libc: Implement wrappers for sys_{open,read,write}

read() and close() are in unistd.h, but open() in fnctl.h.
I thought only the definitions for O_SOMETHING were in fnctl.h, but it is as it is.
Don't know why, but let's not anger the Unix gods.

The FILE* C API is pending as well.

apps/src/init.c

@@ -1,3 +1,4 @@
+#include <fcntl.h>
 #include <luna.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -31,17 +32,16 @@ int main()
 
     printf("Opening %s for reading...\n", filename);
 
-    int fd = syscall(SYS_open, filename, 1);
+    int fd = open(filename, O_RDONLY);
     if (fd < 0)
     {
         perror("open");
         // return 1;
     }
-    else { printf("Got fd %d\n", fd); }
 
     char buf[4096];
 
-    ssize_t nread = syscall(SYS_read, fd, sizeof(buf), buf);
+    ssize_t nread = read(fd, buf, sizeof(buf));
     if (nread < 0)
     {
         perror("read");
@@ -56,7 +56,7 @@ int main()
         printf("%s", buf);
     }
 
-    if (syscall(SYS_close, fd) < 0)
+    if (close(fd) < 0)
     {
         perror("close");
         // return 1;

libs/libc/include/fcntl.h

@@ -0,0 +1,17 @@
+#ifndef _FCNTL_H
+#define _FCNTL_H
+
+#define O_RDONLY 1
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    int open(const char*, int);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/sys/types.h

@@ -1,4 +1,8 @@
 #ifndef _SYS_TYPES_H
 #define _SYS_TYPES_H
+
 typedef long int pid_t;
+typedef unsigned long int size_t;
+typedef long int ssize_t;
+
 #endif

libs/libc/include/unistd.h

@@ -1,10 +1,13 @@
 #ifndef _UNISTD_H
 #define _UNISTD_H
+
 #include <sys/types.h>
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
+
     int execv(const char*, char* const[]);
     int execve(const char*, char* const[], char* const[]);
     int execvp(const char*, char* const[]);
@@ -12,7 +15,11 @@ extern "C"
     long syscall(long, ...);
     unsigned int sleep(unsigned int);
 
+    ssize_t read(int, void*, size_t);
+    int close(int);
+
 #ifdef __cplusplus
 }
 #endif
+
 #endif

libs/libc/src/fcntl.cpp

@@ -0,0 +1,11 @@
+#include <fcntl.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+extern "C"
+{
+    int open(const char* pathname, int flags)
+    {
+        return (int)syscall(SYS_open, pathname, flags);
+    }
+}

libs/libc/src/unistd.cpp

@@ -74,4 +74,14 @@ extern "C"
     {
         return msleep(seconds * 1000);
     }
+
+    ssize_t read(int fd, void* buf, size_t count)
+    {
+        return syscall(SYS_read, fd, count, buf); // yes, our read() syscall is in the wrong order.
+    }
+
+    int close(int fd)
+    {
+        return (int)syscall(SYS_close, fd);
+    }
 }