From c8e1e71eb526475dd431443345262c2e5a627831 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nnoll523@gmail.com>
Date: Sat, 23 Oct 2021 11:17:25 -0700
Subject: chore(rename): libn -> base

---
 sys/base/mmap.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 sys/base/mmap.c

(limited to 'sys/base/mmap.c')

diff --git a/sys/base/mmap.c b/sys/base/mmap.c
new file mode 100644
index 0000000..6edfe28
--- /dev/null
+++ b/sys/base/mmap.c
@@ -0,0 +1,43 @@
+#include <u.h>
+#include <base.h>
+
+#include <sys/mman.h>
+
+mmap·Reader
+mmap·open(byte *filename)
+{
+    int     fd;
+    int    err;
+    void  *buf;
+    io·Stream  *s;
+    io·Stat     st;
+
+    s   = io·open(filename, "r");
+    fd  = io·fd(s);
+    err = io·stat(s, &st);
+    if (err) {
+        errorf("file stat: error code %d", err);
+        goto ERROR;
+    }
+
+    buf = mmap(nil, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if (!buf) {
+        errorf("mmap: failed");
+        goto ERROR;
+    }
+    // NOTE: posix systems require that reference kept to mmap file after fd is closed
+    io·close(s);
+    return (mmap·Reader){.len=st.st_size, .buf=buf};
+
+ERROR:
+    io·close(s);
+    return (mmap·Reader){ 0 };
+}
+
+error
+mmap·close(mmap·Reader rdr)
+{
+    munmap(rdr.buf, rdr.len);
+
+    return 0;
+}
-- 
cgit v1.2.1