Refactor libc stubs into libwrap

The --wrap feature of GNU ld supports a cleaner framework for linking in
alternative implementations of libc functions without cpp hacks.
Place wrappers in separate object files to reduce static code size.

20 files changed, 250 insertions, 0 deletions

diff --git a/bsp/libwrap/sys/_exit.c b/bsp/libwrap/sys/_exit.c
new file mode 100644
index 0000000..7261891
--- /dev/null
+++ b/bsp/libwrap/sys/_exit.c
@@ -0,0 +1,17 @@
+/* See LICENSE of license details. */
+
+#include <unistd.h>
+#include "platform.h"
+
+void __wrap__exit(int code)
+{
+//volatile uint32_t* leds = (uint32_t*) (GPIO_BASE_ADDR + GPIO_OUT_OFFSET);
+  const char message[] = "\nProgam has exited with code:";
+//*leds = (~(code));
+
+  write(STDERR_FILENO, message, sizeof(message) - 1);
+  write_hex(STDERR_FILENO, code);
+  write(STDERR_FILENO, "\n", 1);
+
+  for (;;);
+}
diff --git a/bsp/libwrap/sys/close.c b/bsp/libwrap/sys/close.c
new file mode 100644
index 0000000..e4f8e14
--- /dev/null
+++ b/bsp/libwrap/sys/close.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_close(int fd)
+{
+  return _stub(EBADF);
+}
diff --git a/bsp/libwrap/sys/execve.c b/bsp/libwrap/sys/execve.c
new file mode 100644
index 0000000..6178a01
--- /dev/null
+++ b/bsp/libwrap/sys/execve.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_execve(const char* name, char* const argv[], char* const env[])
+{
+  return _stub(ENOMEM);
+}
diff --git a/bsp/libwrap/sys/fork.c b/bsp/libwrap/sys/fork.c
new file mode 100644
index 0000000..13a3e65
--- /dev/null
+++ b/bsp/libwrap/sys/fork.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int fork(void)
+{
+  return _stub(EAGAIN);
+}
diff --git a/bsp/libwrap/sys/fstat.c b/bsp/libwrap/sys/fstat.c
new file mode 100644
index 0000000..6ea3e6a
--- /dev/null
+++ b/bsp/libwrap/sys/fstat.c
@@ -0,0 +1,16 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include "stub.h"
+
+int __wrap_fstat(int fd, struct stat* st)
+{
+  if (isatty(fd)) {
+    st->st_mode = S_IFCHR;
+    return 0;
+  }
+
+  return _stub(EBADF);
+}
diff --git a/bsp/libwrap/sys/getpid.c b/bsp/libwrap/sys/getpid.c
new file mode 100644
index 0000000..5aa510b
--- /dev/null
+++ b/bsp/libwrap/sys/getpid.c
@@ -0,0 +1,6 @@
+/* See LICENSE of license details. */
+
+int __wrap_getpid(void)
+{
+  return 1;
+}
diff --git a/bsp/libwrap/sys/isatty.c b/bsp/libwrap/sys/isatty.c
new file mode 100644
index 0000000..55eab0a
--- /dev/null
+++ b/bsp/libwrap/sys/isatty.c
@@ -0,0 +1,11 @@
+/* See LICENSE of license details. */
+
+#include <unistd.h>
+
+int __wrap_isatty(int fd)
+{
+  if (fd == STDOUT_FILENO || fd == STDERR_FILENO)
+    return 1;
+
+  return 0;
+}
diff --git a/bsp/libwrap/sys/kill.c b/bsp/libwrap/sys/kill.c
new file mode 100644
index 0000000..9c56632
--- /dev/null
+++ b/bsp/libwrap/sys/kill.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_kill(int pid, int sig)
+{
+  return _stub(EINVAL);
+}
diff --git a/bsp/libwrap/sys/link.c b/bsp/libwrap/sys/link.c
new file mode 100644
index 0000000..9340cad
--- /dev/null
+++ b/bsp/libwrap/sys/link.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_link(const char *old_name, const char *new_name)
+{
+  return _stub(EMLINK);
+}
diff --git a/bsp/libwrap/sys/lseek.c b/bsp/libwrap/sys/lseek.c
new file mode 100644
index 0000000..46f58fa
--- /dev/null
+++ b/bsp/libwrap/sys/lseek.c
@@ -0,0 +1,14 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "stub.h"
+
+off_t __wrap_lseek(int fd, off_t ptr, int dir)
+{
+  if (isatty(fd))
+    return 0;
+
+  return _stub(EBADF);
+}
diff --git a/bsp/libwrap/sys/open.c b/bsp/libwrap/sys/open.c
new file mode 100644
index 0000000..d1871f9
--- /dev/null
+++ b/bsp/libwrap/sys/open.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_open(const char* name, int flags, int mode)
+{
+  return _stub(ENOENT);
+}
diff --git a/bsp/libwrap/sys/openat.c b/bsp/libwrap/sys/openat.c
new file mode 100644
