atmega_common: provide implementation for POSIX syscalls

cpu/atmega_common/posix_unistd.c

+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @brief   Implements various POSIX syscalls
+ * @author  Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifdef MODULE_VFS
+#include "vfs.h"
+#elif defined(MODULE_UART_STDIO)
+#include "uart_stdio.h"
+#endif
+
+int close(int fd)
+{
+#ifdef MODULE_VFS
+    int res = vfs_close(fd);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#else
+    (void)fd;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+off_t lseek(int fd, off_t off, int whence)
+{
+#ifdef MODULE_VFS
+    off_t res = vfs_lseek(fd, off, whence);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#else
+    (void)fd;
+    (void)off;
+    (void)whence;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+int fcntl(int fd, int cmd, int arg)
+{
+#ifdef MODULE_VFS
+    int res = vfs_fcntl(fd, cmd, arg);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#else
+    (void)fd;
+    (void)cmd;
+    (void)arg;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+int fstat(int fd, struct stat *buf)
+{
+#ifdef MODULE_VFS
+    int res = vfs_fstat(fd, buf);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#else
+    (void)fd;
+    (void)buf;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+ssize_t read(int fd, void *dest, size_t count)
+{
+#ifdef MODULE_VFS
+    ssize_t res = vfs_read(fd, dest, count);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#elif defined(MODULE_UART_STDIO)
+    if (fd == 0) {
+        return uart_stdio_read(dest, count);
+    }
+    errno = EBADF;
+    return -1;
+#else
+    (void)fd;
+    (void)dest;
+    (void)count;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+ssize_t write(int fd, const void *src, size_t count)
+{
+#ifdef MODULE_VFS
+    ssize_t res = vfs_write(fd, src, count);
+    if (res < 0) {
+        errno = -res;
+        return -1;
+    }
+    return res;
+#elif defined(MODULE_UART_STDIO)
+    if (fd == 0) {
+        return uart_stdio_write(src, count);
+    }
+    errno = EBADF;
+    return -1;
+#else
+    (void)fd;
+    (void)src;
+    (void)count;
+    errno = ENODEV;
+    return -1;
+#endif
+}
+
+/** @} */