Want to fill Structure for Metadata - c

Question

Here i have one directory which has number of files.
I want to fill this files all information in one structure.
I have two structures which are following.
struct files {
char *file_name;
int file_size;
};
typedef struct file_header {
int file_count;
struct files file[variable as per number of files];
} metadata;
i want to make one header which contains all information regarding these files.
like if i have 3 files than i want to make this structure like this in file_count = 3 and how can i allocate second variable value? and want to store file name and file size as per file.
i want file structure like this
file_count = 3
file[0].file_name = "a.txt"
file[0].file_size = 1024
file[1].file_name = "b.txt"
file[1].file_size = 818
file[2].file_name = "c.txt"
file[2].file_size = 452
I have all logic about file name and file size but how can i fill these things in this structure.?
Code :
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
char path[1024] = "/home/test/main/Integration/testing/package_DIR";
//int count = 5;
struct files {
char *file_name;
int file_size;
};
typedef struct file_header {
int file_count;
struct files file[5];
} metadata;
metadata *create_header();
int main() {
FILE *file = fopen("/home/test/main/Integration/testing/file.txt", "w");
metadata *header;
header = create_header();
if(header != NULL)
{
printf("size of Header is %d\n",sizeof(metadata));
}
if (file != NULL) {
if (fwrite(&header, sizeof(metadata), 1, file) < 1) {
puts("short count on fwrite");
}
fclose(file);
}
file = fopen("/home/test/main/Integration/testing/file.txt", "rb");
if (file != NULL) {
metadata header = { 0 };
if (fread(&header, sizeof(header), 1, file) < 1) {
puts("short count on fread");
}
fclose(file);
printf("File Name = %s\n", header.file[0].file_name);
printf("File count = %d\n", header.file_count);
printf("File Size = %d\n", header.file[0].file_size);
}
return 0;
}
metadata *create_header()
{
int file_count = 0;
DIR * dirp;
struct dirent * entry;
dirp = opendir(path);
metadata *header = (metadata *)malloc(sizeof(metadata));
while ((entry = readdir(dirp)) != NULL) {
if (entry->d_type == DT_REG) { /* If the entry is a regular file */
header->file[file_count].file_name = (char *)malloc(sizeof(char)*strlen(entry->d_name));
strcpy(header->file[file_count].file_name,entry->d_name);
//Put static but i have logic for this i will apply later.
header->file[file_count].file_size = 10;
file_count++;
}
}
header->file_count = file_count;
closedir(dirp);
//printf("File Count : %d\n", file_count);
return header;
}
output :
size of Header is 88
ile Name = �~8
File count = 29205120
File Size = -586425488
Its shows different output. so whats problem here?

Answer 1

Among other things, you are using sizeof on a pointer variable, but seem to think that gives you the size of the object being pointed to. It doesn't. To do that, use the asterisk operator to make the expression have the type that the pointer points at:
printf("size of Header is %d\n", sizeof *metadata);
As a side note, notice that sizeof is not a function, so you don't need parenthesis. When you do see parenthesis, that's when they're part of the expression (a cast).

Answer 2

You are not leaving enough room for the null-terminator:
header->file[file_count].file_name = (char *)malloc(sizeof(char)*strlen(entry->d_name));