index 0000000..7f1c945
--- /dev/null
+++ b/bsp/libwrap/sys/openat.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_openat(int dirfd, const char* name, int flags, int mode)
+{
+  return _stub(ENOENT);
+}
diff --git a/bsp/libwrap/sys/read.c b/bsp/libwrap/sys/read.c
new file mode 100644
index 0000000..4e57f08
--- /dev/null
+++ b/bsp/libwrap/sys/read.c
@@ -0,0 +1,30 @@
+/* See LICENSE of license details. */
+
+#include <stdint.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "platform.h"
+#include "stub.h"
+
+ssize_t __wrap_read(int fd, void* ptr, size_t len)
+{
+  uint8_t * current = (uint8_t *)ptr;
+  volatile uint32_t * uart_rx = (uint32_t *)(UART0_BASE_ADDR + UART_REG_RXFIFO);
+  volatile uint8_t * uart_rx_cnt = (uint8_t *)(UART0_BASE_ADDR + UART_REG_RXCTRL + 2);
+
+  ssize_t result = 0;
+
+  if (isatty(fd)) {
+    for (current = (uint8_t *)ptr;
+        (current < ((uint8_t *)ptr) + len) && (*uart_rx_cnt > 0);
+        current ++) {
+      *current = *uart_rx;
+      result++;
+    }
+    return result;
+  }
+
+  return _stub(EBADF);
+}
diff --git a/bsp/libwrap/sys/sbrk.c b/bsp/libwrap/sys/sbrk.c
new file mode 100644
index 0000000..6e6b36a
--- /dev/null
+++ b/bsp/libwrap/sys/sbrk.c
@@ -0,0 +1,16 @@
+/* See LICENSE of license details. */
+
+#include <stddef.h>
+
+void *__wrap_sbrk(ptrdiff_t incr)
+{
+  extern char _end[];
+  extern char _heap_end[];
+  static char *curbrk = _end;
+
+  if ((curbrk + incr < _end) || (curbrk + incr > _heap_end))
+    return NULL - 1;
+
+  curbrk += incr;
+  return curbrk - incr;
+}
diff --git a/bsp/libwrap/sys/stat.c b/bsp/libwrap/sys/stat.c
new file mode 100644
index 0000000..1ccc2f4
--- /dev/null
+++ b/bsp/libwrap/sys/stat.c
@@ -0,0 +1,10 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include <sys/stat.h>
+#include "stub.h"
+
+int __wrap_stat(const char* file, struct stat* st)
+{
+  return _stub(EACCES);
+}
diff --git a/bsp/libwrap/sys/stub.h b/bsp/libwrap/sys/stub.h
new file mode 100644
index 0000000..fb5e5be
--- /dev/null
+++ b/bsp/libwrap/sys/stub.h
@@ -0,0 +1,10 @@
+/* See LICENSE of license details. */
+#ifndef _SIFIVE_SYS_STUB_H
+#define _SIFIVE_SYS_STUB_H
+
+static inline int _stub(int err)
+{
+  return -1;
+}
+
+#endif /* _SIFIVE_SYS_STUB_H */
diff --git a/bsp/libwrap/sys/times.c b/bsp/libwrap/sys/times.c
new file mode 100644
index 0000000..26a9566
--- /dev/null
+++ b/bsp/libwrap/sys/times.c
@@ -0,0 +1,10 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include <sys/times.h>
+#include "stub.h"
+
+clock_t __wrap_times(struct tms* buf)
+{
+  return _stub(EACCES);
+}
diff --git a/bsp/libwrap/sys/unlink.c b/bsp/libwrap/sys/unlink.c
new file mode 100644
index 0000000..b62b1ba
--- /dev/null
+++ b/bsp/libwrap/sys/unlink.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_unlink(const char* name)
+{
+  return _stub(ENOENT);
+}
diff --git a/bsp/libwrap/sys/wait.c b/bsp/libwrap/sys/wait.c
new file mode 100644
index 0000000..ea3225b
--- /dev/null
+++ b/bsp/libwrap/sys/wait.c
@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int wait(int* status)
+{
+  return _stub(ECHILD);
+}
diff --git a/bsp/libwrap/sys/write.c b/bsp/libwrap/sys/write.c
new file mode 100644
index 0000000..d00eb17
--- /dev/null
+++ b/bsp/libwrap/sys/write.c
@@ -0,0 +1,29 @@
+/* See LICENSE of license details. */
+
+#include <stdint.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "platform.h"
+#include "stub.h"
+
+ssize_t __wrap_write(int fd, const void* ptr, size_t len)
+{
+  const uint8_t * current = (const char *)ptr;
+
+  if (isatty(fd)) {
+    for (size_t jj = 0; jj < len; jj++) {
+      while (UART0_REG(UART_REG_TXFIFO) & 0x80000000) ;
+      UART0_REG(UART_REG_TXFIFO) = current[jj];
+
+      if (current[jj] == '\n') {
+        while (UART0_REG(UART_REG_TXFIFO) & 0x80000000) ;
+        UART0_REG(UART_REG_TXFIFO) = '\r';
+      }
+    }
+    return len;
+  }
+
+  return _stub(EBADF);
+}