RossComputerGuy/stardustos

/**
 * NewLand Kernel - (C) 2019 Tristan Ross
 */
#include <newland/arch/proc.h>
#include <newland/fs/procfs.h>
#include <newland/alloc.h>
#include <newland/fs.h>
#include <newland/errno.h>
#include <stdio.h>
#include <string.h>

static list_t procs = { NULL };

static void procfs_cleanup() {
    if (liblist_length(&procs) != process_count()) {
        for (size_t i = 0; i < liblist_length(&procs); i++) {
            fs_node_t* node = (fs_node_t*)liblist_get(&procs, i);
            proc_t* proc = process_get(i);
            char name[NAME_MAX];
            snprintf(name, NAME_MAX, "%lu", proc->id);
            if (node->impl == NULL || !!strcmp(name, node->name)) {
                liblist_remove(&procs, node);
                kfree(node);
                continue;
            }
        }
    }
}

static int procfs_get_child(fs_node_t* node, fs_node_t** childptr, size_t index) {
    procfs_cleanup();
    if (liblist_indexof(&procs, node) == -1) {
        // TODO: add /self symlink
        if (index >= process_count()) return -NEWLAND_ENOENT;
        if (liblist_get(&procs, index) == NULL) {
            char name[NAME_MAX];
            snprintf(name, NAME_MAX, "%lu", index);
            int r = fs_node_create(childptr, name, 6 << FS_NODE_DIR);
            if (r < 0) return r;
            (*childptr)->impl = process_get(index);
            r = liblist_add(&procs, *childptr);
            if (r < 0) {
                kfree(*childptr);
                return r;
            }
            return 0;
        } else {
          *childptr = (fs_node_t*)liblist_get(&procs, index);
            return 0;
        }
    }
    return -NEWLAND_ENOENT;
}

static int procfs_mount(fs_node_t** targetptr, fs_node_t* source, unsigned long flags, const void* data) {
    int r = fs_node_create(targetptr, "/", 6 << FS_NODE_DIR);
    if (r < 0) return r;
    (*targetptr)->opts.get_child = procfs_get_child;
    return 0;
}

static int procfs_umount(fs_node_t** targetptr) {
    kfree(*targetptr);
    *targetptr = NULL;
    return 0;
}

static fs_opts_t procfs_opts = { .mount = procfs_mount, .umount = procfs_umount };

int procfs_init() {
    return register_fs("procfs", FS_PSEUDO, procfs_opts);
}