ptr = malloc(sizeof(node));
ptr->ino = s->st_ino;
ptr->f_size = s->st_size;
ptr->a_tm = s->st_atime;
ptr->m_tm = s->st_mtime;
ptr->c_tm = s->st_ctime;
ptr->next = NULL;
tmp->next = ptr;
tmp = tmp->next;
}
}
while(tmp != NULL){
printf("%ld\n", tmp->ino);
printf("%ld\n", tmp->f_size);
printf("%ld\n", tmp->a_tm);
printf("%ld\n", tmp->m_tm);
printf("%ld\n", tmp->c_tm);
tmp = tmp->next;
}
}
return 0;
}
void printll(node *head){
node *ptr;
if(head == NULL)
printf("The linked list is NULL\n");
ptr = head;
while(ptr != NULL){
printf("%ld\n", ptr->ino);
printf("%ld\n", ptr->f_size);
printf("%ld\n", ptr->a_tm);
printf("%ld\n", ptr->m_tm);
printf("%ld\n", ptr->c_tm);
ptr = ptr->next;
}
}

Answer 1

Here's the code for creaiting the linked list using ftw
#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <libgen.h>
#include <ftw.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
typedef struct node{
long ino;
long f_size;
long a_tm;
long m_tm;
long c_tm;
struct node *next;
}node;
node *c, *tmp = NULL, *loc;
static node *head = NULL;
void printll(node *head); //printing of linked list
static int disp(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw);
static int linked(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw);
void add_at_end(node *p);
/* ------------------Main---------------------*/
int main(int argc, char *argv[]){
int flags = 0;
if(argc > 2 && strchr(argv[2], 'd') != NULL)
flags |= FTW_DEPTH;
printf("File_type\tF_size\t\tPath\t\t\t\t\t\t\tInode\n");
if(nftw((argc < 2) ? "." : argv[1], disp, 20, flags) == -1) {
perror("nftw");
return -1;
}
nftw((argc < 2) ? "." : argv[1], linked, 20, flags);
printf("\n");
printll(tmp);
int num, fd;
char f_name[100], dest[100], str_ent[100];
char c, dl;
struct stat fb;
while(1){
printf("1. Add a file\n");
printf("2. Delete a file\n");
printf("3. Add a directory\n");
printf("4. Delete a directory\n");
printf("Enter the operation num to perform\n");
scanf(" %d", &num);
switch(num){
case 1:
printf("File Name: ");
scanf("%s", f_name);
printf("Destination: ");
scanf("%s", dest);
strcat(dest, f_name);
open(dest, O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
printf("File %s is successfully added.\n", f_name);
printf("Do you want to write to this file (Y/N)? \n");
scanf(" %c", &c);
if(c == 'y' || c == 'Y'){
FILE *f;
f = fopen(dest, "w");
printf("How many lines do you want to enter: ");
scanf("%d", &num);
printf("Enter content\n");
for(int i = 0; i < num+1; i++){
fgets(str_ent, sizeof str_ent, stdin);
fputs(str_ent, f);
}
printf("The content you entered is written to the file\n");
fclose(f);
stat(dest, &fb);
loc = malloc(sizeof(node));
loc->ino = fb.st_ino;
loc->f_size = fb.st_size;
loc->a_tm = fb.st_atime;
loc->m_tm = fb.st_mtime;
loc->c_tm = fb.st_ctime;
loc->next = NULL;
node *b;
b = tmp;
while(b->next != NULL)
b = b->next;
b->next = loc;
printf("File added to linked list successfully\n");
break;
} else if( c == 'n' || c == 'N'){
stat(dest, &fb);
loc = malloc(sizeof(node));
loc->ino = fb.st_ino;
loc->f_size = fb.st_size;
loc->a_tm = fb.st_atime;
loc->m_tm = fb.st_mtime;
loc->c_tm = fb.st_ctime;
loc->next = NULL;
node *b;
b = tmp;
while(b->next != NULL)
b = b->next;
b->next = loc;
printf("File added to linked list successfully\n");
free(loc);
break;
}
case 2:
printf("File Name: ");
scanf("%s", f_name);
printf("Destination: ");
scanf("%s", dest);
strcat(dest, f_name);
stat(dest, &fb);
printf("The inode for removed file is: %ld\n", fb.st_ino);
loc = malloc(sizeof(node));
loc->ino = fb.st_ino;
