From: Masatake YAMATO <yamato@redhat.com>
Date: Mon, 18 Sep 2023 06:39:39 +0000 (+0900)
Subject: lsfd: collect the device number for mqueue fs in the initialization stage
X-Git-Tag: v2.40-rc1~237^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e3dedb011e1fe578e921c0c6858e9b3d9b79ec84;p=thirdparty%2Futil-linux.git

lsfd: collect the device number for mqueue fs in the initialization stage

Though lsfd reads device minor numbers for file-systems having "nodev"
from /proc/$pid/mountinfo, we observed lsfd failed to resolve the
values of SOURCE column for mqueue files on s390 CI/CD env. It seems
that /proc/$pid/mountinfo doesn't provide enough information.

This change makes lsfd open a mqueue file in lsfd's initialization
stage as a new data source for resolving; lsfd can collect an
actually-used minor number from the file descriptor with fstat(2).

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---

diff --git a/meson.build b/meson.build
index 8e3d6bb1d9..6c23797beb 100644
--- a/meson.build
+++ b/meson.build
@@ -2615,12 +2615,16 @@ if not is_disabler(exe)
   bashcompletions += ['lsblk']
 endif
 
+mq_libs = []
+mq_libs += cc.find_library('rt', required : true)
+
 exe = executable(
   'lsfd',
   lsfd_sources,
   include_directories : includes,
   link_with : [lib_common,
                lib_smartcols],
+  dependencies : mq_libs,
   install_dir : usrbin_exec_dir,
   install : true)
 if not is_disabler(exe)
@@ -3377,9 +3381,6 @@ exe = executable(
   build_by_default: program_tests)
 exes += exe
 
-mq_libs = []
-mq_libs += cc.find_library('rt', required : true)
-
 if LINUX
   exe = executable(
     'test_mkfds',
diff --git a/misc-utils/Makemodule.am b/misc-utils/Makemodule.am
index dd6204afdd..e794d8cb12 100644
--- a/misc-utils/Makemodule.am
+++ b/misc-utils/Makemodule.am
@@ -267,7 +267,7 @@ lsfd_SOURCES = \
 	misc-utils/lsfd-sock-xinfo.c \
 	misc-utils/lsfd-unkn.c \
 	misc-utils/lsfd-fifo.c
-lsfd_LDADD = $(LDADD) libsmartcols.la libcommon.la
+lsfd_LDADD = $(LDADD) $(MQ_LIBS) libsmartcols.la libcommon.la
 lsfd_CFLAGS = $(AM_CFLAGS) -I$(ul_libsmartcols_incdir)
 endif
 
diff --git a/misc-utils/lsfd-file.c b/misc-utils/lsfd-file.c
index 186ce62e5e..f65910d31c 100644
--- a/misc-utils/lsfd-file.c
+++ b/misc-utils/lsfd-file.c
@@ -34,6 +34,10 @@
 #include <linux/sched.h>
 #include <sys/shm.h>
 
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <mqueue.h>		/* mq_open */
+
 #include "buffer.h"
 #include "idcache.h"
 #include "strutils.h"
@@ -460,6 +464,34 @@ static unsigned long get_minor_for_sysvipc(void)
 	return m;
 }
 
+static unsigned long get_minor_for_mqueue(void)
+{
+	mqd_t mq;
+	char mq_name[BUFSIZ];
+	struct mq_attr attr = {
+		.mq_maxmsg = 1,
+		.mq_msgsize = 1,
+	};
+
+	pid_t self = getpid();
+	struct stat sb;
+
+	snprintf(mq_name, sizeof(mq_name), "/.lsfd-mqueue-nodev-test:%d", self);
+	mq = mq_open(mq_name, O_CREAT|O_EXCL | O_RDONLY, S_IRUSR | S_IWUSR, &attr);
+	if (mq < 0)
+		return 0;
+
+	if (fstat((int)mq, &sb) < 0) {
+		mq_close(mq);
+		mq_unlink(mq_name);
+		return 0;
+	}
+
+	mq_close(mq);
+	mq_unlink(mq_name);
+	return minor(sb.st_dev);
+}
+
 static void file_class_initialize(void)
 {
 	unsigned long m;
@@ -474,6 +506,10 @@ static void file_class_initialize(void)
 	m = get_minor_for_sysvipc();
 	if (m)
 		add_nodev(m, "tmpfs");
+
+	m = get_minor_for_mqueue();
+	if (m)
+		add_nodev(m, "mqueue");
 }
 
 static void file_class_finalize(void)