bitkeeper revision 1.1724 (42b7d6f60v0z2ZEkw36W_1joFfySfw)

Make xs_read/read_reply allocate an extra byte and put a nul character
at the end of objects to allow easy use as a string.
From: Rusty Russell <rusty@rustcorp.com.au>                                     
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

3 files changed, 10 insertions, 6 deletions

diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
index e41ca652bd..c11e02ae1e 100644
--- a/tools/xenstore/xs.c
+++ b/tools/xenstore/xs.c
@@ -131,6 +131,7 @@ static int get_error(const char *errorstring)
 	return xsd_errors[i].errnum;
 }
 
+/* Adds extra nul terminator, because we generally (always?) hold strings. */
 static void *read_reply(int fd, enum xsd_sockmsg_type *type, unsigned int *len)
 {
 	struct xsd_sockmsg msg;
@@ -140,7 +141,7 @@ static void *read_reply(int fd, enum xsd_sockmsg_type *type, unsigned int *len)
 	if (!read_all(fd, &msg, sizeof(msg)))
 		return NULL;
 
-	ret = malloc(msg.len);
+	ret = malloc(msg.len + 1);
 	if (!ret)
 		return NULL;
 
@@ -154,6 +155,7 @@ static void *read_reply(int fd, enum xsd_sockmsg_type *type, unsigned int *len)
 	*type = msg.type;
 	if (len)
 		*len = msg.len;
+	((char *)ret)[msg.len] = '\0';
 	return ret;
 }
 
@@ -269,9 +271,9 @@ char **xs_directory(struct xs_handle *h, const char *path, unsigned int *num)
 	return ret;
 }
 
-/* Get the value of a single file.
+/* Get the value of a single file, nul terminated.
  * Returns a malloced value: call free() on it after use.
- * len indicates length in bytes.
+ * len indicates length in bytes, not including the nul.
  */
 void *xs_read(struct xs_handle *h, const char *path, unsigned int *len)
 {
diff --git a/tools/xenstore/xs.h b/tools/xenstore/xs.h
index b778cedd65..09d5a20937 100644
--- a/tools/xenstore/xs.h
+++ b/tools/xenstore/xs.h
@@ -45,9 +45,9 @@ void xs_daemon_close(struct xs_handle *);
  */
 char **xs_directory(struct xs_handle *h, const char *path, unsigned int *num);
 
-/* Get the value of a single file.
+/* Get the value of a single file, nul terminated.
  * Returns a malloced value: call free() on it after use.
- * len indicates length in bytes.
+ * len indicates length in bytes, not including the nul.
  */
 void *xs_read(struct xs_handle *h, const char *path, unsigned int *len);
 
diff --git a/tools/xenstore/xs_test.c b/tools/xenstore/xs_test.c
index 29929b7693..6ce5d701af 100644
--- a/tools/xenstore/xs_test.c
+++ b/tools/xenstore/xs_test.c
@@ -240,6 +240,8 @@ static void do_read(unsigned int handle, char *path)
 	if (!value)
 		failed(handle);
 
+	/* It's supposed to nul terminate for us. */
+	assert(value[len] == '\0');
 	if (handle)
 		printf("%i:%.*s\n", handle, len, value);
 	else
@@ -261,7 +263,7 @@ static void do_write(unsigned int handle, char *path, char *flags, char *data)
 	else
 		barf("write flags 'none', 'create' or 'excl' only");
 
-	if (!xs_write(handles[handle], path, data, strlen(data)+1, f))
+	if (!xs_write(handles[handle], path, data, strlen(data), f))
 		failed(handle);
 }