dump: Fix build with newer gcc

[Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Eric Blake 6 years ago

gcc 8 on rawhide is picky enough to complain:

/home/dummy/qemu/dump.c: In function 'create_header32':
/home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
     strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

But we already have SIG_LEN defined as the right length without needing
to do a strlen(), and memcpy() is better than strncpy() when we know
we do not want a trailing NUL byte.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 dump.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dump.c b/dump.c
index 669f715274d..b54cd42b217 100644
--- a/dump.c
+++ b/dump.c
@@ -814,7 +814,7 @@ static void create_header32(DumpState *s, Error **errp)
     size = sizeof(DiskDumpHeader32);
     dh = g_malloc0(size);

-    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
+    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
     dh->header_version = cpu_to_dump32(s, 6);
     block_size = s->dump_info.page_size;
     dh->block_size = cpu_to_dump32(s, block_size);
@@ -926,7 +926,7 @@ static void create_header64(DumpState *s, Error **errp)
     size = sizeof(DiskDumpHeader64);
     dh = g_malloc0(size);

-    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
+    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
     dh->header_version = cpu_to_dump32(s, 6);
     block_size = s->dump_info.page_size;
     dh->block_size = cpu_to_dump32(s, block_size);
-- 
2.14.3

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Philippe Mathieu-Daudé 6 years ago

On 03/27/2018 05:21 PM, Eric Blake wrote:
> gcc 8 on rawhide is picky enough to complain:
> 
> /home/dummy/qemu/dump.c: In function 'create_header32':
> /home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
>      strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> But we already have SIG_LEN defined as the right length without needing
> to do a strlen(), and memcpy() is better than strncpy() when we know
> we do not want a trailing NUL byte.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> ---
>  dump.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/dump.c b/dump.c
> index 669f715274d..b54cd42b217 100644
> --- a/dump.c
> +++ b/dump.c
> @@ -814,7 +814,7 @@ static void create_header32(DumpState *s, Error **errp)
>      size = sizeof(DiskDumpHeader32);
>      dh = g_malloc0(size);
> 
> -    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
> +    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
>      dh->header_version = cpu_to_dump32(s, 6);
>      block_size = s->dump_info.page_size;
>      dh->block_size = cpu_to_dump32(s, block_size);
> @@ -926,7 +926,7 @@ static void create_header64(DumpState *s, Error **errp)
>      size = sizeof(DiskDumpHeader64);
>      dh = g_malloc0(size);
> 
> -    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
> +    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
>      dh->header_version = cpu_to_dump32(s, 6);
>      block_size = s->dump_info.page_size;
>      dh->block_size = cpu_to_dump32(s, block_size);
>

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Marc-André Lureau 6 years ago

On Tue, Mar 27, 2018 at 10:21 PM, Eric Blake <eblake@redhat.com> wrote:
> gcc 8 on rawhide is picky enough to complain:
>
> /home/dummy/qemu/dump.c: In function 'create_header32':
> /home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
>      strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> But we already have SIG_LEN defined as the right length without needing
> to do a strlen(), and memcpy() is better than strncpy() when we know
> we do not want a trailing NUL byte.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>


> ---
>  dump.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/dump.c b/dump.c
> index 669f715274d..b54cd42b217 100644
> --- a/dump.c
> +++ b/dump.c
> @@ -814,7 +814,7 @@ static void create_header32(DumpState *s, Error **errp)
>      size = sizeof(DiskDumpHeader32);
>      dh = g_malloc0(size);
>
> -    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
> +    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
>      dh->header_version = cpu_to_dump32(s, 6);
>      block_size = s->dump_info.page_size;
>      dh->block_size = cpu_to_dump32(s, block_size);
> @@ -926,7 +926,7 @@ static void create_header64(DumpState *s, Error **errp)
>      size = sizeof(DiskDumpHeader64);
>      dh = g_malloc0(size);
>
> -    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
> +    memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
>      dh->header_version = cpu_to_dump32(s, 6);
>      block_size = s->dump_info.page_size;
>      dh->block_size = cpu_to_dump32(s, block_size);
> --
> 2.14.3
>

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by no-reply@patchew.org 6 years ago

Hi,

This series failed docker-build@min-glib build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

Type: series
Message-id: 20180327202152.1799131-1-eblake@redhat.com
Subject: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

=== TEST SCRIPT BEGIN ===
#!/bin/bash
set -e
git submodule update --init dtc
# Let docker tests dump environment info
export SHOW_ENV=1
export J=8
time make docker-test-build@min-glib
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
cc8ef6a6be dump: Fix build with newer gcc

