Handle disk partitioning

kernel/diskpart/diskpart.c

@@ -0,0 +1,15 @@
+#include <stdint.h>
+#include <stddef.h>
+#include "storedev/storedev.h"
+#include "mbr.h"
+#include "util/util.h"
+#include "kprintf.h"
+
+void diskpart_init(void) {
+  LOG("diskpart", "probing for disks with partitions\n");
+
+  StoreDev *sd, *sdtmp;
+  LL_FOREACH_SAFE(STOREDEV_LIST.head, sd, sdtmp) {
+    diskpart_mbr_probe(sd);
+  }
+}

kernel/diskpart/diskpart.h

@@ -0,0 +1,6 @@
+#ifndef DISKPART_DISKPART_H_
+#define DISKPART_DISKPART_H_
+
+void diskpart_init(void);
+
+#endif // DISKPART_DISKPART_H_

kernel/diskpart/mbr.c

@@ -0,0 +1,77 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+#include "storedev/storedev.h"
+#include "mbr.h"
+#include "diskpart.h"
+#include "compiler/attr.h"
+#include "errors.h"
+#include "kprintf.h"
+#include "hal/hal.h"
+#include "util/util.h"
+#include "dev/dev.h"
+
+typedef struct {
+  uint8_t driveattrs;
+  uint8_t chs_start_addr[3];
+  uint8_t parttype;
+  uint8_t chs_last_sect_addr[3];
+  uint32_t startlba;
+  uint32_t sectorcount;
+} PACKED PTE;
+
+typedef struct {
+  uint8_t bootcode[440];
+  uint8_t signature[4];
+  uint8_t resv[2];
+  PTE pte1;
+  PTE pte2;
+  PTE pte3;
+  PTE pte4;
+  uint8_t validsign[2];
+} PACKED MBR;
+
+void diskpart_mbr_expose_partitions(StoreDev *sd, MBR *mbr) {
+  PTE *parts[4] = { &mbr->pte1, &mbr->pte2, &mbr->pte3, &mbr->pte4 };
+
+  for (size_t i = 0; i < 4; i++) {
+    char *name = NULL;
+    spinlock_acquire(&DEVTABLE.spinlock);
+    for (size_t i = 0; i < LEN(DEVTABLE.devs); i++) {
+      Dev *dev = &DEVTABLE.devs[i];
+      if (dev->extra == sd) {
+        name = (char *)dev->ident;
+      }
+    }
+    spinlock_release(&DEVTABLE.spinlock);
+
+    PartSdInitExtra extra = {
+      .parent = sd,
+      .sectorcount = parts[i]->sectorcount,
+      .startsector = parts[i]->startlba,
+    };
+
+    char name1[100];
+    ksprintf(name1, "%s-part%zu", name, i+1);
+    kprintf("%s\n", name1);
+    storedev_create(STOREDEV_PARTSD, name1, &extra);
+  }
+}
+
+bool diskpart_mbr_probe(StoreDev *sd) {
+  LOG("diskpart", "probing for MBR\n");
+
+  MBR mbr;
+  hal_memset(&mbr, 0, sizeof(mbr));
+  sd->read(sd, (uint8_t *const)&mbr, 0, 0, sizeof(mbr));
+
+  if (!(mbr.validsign[0] == 0x55 && mbr.validsign[1] == 0xAA)) {
+    return false;
+  }
+
+  LOG("diskpart", "got valid MBR on %s\n", storedev_strings[sd->sdtype]);
+
+  diskpart_mbr_expose_partitions(sd, &mbr);
+
+  return true;
+}

kernel/diskpart/mbr.h

@@ -0,0 +1,9 @@
+#ifndef DISKPART_MBR_H_
+#define DISKPART_MBR_H_
+    
+#include <stdbool.h>
+#include "storedev/storedev.h"
+
+bool diskpart_mbr_probe(StoreDev *sd);
+
+#endif // DISKPART_MBR_H_