Get rid of libc, take just parts of it

1 files changed, 80 insertions, 2 deletions

diff --git a/app/platform/retarget.cpp b/app/platform/retarget.cpp
index 52be99f..524840e 100644
--- a/app/platform/retarget.cpp
+++ b/app/platform/retarget.cpp
@@ -1,9 +1,22 @@
-extern "C" void vApplicationMallocFailedHook(void)
+#include "unistd.h"
+#include <cassert>
+#include <cstdio>
+#include <cstdlib>
+#include <cerrno>
+#include "third_party/printf/printf.h"
+
+#ifdef errno
+#undef errno
+#endif
+
+int errno{};
+
+extern "C" [[noreturn]] void vApplicationMallocFailedHook(void)
 {
     for (;;);
 }
 
-extern "C" void vApplicationStackOverflowHook(void *task_handle, char *task_name)
+extern "C" [[noreturn]] void vApplicationStackOverflowHook(void *task_handle, char *task_name)
 {
     (void) task_handle;
     (void) task_name;
@@ -13,3 +26,68 @@ extern "C" void vApplicationStackOverflowHook(void *task_handle, char *task_name
 extern "C" void vApplicationIdleHook(void)
 {
 }
+
+extern "C" [[noreturn]] void _exit(int __status)
+{
+    (void) __status;
+    for (;;);
+}
+
+/* func can be NULL, in which case no function information is given.  */
+extern "C" [[noreturn]] void __assert_func (
+        const char *file, int line, const char *func, const char *failedexpr)
+{
+  dprintf(STDERR_FILENO,
+	   "assertion \"%s\" failed: file \"%s\", line %d%s%s\n",
+	   failedexpr, file, line,
+	   func ? ", function: " : "", func ? func : "");
+  abort();
+  /* NOTREACHED */
+}
+
+extern "C" ssize_t read(int fd, void *buf, size_t nbytes)
+{
+    (void) fd;
+    (void) buf;
+    (void) nbytes;
+    errno = ENOSYS;
+    return -1;
+}
+
+extern "C" ssize_t write(int fd, const void *buf, size_t nbytes)
+{
+    (void) fd;
+    (void) buf;
+    (void) nbytes;
+    errno = ENOSYS;
+    return -1;
+}
+
+static void dputchar2(char c, void* fd)
+{
+    write(reinterpret_cast<int>(fd), &c, 1);
+}
+
+static void dputchar(char c, int fd)
+{
+    write(fd, &c, 1);
+}
+
+extern "C" int dprintf(int fd, const char * format, ...)
+{
+    va_list args;
+    va_start(args, format);
+    const int ret = vfctprintf(dputchar2, reinterpret_cast<void *>(fd), format, args);
+    va_end(args);
+    return ret;
+}
+
+extern "C" int vdprintf(int fd, const char * format, va_list args)
+{
+    return vfctprintf(dputchar2, reinterpret_cast<void *>(fd), format, args);
+}
+
+extern "C" void putchar_(char c)
+{
+    dputchar(c, STDIN_FILENO);
+}