=== OUTPUT BEGIN ===
Submodule 'dtc' (git://git.qemu-project.org/dtc.git) registered for path 'dtc'
Cloning into '/var/tmp/patchew-tester-tmp-vs3sdjpj/src/dtc'...
Submodule path 'dtc': checked out 'e54388015af1fb4bf04d0bca99caba1074d9cc42'
  BUILD   min-glib
make[1]: Entering directory '/var/tmp/patchew-tester-tmp-vs3sdjpj/src'
  GEN     /var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700/qemu.tar
Cloning into '/var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700/qemu.tar.vroot'...
done.
Checking out files:  38% (2340/6066)   
Checking out files:  39% (2366/6066)   
Checking out files:  40% (2427/6066)   
Checking out files:  41% (2488/6066)   
Checking out files:  42% (2548/6066)   
Checking out files:  43% (2609/6066)   
Checking out files:  44% (2670/6066)   
Checking out files:  45% (2730/6066)   
Checking out files:  46% (2791/6066)   
Checking out files:  47% (2852/6066)   
Checking out files:  48% (2912/6066)   
Checking out files:  49% (2973/6066)   
Checking out files:  50% (3033/6066)   
Checking out files:  51% (3094/6066)   
Checking out files:  52% (3155/6066)   
Checking out files:  52% (3178/6066)   
Checking out files:  53% (3215/6066)   
Checking out files:  54% (3276/6066)   
Checking out files:  55% (3337/6066)   
Checking out files:  56% (3397/6066)   
Checking out files:  57% (3458/6066)   
Checking out files:  58% (3519/6066)   
Checking out files:  58% (3526/6066)   
Checking out files:  59% (3579/6066)   
Checking out files:  60% (3640/6066)   
Checking out files:  61% (3701/6066)   
Checking out files:  62% (3761/6066)   
Checking out files:  63% (3822/6066)   
Checking out files:  64% (3883/6066)   
Checking out files:  65% (3943/6066)   
Checking out files:  66% (4004/6066)   
Checking out files:  67% (4065/6066)   
Checking out files:  68% (4125/6066)   
Checking out files:  69% (4186/6066)   
Checking out files:  70% (4247/6066)   
Checking out files:  71% (4307/6066)   
Checking out files:  72% (4368/6066)   
Checking out files:  73% (4429/6066)   
Checking out files:  74% (4489/6066)   
Checking out files:  75% (4550/6066)   
Checking out files:  76% (4611/6066)   
Checking out files:  77% (4671/6066)   
Checking out files:  78% (4732/6066)   
Checking out files:  79% (4793/6066)   
Checking out files:  80% (4853/6066)   
Checking out files:  81% (4914/6066)   
Checking out files:  82% (4975/6066)   
Checking out files:  83% (5035/6066)   
Checking out files:  84% (5096/6066)   
Checking out files:  85% (5157/6066)   
Checking out files:  86% (5217/6066)   
Checking out files:  87% (5278/6066)   
Checking out files:  88% (5339/6066)   
Checking out files:  89% (5399/6066)   
Checking out files:  90% (5460/6066)   
Checking out files:  91% (5521/6066)   
Checking out files:  92% (5581/6066)   
Checking out files:  93% (5642/6066)   
Checking out files:  94% (5703/6066)   
Checking out files:  95% (5763/6066)   
Checking out files:  96% (5824/6066)   
Checking out files:  97% (5885/6066)   
Checking out files:  98% (5945/6066)   
Checking out files:  99% (6006/6066)   
Checking out files: 100% (6066/6066)   
Checking out files: 100% (6066/6066), done.
Your branch is up-to-date with 'origin/test'.
Submodule 'dtc' (git://git.qemu-project.org/dtc.git) registered for path 'dtc'
Cloning into '/var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700/qemu.tar.vroot/dtc'...
Submodule path 'dtc': checked out 'e54388015af1fb4bf04d0bca99caba1074d9cc42'
Submodule 'ui/keycodemapdb' (git://git.qemu.org/keycodemapdb.git) registered for path 'ui/keycodemapdb'
Cloning into '/var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700/qemu.tar.vroot/ui/keycodemapdb'...
Submodule path 'ui/keycodemapdb': checked out '6b3d716e2b6472eb7189d3220552280ef3d832ce'
tar: /var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700/qemu.tar: Wrote only 2048 of 10240 bytes
tar: Error is not recoverable: exiting now
failed to create tar file
  COPY    RUNNER
    RUN test-build in qemu:min-glib 
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now
/var/tmp/qemu/run: line 32: prep_fail: command not found
Environment variables:
HOSTNAME=1014623e0fbf
MAKEFLAGS= -j8
J=8
CCACHE_DIR=/var/tmp/ccache
EXTRA_CONFIGURE_OPTS=
V=
SHOW_ENV=1
PATH=/usr/lib/ccache:/usr/lib64/ccache:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
TARGET_LIST=
SHLVL=1
HOME=/root
TEST_DIR=/tmp/qemu-test
FEATURES= dtc
DEBUG=
_=/usr/bin/env

