From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sat, 2 Jul 2016 21:14:26 +0000 (+0000)
Subject: msghdr.c: limit SCM_RIGHTS output in abbrev mode
X-Git-Tag: v4.13~75
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d35d5ecc4d8ac1bd3617e6f5f85ca738041130eb;p=strace

msghdr.c: limit SCM_RIGHTS output in abbrev mode

* msghdr.c (print_scm_rights): Do not print more than max_strlen
descriptors in abbrev mode.
* tests/msg_control.c (DEFAULT_STRLEN): New macro.
(print_fds): Use it.
(test_scm_rights3): New function.
(main): Use it to test SCM_RIGHTS output in abbrev mode.
* tests/msg_control-v.c: New file.
* tests/msg_control-v.test: New test.
* tests/.gitignore: Add msg_control-v.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add msg_control-v.test.
---

diff --git a/msghdr.c b/msghdr.c
index c4d8aef3..0f9ba714 100644
--- a/msghdr.c
+++ b/msghdr.c
@@ -66,6 +66,10 @@ print_scm_rights(struct tcb *tcp, const void *cmsg_data, const size_t data_len)
 	for (i = 0; i < nfds; ++i) {
 		if (i)
 			tprints(", ");
+		if (abbrev(tcp) && i >= max_strlen) {
+			tprints("...");
+			break;
+		}
 		printfd(tcp, fds[i]);
 	}
 
diff --git a/tests/.gitignore b/tests/.gitignore
index 1ca49ca4..fecd592c 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -138,6 +138,7 @@ mount
 move_pages
 mq
 msg_control
+msg_control-v
 munlockall
 nanosleep
 net-accept-connect
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 51c2c7e7..fdc3b817 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -192,6 +192,7 @@ check_PROGRAMS = \
 	move_pages \
 	mq \
 	msg_control \
+	msg_control-v \
 	munlockall \
 	nanosleep \
 	net-accept-connect \
@@ -505,6 +506,7 @@ DECODER_TESTS = \
 	move_pages.test \
 	mq.test \
 	msg_control.test \
+	msg_control-v.test \
 	munlockall.test \
 	nanosleep.test \
 	net-icmp_filter.test \
diff --git a/tests/msg_control-v.c b/tests/msg_control-v.c
new file mode 100644
index 00000000..d2a5653a
--- /dev/null
+++ b/tests/msg_control-v.c
@@ -0,0 +1,3 @@
+/* This file is part of msg_control-v strace test. */
+#define VERBOSE_MSGHDR
+#include "msg_control.c"
diff --git a/tests/msg_control-v.test b/tests/msg_control-v.test
new file mode 100755
index 00000000..41f98428
--- /dev/null
+++ b/tests/msg_control-v.test
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# Check verbose decoding of struct msghdr ancillary data.
+
+. "${srcdir=.}/init.sh"
+run_strace_match_diff -v -a21 -e trace=sendmsg
diff --git a/tests/msg_control.c b/tests/msg_control.c
index 4e0c258e..cecd5e8d 100644
--- a/tests/msg_control.c
+++ b/tests/msg_control.c
@@ -60,6 +60,8 @@ get_cmsghdr(void *const page, const size_t len)
 	return page - CMSG_ALIGN(len);
 }
 
+#define DEFAULT_STRLEN 32
+
 static void
 print_fds(const struct cmsghdr *const cmsg, const size_t cmsg_len)
 {
@@ -74,6 +76,12 @@ print_fds(const struct cmsghdr *const cmsg, const size_t cmsg_len)
 	for (i = 0; i < nfd; ++i) {
 		if (i)
 			printf(", ");
+#ifndef VERBOSE_MSGHDR
+		if (i >= DEFAULT_STRLEN) {
+			printf("...");
+			break;
+		}
+#endif
 		printf("%d", fdp[i]);
 	}
 	printf("]");
@@ -194,6 +202,33 @@ test_scm_rights2(struct msghdr *const mh,
 	       (unsigned long) msg_controllen, rc, errno2name());
 }
 
+static void
+test_scm_rights3(struct msghdr *const mh, void *const page, const size_t nfds)
+{
+	const size_t len = CMSG_SPACE(sizeof(int) * nfds);
+	struct cmsghdr *cmsg = get_cmsghdr(page, len);
+
+	cmsg->cmsg_len = CMSG_LEN(sizeof(int) * nfds);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	int *fdp = (int *) CMSG_DATA(cmsg);
+	size_t i;
+	for (i = 0; i < nfds; ++i)
+		fdp[i] = i;
+
+	mh->msg_control = cmsg;
+	mh->msg_controllen = len;
+
+	int rc = sendmsg(-1, mh, 0);
+	printf("sendmsg(-1, {msg_name=NULL, msg_namelen=0, msg_iov=NULL"
+	       ", msg_iovlen=0, msg_control=[{cmsg_len=%u"
+	       ", cmsg_level=SOL_SOCKET, cmsg_type=SCM_RIGHTS",
+	       (unsigned) cmsg->cmsg_len);
+	print_fds(cmsg, cmsg->cmsg_len);
+	printf("}], msg_controllen=%lu, msg_flags=0}, 0) = %d %s (%m)\n",
+	       (unsigned long) len, rc, errno2name());
+}
+
 static void
 print_security(const struct cmsghdr *const cmsg, const size_t cmsg_len)
 {
@@ -339,6 +374,10 @@ test_sol_socket(struct msghdr *const mh, void *const page)
 		}
 	}
 
+	test_scm_rights3(mh, page, DEFAULT_STRLEN - 1);
+	test_scm_rights3(mh, page, DEFAULT_STRLEN);
+	test_scm_rights3(mh, page, DEFAULT_STRLEN + 1);
+
 	test_unknown_type(mh, page, VAL_STR(SOL_SOCKET), "SCM_???");
 }