How to get total size of subdirectories in C? - c

Question

Is there a way to get the total size of subdirectories with recursivity?
For example:
Dir1
-- FileA.txt (90)
-- SubDir2 (4096)
---- FileB.txt (100)
---- FileC.txt (400)
When I try to get the size of SubDir2, it gives me 4186. The expected answer I wish to get is 4596.
My program counts the size of FileA instead of FileB and FileC. How to make it count FileB and FileC?
To start, I have to use these headers:
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
Then, I made this function to call it recursively:
static DIR *dir;
void goDir(char* argv[])
{
struct dirent *dit;
struct stat st;
int size = 0;
static int total_size = 0;
char filePath[NAME_MAX];
while ((dit = readdir(dir)) != NULL)
{
sprintf(filePath, "%s/%s", argv[1], dit->d_name); // To show correctly the size and name of files
lstat(filePath, &st);
// To skip . and ..
if ( (strcmp(dit->d_name, ".") == 0) || (strcmp(dit->d_name, "..") == 0) ) continue;
size = st.st_size;
if(S_ISDIR(st.st_mode))
{
goDir(argv); // For Recursivity
total_size += size;
printf("DIR\t");
printf("MODE: %lo\t", (unsigned long) st.st_mode);
printf("SIZE: %d\t", total_size);
printf("%s\n", dit->d_name);
}
else
{
total_size += size;
printf("FILES\t");
printf("MODE: %lo\t", (unsigned long) st.st_mode);
printf("SIZE: %d\t", size);
printf("%s\n", dit->d_name);
}
}
}
And then, my main program:
int main (int argc, char *argv[])
{
if ( argc != 2 ) {
printf("Usage: Program <Directory>\n");
return 1;
}
if ((dir = opendir(argv[1])) == NULL) return 1;
goDir(argv);
closedir(dir);
return 0;
}

Answer 1

Your goDir() function never opens a new directory, or closes the directory once it has finished. That is going to lead to problems — basically, you are not traversing down your directory hierarchy.
You'll need to make dir a local (non-static) variable in the goDir() function; you'll open and close directories; and instead of passing argv, you'll pass a directory name, etc.
While you're at it, you should change goDir() to return the size it finds, and lose the static variable total_size.
This code looks semi-plausible:
#include <stdio.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#ifndef NAME_MAX
#define NAME_MAX 1024
#endif
static long goDir(char *dirname)
{
DIR *dir = opendir(dirname);
if (dir == 0)
return 0;
struct dirent *dit;
struct stat st;
long size = 0;
long total_size = 0;
char filePath[NAME_MAX];
while ((dit = readdir(dir)) != NULL)
{
if ( (strcmp(dit->d_name, ".") == 0) || (strcmp(dit->d_name, "..") == 0) )
continue;
sprintf(filePath, "%s/%s", dirname, dit->d_name);
if (lstat(filePath, &st) != 0)
continue;
size = st.st_size;
if (S_ISDIR(st.st_mode))
{
long dir_size = goDir(filePath) + size;
printf("DIR\t");
printf("MODE: %lo\t", (unsigned long) st.st_mode);
printf("SIZE: %ld\t", dir_size);
printf("%s\n", filePath);
total_size += dir_size;
}
else
{
total_size += size;
printf("FILES\t");
printf("MODE: %lo\t", (unsigned long) st.st_mode);
printf("SIZE: %ld\t", size);
printf("%s\n", filePath);
}
}
return total_size;
}
int main(int argc, char *argv[])
{
if (argc != 2)
{
fprintf(stderr, "Usage: %s <Directory>\n", argv[0]);
return 1;
}
long size = goDir(argv[1]);
printf("Total size: %ld\n", size);
return 0;
}
It compiles and runs. It does not give the same answer as du -k, mainly because it does not round up the size of files to an integral number of disk blocks. You'd need to look at st_blksize and/or st_blocks in the struct stat to get that information.

Answer 2

You'll have to use a hash table to keep track of the occurrences of inodes. So that they are not counted twice.