From 837c9eeccdc4bc99382394121bbb1b63eba2b866 Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Wed, 1 Nov 2023 08:18:11 +0900
Subject: [PATCH 1/7] lsfd: make the order of calling finalize_* and
 initialize_* consistent

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 misc-utils/lsfd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index 862a0d4e0b2..0bb02e28210 100644
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -2323,9 +2323,9 @@ int main(int argc, char *argv[])
 	/* cleanup */
 	delete(&ctl.procs, &ctl);
 
-	finalize_ipc_table();
 	finalize_devdrvs();
 	finalize_classes();
+	finalize_ipc_table();
 	finalize_nodevs();
 
 	return 0;

From f5bc75bff728036d140e9fdd54594166437f5114 Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Thu, 2 Nov 2023 00:05:12 +0900
Subject: [PATCH 2/7] lsfd: utilize /proc/tty/drivers for filling SOURCE column
 of tty devices

The original code referenced /proc/devices using major numbers as keys to obtain
the name of the device driver corresponding to a file descriptor.

However, it turnes out that some drivers share a same major number;
there are cases that a key is not unique.

  Character devices:
    1 mem
    4 /dev/vc/0
    4 tty
    4 ttyS
    ...

About tty-related devices, /proc/tty/drivers is better information
source; both major and minor numbers can be used as keys:

  /dev/tty             /dev/tty        5       0 system:/dev/tty
  /dev/console         /dev/console    5       1 system:console
  /dev/ptmx            /dev/ptmx       5       2 system
  /dev/vc/0            /dev/vc/0       4       0 system:vtmaster
  usbserial            /dev/ttyUSB   188 0-511 serial
  dbc_serial           /dev/ttyDBC   242 0-63 serial
  serial               /dev/ttyS       4 64-95 serial
  pty_slave            /dev/pts      136 0-1048575 pty:slave
  pty_master           /dev/ptm      128 0-1048575 pty:master
  unknown              /dev/tty        4 1-63 console

This commit extracts the second column of the /proc/tty/drivers as
driver names after removing "/dev": tty, console, ptmx, ...

With the orinal code:

  # lsfd -n -p 1789 -Q '(FD == 25)'
  systemd-logind  1789 root    25  rw-  CHR /dev/vc/0:6   432    25 /dev/tty6
--------------------------------------------^^^^^^^^^^^
With this commit:

  # ./lsfd -n -p 1789 -Q '(FD == 25)'
  systemd-logind  1789 root    25  rw---- CHR tty:6 432 25 /dev/tty6
----------------------------------------------^^^^^

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 misc-utils/lsfd-cdev.c | 169 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 164 insertions(+), 5 deletions(-)

diff --git a/misc-utils/lsfd-cdev.c b/misc-utils/lsfd-cdev.c
index 70751bab970..3cb133fb080 100644
--- a/misc-utils/lsfd-cdev.c
+++ b/misc-utils/lsfd-cdev.c
@@ -22,6 +22,7 @@
 #include "lsfd.h"
 
 static struct list_head miscdevs;
+static struct list_head ttydrvs;
 
 struct miscdev {
 	struct list_head miscdevs;
@@ -29,6 +30,13 @@ struct miscdev {
 	char *name;
 };
 
+struct ttydrv {
+	struct list_head ttydrvs;
+	unsigned long major;
+	unsigned long minor_start, minor_end;
+	char *name;
+};
+
 struct cdev {
 	struct file file;
 	const char *devdrv;
@@ -38,7 +46,7 @@ struct cdev {
 
 struct cdev_ops {
 	const struct cdev_ops *parent;
-	bool (*probe)(const struct cdev *);
+	bool (*probe)(struct cdev *);
 	char * (*get_name)(struct cdev *);
 	bool (*fill_column)(struct proc *,
 			    struct cdev *,
@@ -139,22 +147,97 @@ static void read_misc(struct list_head *miscdevs_list, FILE *misc_fp)
 	}
 }
 
