1 files changed, 79 insertions, 0 deletions

diff --git a/src/kernel/drive.c b/src/kernel/drive.c
index bc1c67d..6a1d12e 100644
--- a/src/kernel/drive.c
+++ b/src/kernel/drive.c
@@ -1,5 +1,7 @@
 #include "drive.h"
 #include "panic.h"
+#include "pmap.h"
+#include "util.h"
 #include "fat.h"
 #include "log.h"
 
@@ -40,6 +42,7 @@ static inline void determine_fs(struct drive *d) {
   if (try_fat_init_drive(d))
     return;
 
+  d->mapped_to = 0;
   d->fs_type = "Unknown";
   d->get_file = &unknown_get_file;
   d->free_file = &unknown_no_call;
@@ -58,7 +61,83 @@ static inline void determine_fs(struct drive *d) {
 //do not need to make ready or done
 void commit_drive(struct drive data) {
   determine_fs(&data);
+  data.mapped_to = 0;
   drives[n_drives] = data;
   data.done(drives + n_drives);
   ++n_drives;
+}
+
+void map_path(const char *full, struct drive **d, const char **path) {
+  *d = 0;
+  *path = 0;
+
+  switch (full[0]) {
+  case '/':
+    for (struct drive *i = drives; i < drives + n_drives; ++i) {
+      if (!i->mapped_to)
+        continue;
+      uint32_t j = 0;
+      while (1) {
+        if (!i->mapped_to[j]) {
+          if (!*path || (j >= *path - full)) {
+            *path = full + j + 1;
+            *d = i;
+          }
+          break;
+        }
+        else if (i->mapped_to[j] != full[j + 1])
+          break;
+        ++j;
+      }
+    }
+    return;
+
+    uint32_t id;
+  case ':':
+    id = 0;
+    for (uint32_t i = 1; i < 9; ++i) {
+      id *= 16;
+      const char c = full[i];
+      if ((c >= '0') && (c <= '9'))
+        id += c - '0';
+      else if ((c >= 'a') && (c <= 'f'))
+        id += c - 'a' + 10;
+      else
+        return;
+    }
+    if (full[9] != ':')
+      return;
+    for (struct drive *i = drives; i < drives + n_drives; ++i)
+      if (i->uid == id) {
+        *d = i;
+        *path = full + 10;
+        return;
+      }
+  }
+}
+
+void map_drives() {
+  for (struct drive *d = drives; d < drives + n_drives; ++d) {
+    file_id_t fid = d->get_file(d, "_fstab");
+    if (!fid)
+      continue;
+
+    const uint32_t len = d->get_file_length(d, fid);
+    void *fstab = allocate_kernel_pages(len / 512 + 1);
+    fmcpy(fstab, d, fid, 0, len);
+    d->free_file(d, fid);
+    const uint32_t n_entries = *(uint32_t *)fstab;
+
+    uint32_t next_id = *(uint32_t *)(fstab + 4);
+    fstab += 8;
+    for (uint32_t i = 0; i < n_entries; ++i) {
+      for (struct drive *dd = drives; dd < drives + n_drives; ++dd)
+        if (dd->uid == next_id)
+          dd->mapped_to = fstab + 4;
+      const uint32_t plen = *(uint32_t *)fstab;
+      next_id = *(uint32_t *)(fstab + 4 + plen);
+      *(char *)(fstab + 4 + plen) = '\0';
+      fstab += 8 + plen;
+    }
+  }
 }
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