refactor: one more step towards arch-agnostic design

[lunaix-os.git] / lunaix-os / kernel / fs / iso9660 / file.c

diff --git a/lunaix-os/kernel/fs/iso9660/file.c b/lunaix-os/kernel/fs/iso9660/file.c
index 6813c22a484ad50d27183630fb3a820c85b316d1..34d3b47fcf7cfffa091e4791dc53dc9b5a29a9c3 100644 (file)
--- a/lunaix-os/kernel/fs/iso9660/file.c
+++ b/lunaix-os/kernel/fs/iso9660/file.c
@@ -1,5 +1,9 @@
 #include <lunaix/fs.h>
 #include <lunaix/fs/iso9660.h>
+#include <lunaix/mm/valloc.h>
+#include <lunaix/spike.h>
+
+#include <klibc/string.h>
 
 int
 iso9660_open(struct v_inode* this, struct v_file* file)
@@ -18,15 +22,68 @@ iso9660_close(struct v_file* file)
 int
 iso9660_read(struct v_inode* inode, void* buffer, size_t len, size_t fpos)
 {
-    // TODO
-    return 0;
+    // This read implementation handle both interleaved and non-interleaved
+    // structuring
+
+    struct iso_inode* isoino = inode->data;
+    struct device* bdev = inode->sb->dev;
+
+    len = MIN(fpos + len, inode->fsize);
+    if (len <= fpos) {
+        return 0;
+    }
+
+    len -= fpos;
+
+    size_t fu_len = isoino->fu_size * ISO9660_BLKSZ;
+    // if fpos is not FU aligned, then we must do an extra read.
+    size_t fu_to_read =
+      ICEIL(len, fu_len) + (fpos > fu_len && (fpos % fu_len) != 0);
+    size_t sec = (fpos % fu_len) / ISO9660_BLKSZ;
+    size_t wd_start = fpos % ISO9660_BLKSZ,
+           wd_len = MIN(len, ISO9660_BLKSZ - wd_start), i = 0;
+
+    // how many blocks (file unit + gaps) before of our current read position
+    size_t true_offset = (fpos / fu_len);
+    true_offset = true_offset * (isoino->fu_size + isoino->gap_size);
+
+    void* rd_buffer = valloc(ISO9660_BLKSZ);
+
+    true_offset += sec + inode->lb_addr;
+
+    int errno = 0;
+    while (fu_to_read) {
+        for (; sec < isoino->fu_size && i < len; sec++) {
+            errno = bdev->read(
+              bdev, rd_buffer, true_offset * ISO9660_BLKSZ, ISO9660_BLKSZ);
+
+            if (errno < 0) {
+                errno = EIO;
+                goto done;
+            }
+
+            memcpy(buffer + i, rd_buffer + wd_start, wd_len);
+
+            i += wd_len;
+            true_offset++;
+            wd_start = 0;
+            wd_len = MIN(len - i, ISO9660_BLKSZ);
+        }
+        sec = 0;
+        fu_to_read--;
+    }
+    errno = i;
+
+done:
+    vfree(rd_buffer);
+    return errno;
 }
 
 int
 iso9660_write(struct v_inode* inode, void* buffer, size_t len, size_t fpos)
 {
     // TODO
-    return EROFS;
+    return ENOTSUP;
 }
 
 int