From 1e40fc6fa9c4e394195fd2972c8831526c684f5e Mon Sep 17 00:00:00 2001
From: Jamie Gritton <jamie@FreeBSD.org>
Date: Sat, 26 Feb 2022 17:45:28 -0800
Subject: [PATCH] MFC posixshm: Add a -j option to posixshmcontrol ls, to
 specify a jail

PR:		257556
Reported by:	grembo@

(cherry picked from commit be7cf3f4b8c2818155f5a4a83c64c9ef6a60a320)
---
 usr.bin/posixshmcontrol/Makefile          |  2 +-
 usr.bin/posixshmcontrol/posixshmcontrol.1 |  8 ++++-
 usr.bin/posixshmcontrol/posixshmcontrol.c | 39 +++++++++++++++++++----
 3 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/usr.bin/posixshmcontrol/Makefile b/usr.bin/posixshmcontrol/Makefile
index c6f847e1847..e5e9588df7b 100644
--- a/usr.bin/posixshmcontrol/Makefile
+++ b/usr.bin/posixshmcontrol/Makefile
@@ -1,6 +1,6 @@
 # $FreeBSD$
 
 PROG=   posixshmcontrol
-LIBADD=	util
+LIBADD=	jail util
 
 .include <bsd.prog.mk>
diff --git a/usr.bin/posixshmcontrol/posixshmcontrol.1 b/usr.bin/posixshmcontrol/posixshmcontrol.1
index f6743b070b5..1d8c3438b16 100644
--- a/usr.bin/posixshmcontrol/posixshmcontrol.1
+++ b/usr.bin/posixshmcontrol/posixshmcontrol.1
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 18, 2020
+.Dd February 26, 2022
 .Dt POSIXSHMCONTROL 1
 .Os
 .Sh NAME
@@ -45,6 +45,7 @@
 .Ar ls
 .Op Fl h
 .Op Fl n
+.Op Fl j Ar jail
 .Nm
 .Ar dump
 .Op Pa path \&...
@@ -87,6 +88,11 @@ Unlink the paths specified.
 .It Ic ls
 List all linked named shared memory segments visible to the caller.
 For each segment, the user and group owner, size, and path are displayed.
+The
+.Fl j
+option limits the output to segments within the specified
+.Ar jail
+name or id.
 .It Ic dump
 Output raw bytes values from the segment to standard output.
 .It Ic stat
diff --git a/usr.bin/posixshmcontrol/posixshmcontrol.c b/usr.bin/posixshmcontrol/posixshmcontrol.c
index 47a19b78a9d..f64fcd3dd66 100644
--- a/usr.bin/posixshmcontrol/posixshmcontrol.c
+++ b/usr.bin/posixshmcontrol/posixshmcontrol.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <fcntl.h>
 #include <grp.h>
+#include <jail.h>
 #include <libutil.h>
 #include <pwd.h>
 #include <stdbool.h>
@@ -54,7 +55,7 @@ usage(void)
 	fprintf(stderr, "Usage:\n"
 	    "posixshmcontrol create [-m <mode>] [-l <largepage>] <path> ...\n"
 	    "posixshmcontrol rm <path> ...\n"
-	    "posixshmcontrol ls [-h] [-n]\n"
+	    "posixshmcontrol ls [-h] [-n] [-j jail]\n"
 	    "posixshmcontrol dump <path> ...\n"
 	    "posixshmcontrol stat [-h] [-n] <path> ...\n"
 	    "posixshmcontrol truncate [-s <newlen>] <path> ...\n");
@@ -221,17 +222,19 @@ shm_decode_mode(mode_t m, char *str)
 static int
 list_shm(int argc, char **argv)
 {
-	char *buf, *bp, sizebuf[8], str[10];
+	char *buf, *bp, *ep, jailpath[MAXPATHLEN], sizebuf[8], str[10];
+	const char *jailparam;
 	const struct kinfo_file *kif;
 	struct stat st;
-	int c, error, fd, mib[3], ret;
-	size_t len, miblen;
-	bool hsize, uname;
+	int c, error, fd, jid, mib[3], ret;
+	size_t len, jailpathlen, miblen;
+	bool hsize, jailed, uname;
 
 	hsize = false;
+	jailed = false;
 	uname = true;
 
-	while ((c = getopt(argc, argv, "hn")) != -1) {
+	while ((c = getopt(argc, argv, "hj:n")) != -1) {
 		switch (c) {
 		case 'h':
 			hsize = true;
@@ -239,6 +242,28 @@ list_shm(int argc, char **argv)
 		case 'n':
 			uname = false;
 			break;
+		case 'j':
+			jid = strtoul(optarg, &ep, 10);
+			if (ep > optarg && !*ep) {
+				jailparam = "jid";
+				jailed = jid > 0;
+			} else {
+				jailparam = "name";
+				jailed = true;
+			}
+			if (jailed) {
+				if (jail_getv(0, jailparam, optarg, "path",
+				    jailpath, NULL) < 0) {
+					if (errno == ENOENT)
+						warnx("no such jail: %s", optarg);
+					else
+						warnx("%s", jail_errmsg);
+					return (1);
+				}
+				jailpathlen = strlen(jailpath);
+				jailpath[jailpathlen] = '/';
+			}
+			break;
 		default:
 			usage();
 			return (2);
@@ -279,6 +304,8 @@ list_shm(int argc, char **argv)
 		kif = (const struct kinfo_file *)(void *)bp;
 		if (kif->kf_structsize == 0)
 			break;
+		if (jailed && strncmp(kif->kf_path, jailpath, jailpathlen + 1))
+			continue;
 		fd = shm_open(kif->kf_path, O_RDONLY, 0);
 		if (fd == -1) {
 			warn("open %s", kif->kf_path);