From b2f321c0b832245a9a8a89abbc79a0001f8ba1c2 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Fri, 28 Oct 2022 17:02:08 +0200
Subject: [PATCH] libc: Parse the mode string

---
 libs/libc/src/file.cpp | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/libs/libc/src/file.cpp b/libs/libc/src/file.cpp
index af14e3fc..77b5c9c6 100644
--- a/libs/libc/src/file.cpp
+++ b/libs/libc/src/file.cpp
@@ -3,13 +3,14 @@
 #include <luna.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 FILE* stderr;
 FILE* stdout;
 FILE* stdin;
 
-void file_read_buf(FILE* stream)
+static void file_read_buf(FILE* stream)
 {
     if (!stream->f_buf)
     {
@@ -31,6 +32,29 @@ void file_read_buf(FILE* stream)
     stream->f_bufsize = nread;
 }
 
+static int file_parse_mode(const char* mode)
+{
+    int flags = 0;
+    switch (mode[0])
+    {
+    case 'r': flags |= O_RDONLY; break;
+    case 'w':
+        flags |= O_WRONLY;
+        flags |= O_CREAT;
+        flags |= O_TRUNC;
+        break;
+    case 'a':
+        flags |= O_WRONLY;
+        flags |= O_CREAT;
+        flags |= O_APPEND;
+        break;
+    default: errno = EINVAL; return -1;
+    }
+
+    if (strchr(mode, '+')) flags |= O_RDWR;
+    return flags;
+}
+
 extern "C"
 {
     int fclose(FILE* stream)
@@ -56,7 +80,9 @@ extern "C"
 
     FILE* fopen(const char* pathname, const char* mode)
     {
-        int fd = open(pathname, O_RDWR); // FIXME: Use the mode string.
+        int flags = file_parse_mode(mode);
+        if (flags < 0) return NULL;
+        int fd = open(pathname, flags, 0666); // If we create the file, create it as rw-rw-rw-.
         if (fd < 0) { return 0; }
         return fdopen(fd, mode);
     }
@@ -78,10 +104,12 @@ extern "C"
         return stream;
     }
 
-    FILE* freopen(const char* pathname, const char*,
+    FILE* freopen(const char* pathname, const char* mode,
                   FILE* stream) // FIXME: If pathname is NULL, open the original file with the new mode.
     {
-        int fd = open(pathname, O_RDWR); // FIXME: Use the mode string.
+        int flags = file_parse_mode(mode);
+        if (flags < 0) return NULL;
+        int fd = open(pathname, flags, 0666); // If we create the file, create it as rw-rw-rw-.
         if (fd < 0) { return 0; }
 
         fflush(stream); // To make it future-proof.