[PATCH v6 2/3] netlink: introduce a basic netlink attributes parser
JingPiao Chen
chenjingpiao at gmail.com
Wed Jun 21 16:24:23 UTC 2017
* linux/unix_diag.h (UNIX_DIAG_*): New enum.
* nlattr.c: New file.
* nlattr.h: Likewise.
* Makefile.am (strace_SOURCES): Add them.
* netlink_sock_diag.c: Include "nlattr.h" and "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.siron at epita.fr>
---
Makefile.am | 2 +
linux/unix_diag.h | 11 +++-
netlink_sock_diag.c | 13 ++++-
nlattr.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++
nlattr.h | 37 ++++++++++++++
xlat/unix_diag_attrs.in | 8 +++
6 files changed, 198 insertions(+), 3 deletions(-)
create mode 100644 nlattr.c
create mode 100644 nlattr.h
create mode 100644 xlat/unix_diag_attrs.in
diff --git a/Makefile.am b/Makefile.am
index 0d75970..76be3ca 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -175,6 +175,8 @@ strace_SOURCES = \
netlink.c \
netlink.h \
netlink_sock_diag.c \
+ nlattr.c \
+ nlattr.h \
nsfs.c \
nsfs.h \
nsig.h \
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 bdefe8b..d854808 100644
--- a/netlink_sock_diag.c
+++ b/netlink_sock_diag.c
@@ -29,6 +29,7 @@
#include "defs.h"
#include "netlink.h"
+#include "nlattr.h"
#include <arpa/inet.h>
#include <linux/inet_diag.h>
@@ -54,6 +55,7 @@
# include "xlat/smc_states.h"
#endif
+#include "xlat/unix_diag_attrs.h"
#include "xlat/unix_diag_show.h"
static void
@@ -112,7 +114,8 @@ 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_???");
@@ -130,10 +133,18 @@ 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_???");
+ }
}
static void
diff --git a/nlattr.c b/nlattr.c
new file mode 100644
index 0000000..8c51629
--- /dev/null
+++ b/nlattr.c
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron at epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao at gmail.com>
+ * Copyright (c) 2016-2017 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 "netlink.h"
+
+static bool
+fetch_nlattr(struct tcb *const tcp, struct nlattr *const nlattr,
+ const kernel_ulong_t addr, const kernel_ulong_t len)
+{
+ if (len < sizeof(struct nlattr)) {
+ printstrn(tcp, addr, len);
+ return false;
+ }
+
+ if (umove_or_printaddr(tcp, addr, nlattr))
+ return false;
+
+ return true;
+}
+
+static void
+print_nlattr(const struct nlattr *const nla,
+ const struct xlat *const table,
+ const char *const dflt)
+{
+ tprintf("{nla_len=%u, nla_type=", nla->nla_len);
+ if (nla->nla_type & NLA_F_NESTED)
+ tprints("NLA_F_NESTED|");
+ if (nla->nla_type & NLA_F_NET_BYTEORDER)
+ tprints("NLA_F_NET_BYTEORDER|");
+ printxval(table, nla->nla_type & NLA_TYPE_MASK, dflt);
+ tprints("}");
+}
+
+static void
+decode_nlattr_with_data(struct tcb *tcp,
+ const struct nlattr *const nla,
+ kernel_ulong_t addr,
+ kernel_ulong_t len,
+ const struct xlat *const table,
+ const char *const dflt)
+{
+ const unsigned int nla_len = nla->nla_len > len ? len : nla->nla_len;
+
+ if (nla_len > NLA_HDRLEN)
+ tprints("{");
+
+ print_nlattr(nla, table, dflt);
+
+ if (nla_len > NLA_HDRLEN) {
+ tprints(", ");
+ printstrn(tcp, addr + NLA_HDRLEN, nla_len - NLA_HDRLEN);
+ tprints("}");
+ }
+}
+
+void
+decode_nlattr(struct tcb *const tcp,
+ kernel_ulong_t addr,
+ kernel_ulong_t len,
+ const struct xlat *const table,
+ const char *const dflt)
+{
+ struct nlattr nla;
+ bool print_array = false;
+ unsigned int elt;
+
+ for (elt = 0; fetch_nlattr(tcp, &nla, addr, len); elt++) {
+ if (abbrev(tcp) && elt == max_strlen) {
+ tprints("...");
+ break;
+ }
+
+ const unsigned long nla_len = NLA_ALIGN(nla.nla_len);
+ kernel_ulong_t next_addr = 0;
+ kernel_ulong_t next_len = 0;
+
+ if (nla.nla_len >= NLA_HDRLEN) {
+ next_len = (len >= nla_len) ? len - nla_len : 0;
+
+ if (next_len && addr + nla_len > addr)
+ next_addr = addr + nla_len;
+ }
+
+ if (!print_array && next_addr) {
+ tprints("[");
+ print_array = true;
+ }
+
+ decode_nlattr_with_data(tcp, &nla, addr, len, table, dflt);
+
+ if (!next_addr)
+ break;
+
+ tprints(", ");
+ addr = next_addr;
+ len = next_len;
+ }
+
+ if (print_array) {
+ tprints("]");
+ }
+}
diff --git a/nlattr.h b/nlattr.h
new file mode 100644
index 0000000..ade2271
--- /dev/null
+++ b/nlattr.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron at epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao at gmail.com>
+ * Copyright (c) 2016-2017 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.
+ */
+
+#ifndef STRACE_NLATTR_H
+#define STRACE_NLATTR_H
+
+extern void
+decode_nlattr(struct tcb *, kernel_ulong_t addr, kernel_ulong_t len,
+ const struct xlat *, const char *);
+
+#endif /* !STRACE_NLATTR_H */
diff --git a/xlat/unix_diag_attrs.in b/xlat/unix_diag_attrs.in
new file mode 100644
index 0000000..4c3d9b2
--- /dev/null
+++ b/xlat/unix_diag_attrs.in
@@ -0,0 +1,8 @@
+#unconditional
+UNIX_DIAG_NAME
+UNIX_DIAG_VFS
+UNIX_DIAG_PEER
+UNIX_DIAG_ICONS
+UNIX_DIAG_RQLEN
+UNIX_DIAG_MEMINFO
+UNIX_DIAG_SHUTDOWN
--
2.7.4
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