From 3dbaad0a1f27b96462541e1189efe37ffa913e9a Mon Sep 17 00:00:00 2001
From: Albert Ou <albert@sifive.com>
Date: Tue, 13 Dec 2016 15:05:19 -0800
Subject: 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.
---
 bsp/libwrap/libwrap.mk       | 54 ++++++++++++++++++++++++++++++++++++++++++++
 bsp/libwrap/misc/write_hex.c | 19 ++++++++++++++++
 bsp/libwrap/stdlib/malloc.c  | 17 ++++++++++++++
 bsp/libwrap/sys/_exit.c      | 17 ++++++++++++++
 bsp/libwrap/sys/close.c      |  9 ++++++++
 bsp/libwrap/sys/execve.c     |  9 ++++++++
 bsp/libwrap/sys/fork.c       |  9 ++++++++
 bsp/libwrap/sys/fstat.c      | 16 +++++++++++++
 bsp/libwrap/sys/getpid.c     |  6 +++++
 bsp/libwrap/sys/isatty.c     | 11 +++++++++
 bsp/libwrap/sys/kill.c       |  9 ++++++++
 bsp/libwrap/sys/link.c       |  9 ++++++++
 bsp/libwrap/sys/lseek.c      | 14 ++++++++++++
 bsp/libwrap/sys/open.c       |  9 ++++++++
 bsp/libwrap/sys/openat.c     |  9 ++++++++
 bsp/libwrap/sys/read.c       | 30 ++++++++++++++++++++++++
 bsp/libwrap/sys/sbrk.c       | 16 +++++++++++++
 bsp/libwrap/sys/stat.c       | 10 ++++++++
 bsp/libwrap/sys/stub.h       | 10 ++++++++
 bsp/libwrap/sys/times.c      | 10 ++++++++
 bsp/libwrap/sys/unlink.c     |  9 ++++++++
 bsp/libwrap/sys/wait.c       |  9 ++++++++
 bsp/libwrap/sys/write.c      | 29 ++++++++++++++++++++++++
 23 files changed, 340 insertions(+)
 create mode 100644 bsp/libwrap/libwrap.mk
 create mode 100644 bsp/libwrap/misc/write_hex.c
 create mode 100644 bsp/libwrap/stdlib/malloc.c
 create mode 100644 bsp/libwrap/sys/_exit.c
 create mode 100644 bsp/libwrap/sys/close.c
 create mode 100644 bsp/libwrap/sys/execve.c
 create mode 100644 bsp/libwrap/sys/fork.c
 create mode 100644 bsp/libwrap/sys/fstat.c
 create mode 100644 bsp/libwrap/sys/getpid.c
 create mode 100644 bsp/libwrap/sys/isatty.c
 create mode 100644 bsp/libwrap/sys/kill.c
 create mode 100644 bsp/libwrap/sys/link.c
 create mode 100644 bsp/libwrap/sys/lseek.c
 create mode 100644 bsp/libwrap/sys/open.c
 create mode 100644 bsp/libwrap/sys/openat.c
 create mode 100644 bsp/libwrap/sys/read.c
 create mode 100644 bsp/libwrap/sys/sbrk.c
 create mode 100644 bsp/libwrap/sys/stat.c
 create mode 100644 bsp/libwrap/sys/stub.h
 create mode 100644 bsp/libwrap/sys/times.c
 create mode 100644 bsp/libwrap/sys/unlink.c
 create mode 100644 bsp/libwrap/sys/wait.c
 create mode 100644 bsp/libwrap/sys/write.c

(limited to 'bsp/libwrap')

diff --git a/bsp/libwrap/libwrap.mk b/bsp/libwrap/libwrap.mk
new file mode 100644
index 0000000..313ed00
--- /dev/null
+++ b/bsp/libwrap/libwrap.mk
@@ -0,0 +1,54 @@
+# See LICENSE for license details.
+
+ifndef _SIFIVE_MK_LIBWRAP
+_SIFIVE_MK_LIBWRAP := # defined
+
+LIBWRAP_DIR := $(dir $(lastword $(MAKEFILE_LIST)))
+LIBWRAP_DIR := $(LIBWRAP_DIR:/=)
+
+LIBWRAP_SRCS := \
+	stdlib/malloc.c \
+	sys/open.c \
+	sys/lseek.c \
+	sys/read.c \
+	sys/write.c \
+	sys/fstat.c \
+	sys/stat.c \
+	sys/close.c \
+	sys/link.c \
+	sys/unlink.c \
+	sys/execve.c \
+	sys/fork.c \
+	sys/getpid.c \
+	sys/kill.c \
+	sys/wait.c \
+	sys/isatty.c \
+	sys/times.c \
+	sys/sbrk.c \
+	sys/_exit.c \
+	misc/write_hex.c
+
+LIBWRAP_SRCS := $(foreach f,$(LIBWRAP_SRCS),$(LIBWRAP_DIR)/$(f))
+LIBWRAP_OBJS := $(LIBWRAP_SRCS:.c=.o)
+
+LIBWRAP_SYMS := malloc free \
+	open lseek read write fstat stat close link unlink \
+	execve fork getpid kill wait \
+	isatty times sbrk _exit
+
+LIBWRAP := libwrap.a
+
+LINK_DEPS += $(LIBWRAP)
+
+LDFLAGS += $(foreach s,$(LIBWRAP_SYMS),-Wl,--wrap=$(s))
+LDFLAGS += -L. -Wl,--start-group -lwrap -lc -Wl,--end-group
+
+CLEAN_OBJS += $(LIBWRAP_OBJS)
+
+$(LIBWRAP_OBJS): %.o: %.c $(HEADERS)
+	$(CC) $(CFLAGS) $(INCLUDES) -c -o $@ $<
+
+$(LIBWRAP): $(LIBWRAP_OBJS)
+	$(AR) rcs $@ $^
+
+endif # _SIFIVE_MK_LIBWRAP
diff --git a/bsp/libwrap/misc/write_hex.c b/bsp/libwrap/misc/write_hex.c
new file mode 100644
index 0000000..e678bdc
--- /dev/null
+++ b/bsp/libwrap/misc/write_hex.c
@@ -0,0 +1,19 @@
+/* See LICENSE of license details. */
+
+#include <stdint.h>
+#include <unistd.h>
+#include "platform.h"
+
+void write_hex(int fd, uint32_t hex)
+{
+  uint8_t ii;
+  uint8_t jj;
+  char towrite;
+  write(fd , "0x", 2);
+  for (ii = 8 ; ii > 0; ii--) {
+    jj = ii - 1;
+    uint8_t digit = ((hex & (0xF << (jj*4))) >> (jj*4));
+    towrite = digit < 0xA ? ('0' + digit) : ('A' +  (digit - 0xA));
+    write(fd, &towrite, 1);
+  }
+}
diff --git a/bsp/libwrap/stdlib/malloc.c b/bsp/libwrap/stdlib/malloc.c
new file mode 100644
index 0000000..8f4f432
--- /dev/null
+++ b/bsp/libwrap/stdlib/malloc.c
@@ -0,0 +1,17 @@
+/* See LICENSE for license details. */
+
+/* These functions are intended for embedded RV32 systems and are
+   obviously incorrect in general. */
+
+void* __wrap_malloc(unsigned long sz)
+{
+  extern void* sbrk(long);
+  void* res = sbrk(sz);
+  if ((long)res == -1)
+    return 0;
+  return res;
+}
+
+void __wrap_free(void* ptr)
+{
+}
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);
+}
-- 
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