From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
qemu-block@nongnu.org, 1803872@bugs.launchpad.net,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Cédric Le Goater" <clg@kaod.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Howard Spoelstra" <hsp.cat7@gmail.com>,
"Jeff Cody" <jcody@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Stefan Weil" <sw@weilnetz.de>,
"Markus Armbruster" <armbru@redhat.com>,
"Kevin Wolf" <kwolf@redhat.com>, "Eric Blake" <eblake@redhat.com>,
"Ben Pye" <ben@curlybracket.co.uk>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Thomas Huth" <thuth@redhat.com>,
"Igor Mammedov" <imammedo@redhat.com>,
"Liu Yuan" <namei.unix@gmail.com>,
"David Gibson" <david@gibson.dropbear.id.au>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Max Reitz" <mreitz@redhat.com>
Subject: [Qemu-devel] [PATCH v3 1/5] qemu/compiler: Define QEMU_NONSTRING
Date: Tue, 18 Dec 2018 18:51:18 +0100 [thread overview]
Message-ID: <20181218175122.3229-2-philmd@redhat.com> (raw)
In-Reply-To: <20181218175122.3229-1-philmd@redhat.com>
GCC 8 introduced the -Wstringop-truncation checker to detect truncation by
the strncat and strncpy functions (closely related to -Wstringop-overflow,
which detect buffer overflow by string-modifying functions declared in
<string.h>).
Add the QEMU_NONSTRING macro which checks if the compiler supports this
attribute.
>From the GCC manual [*]:
The nonstring variable attribute specifies that an object or member
declaration with type array of char, signed char, or unsigned char,
or pointer to such a type is intended to store character arrays that
do not necessarily contain a terminating NUL. This is useful in detecting
uses of such arrays or pointers with functions that expect NUL-terminated
strings, and to avoid warnings when such an array or pointer is used as
an argument to a bounded string manipulation function such as strncpy.
[*] https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
include/qemu/compiler.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 261842beae..2d8f507c73 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -151,6 +151,21 @@
# define QEMU_ERROR(X)
#endif
+/*
+ * The nonstring variable attribute specifies that an object or member
+ * declaration with type array of char or pointer to char is intended
+ * to store character arrays that do not necessarily contain a terminating
+ * NUL character. This is useful in detecting uses of such arrays or pointers
+ * with functions that expect NUL-terminated strings, and to avoid warnings
+ * when such an array or pointer is used as an argument to a bounded string
+ * manipulation function such as strncpy.
+ */
+#if __has_attribute(nonstring)
+# define QEMU_NONSTRING __attribute__((nonstring))
+#else
+# define QEMU_NONSTRING
+#endif
+
/* Implement C11 _Generic via GCC builtins. Example:
*
* QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x)
--
2.17.2
next prev parent reply other threads:[~2018-12-18 17:52 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 17:51 [Qemu-devel] [PATCH v3 0/5] Fix strncpy() warnings for GCC8 new -Wstringop-truncation Philippe Mathieu-Daudé
2018-12-18 17:51 ` Philippe Mathieu-Daudé [this message]
2018-12-18 18:29 ` [Qemu-devel] [PATCH v3 1/5] qemu/compiler: Define QEMU_NONSTRING Eric Blake
2018-12-18 19:28 ` Philippe Mathieu-Daudé
2018-12-18 17:51 ` [Qemu-devel] [PATCH v3 2/5] block/sheepdog: Use QEMU_NONSTRING for non NUL-terminated arrays Philippe Mathieu-Daudé
2018-12-18 18:30 ` Eric Blake
2018-12-18 23:09 ` Michael S. Tsirkin
2018-12-19 9:22 ` Philippe Mathieu-Daudé
2018-12-18 17:51 ` [Qemu-devel] [PATCH v3 3/5] hw/acpi: " Philippe Mathieu-Daudé
2018-12-19 9:15 ` Igor Mammedov
2018-12-19 9:20 ` Philippe Mathieu-Daudé
2018-12-19 9:57 ` Igor Mammedov
2018-12-19 10:10 ` Andrew Jones
2018-12-19 12:43 ` Philippe Mathieu-Daudé
2018-12-19 13:00 ` Andrew Jones
2018-12-20 15:18 ` Igor Mammedov
2018-12-20 16:29 ` Philippe Mathieu-Daudé
2018-12-18 17:51 ` [Qemu-devel] [PATCH v3 4/5] migration: " Philippe Mathieu-Daudé
2019-01-02 11:41 ` Dr. David Alan Gilbert
2018-12-18 17:51 ` [Qemu-devel] [PATCH v3 5/5] migration: Use strnlen() for fixed-size string Philippe Mathieu-Daudé
2018-12-18 23:16 ` Michael S. Tsirkin
2018-12-19 9:24 ` Philippe Mathieu-Daudé
2018-12-18 17:54 ` [Qemu-devel] [PATCH v3 0/5] Fix strncpy() warnings for GCC8 new -Wstringop-truncation Philippe Mathieu-Daudé
2018-12-18 23:08 ` Michael S. Tsirkin
2018-12-24 23:09 ` no-reply
-- strict thread matches above, loose matches on Subject: below --
2018-11-18 13:45 [Qemu-devel] [Bug 1803872] [NEW] gcc 8.2 reports stringop-truncation when building qemu Amir Gonnen
2018-11-18 14:52 ` [Qemu-devel] [Bug 1803872] " Amir Gonnen
2018-12-18 12:42 ` [Qemu-devel] [Bug 1803872] Re: [PATCH v2 3/3] migration: Replace strncpy() by strpadcpy(pad='\0') elmarco
2018-12-18 19:29 ` [Qemu-devel] [Bug 1803872] Re: [PATCH v3 4/5] migration: Use QEMU_NONSTRING for non NUL-terminated arrays Eric Blake
2018-12-18 19:33 ` [Qemu-devel] [Bug 1803872] Re: [PATCH v3 5/5] migration: Use strnlen() for fixed-size string Eric Blake
2018-12-18 21:24 ` [Qemu-devel] " Paolo Bonzini
2018-12-18 21:36 ` [Qemu-devel] [Bug 1803872] Re: [PATCH v3 4/5] migration: Use QEMU_NONSTRING for non NUL-terminated arrays Eric Blake
2019-04-24 6:01 ` [Qemu-devel] [Bug 1803872] Re: gcc 8.2 reports stringop-truncation when building qemu Thomas Huth
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