can mmap a file now

Author: domspad

iso9660.c

@@ -14,14 +14,21 @@ void *sector(void *baseptr, unsigned int sectornum)
     return &cdimg[sectornum * 2048];
 }
 
-DiskFile * iso9660_enumfiles(void *baseptr)
+const DirectoryRecord *get_first_entry(void *baseptr)
 {
+    
     const PrimaryVolumeDescriptor *pvd = sector(baseptr, 16);
 
     const DirectoryRecord *rootrecord = &pvd->root_directory_record;
     assert(rootrecord->record_len == sizeof(DirectoryRecord) + rootrecord->id_len);
 
     const DirectoryRecord *entry = sector(baseptr, rootrecord->data_sector);
+    return entry;
+}
+
+DiskFile * iso9660_enumfiles(void *baseptr)
+{
+    const DirectoryRecord *entry = get_first_entry(baseptr);
     int i=0;
     do {
         DiskFile *fp = &g_files[i++];

iso9660.h

@@ -89,6 +89,8 @@ typedef struct PACKED PathTableEntry {
     // and then a padding byte if id_len is odd
 } PathTableEntry;
 
+
+const DirectoryRecord *get_first_entry(void *baseptr);
 #define NEXT_PATH_TABLE_ENTRY(E) \
     ((PathTableEntry *) (((u8 *) E) + sizeof(PathTableEntry) + E->id_len + (E->id_len & 0x1)))
 

kmain.c

@@ -1,12 +1,12 @@
 #include "asmhelpers.h"
 #include "kb.h"
 #include "vgatext.h"
-#include "memlib.h"
 #include "video.h"
 #include "ata.h"
 #include "DiskFile.h"
 #include "kernel.h"
 #include "virtualmem.h"
+#include "memlib.h"
 
 extern char START_BSS[], END_BSS[];
 void setup_interrupts(void *idtaddr);
@@ -27,10 +27,10 @@ kmain(void)
     init_ata();
     ata_disk *d = &disks[0];
     mmap_disk(d);
-
-    DiskFile * df = iso9660_fopen_r((void *) 0x100000, "STARWARS.VGA");
+    kprintf("got to here\n");
+    mmap("STARWARS.VGA", 0x70000000);
     setup_timer(30);
-    play_video(df->data + 4000 * 200);
+    play_video(0x70000000 + 4000 * 200);
 
     while (1) yield();
 

memlib.c

@@ -114,3 +114,12 @@ char *strcpy(char * dest, const char * src)
         ;
     return ret;
 }
+
+int
+strcmp(const char *s1, const char *s2)
+{
+    for ( ; *s1 == *s2; s1++, s2++)
+        if (*s1 == '\0')
+            return 0;
+    return ((*(unsigned char *)s1 < *(unsigned char *)s2) ? -1 : +1);
+}

memlib.h

@@ -3,4 +3,23 @@
 
 #include <string.h>
 
+
+void * memcpy(void *_dest, const void *_src, size_t n);
+
+void * memset(void *_dest, int val, size_t length);
+
+void *memmove(void *dest, const void *src, size_t n);
+
+int memcmp(const void *s1, const void *s2, size_t n);
+int strncmp(const char *s1, const char *s2, size_t n);
+int strcmp(const char *s1, const char *s2);
+
+char *strncpy(char *dest, const char *src, size_t n);
+int strlen(const char *s);
+
+char *strchr(const char *s, int c);
+
+char *strcat(char *dest, const char *src);
+
+char *strcpy(char * dest, const char * src);
 #endif

virtualmem.c

@@ -1,6 +1,9 @@
 #include "kernel.h"
 #include "asmhelpers.h"
 #include "ata.h"
+#include "iso9660.h"
+#include "memlib.h"
+#include "virtualmem.h"
 
 #define PAGEDIR_ADDR 0x80000
 #define PT0_ADDR 0x81000
@@ -64,12 +67,44 @@ handle_page_fault()
 
 void
 mmap_disk(ata_disk *d) {
-    uint32_t iso_page_start = 0x100;
     uint32_t page_size = 0x1000;
     uint32_t npages = d->max_lba * d->sector_size / page_size + 1;
-
+    
     for (uint32_t i = 0; i < npages; i++) {
         uint32_t lba = i * page_size / d->sector_size;
-        ptable[i + iso_page_start] = DISK_MEMORY_ADDR_FLAG + (lba << 4); // 0x4[lba]0
+        uint32_t page_table_index = i + (ISO_START >> 12);
+        ptable[page_table_index] = DISK_MEMORY_ADDR_FLAG + (lba << 4); // 0x4[lba]0
+    }
+}
+
+const DirectoryRecord *find_file(const char* filename){
+    
+    const DirectoryRecord *entry = get_first_entry((void*)(uint32_t)(ISO_START) ); 
+    while((entry->record_len > 0)){
+       if( strncmp(filename, entry->id, strlen(filename)) == 0) {
+            return entry;
+       }
+       entry = NEXT_DIR_ENTRY(entry);
+    }
+    return NULL;
+}
+
+int 
+mmap(char *filename, uint32_t virt_addr){
+    // using the mmaped iso, determine the first lba and size of file
+    uint32_t first_lba;
+    uint32_t num_lbas;
+    const DirectoryRecord *entry = find_file(filename);
+    if (entry == NULL){
+        kprintf("can't find %s\n", filename);
+        return -1;
     }
+    first_lba = entry->data_sector;
+    num_lbas = entry->data_len / 2048;
+    kprintf("%s at %x for %d sectors\n", filename, first_lba, num_lbas);
+    // mmap the file to the given virt addr using "the fours" scheme.
+    // (assumes ratio of sector size to page size is 1 : 2
+    for(uint32_t lba = 0; lba < num_lbas; lba += 2)
+        ptable[(virt_addr >> 12) + lba/2] = DISK_MEMORY_ADDR_FLAG + ((first_lba + lba) << 4); //0x4[lba]0
+    return 0;
 }

virtualmem.h

@@ -1,9 +1,10 @@
 #ifndef VIRTUALMEM_H
 #define VIRTUALMEM_H
-
+#define ISO_START 0x100000
 #include "ata.h"
 
 void handle_page_fault(void);
 void setup_paging(void);
 void mmap_disk(ata_disk *d);
+int mmap(char *filename, uint32_t virt_addr);
 #endif