+#define TTY_DRIVERS_LINE_LEN0 1023
+#define TTY_DRIVERS_LINE_LEN  (TTY_DRIVERS_LINE_LEN0 + 1)
+static struct ttydrv *new_ttydrv(unsigned int major,
+				 unsigned int minor_start, unsigned int minor_end,
+				 const char *name)
+{
+	struct ttydrv *ttydrv = xmalloc(sizeof(*ttydrv));
+
+	INIT_LIST_HEAD(&ttydrv->ttydrvs);
+
+	ttydrv->major = major;
+	ttydrv->minor_start = minor_start;
+	ttydrv->minor_end = minor_end;
+	ttydrv->name = xstrdup(name);
+
+	return ttydrv;
+}
+
+static void free_ttydrv(struct ttydrv *ttydrv)
+{
+	free(ttydrv->name);
+	free(ttydrv);
+}
+
+static struct ttydrv *read_ttydrv(const char *line)
+{
+	const char *p;
+	char name[TTY_DRIVERS_LINE_LEN];
+	unsigned long major;
+	unsigned long minor_range[2];
+
+	p = strchr(line, ' ');
+	if (p == NULL)
+		return NULL;
+
+	p = strstr(p, "/dev/");
+	if (p == NULL)
+		return NULL;
+	p += (sizeof("/dev/") - 1); /* Ignore the last null byte. */
+
+	if (sscanf(p, "%" stringify_value(TTY_DRIVERS_LINE_LEN0) "[^ ]", name) != 1)
+		return NULL;
+
+	p += strlen (name);
+	if (sscanf(p, " %lu %lu-%lu ", &major,
+		   minor_range, minor_range + 1) != 3) {
+		if (sscanf(p, " %lu %lu ", &major, minor_range) == 2)
+			minor_range[1] = minor_range[0];
+		else
+			return NULL;
+	}
+
+	return new_ttydrv(major, minor_range[0], minor_range[1], name);
+}
+
+static void read_tty_drivers(struct list_head *ttydrvs_list, FILE *ttydrvs_fp)
+{
+	char line[TTY_DRIVERS_LINE_LEN];
+
+	while (fgets(line, sizeof(line), ttydrvs_fp)) {
+		struct ttydrv *ttydrv = read_ttydrv(line);
+		if (ttydrv)
+			list_add_tail(&ttydrv->ttydrvs, ttydrvs_list);
+	}
+}
+
 static void cdev_class_initialize(void)
 {
 	FILE *misc_fp;
+	FILE *ttydrvs_fp;
 
 	INIT_LIST_HEAD(&miscdevs);
+	INIT_LIST_HEAD(&ttydrvs);
 
 	misc_fp = fopen("/proc/misc", "r");
 	if (misc_fp) {
 		read_misc(&miscdevs, misc_fp);
 		fclose(misc_fp);
 	}
+
+	ttydrvs_fp = fopen("/proc/tty/drivers", "r");
+	if (ttydrvs_fp) {
+		read_tty_drivers(&ttydrvs, ttydrvs_fp);
+		fclose(ttydrvs_fp);
+	}
 }
 
 static void cdev_class_finalize(void)
 {
 	list_free(&miscdevs, struct miscdev, miscdevs, free_miscdev);
+	list_free(&ttydrvs,  struct ttydrv,  ttydrvs,  free_ttydrv);
 }
 
 const char *get_miscdev(unsigned long minor)
@@ -168,10 +251,27 @@ const char *get_miscdev(unsigned long minor)
 	return NULL;
 }
 
+static const struct ttydrv *get_ttydrv(unsigned long major,
+				       unsigned long minor)
+{
+	struct list_head *c;
+
+	list_for_each(c, &ttydrvs) {
+		struct ttydrv *ttydrv = list_entry(c, struct ttydrv, ttydrvs);
+		if (ttydrv->major == major
+		    && ttydrv->minor_start <= minor
+		    && minor <= ttydrv->minor_end)
+			return ttydrv;
+	}
+
+	return NULL;
+}
+
+
 /*
  * generic (fallback implementation)
  */
-static bool cdev_generic_probe(const struct cdev *cdev __attribute__((__unused__))) {
+static bool cdev_generic_probe(struct cdev *cdev __attribute__((__unused__))) {
 	return true;
 }
 
@@ -210,7 +310,7 @@ static struct cdev_ops cdev_generic_ops = {
 /*
  * misc device driver
  */
-static bool cdev_misc_probe(const struct cdev *cdev) {
+static bool cdev_misc_probe(struct cdev *cdev) {
 	return cdev->devdrv && strcmp(cdev->devdrv, "misc") == 0;
 }
 
@@ -254,7 +354,7 @@ static struct cdev_ops cdev_misc_ops = {
 /*
  * tun devcie driver
  */
-static bool cdev_tun_probe(const struct cdev *cdev)
+static bool cdev_tun_probe(struct cdev *cdev)
 {
 	const char *miscdev;
 
@@ -325,13 +425,72 @@ static struct cdev_ops cdev_tun_ops = {
 	.handle_fdinfo = cdev_tun_handle_fdinfo,
 };
 
