From eb00ca816f642fa48c0fff2e32cce54a49f04987 Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benpicco@googlemail.com>
Date: Mon, 24 Aug 2020 23:53:10 +0200
Subject: [PATCH] picolibc: enable read/write etc. functions without VFS

The read()/write() functions still work without VFS when
reading/writing to stdin, stdout or stderr.

Provide dummy functions for the remaining fs functions so
linking does not fail with !VFS.
---
 sys/picolibc_syscalls_default/syscalls.c | 80 ++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 5 deletions(-)

diff --git a/sys/picolibc_syscalls_default/syscalls.c b/sys/picolibc_syscalls_default/syscalls.c
index 1782610d08..a54397d2bf 100644
--- a/sys/picolibc_syscalls_default/syscalls.c
+++ b/sys/picolibc_syscalls_default/syscalls.c
@@ -23,6 +23,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <sys/times.h>
+#include <unistd.h>
 
 #include "log.h"
 #include "periph/pm.h"
@@ -55,8 +56,8 @@ _exit(int n)
 __attribute__ ((weak))
 int kill(pid_t pid, int sig)
 {
-    (void) pid;
-    (void) sig;
+    (void)pid;
+    (void)sig;
     errno = ESRCH;                         /* not implemented yet */
     return -1;
 }
@@ -129,6 +130,9 @@ pid_t getpid(void)
 
 #if MODULE_VFS
 #include "vfs.h"
+#else
+#include <sys/stat.h>
+#endif
 
 /**
  * @brief Open a file
@@ -144,6 +148,7 @@ pid_t getpid(void)
  */
 int open(const char *name, int flags, int mode)
 {
+#ifdef MODULE_VFS
     int fd = vfs_open(name, flags, mode);
     if (fd < 0) {
         /* vfs returns negative error codes */
@@ -151,6 +156,13 @@ int open(const char *name, int flags, int mode)
         return -1;
     }
     return fd;
+#else
+    (void)name;
+    (void)flags;
+    (void)mode;
+    errno = ENODEV;
+    return -1;
+#endif
 }
 
 /**
@@ -167,6 +179,7 @@ int open(const char *name, int flags, int mode)
  */
 _READ_WRITE_RETURN_TYPE read(int fd, void *dest, size_t count)
 {
+#ifdef MODULE_VFS
     int res = vfs_read(fd, dest, count);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -174,6 +187,14 @@ _READ_WRITE_RETURN_TYPE read(int fd, void *dest, size_t count)
         return -1;
     }
     return res;
+#else
+    if (fd != STDIN_FILENO) {
+        errno = ENOTSUP;
+        return -1;
+    }
+
+    return stdio_read(dest, count);
+#endif
 }
 
 /**
@@ -190,6 +211,7 @@ _READ_WRITE_RETURN_TYPE read(int fd, void *dest, size_t count)
  */
 _READ_WRITE_RETURN_TYPE write(int fd, const void *src, size_t count)
 {
+#ifdef MODULE_VFS
     int res = vfs_write(fd, src, count);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -197,6 +219,14 @@ _READ_WRITE_RETURN_TYPE write(int fd, const void *src, size_t count)
         return -1;
     }
     return res;
+#else
+    if (fd != STDOUT_FILENO && fd != STDERR_FILENO) {
+        errno = ENOTSUP;
+        return -1;
+    }
+
+    return stdio_write(src, count);
+#endif
 }
 
 /**
@@ -214,6 +244,7 @@ _READ_WRITE_RETURN_TYPE write(int fd, const void *src, size_t count)
  */
 int close(int fd)
 {
+#ifdef MODULE_VFS
     int res = vfs_close(fd);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -221,6 +252,11 @@ int close(int fd)
         return -1;
     }
     return res;
+#else
+    (void)fd;
+    errno = ENOTSUP;
+    return -1;
+#endif
 }
 
 /**
@@ -250,8 +286,9 @@ clock_t times(struct tms *ptms)
  * @return       0 on success
  * @return       -1 on error, @c errno set to a constant from errno.h to indicate the error
  */
-int fcntl (int fd, int cmd, int arg)
+int fcntl(int fd, int cmd, int arg)
 {
+#ifdef MODULE_VFS
     int res = vfs_fcntl(fd, cmd, arg);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -259,6 +296,13 @@ int fcntl (int fd, int cmd, int arg)
         return -1;
     }
     return res;
+#else
+    (void)fd;
+    (void)cmd;
+    (void)arg;
+    errno = ENOTSUP;
+    return -1;
+#endif
 }
 
 /**
@@ -282,6 +326,7 @@ int fcntl (int fd, int cmd, int arg)
  */
 off_t lseek(int fd, _off_t off, int whence)
 {
+#ifdef MODULE_VFS
     int res = vfs_lseek(fd, off, whence);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -289,6 +334,13 @@ off_t lseek(int fd, _off_t off, int whence)
         return -1;
     }
     return res;
+#else
+    (void)fd;
+    (void)off;
+    (void)whence;
+    errno = ENOTSUP;
+    return -1;
+#endif
 }
 
 /**
@@ -304,6 +356,7 @@ off_t lseek(int fd, _off_t off, int whence)
  */
 int fstat(int fd, struct stat *buf)
 {
+#ifdef MODULE_VFS
     int res = vfs_fstat(fd, buf);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -311,6 +364,12 @@ int fstat(int fd, struct stat *buf)
         return -1;
     }
     return 0;
+#else
+    (void)fd;
+    (void)buf;
+    errno = ENOTSUP;
+    return -1;
+#endif
 }
 
 /**
@@ -326,6 +385,7 @@ int fstat(int fd, struct stat *buf)
  */
 int stat(const char *name, struct stat *st)
 {
+#ifdef MODULE_VFS
     int res = vfs_stat(name, st);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -333,6 +393,12 @@ int stat(const char *name, struct stat *st)
         return -1;
     }
     return 0;
+#else
+    (void)name;
+    (void)st;
+    errno = ENODEV;
+    return -1;
+#endif
 }
 
 /**
@@ -345,6 +411,7 @@ int stat(const char *name, struct stat *st)
  */
 int unlink(const char *path)
 {
+#ifdef MODULE_VFS
     int res = vfs_unlink(path);
     if (res < 0) {
         /* vfs returns negative error codes */
@@ -352,6 +419,9 @@ int unlink(const char *path)
         return -1;
     }
     return 0;
+#else
+    (void)path;
+    errno = ENODEV;
+    return -1;
+#endif
 }
-
-#endif /* MODULE_VFS */