Configure options:
--enable-werror --target-list=x86_64-softmmu,aarch64-softmmu --prefix=/tmp/qemu-test/install

ERROR: DTC (libfdt) version >= 1.4.2 not present.
       Please install the DTC (libfdt) devel package

Traceback (most recent call last):
  File "./tests/docker/docker.py", line 407, in <module>
    sys.exit(main())
  File "./tests/docker/docker.py", line 404, in main
    return args.cmdobj.run(args, argv)
  File "./tests/docker/docker.py", line 261, in run
    return Docker().run(argv, args.keep, quiet=args.quiet)
  File "./tests/docker/docker.py", line 229, in run
    quiet=quiet)
  File "./tests/docker/docker.py", line 147, in _do_check
    return subprocess.check_call(self._command + cmd, **kwargs)
  File "/usr/lib64/python2.7/subprocess.py", line 186, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['docker', 'run', '--label', 'com.qemu.instance.uuid=9bb3bdfc34af11e8ba6d52540069c830', '-u', '0', '--security-opt', 'seccomp=unconfined', '--rm', '--net=none', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=8', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/root/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-vs3sdjpj/src/docker-src.2018-03-31-02.48.49.8700:/var/tmp/qemu:z,ro', 'qemu:min-glib', '/var/tmp/qemu/run', 'test-build']' returned non-zero exit status 1
make[1]: *** [tests/docker/Makefile.include:129: docker-run] Error 1
make[1]: Leaving directory '/var/tmp/patchew-tester-tmp-vs3sdjpj/src'
make: *** [tests/docker/Makefile.include:163: docker-run-test-build@min-glib] Error 2

real	0m45.367s
user	0m9.556s
sys	0m6.714s
=== OUTPUT END ===

Test command exited with code: 2


---
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Please send your feedback to patchew-devel@redhat.com

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Eric Blake 6 years ago

On 03/27/2018 03:21 PM, Eric Blake wrote:
> gcc 8 on rawhide is picky enough to complain:
> 
> /home/dummy/qemu/dump.c: In function 'create_header32':
> /home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
>      strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> But we already have SIG_LEN defined as the right length without needing
> to do a strlen(), and memcpy() is better than strncpy() when we know
> we do not want a trailing NUL byte.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  dump.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

I'll include this in my qapi+misc pull request for 2.12-rc2

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Eric Blake 6 years ago

On 04/03/2018 01:46 PM, Eric Blake wrote:
> On 03/27/2018 03:21 PM, Eric Blake wrote:
>> gcc 8 on rawhide is picky enough to complain:
>>
>> /home/dummy/qemu/dump.c: In function 'create_header32':
>> /home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
>>      strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
>>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> But we already have SIG_LEN defined as the right length without needing
>> to do a strlen(), and memcpy() is better than strncpy() when we know
>> we do not want a trailing NUL byte.
>>
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> ---
>>  dump.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> I'll include this in my qapi+misc pull request for 2.12-rc2

That pull request was abandoned; Paolo, do you want to pick this up in
your misc tree?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH for-2.12] dump: Fix build with newer gcc

Posted by Paolo Bonzini 6 years ago

On 06/04/2018 17:06, Eric Blake wrote:
> On 04/03/2018 01:46 PM, Eric Blake wrote:
>> On 03/27/2018 03:21 PM, Eric Blake wrote:
>>> gcc 8 on rawhide is picky enough to complain:
>>>
>>> /home/dummy/qemu/dump.c: In function 'create_header32':
>>> /home/dummy/qemu/dump.c:817:5: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]
>>>      strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
>>>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> But we already have SIG_LEN defined as the right length without needing
>>> to do a strlen(), and memcpy() is better than strncpy() when we know
>>> we do not want a trailing NUL byte.
>>>
>>> Signed-off-by: Eric Blake <eblake@redhat.com>
>>> ---
>>>  dump.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> I'll include this in my qapi+misc pull request for 2.12-rc2
> 
> That pull request was abandoned; Paolo, do you want to pick this up in
> your misc tree?
> 

Ok.

Paolo