On Sun, Jun 18, 2017 at 05:54:05PM +0800, JingPiao Chen wrote:
> On Sun, Jun 18, 2017 at 11:19:50AM +0300, Dmitry V. Levin wrote:
> > On Sun, Jun 18, 2017 at 01:18:28PM +0800, JingPiao Chen wrote:
> > > * defs.h (decode_nlattr): New prototype.
> >
> > This is moved to nlattr.h by patch 13/16; why not put it there in the
> > first place?
> >
> > > * linux/unix_diag.h (UNIX_DIAG_*): New enum.
> > > * nlattr.c: New file.
> > > * Makefile.am (strace_SOURCES): Add it.
> > > * netlink_sock_diag.c: Include "xlat/unix_diag_attrs.h".
> > > (decode_unix_diag_msg): Use decode_nlattr.
> > > * xlat/unix_diag_attrs.in: New file.
> > >
> > > co-authored-by: Fabien Siron <fabien.si...@epita.fr>
> > > ---
> > > Makefile.am | 1 +
> > > defs.h | 3 ++
> > > linux/unix_diag.h | 11 +++-
> > > netlink_sock_diag.c | 8 +++
> > > nlattr.c | 131
> > > ++++++++++++++++++++++++++++++++++++++++++++++++
> > > xlat/unix_diag_attrs.in | 8 +++
> > > 6 files changed, 160 insertions(+), 2 deletions(-)
> > > create mode 100644 nlattr.c
> > > create mode 100644 xlat/unix_diag_attrs.in
> > >
> > > diff --git a/Makefile.am b/Makefile.am
> > > index e22d480..132b5e1 100644
> > > --- a/Makefile.am
> > > +++ b/Makefile.am
> > > @@ -173,6 +173,7 @@ strace_SOURCES = \
> > > net.c \
> > > netlink.c \
> > > netlink_sock_diag.c \
> > > + nlattr.c \
> > > nsfs.c \
> > > nsfs.h \
> > > nsig.h \
> > > diff --git a/defs.h b/defs.h
> > > index 487e51b..19653f3 100644
> > > --- a/defs.h
> > > +++ b/defs.h
> > > @@ -632,6 +632,9 @@ tprint_iov_upto(struct tcb *, kernel_ulong_t len,
> > > kernel_ulong_t addr,
> > >
> > > extern void
> > > decode_netlink(struct tcb *, int fd, kernel_ulong_t addr, kernel_ulong_t
> > > len);
> > > +extern void
> > > +decode_nlattr(struct tcb *, kernel_ulong_t addr, kernel_ulong_t len,
> > > + const struct xlat *, const char *);
> > >
> > > extern void tprint_open_modes(unsigned int);
> > > extern const char *sprint_open_modes(unsigned int);
> > > diff --git a/linux/unix_diag.h b/linux/unix_diag.h
> > > index a6b62ba..3c9d99f 100644
> > > --- a/linux/unix_diag.h
> > > +++ b/linux/unix_diag.h
> > > @@ -27,7 +27,14 @@ struct unix_diag_msg {
> > > uint32_t udiag_cookie[2];
> > > };
> > >
> > > -#define UNIX_DIAG_NAME 0
> > > -#define UNIX_DIAG_PEER 2
> > > +enum {
> > > + UNIX_DIAG_NAME,
> > > + UNIX_DIAG_VFS,
> > > + UNIX_DIAG_PEER,
> > > + UNIX_DIAG_ICONS,
> > > + UNIX_DIAG_RQLEN,
> > > + UNIX_DIAG_MEMINFO,
> > > + UNIX_DIAG_SHUTDOWN,
> > > +};
> > >
> > > #endif /* !STRACE_LINUX_UNIX_DIAG_H */
> > > diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
> > > index 8dbfd07..e515810 100644
> > > --- a/netlink_sock_diag.c
> > > +++ b/netlink_sock_diag.c
> > > @@ -55,6 +55,7 @@
> > > # include "xlat/smc_states.h"
> > > #endif
> > >
> > > +#include "xlat/unix_diag_attrs.h"
> > > #include "xlat/unix_diag_show.h"
> > >
> > > static void
> > > @@ -135,6 +136,13 @@ decode_unix_diag_msg(struct tcb *const tcp,
> > > } else
> > > tprints("...");
> > > tprints("}");
> > > +
> > > + if (len > NLA_ALIGN(sizeof(msg))) {
> > > + tprints(", ");
> > > + decode_nlattr(tcp, addr + NLA_ALIGN(sizeof(msg)),
> > > + len - NLA_ALIGN(sizeof(msg)),
> > > + unix_diag_attrs, "UNIX_DIAG_???");
> > > + }
> >
> > Please move this to "!umoven_or_printaddr" branch of the "if" statement
> > above.
> Your expected output is
>
> {udiag_family=AF_UNIX, udiag_type=SOCK_STREAM
> , udiag_state=TCP_FIN_WAIT1, udiag_ino=0
> , udiag_cookie=[0, 0], {nla=0, nla_type=INET_DIAG_NONE}}
>
> or
>
> {udiag_family=AF_UNIX, udiag_type=SOCK_STREAM
> , udiag_state=TCP_FIN_WAIT1, udiag_ino=0
> , udiag_cookie=[0, 0]}, {nla=0, nla_type=INET_DIAG_NONE}
>
> second output I using following implementation:
>
> diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
> index 8dbfd07..f92253e 100644
> --- a/netlink_sock_diag.c
> +++ b/netlink_sock_diag.c
> @@ -113,7 +115,8 @@ decode_unix_diag_msg(struct tcb *const tcp,
> const kernel_ulong_t len)
> {
> struct unix_diag_msg msg = { .udiag_family = family };
> - const size_t offset = sizeof(msg.udiag_family);
> + size_t offset = sizeof(msg.udiag_family);
> + bool decode_nla = false;
>
> tprints("{udiag_family=");
> printxval(addrfams, msg.udiag_family, "AF_???");
> @@ -131,10 +134,18 @@ decode_unix_diag_msg(struct tcb *const tcp,
> ", udiag_cookie=[%" PRIu32 ", %" PRIu32 "]",
> msg.udiag_ino,
> msg.udiag_cookie[0], msg.udiag_cookie[1]);
> + decode_nla = true;
> }
> } else
> tprints("...");
> tprints("}");
> +
> + offset = NLMSG_ALIGN(sizeof(msg));
> + if (decode_nla && len > offset) {
> + tprints(", ");
> + decode_nlattr(tcp, addr + offset, len - offset,
> + unix_diag_attrs, "UNIX_DIAG_???");
> + }Yes, this implementation is correct: we shouldn't try decoding nlattrs if the basic decoding was not successful. -- ldv
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