Created student weenix repository

1 files changed, 66 insertions, 0 deletions

diff --git a/user/lib/ld-weenix/ldalloc.c b/user/lib/ld-weenix/ldalloc.c
new file mode 100644
index 0000000..c5e79e7
--- /dev/null
+++ b/user/lib/ld-weenix/ldalloc.c
@@ -0,0 +1,66 @@
+/*
+ *  File: ldalloc.c
+ *  Date: 28 March 1998
+ *  Acct: David Powell (dep)
+ *  Desc: simple allocation routines
+ */
+
+#include "ldalloc.h"
+#include "ldutil.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+static unsigned long start;
+static unsigned long pos;
+static unsigned long amount;
+
+/* This function initializes the simple memory allocator.  We basically
+ * allocate a specified number of pages to use as scratch memory for
+ * the linker itself.  No deallocation functionality is provided; the
+ * amount of memory used should be small, and is usually needed for the
+ * duration of the program's execution, anyway.
+ *
+ * All this function does is mmap the specified number of pages of
+ * /dev/zero to provide the memory for our little memory-wading-pool. */
+
+void _ldainit(unsigned long pagesize, unsigned long pages)
+{
+    amount = pagesize * pages;
+    pos = 0;
+
+    start = (unsigned long)mmap(NULL, amount, PROT_READ | PROT_WRITE,
+                                MAP_PRIVATE | MAP_ANON, -1, 0);
+    if (start == (unsigned long)MAP_FAILED)
+    {
+        fprintf(stderr, "ld-weenix: panic - unable to map /dev/zero\n");
+        exit(1);
+    }
+}
+
+/* This function allocates a block of memory of the specified size from
+ * our memory pool.  The memory is word-aligned, and cannot be freed. */
+
+void *_ldalloc(unsigned long size)
+{
+    unsigned long next;
+
+    if (size & 3)
+    {
+        size = (size & ~3) + 4;
+    }
+
+    if (pos + size > amount)
+    {
+        fprintf(stderr,
+                "ld.so.1: panic - unable to allocate %lu bytes (_ldalloc)\n",
+                size);
+        exit(1);
+    }
+
+    next = start + pos;
+    pos += size;
+
+    return (void *)next;
+}