C Modify Array in Struct

Question

I am writing an operating system in C. I have a basic file system using structs. I am writing a command line, and I want a function to create a new file. I have one set up, but it does not work. The struct initializes fine, but it is not added into the folder. Each file is a struct of the file type below:

typedef struct {
    char** content; // Address of the text in the file
    char* name;     // Filename
    size_t size;    // Included from stddef.h - set by the function
} file;

Each directory is a struct of the dir type below:

typedef struct {
    file* files[256]; // The files in the directory
    char* name;       // The directory name
    size_t index;     // The index of the next file - basically the length of the files array - starts at 0
} dir;

My new_file function is as follows:

void new(dir* folder, char* name, char* content) { 
    // Folder is a dir* so we can modify the actual struct, not a copy
    file f;
    f.name = name;
    f.content = &content;
    folder -> files[folder -> index] = &f;
    folder -> index++;
}

I am a beginner at C, but I cannot tell what the problem is. Please help!

More Info

The new function (basically):

void new(char* name, char* content, dir* folder) {
    file new = new_file(name, content);
    add_file(folder, new);
}

The add_file function:

void add_file(dir* folder, file f) {
    folder -> files[folder -> dirnum] = f;
    folder -> dirnum++;
}

The function I call to try and read the file:

char* read(dir* folder, char* name) {
    file f = find_file(*folder, name);
    return f.content;
}

With find_file being:

file find_file(folder, name) {
    for (size_t i = 0; i < folder.filenum; i++) {
        file f = *folder.files[i];
        if (strcmp(f.name, name, '\0')) {
            return f;
        }
    }
}

And strcmp being a string comparison function I wrote.
After some modifications of the source code, the following bug occurs. When you run (in the command line):

new hi file // Same as new("hi", "file", &root)
open hi // Same as read(&root, "hi")

The output is open hi.

When I run the new function, folder.files[0] exists. However, folder.files[0] -> name equals g→. Any idea why?

Answer 1

issue is

void new(dir* folder, char* name, char* content) { 
// Folder is a dir* so we can modify the actual struct, not a copy
   file f;
   .......
   folder -> files[folder -> index] = &f;

here f is in local variable.

storing address of which is not wise thing to do.

alternatively you can do one of these two things

1. easiest is declare global array of files and use them. // only to test its very bad idea but easy enough to check that this solves issue.
2. proper thing is allocate memory using likes of malloc and free it when deleted.

in actual file system this list is mentained on disk. refer easiest file system to study i.e. FAT16

I have used chans FATFS implementation. it is easy to understand. and well documented.