[PATCH] misc: Make grub_vsnprintf C99/POSIX conformant

[PATCH] misc: Make grub_vsnprintf C99/POSIX conformant

[Glenn Washburn]

To comply with C99 and POSIX standards, snprintf should return the
number of bytes that would be written to the string (excluding the
terminating NULL byte) if the buffer size was big enough. Before this
change, the return value was the minimum of the standard return and
the length of the buffer. Rarely is the return value of grub_snprintf
or grub_vsnprintf used with current code, and the few places where it is
used do not need to be changed.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/kern/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index 95bf7860f3da..afb41bd63a6a 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -1201,7 +1201,7 @@ grub_vsnprintf (char *str, grub_size_t n, const char *fmt, va_list ap)
 
   free_printf_args (&args);
 
-  return ret < n ? ret : n;
+  return ret;
 }
 
 int
-- 
2.34.1


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Re: [PATCH] misc: Make grub_vsnprintf C99/POSIX conformant

[Daniel Kiper]

On Fri, Aug 18, 2023 at 12:15:27PM -0500, Glenn Washburn wrote:
> To comply with C99 and POSIX standards, snprintf should return the
> number of bytes that would be written to the string (excluding the
> terminating NULL byte) if the buffer size was big enough. Before this
> change, the return value was the minimum of the standard return and
> the length of the buffer. Rarely is the return value of grub_snprintf
> or grub_vsnprintf used with current code, and the few places where it is
> used do not need to be changed.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Daniel

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