diff mbox series

cdefs: Limit definition of fortification macros

Message ID 20230130133217.497398-1-siddhesh@sourceware.org
State Committed
Commit 2337e04e21ba6040926ec871e403533f77043c40
Headers
Series cdefs: Limit definition of fortification macros |

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dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Siddhesh Poyarekar Jan. 30, 2023, 1:32 p.m. UTC 
  Define the __glibc_fortify and other macros only when __FORTIFY_LEVEL >
0.  This has the effect of not defining these macros on older C90
compilers that do not have support for variable length argument lists.

Also trim off the trailing backslashes from the definition of
__glibc_fortify and __glibc_fortify_n macros.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---

Only tested for sanity.  Florian, can you please verify that this
resolves the original problem?

 misc/sys/cdefs.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Florian Weimer Feb. 1, 2023, 5:48 p.m. UTC | #1 
* Siddhesh Poyarekar:

> Define the __glibc_fortify and other macros only when __FORTIFY_LEVEL >
> 0.  This has the effect of not defining these macros on older C90
> compilers that do not have support for variable length argument lists.
>
> Also trim off the trailing backslashes from the definition of
> __glibc_fortify and __glibc_fortify_n macros.
>
> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> ---
>
> Only tested for sanity.  Florian, can you please verify that this
> resolves the original problem?
>
>  misc/sys/cdefs.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
> index 66d6702123..c37a3ff637 100644
> --- a/misc/sys/cdefs.h
> +++ b/misc/sys/cdefs.h
> @@ -152,6 +152,7 @@
>  # define __glibc_objsize(__o) __bos (__o)
>  #endif
>  
> +#if __USE_FORTIFY_LEVEL > 0
>  /* Compile time conditions to choose between the regular, _chk and _chk_warn
>     variants.  These conditions should get evaluated to constant and optimized
>     away.  */
> @@ -187,7 +188,7 @@
>     ? __ ## f ## _alias (__VA_ARGS__)					      \
>     : (__glibc_unsafe_len (__l, __s, __osz)				      \
>        ? __ ## f ## _chk_warn (__VA_ARGS__, __osz)			      \
> -      : __ ## f ## _chk (__VA_ARGS__, __osz)))			      \
> +      : __ ## f ## _chk (__VA_ARGS__, __osz)))
>  
>  /* Fortify function f, where object size argument passed to f is the number of
>     elements and not total size.  */
> @@ -197,7 +198,8 @@
>     ? __ ## f ## _alias (__VA_ARGS__)					      \
>     : (__glibc_unsafe_len (__l, __s, __osz)				      \
>        ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s))		      \
> -      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))		      \
> +      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))
> +#endif
>  
>  #if __GNUC_PREREQ (4,3)
>  # define __warnattr(msg) __attribute__((__warning__ (msg)))

Seems reasonable, thanks.  I believe it works with those old compilers.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Florian
diff mbox series

Patch

diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 66d6702123..c37a3ff637 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -152,6 +152,7 @@ 
 # define __glibc_objsize(__o) __bos (__o)
 #endif
 
+#if __USE_FORTIFY_LEVEL > 0
 /* Compile time conditions to choose between the regular, _chk and _chk_warn
    variants.  These conditions should get evaluated to constant and optimized
    away.  */
@@ -187,7 +188,7 @@ 
    ? __ ## f ## _alias (__VA_ARGS__)					      \
    : (__glibc_unsafe_len (__l, __s, __osz)				      \
       ? __ ## f ## _chk_warn (__VA_ARGS__, __osz)			      \
-      : __ ## f ## _chk (__VA_ARGS__, __osz)))			      \
+      : __ ## f ## _chk (__VA_ARGS__, __osz)))
 
 /* Fortify function f, where object size argument passed to f is the number of
    elements and not total size.  */
@@ -197,7 +198,8 @@ 
    ? __ ## f ## _alias (__VA_ARGS__)					      \
    : (__glibc_unsafe_len (__l, __s, __osz)				      \
       ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s))		      \
-      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))		      \
+      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))
+#endif
 
 #if __GNUC_PREREQ (4,3)
 # define __warnattr(msg) __attribute__((__warning__ (msg)))