loc->f_size = fb.st_size;
loc->a_tm = fb.st_atime;
loc->m_tm = fb.st_mtime;
loc->c_tm = fb.st_ctime;
loc->next = NULL;
if(loc->ino == tmp->ino){
tmp = tmp->next;
printf("The node is shifted to next and break is here\n");
break;
} else {
node *bu, *cu;
bu = tmp; //tmp
cu = tmp; //tmp2
while(cu->ino != loc->ino){
bu = cu;
cu = cu->next;
}
bu->next = cu->next;
free(cu);
cu = NULL;
unlink(dest);
printf("File %s has been removed & linked list it updated.\n", f_name);
break;
}
case 3:
printf("Dir Name: ");
scanf("%s", f_name);
printf("\nDestination: ");
scanf("%s", dest);
strcat(dest, f_name);
mkdir(dest, 00700);
stat(dest, &fb);
loc = malloc(sizeof(node));
loc->ino = fb.st_ino;
loc->f_size = fb.st_size;
loc->a_tm = fb.st_atime;
loc->m_tm = fb.st_mtime;
loc->c_tm = fb.st_ctime;
loc->next = NULL;
printf("Directory %s successfully added at %s\n", f_name, dest);
break;
case 4:
printf("Dir Name: ");
scanf("%s", f_name);
printf("Destination: ");
scanf("%s", dest);
rmdir(dest);
printf("The directory has been deleted successfully\n");
break;
default:
printf("Operation doesn't exits\n");
exit(0);
}
printf("Do you want to continue with file operations (Y/N)? ");
scanf(" %c", &c);
if(c == 'y' || c == 'Y')
continue;
else
break;
}
while(1){
printf("Do you want to print Director structure OR Linked List (D/L)? ");
scanf(" %c", &dl);
if(dl == 'd' || dl == 'D')
nftw((argc < 2) ? "." : argv[1], disp, 20, flags);
if(dl == 'l' || dl == 'L')
printll(tmp);
printf("Do you want to continue the print? ");
scanf(" %c", &c);
if(c == 'y' || c == 'Y')
continue;
else
break;
}
free(tmp);
exit(EXIT_SUCCESS);
}
/* ----------------Main exit--------------------*/
/* ----------------Display Dir tree structure --------------------*/
static int disp(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw){
printf("%-3s\t\t%7jd\t\t%-40s\t\t%ld\n",
(typeflag == FTW_D) ? "d" : (typeflag == FTW_F) ? "f": "???",
s->st_size, fpath, s->st_ino);
return 0;
}
/* ----------------xx-xx-------------------*/
/* -----------------Linked list function ----------------- */
static int linked(const char *fpath,
const struct stat *s,
int typeflag,
struct FTW *ftw){
struct dirent *r;
DIR *d;
int files = 0;
if(typeflag == FTW_D){
d= opendir(fpath);
while((r = readdir(d)) != NULL)
files++;
}
if(typeflag == FTW_F || files == 2){
if(head == NULL){
head = malloc(sizeof(node));
head->ino = s->st_ino;
head->f_size = s->st_size;
head->a_tm = s->st_atime;
head->m_tm = s->st_mtime;
head->c_tm = s->st_ctime;
head->next = NULL;
tmp = head;
} else if(head != NULL) {
node *c = (struct node *)malloc(sizeof(node));
c->ino = s->st_ino;
c->f_size = s->st_size;
c->a_tm = s->st_atime;
c->m_tm = s->st_mtime;
c->c_tm = s->st_ctime;
c->next = NULL;
add_at_end(c);
}
}
return 0;
}
/* ------------------xx-------xx--------------------------- */
/* ---------------function to add at end ---------------- */
void add_at_end(node *p){
node *c2 = (struct node *)malloc(sizeof(node));
c2 = tmp;
while(c2->next != NULL)
c2 = c2->next;
c2->next = p;
}
/* --------------------------x--x-------------------------*/
/* -----------------------Printing linked list ------------------------- */
void printll(node *head){
node *ptr;
if(head == NULL)
printf("The linked list is NULL\n");
ptr = head;
while(ptr != NULL){
printf("%ld\n", ptr->ino);
printf("%ld\n", ptr->f_size);
printf("%ld\n", ptr->a_tm);
printf("%ld\n", ptr->m_tm);
printf("%ld\n", ptr->c_tm);
ptr = ptr->next;
printf("\n");
}
}
/* ------------------------x---x--------------------------------------- */