[PATCH v4] netlink: decode libudev netlink header
Harsha Sharma
harshasharmaiitr at gmail.com
Mon Jan 29 21:22:46 UTC 2018
On Wed, Jan 10, 2018 at 8:46 AM, Dmitry V. Levin <ldv at altlinux.org> wrote:
> On Tue, Jan 09, 2018 at 01:49:36AM +0530, Harsha Sharma wrote:
>> * defs.h (decode_netlink_kobject_uevent): New prototype.
>> * netlink.c (decode_netlink): Decode family kobject_uevent.
>> * netlink_kobject_uevent.h: New file.
>> * netlink_object_uevent.c: New file.
>> * Makefile.am (strace_SOURCES): Add them.
>>
>> Signed-off-by: Harsha Sharma <harshasharmaiitr at gmail.com>
>> ---
>> Changes in v4:
>> * Minor changes in decode_netlink_kobject_uevent
>>
>> Changes in v3:
>> * Change changelog
>> * minor changes in decode_netlink_kobject_uevent
>> * omit irrelevant comments in netlink_kobject_uevent.h
>>
>> Changes in v2:
>> * New file netlink_kobject_uevent.c
>> * change location of netlink_kobject_uevent.h
>> * add comments in netlink_kobject_uevent.h
>> * add new files in Makefile.am
>> * add func decode_netlink_kobject_uevent in defs.h
>> * Use macros from print_fields.h instead of tprintf
>> * minor changes in decode_netlink_kobject_uevent (including name)
>>
>> Makefile.am | 2 ++
>> defs.h | 3 +++
>> netlink.c | 2 +-
>> netlink_kobject_uevent.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++
>> netlink_kobject_uevent.h | 17 +++++++++++++
>> 5 files changed, 87 insertions(+), 1 deletion(-)
>> create mode 100644 netlink_kobject_uevent.c
>> create mode 100644 netlink_kobject_uevent.h
>>
>> diff --git a/Makefile.am b/Makefile.am
>> index 670046a5..719516e1 100644
>> --- a/Makefile.am
>> +++ b/Makefile.am
>> @@ -194,6 +194,8 @@ strace_SOURCES = \
>> netlink.c \
>> netlink.h \
>> netlink_crypto.c \
>> + netlink_kobject_uevent.c \
>> + netlink_kobject_uevent.h \
>> netlink_sock_diag.h \
>> netlink_inet_diag.c \
>> netlink_netlink_diag.c \
>> diff --git a/defs.h b/defs.h
>> index e7d7b2df..6aafeb28 100644
>> --- a/defs.h
>> +++ b/defs.h
>> @@ -694,6 +694,9 @@ DECL_NETLINK(route);
>> DECL_NETLINK(selinux);
>> DECL_NETLINK(sock_diag);
>>
>> +extern void
>> +decode_netlink_kobject_uevent(struct tcb *, kernel_ulong_t addr,
>> + kernel_ulong_t len);
>> extern int tv_nz(const struct timeval *);
>> extern int tv_cmp(const struct timeval *, const struct timeval *);
>> extern double tv_float(const struct timeval *);
>> diff --git a/netlink.c b/netlink.c
>> index beb6ea4a..a714d29a 100644
>> --- a/netlink.c
>> +++ b/netlink.c
>> @@ -629,7 +629,7 @@ decode_netlink(struct tcb *const tcp,
>> const int family = get_fd_nl_family(tcp, fd);
>>
>> if (family == NETLINK_KOBJECT_UEVENT) {
>> - printstrn(tcp, addr, len);
>> + decode_netlink_kobject_uevent(tcp, addr, len);
>> return;
>> }
>>
>> diff --git a/netlink_kobject_uevent.c b/netlink_kobject_uevent.c
>> new file mode 100644
>> index 00000000..813638da
>> --- /dev/null
>> +++ b/netlink_kobject_uevent.c
>> @@ -0,0 +1,64 @@
>> +/*
>> + * Copyright (c) 2018 Harsha Sharma <harshasharmaiittr at gmail.com>
>> + * Copyright (c) 2017 The strace developers.
>> + * All rights reserved.
>> + *
>> + * Redistribution and use in source and binary forms, with or without
>> + * modification, are permitted provided that the following conditions
>> + * are met:
>> + * 1. Redistributions of source code must retain the above copyright
>> + * notice, this list of conditions and the following disclaimer.
>> + * 2. Redistributions in binary form must reproduce the above copyright
>> + * notice, this list of conditions and the following disclaimer in the
>> + * documentation and/or other materials provided with the distribution.
>> + * 3. The name of the author may not be used to endorse or promote products
>> + * derived from this software without specific prior written permission.
>> + *
>> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
>> + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
>> + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
>> + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
>> + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
>> + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
>> + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
>> + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>> + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
>> + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>> + */
>> +
>> +#include "defs.h"
>> +#include "print_fields.h"
>> +#include "netlink_kobject_uevent.h"
>> +
>> +#include <arpa/inet.h>
>> +
>> +void
>> +decode_netlink_kobject_uevent(struct tcb *tcp, kernel_ulong_t addr,
>> + kernel_ulong_t len)
>> +{
>> + struct udev_monitor_netlink_header uh;
>> + const char *prefix = "libudev";
>> +
>> + if (len >= sizeof(uh)) {
>> + if (!umove_or_printaddr(tcp, addr, &uh)) {
>> + if (strcmp(uh.prefix, prefix) == 0) {
>> + PRINT_FIELD_CSTRING("{", uh, prefix);
>> + tprintf(", magic=htonl(%#x)", ntohl(uh.magic));
>> + PRINT_FIELD_U(", ", uh, header_size);
>> + PRINT_FIELD_U(", ", uh, properties_off);
>> + PRINT_FIELD_U(", ", uh, properties_len);
>> + PRINT_FIELD_X(", ", uh, filter_subsystem_hash);
>> + PRINT_FIELD_X(", ", uh, filter_devtype_hash);
>> + PRINT_FIELD_X(", ", uh, filter_tag_bloom_hi);
>> + PRINT_FIELD_X(", ", uh, filter_tag_bloom_lo);
>
> Sorry but you must have missed my comment:
> all these filter_* fields are hashes stored in network byte order.
>
>> + tprints("}");
>> + printstrn(tcp, addr - sizeof(uh),
>> + len - sizeof(uh));
>
> This would print {...}"..." which is not a correct output.
Can you please tell how the expected output is supposed to be printed
after the header?
It'll be a great help.
> I think it's time to add a test for this new parser.
I'll add the test for this once I get this working.
Thanks for your time and sorry for the delay.
Regards,
Harsha Sharma
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