From a04d2c3513ad04e4b68782a890680c18b5137d36 Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Thu, 11 Aug 2016 22:25:18 +0200
Subject: [PATCH] Complete mkfs

---
 programs/mkfs/include/fat32_specs.hpp |  1 +
 programs/mkfs/src/main.cpp            | 67 +++++++++++++++++++++++++--
 2 files changed, 65 insertions(+), 3 deletions(-)
 create mode 120000 programs/mkfs/include/fat32_specs.hpp

diff --git a/programs/mkfs/include/fat32_specs.hpp b/programs/mkfs/include/fat32_specs.hpp
new file mode 120000
index 00000000..66d0787a
--- /dev/null
+++ b/programs/mkfs/include/fat32_specs.hpp
@@ -0,0 +1 @@
+../../../kernel/include/fs/fat32_specs.hpp
\ No newline at end of file
diff --git a/programs/mkfs/src/main.cpp b/programs/mkfs/src/main.cpp
index 962bc4c7..48b22f90 100644
--- a/programs/mkfs/src/main.cpp
+++ b/programs/mkfs/src/main.cpp
@@ -10,6 +10,9 @@
 #include <errors.hpp>
 #include <io.hpp>
 #include <print.hpp>
+#include <math.hpp>
+
+#include "fat32_specs.hpp"
 
 static constexpr const size_t BUFFER_SIZE = 4096;
 
@@ -32,11 +35,69 @@ int main(int argc, char* argv[]){
         if(code){
             printf("mkfs: error: %s\n", std::error_message(code));
             exit(1);
-        } else {
-            printf("mkfs: Creating Fat32 filesystem on %s\n", device_str);
-            printf("mkfs: device size: %m\n", size);
         }
 
+        printf("mkfs: Creating Fat32 filesystem on %s\n", device_str);
+        printf("mkfs: Device size: %m\n", size);
+
+        uint64_t sector_size = 512;
+        uint64_t sectors_per_cluster = 8;
+        uint64_t sectors = size / sector_size;
+
+        uint64_t available_sectors = sectors - sectors_per_cluster;
+        uint64_t available_clusters = available_sectors / sectors_per_cluster;
+
+        // Compute the size of the FAT
+        uint64_t fat_size_bytes = available_clusters * sizeof(uint32_t);
+        uint64_t fat_size_sectors = std::ceil_divide(fat_size_bytes, sector_size);
+        uint64_t fat_size_clusters = std::ceil_divide(fat_size_sectors, sectors_per_cluster);
+        fat_size_sectors = fat_size_clusters * sectors_per_cluster;
+
+        printf("mkfs: Device sectors : %u\n", sectors);
+        printf("mkfs: Available sectors : %u\n", available_sectors);
+        printf("mkfs: FAT sectors : %u\n", fat_size_sectors);
+
+        uint64_t free_clusters = available_clusters - fat_size_clusters - 1;
+        uint64_t free_sectors = free_clusters * sectors_per_cluster;
+
+        printf("mkfs: Free sectors : %u\n", free_sectors);
+        printf("mkfs: Free clusters : %u\n", free_clusters);
+
+        auto* fat_bs = new fat32::fat_bs_t();
+
+        fat_bs->bytes_per_sector = sector_size;
+        fat_bs->sectors_per_cluster = sectors_per_cluster;
+        fat_bs->reserved_sectors = sectors_per_cluster - 2;
+        fat_bs->number_of_fat = 1;
+        fat_bs->root_directories_entries = 0;
+        fat_bs->total_sectors = 0;
+        fat_bs->total_sectors_long = sectors;
+        fat_bs->sectors_per_fat = 0;
+        fat_bs->sectors_per_fat_long = fat_size_sectors;
+        fat_bs->root_directory_cluster_start = 2;
+        fat_bs->fs_information_sector = 1;
+        std::copy_n(&fat_bs->file_system_type[0], "FAT32", 5);
+        fat_bs->signature = 0xAA55;
+
+        // TODO Write fat_bs to write
+
+        auto* fat_is = new fat32::fat_is_t();
+
+        fat_is->allocated_clusters = 1;
+        fat_is->free_clusters = free_clusters;
+        fat_is->signature_start = 0x52526141;
+        fat_is->signature_middle = 0x72724161;
+        fat_is->signature_end = 0x000055AA;
+
+        // TODO Write fat_bs
+
+        //TODO Write FAT
+
+        //TODO Write Root Cluster
+
+        delete fat_is;
+        delete fat_bs;
+
         exit(0);
     }