libc: Add backtrace_symbols[_fd] functions

specified here:
https://linux.die.net/man/3/backtrace_symbols

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

include/execinfo.h

@@ -59,6 +59,9 @@ extern "C"
 #define EXTERN extern
 #endif
 
+FAR char **backtrace_symbols(FAR void *const *buffer, int size);
+void backtrace_symbols_fd(FAR void *const *buffer, int size, int fd);
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

libs/libc/misc/Make.defs

@@ -36,7 +36,7 @@ endif
 
 CSRCS += lib_dumpbuffer.c lib_dumpvbuffer.c lib_fnmatch.c lib_debug.c
 CSRCS += lib_crc64.c lib_crc32.c lib_crc16.c lib_crc8.c lib_crc8ccitt.c
-CSRCS += lib_crc8table.c lib_glob.c
+CSRCS += lib_crc8table.c lib_glob.c lib_execinfo.c
 
 # Keyboard driver encoder/decoder
 

libs/libc/misc/lib_execinfo.c

@@ -0,0 +1,90 @@
+/****************************************************************************
+ * libs/libc/misc/lib_execinfo.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <execinfo.h>
+#include <stdio.h>
+
+#include "libc.h"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static FAR char **backtrace_malloc(FAR void *const *buffer, int size)
+{
+  size_t length = 0;
+
+  if (size <= 0)
+    {
+      return NULL;
+    }
+
+  while (size-- > 0)
+    {
+      int ret = sprintf(NULL, "%pS", *buffer++);
+      if (ret < 0)
+        {
+          return NULL;
+        }
+
+      length += sizeof(FAR char *) + ret + 1;
+    }
+
+  return lib_malloc(length);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+FAR char **backtrace_symbols(FAR void *const *buffer, int size)
+{
+  FAR char **syms;
+  FAR char *buf;
+  int i;
+
+  syms = backtrace_malloc(buffer, size);
+  if (syms != NULL)
+    {
+      buf = syms[size];
+      for (i = 0; i < size; i++)
+        {
+          syms[i] = buf;
+          buf += sprintf(buf, "%pS", buffer[i]);
+          buf += 1;
+        }
+    }
+
+  return syms;
+}
+
+void backtrace_symbols_fd(FAR void *const *buffer, int size, int fd)
+{
+  int i;
+
+  for (i = 0; i < size; i++)
+    {
+      dprintf(fd, "%pS\n", buffer[i]);
+    }
+}