[v3,1/3] linux: Update the mremap C implementation [BZ #31968]
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Commit Message
Update the mremap C implementation to support the optional argument for
MREMAP_DONTUNMAP added in Linux 5.7 since it may not always be correct
to implement a variadic function as a non-variadic function on all Linux
targets. Return MAP_FAILED and set errno to EINVAL for unknown flag bits.
This fixes BZ #31968.
Note: A test must be added when a new flag bit is introduced.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
sysdeps/unix/sysv/linux/mremap.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
Comments
On 17/07/24 04:59, H.J. Lu wrote:
> Update the mremap C implementation to support the optional argument for
> MREMAP_DONTUNMAP added in Linux 5.7 since it may not always be correct
> to implement a variadic function as a non-variadic function on all Linux
> targets. Return MAP_FAILED and set errno to EINVAL for unknown flag bits.
> This fixes BZ #31968.
>
> Note: A test must be added when a new flag bit is introduced.
>
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> sysdeps/unix/sysv/linux/mremap.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/sysdeps/unix/sysv/linux/mremap.c b/sysdeps/unix/sysv/linux/mremap.c
> index 4f770799c4..1ada5c1f40 100644
> --- a/sysdeps/unix/sysv/linux/mremap.c
> +++ b/sysdeps/unix/sysv/linux/mremap.c
> @@ -20,6 +20,12 @@
> #include <sysdep.h>
> #include <stdarg.h>
> #include <stddef.h>
> +#include <errno.h>
> +
> +#define MREMAP_KNOWN_BITS \
> + (MREMAP_MAYMOVE \
> + | MREMAP_FIXED \
> + | MREMAP_DONTUNMAP)
>
> void *
> __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
> @@ -27,7 +33,13 @@ __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
> va_list va;
> void *new_addr = NULL;
>
> - if (flags & MREMAP_FIXED)
> + if (flags & ~(MREMAP_KNOWN_BITS))
> + {
> + __set_errno (EINVAL);
> + return MAP_FAILED;
> + }
> +
> + if (flags & (MREMAP_FIXED | MREMAP_DONTUNMAP))
> {
> va_start (va, flags);
> new_addr = va_arg (va, void *);
@@ -20,6 +20,12 @@
#include <sysdep.h>
#include <stdarg.h>
#include <stddef.h>
+#include <errno.h>
+
+#define MREMAP_KNOWN_BITS \
+ (MREMAP_MAYMOVE \
+ | MREMAP_FIXED \
+ | MREMAP_DONTUNMAP)
void *
__mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
@@ -27,7 +33,13 @@ __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
va_list va;
void *new_addr = NULL;
- if (flags & MREMAP_FIXED)
+ if (flags & ~(MREMAP_KNOWN_BITS))
+ {
+ __set_errno (EINVAL);
+ return MAP_FAILED;
+ }
+
+ if (flags & (MREMAP_FIXED | MREMAP_DONTUNMAP))
{
va_start (va, flags);
new_addr = va_arg (va, void *);