* libc/argz/argz_add_sep.c (argz_add_sep): Handle empty string

	argument.
	* libc/argz/argz_append.c (argz_append): Handle empty buf argument.
	* libc/argz/argz_create_sep.c (argz_create_sep): Return (NULL, 0)
	on empty input strings.
	* libc/argz/argz_extract.c (argz_extract): Check argz_len before
	looping through argz.
	* libc/argz/argz_stringify.c (argz_stringify): Ditto.

5 files changed, 38 insertions, 23 deletions

diff --git a/newlib/libc/argz/argz_add_sep.c b/newlib/libc/argz/argz_add_sep.c
index 5a56ec931..7dfbb4d6e 100644
--- a/newlib/libc/argz/argz_add_sep.c
+++ b/newlib/libc/argz/argz_add_sep.c
@@ -23,11 +23,14 @@ _DEFUN (argz_add_sep, (argz, argz_len, str, sep),
 
   argz_create_sep (str, sep, &str_argz, &str_argz_len);
 
-  *argz_len += str_argz_len;
+  if (str_argz_len)
+    {
+      *argz_len += str_argz_len;
 
-  if(!(*argz = (char *)realloc(*argz, *argz_len)))
-    return ENOMEM;
+      if(!(*argz = (char *)realloc(*argz, *argz_len)))
+	return ENOMEM;
 
-  memcpy(*argz + last, str_argz, str_argz_len);
+      memcpy(*argz + last, str_argz, str_argz_len);
+    }
   return 0;
 }
diff --git a/newlib/libc/argz/argz_append.c b/newlib/libc/argz/argz_append.c
index 7519e1608..75d5c9315 100644
--- a/newlib/libc/argz/argz_append.c
+++ b/newlib/libc/argz/argz_append.c
@@ -16,13 +16,16 @@ _DEFUN (argz_append, (argz, argz_len, buf, buf_len),
        const char *buf _AND
        size_t buf_len)
 {
-  size_t last = *argz_len;
+  if (buf_len)
+    {
+      size_t last = *argz_len;
 
-  *argz_len += buf_len;
+      *argz_len += buf_len;
 
-  if(!(*argz = (char *)realloc(*argz, *argz_len)))
-    return ENOMEM;
+      if(!(*argz = (char *)realloc(*argz, *argz_len)))
+	return ENOMEM;
 
-  memcpy(*argz + last, buf, buf_len);
+      memcpy(*argz + last, buf, buf_len);
+    }
   return 0;
 }
diff --git a/newlib/libc/argz/argz_create_sep.c b/newlib/libc/argz/argz_create_sep.c
index bf02b492a..cf27c9284 100644
--- a/newlib/libc/argz/argz_create_sep.c
+++ b/newlib/libc/argz/argz_create_sep.c
@@ -25,13 +25,20 @@ _DEFUN (argz_create_sep, (string, sep, argz, argz_len),
   char *token = 0;
   char *iter = 0;
 
+  *argz_len = 0;
+
+  if (!string || string[0] == '\0')
+    {
+      *argz= NULL;
+      return 0;
+    }
+
   delim[0] = sep;
   delim[1] = '\0';
 
   running = strdup(string);
   old_running = running;
 
-  *argz_len = 0;
   while ((token = strsep(&running, delim)))
     {
       len = strlen(token);
diff --git a/newlib/libc/argz/argz_extract.c b/newlib/libc/argz/argz_extract.c
index 289c6e100..56c604684 100644
--- a/newlib/libc/argz/argz_extract.c
+++ b/newlib/libc/argz/argz_extract.c
@@ -17,14 +17,15 @@ _DEFUN (argz_extract, (argz, argz_len, argv),
   int j = 0;
   const size_t count = argz_count(argz, argz_len);
 
-  for (i = argz_len - 2; i > 0; i--)
-    {
-      if (argz[i] == '\0')
-        {
-          j++;
-          argv[count - j] = &argz[i + 1];
-        }
-    }
+  if (argz_len > 1)
+    for (i = argz_len - 2; i > 0; i--)
+      {
+	if (argz[i] == '\0')
+	  {
+	    j++;
+	    argv[count - j] = &argz[i + 1];
+	  }
+      }
   argv[0] = &argz[0];
   argv[count] = NULL;
 }
diff --git a/newlib/libc/argz/argz_stringify.c b/newlib/libc/argz/argz_stringify.c
index 6ff5dd001..febf8b4f9 100644
--- a/newlib/libc/argz/argz_stringify.c
+++ b/newlib/libc/argz/argz_stringify.c
@@ -16,9 +16,10 @@ _DEFUN (argz_stringify, (argz, argz_len, sep),
   size_t i;
 
   /* len includes trailing \0, which we don't want to replace. */
-  for (i = 0; i < argz_len - 1; i++)
-    {
-      if (argz[i] == '\0')
-        argz[i] = sep;
-    }
+  if (argz_len > 1)
+    for (i = 0; i < argz_len - 1; i++)
+      {
+	if (argz[i] == '\0')
+	  argz[i] = sep;
+      }
 }