[PATCH] mini-os: make xenbus_read_integer and xenbus_printf take const strings

[PATCH] mini-os: make xenbus_read_integer and xenbus_printf take const strings

[Samuel Thibault]

mini-os: make xenbus_read_integer and xenbus_printf take const strings

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

diff -r c2472ded5c7c extras/mini-os/include/xenbus.h
--- a/extras/mini-os/include/xenbus.h	Tue Aug 26 15:16:57 2008 +0100
+++ b/extras/mini-os/include/xenbus.h	Tue Aug 26 17:06:09 2008 +0100
@@ -83,12 +83,12 @@ char *xenbus_transaction_end(xenbus_tran
 			     int *retry);
 
 /* Read path and parse it as an integer.  Returns -1 on error. */
-int xenbus_read_integer(char *path);
+int xenbus_read_integer(const char *path);
 
 /* Contraction of snprintf and xenbus_write(path/node). */
 char* xenbus_printf(xenbus_transaction_t xbt,
-                                  char* node, char* path,
-                                  char* fmt, ...);
+                                  const char* node, const char* path,
+                                  const char* fmt, ...);
 
 /* Reset the XenBus system. */
 void fini_xenbus(void);
diff -r c2472ded5c7c extras/mini-os/xenbus/xenbus.c
--- a/extras/mini-os/xenbus/xenbus.c	Tue Aug 26 15:16:57 2008 +0100
+++ b/extras/mini-os/xenbus/xenbus.c	Tue Aug 26 17:06:09 2008 +0100
@@ -633,7 +633,7 @@ xenbus_transaction_end(xenbus_transactio
     return NULL;
 }
 
-int xenbus_read_integer(char *path)
+int xenbus_read_integer(const char *path)
 {
     char *res, *buf;
     int t;
@@ -650,8 +650,8 @@ int xenbus_read_integer(char *path)
 }
 
 char* xenbus_printf(xenbus_transaction_t xbt,
-                                  char* node, char* path,
-                                  char* fmt, ...)
+                                  const char* node, const char* path,
+                                  const char* fmt, ...)
 {
 #define BUFFER_SIZE 256
     char fullpath[BUFFER_SIZE];

Re: [PATCH] mini-os: make xenbus_read_integer and xenbus_printf take const strings

[Daniel P. Berrange]

On Tue, Aug 26, 2008 at 05:17:02PM +0100, Samuel Thibault wrote:
> mini-os: make xenbus_read_integer and xenbus_printf take const strings
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
> 
> diff -r c2472ded5c7c extras/mini-os/include/xenbus.h
> --- a/extras/mini-os/include/xenbus.h	Tue Aug 26 15:16:57 2008 +0100
> +++ b/extras/mini-os/include/xenbus.h	Tue Aug 26 17:06:09 2008 +0100
> @@ -83,12 +83,12 @@ char *xenbus_transaction_end(xenbus_tran
>  			     int *retry);
>  
>  /* Read path and parse it as an integer.  Returns -1 on error. */
> -int xenbus_read_integer(char *path);
> +int xenbus_read_integer(const char *path);
>  
>  /* Contraction of snprintf and xenbus_write(path/node). */
>  char* xenbus_printf(xenbus_transaction_t xbt,
> -                                  char* node, char* path,
> -                                  char* fmt, ...);
> +                                  const char* node, const char* path,
> +                                  const char* fmt, ...);

If you annotate that declaration with

   __attribute__ ((__format__ (printf, 4, 3)))

then gcc will warn you any time a caller gives incorrect args vs
format string, which can catch some otherwise hidden bugs.

Regards,
Daniel
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Re: [PATCH] mini-os: make xenbus_read_integer and xenbus_printf take const strings

[Samuel Thibault]

Daniel P. Berrange, le Tue 26 Aug 2008 17:34:37 +0100, a écrit :
> If you annotate that declaration with
> 
>    __attribute__ ((__format__ (printf, 4, 3)))
> 
> then gcc will warn you any time a caller gives incorrect args vs
> format string, which can catch some otherwise hidden bugs.

Indeed, actually all mini-os's *print* functions should have it, IIRC
there are a lot of fixes needed to have this compile with -Werror :)

Samuel