1 files changed, 98 insertions, 0 deletions
diff --git a/sys/syscall_initrd_file.c b/sys/syscall_initrd_file.c
new file mode 100644
index 0000000..8e34488
--- /dev/null
+++ b/sys/syscall_initrd_file.c
@@ -0,0 +1,98 @@
+#include "api/error.h"
+#include "boot/initrd.h"
+#include "lib/printf.h"
+#include "sys/message.h"
+#include "sys/syscall.h"
+#include "lib/string.h"
+
+int
+s_syscall_initrd_file_name(
+        jove_owned_obj_t *initrd_file,
+        jove_owned_obj_t *message)
+{
+    const char *filename = initrd_file_name(initrd_file);
+    size_t filename_len = strlen(filename);
+
+    size_t bytes_left = message_len(message);
+    size_t bytes_needed = filename_len + sizeof(struct syscall_initrd_file_name_ret);
+
+    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message is too small for file name.");
+    struct syscall_initrd_file_name_ret *payload = message_data(message);
+
+    payload->len = filename_len;
+    memcpy(payload->c_str, filename, filename_len);
+    return 0;
+}
+
+int
+s_syscall_initrd_file_size(jove_owned_obj_t *initrd_file)
+{
+    return initrd_file_size(initrd_file);
+}
+
+int
+s_syscall_initrd_file_read(
+        jove_owned_obj_t *initrd_file,
+        jove_owned_obj_t *message,
+        size_t bytes_left,
+        void *payload_data)
+{
+    //Ensure that the message payload could hold the required read payload.
+    size_t bytes_needed = sizeof(struct syscall_initrd_file_read);
+    CHECK_TOOSMALL(bytes_needed, bytes_left, 
+            "Message is too small to hold read payload.");
+
+    struct syscall_initrd_file_read *payload = payload_data;
+    bytes_needed = payload->read_size;
+    bytes_left = message_len(message);
+
+    //Ensure that the message is big enough to hold the read file data.
+    CHECK_TOOSMALL(bytes_needed, bytes_left,
+            "Message is too small to hold read bytes.");
+
+    size_t file_size = initrd_file_size(initrd_file);
+    char *file_data = initrd_file_data(initrd_file);
+
+    //Ensure that the start index is within the file.
+    if(payload->start_index >= file_size) {
+        klogf("Start index exceeds file length! (%i > %i)\n",
+                payload->start_index, file_size);
+        return -EOOB;
+    }
+
+    //Ensure that the read bounds is within the file.
+    if(payload->start_index + payload->read_size > file_size) {
+        klogf("Read bounds exceed file length! (%i+%i > %i)\n",
+                payload->start_index, payload->read_size, file_size);
+        return -ETOOBIG;
+    }
+    
+    void *read_data = message_data(message);
+    memcpy(read_data, file_data + payload->start_index, payload->read_size);
+    return 0;
+}
+
+int
+_syscall_handle_initrd_file(syscall_context_t *ctx)
+{
+    switch(ctx->header->callid) {
+        case SYSCALL_INITRD_FILE_NAME:
+            if(ctx->target.permissions & SYSCALL_PERM_INITRD_FILE_NAME)
+                return s_syscall_initrd_file_name(
+                        ctx->target.obj, ctx->message.obj);
+            return -EPERM;
+        
+        case SYSCALL_INITRD_FILE_SIZE:
+            if(ctx->target.permissions & SYSCALL_PERM_INITRD_FILE_SIZE)
+                return s_syscall_initrd_file_size(ctx->target.obj);
+            return -EPERM;
+
+        case SYSCALL_INITRD_FILE_READ:
+            if(ctx->target.permissions & SYSCALL_PERM_INITRD_FILE_READ)
+                return s_syscall_initrd_file_read(
+                        ctx->target.obj, ctx->message.obj, ctx->bytes_left, ctx->payload);
+            return -EPERM;
+        default:
+            return -EBADCALL;
+    }
+}