Hack together open()

sw/kernel/filesystems/fat32.h

@@ -43,4 +43,8 @@ int8_t fat32_get_cluster_by_name(char* name, struct fat32_directory_entry* dentr
 int8_t fat32_read_cluster(uint32_t cluster, void* buf);
 uint32_t fat32_next_cluster(uint32_t cluster);
 
+int8_t fat32_file_open(const int8_t* filename);
+int8_t fat32_file_read(int8_t fd, const void* buf, int8_t nbytes);
+int8_t fat32_file_write(int8_t fd, const void* buf, int8_t nbytes);
+int8_t fat32_file_close(int8_t fd);
 #endif

sw/kernel/filesystems/fat32_c.c

@@ -1,10 +1,67 @@
-#include "fat32.h"
-
 #include <devices/sd_card.h>
+#include <process/process.h>
 #include <conio.h>
 #include <stdint.h>
 #include <string.h>
 
+#include "fat32.h"
+#include "fs.h"
+
+static struct fops fat32_file_ops = {fat32_file_open, fat32_file_close, fat32_file_read, fat32_file_write};
+
+int8_t fd_val;
+
+
+//TODO
+int8_t fat32_file_write(int8_t fd, const void* buf, int8_t nbytes) {
+    return -1;
+}
+
+int8_t fat32_file_close(int8_t fd) {
+    return -1;
+}
+
+int8_t fat32_file_open(const int8_t* filename) {
+    int8_t ret;
+    int8_t i;
+    int8_t fd;
+
+    struct fat32_directory_entry dentry;
+
+    struct pcb* pcb = get_pcb_ptr();
+
+    ret = fat32_get_cluster_by_name(filename, &dentry);
+    if (ret) {
+        cprintf("Error finding cluster for filename");
+        return -1;
+    }
+
+    /* try to find an empty file desciptor, fail otherwise */
+    //TODO We start at 3 here because 0, 1, 2 will be reserved later
+    for (i = 3; i < FILE_DESC_SIZE; i++) {
+        if (pcb->file_desc_array[i].flags == !IN_USE) {
+            fd = i;
+            break;
+        }
+    }
+    if (fd == -1){
+        return -1;
+    }
+
+    /* add process */
+    pcb->file_desc_array[fd].f32_dentry = dentry;
+    pcb->file_desc_array[fd].flags = IN_USE;
+    pcb->file_desc_array[fd].file_pos = 0;
+
+    pcb->file_desc_array[fd].file_ops = &fat32_file_ops;
+
+    return fd;
+}
+
+int8_t fat32_file_read(int8_t fd, const void* buf, int8_t nbytes) {
+    struct pcb* pcb = get_pcb_ptr();
+}
+
 int8_t fat32_read_cluster(uint32_t cluster, void* buf) {
     uint8_t error;
     uint32_t addr = (cluster - 2) + data_start_sector;

sw/kernel/filesystems/fs.h

@@ -3,16 +3,18 @@
 
 #include <stdint.h>
 
+#include <process/process.h>
+
 /* syscalls for files */
 int8_t file_read(int8_t fd, void* buf, int8_t nbytes);
 int8_t file_write(int8_t fd, const void* buf, int8_t nbytes);
-int8_t file_open(const uint8_t* filename);
+int8_t file_open(const int8_t* filename);
 int8_t file_close(int8_t fd);
 
 /* syscalls for directories */
 int8_t directory_read(int8_t fd, void* buf, int8_t nbytes);
 int8_t directory_write(int8_t fd, const void* buf, int8_t nbytes);
-int8_t directory_open(const uint8_t* filename);
+int8_t directory_open(const int8_t* filename);
 int8_t directory_close(int8_t fd);
 
 

sw/kernel/process/process.c

@@ -0,0 +1,6 @@
+#include <process/process.h>
+
+
+struct pcb* get_pcb_ptr() {
+    return 0;
+}

sw/kernel/process/process.h

@@ -0,0 +1,46 @@
+#ifndef _PROCESS_H
+#define _PROCESS_H
+
+#include <stdint.h>
+
+#include <filesystems/fat32.h>
+
+#define FILE_DESC_SIZE      8
+
+
+#define IN_USE              1
+
+
+struct fops {
+    int8_t (*open)(const int8_t* filename);
+    int8_t (*close)(int8_t fd);
+    int8_t (*read)(int8_t fd, void* buf, int8_t nbytes);
+    int8_t (*write)(int8_t fd, const void* buf, int8_t nbytes);
+};
+
+struct file_desc {
+    struct fops* file_ops;
+    uint8_t fs_type;
+    union {
+        struct fat32_directory_entry f32_dentry;
+    };
+    uint32_t file_pos;
+    uint32_t flags;
+};
+
+/* Process Control Block struct */
+struct pcb {
+    struct file_desc file_desc_array[FILE_DESC_SIZE];
+    int32_t is_vidmapped;
+    uint8_t args[128];
+    uint32_t execute_return;
+    int32_t pid;
+    int32_t parent_pid;
+    uint32_t parent_esp;
+    uint32_t parent_ebp;
+};
+
+
+struct pcb* get_pcb_ptr();
+
+#endif