From: Masatake YAMATO <yamato@redhat.com>
Date: Sun, 9 May 2021 01:41:34 +0000 (+0900)
Subject: lsfd: add a function to get the name of filesystem from a given minor number
X-Git-Tag: v2.38-rc1~144^2~134
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=269c425f5b4b4ccb13c8773bbe7d3853d9d5a46b;p=thirdparty%2Futil-linux.git

lsfd: add a function to get the name of filesystem from a given minor number

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

diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index 8204ca486b..65aff806c4 100644
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -74,6 +74,15 @@ struct map {
 	unsigned int read:1, write:1, exec:1, shared:1;
 };
 
+/*
+ * /proc/$pid/mountinfo entries
+ */
+struct nodev {
+	struct list_head nodevs;
+	unsigned long minor;
+	char *filesystem;
+};
+
 /*
  * Column related stuffs
  */
@@ -230,11 +239,34 @@ static void free_file(struct file *file)
 	free(file);
 }
 
+static struct nodev* make_nodev(unsigned long minor, const char *filesystem)
+{
+	struct nodev *nodev = xcalloc(1, sizeof(*nodev));
+
+	INIT_LIST_HEAD(&nodev->nodevs);
+	nodev->minor = minor;
+	nodev->filesystem = xstrdup(filesystem);
+
+	return nodev;
+}
+
+static void free_nodev(struct nodev *nodev)
+{
+	free(nodev->filesystem);
+	free(nodev);
+}
+
+static void free_nodevs(struct list_head *nodevs)
+{
+	list_free(nodevs, struct nodev, nodevs, free_nodev);
+}
+
 static void free_proc(struct proc *proc)
 {
 	list_free(&proc->files, struct file, files, free_file);
 
 	free(proc->command);
+	free_nodevs(&proc->nodevs);
 	free(proc);
 }
 
@@ -715,9 +747,43 @@ static void collect_namespace_files(struct proc *proc)
 			       ARRAY_SIZE(namespace_assocs));
 }
 
+static FILE *open_mountinfo(pid_t pid, pid_t tid)
+{
+	return fopenf("r", "/proc/%d/task/%d/mountinfo", pid, tid);
+}
+
+static void read_nodevs(struct list_head *nodevs_list, FILE *mountinfo_fp)
+{
+	/* This can be very long.
+	   A line in mountinfo can have more than 3 paths. */
+	char line[PATH_MAX * 3 + 256];
+	while (fgets(line, sizeof(line), mountinfo_fp)) {
+		struct nodev *nodev;
+		unsigned long major, minor;
+		char filesystem[256];
+
+		/* 23 61 0:22 / /sys rw,nosuid,nodev,noexec,relatime shared:2 - sysfs sysfs rw,seclabel */
+		if(sscanf(line, "%*d %*d %lu:%lu %*s %*s %*s %*[^-] - %s %*[^\n]",
+			  &major, &minor, filesystem) != 3)
+			/* 1600 1458 0:55 / / rw,nodev,relatime - overlay overlay rw,context="s... */
+			if (sscanf(line, "%*d %*d %lu:%lu %*s %*s %*s - %s %*[^\n]",
+				   &major, &minor, filesystem) != 3)
+				continue;
+
+		if (major != 0)
+			continue;
+
+		nodev = make_nodev(minor, filesystem);
+		list_add_tail(&nodev->nodevs, nodevs_list);
+	}
+}
+
 static void fill_proc(struct proc *proc)
 {
+	FILE *mountinfo_fp;
+
 	INIT_LIST_HEAD(&proc->files);
+	INIT_LIST_HEAD(&proc->nodevs);
 
 	proc->command = proc_get_command_name(proc->pid);
 	if (!proc->command)
@@ -733,6 +799,13 @@ static void fill_proc(struct proc *proc)
 
 	collect_namespace_files(proc);
 
+	mountinfo_fp = open_mountinfo(proc->leader->pid,
+				      proc->pid);
+	if (mountinfo_fp) {
+		read_nodevs(&proc->nodevs, mountinfo_fp);
+		fclose(mountinfo_fp);
+	}
+
 	/* If kcmp is not available,
 	 * there is no way to no whether threads share resources.
 	 * In such cases, we must pay the costs: call collect_mem_files()
@@ -1080,6 +1153,17 @@ unsigned long add_name(struct name_manager *nm, const char *name)
 	return e->id;
 }
 
+const char *get_nodev_filesystem(struct proc *proc, unsigned long minor)
+{
+	struct list_head *n;
+	list_for_each (n, &proc->nodevs) {
+		struct nodev *nodev = list_entry(n, struct nodev, nodevs);
+		if (nodev->minor == minor)
+			return nodev->filesystem;
+	}
+	return NULL;
+}
+
 DIR *opendirf(const char *format, ...)
 {
 	va_list ap;
diff --git a/misc-utils/lsfd.h b/misc-utils/lsfd.h
index 6f4e5d840d..a274ad9c70 100644
--- a/misc-utils/lsfd.h
+++ b/misc-utils/lsfd.h
@@ -106,6 +106,7 @@ struct proc {
 	uid_t uid;
 	struct list_head procs;
 	struct list_head files;
+	struct list_head nodevs;
 };
 
 /*
@@ -166,5 +167,6 @@ unsigned long add_name(struct name_manager *nm, const char *name);
 const char *get_partition(dev_t dev);
 const char *get_chrdrv(unsigned long major);
 const char *get_miscdev(unsigned long minor);
+const char *get_nodev_filesystem(struct proc *proc, unsigned long minor);
 
 #endif /* UTIL_LINUX_LSFD_H */