+/*
+ * tty devices
+ */
+struct ttydata {
+	const struct ttydrv *drv;
+};
+
+static bool cdev_tty_probe(struct cdev *cdev) {
+	const struct ttydrv *ttydrv = get_ttydrv(major(cdev->file.stat.st_rdev),
+						 minor(cdev->file.stat.st_rdev));
+	struct ttydata *data;
+
+	if (!ttydrv)
+		return false;
+
+	data = xmalloc(sizeof(struct ttydata));
+	data->drv = ttydrv;
+	cdev->cdev_data = data;
+
+	return true;
+}
+
+static void cdev_tty_free(const struct cdev *cdev)
+{
+	if (cdev->cdev_data)
+		free(cdev->cdev_data);
+}
+
+static bool cdev_tty_fill_column(struct proc *proc  __attribute__((__unused__)),
+				 struct cdev *cdev,
+				 struct libscols_line *ln __attribute__((__unused__)),
+				 int column_id,
+				 size_t column_index __attribute__((__unused__)),
+				 char **str)
+{
+	struct file *file = &cdev->file;
+	struct ttydata *data = cdev->cdev_data;
+
+	switch(column_id) {
+	case COL_SOURCE:
+		if (data->drv->minor_start == data->drv->minor_end)
+			*str = xstrdup(data->drv->name);
+		else
+			xasprintf(str, "%s:%u", data->drv->name,
+				  minor(file->stat.st_rdev));
+		return true;
+	default:
+		return false;
+	}
+}
+
+static struct cdev_ops cdev_tty_ops = {
+	.parent = &cdev_generic_ops,
+	.probe = cdev_tty_probe,
+	.free = cdev_tty_free,
+	.fill_column = cdev_tty_fill_column,
+};
+
 static const struct cdev_ops *cdev_ops[] = {
 	&cdev_tun_ops,
 	&cdev_misc_ops,
+	&cdev_tty_ops,
 	&cdev_generic_ops		  /* This must be at the end. */
 };
 
-static const struct cdev_ops *cdev_probe(const struct cdev *cdev)
+static const struct cdev_ops *cdev_probe(struct cdev *cdev)
 {
 	const struct cdev_ops *r = NULL;
 

From 6919acfff864d36f84d84b5509133377b2f051b5 Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Thu, 2 Nov 2023 00:44:20 +0900
Subject: [PATCH 3/7] lsfd: add PTMX.TTY-INDEX column

tty-index field in /proc/$pid/fdinfo/$fd is the data source of
the column. The value is helpful for looking up the conterpart
of /dev/ptmx.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 misc-utils/lsfd-cdev.c | 50 ++++++++++++++++++++++++++++++++++++++++++
 misc-utils/lsfd.1.adoc |  9 ++++++++
 misc-utils/lsfd.c      |  3 +++
 misc-utils/lsfd.h      |  1 +
 4 files changed, 63 insertions(+)

diff --git a/misc-utils/lsfd-cdev.c b/misc-utils/lsfd-cdev.c
index 3cb133fb080..9bcbea35332 100644
--- a/misc-utils/lsfd-cdev.c
+++ b/misc-utils/lsfd-cdev.c
@@ -35,6 +35,7 @@ struct ttydrv {
 	unsigned long major;
 	unsigned long minor_start, minor_end;
 	char *name;
+	bool is_ptmx;
 };
 
 struct cdev {
@@ -161,6 +162,9 @@ static struct ttydrv *new_ttydrv(unsigned int major,
 	ttydrv->minor_start = minor_start;
 	ttydrv->minor_end = minor_end;
 	ttydrv->name = xstrdup(name);
+	ttydrv->is_ptmx = false;
+	if (strcmp(name, "ptmx") == 0)
+		ttydrv->is_ptmx = true;
 
 	return ttydrv;
 }
@@ -430,6 +434,8 @@ static struct cdev_ops cdev_tun_ops = {
  */
 struct ttydata {
 	const struct ttydrv *drv;
+#define NO_TTY_INDEX -1
+	int tty_index;		/* used only in ptmx devices */
 };
 
 static bool cdev_tty_probe(struct cdev *cdev) {
@@ -442,6 +448,7 @@ static bool cdev_tty_probe(struct cdev *cdev) {
 
 	data = xmalloc(sizeof(struct ttydata));
 	data->drv = ttydrv;
+	data->tty_index = NO_TTY_INDEX;
 	cdev->cdev_data = data;
 
 	return true;
@@ -453,6 +460,21 @@ static void cdev_tty_free(const struct cdev *cdev)
 		free(cdev->cdev_data);
 }
 
+static char * cdev_tty_get_name(struct cdev *cdev)
+{
+	struct ttydata *data = cdev->cdev_data;
+	char *str = NULL;
+
+	if (!data->drv->is_ptmx)
+		return NULL;
+
+	if (data->tty_index == NO_TTY_INDEX)
+		str = xstrdup("tty-index=");
+	else
+		xasprintf(&str, "tty-index=%d", data->tty_index);
+	return str;
+}
+
 static bool cdev_tty_fill_column(struct proc *proc  __attribute__((__unused__)),
 				 struct cdev *cdev,
 				 struct libscols_line *ln __attribute__((__unused__)),
@@ -471,16 +493,44 @@ static bool cdev_tty_fill_column(struct proc *proc  __attribute__((__unused__)),
 			xasprintf(str, "%s:%u", data->drv->name,
 				  minor(file->stat.st_rdev));
 		return true;
+	case COL_PTMX_TTY_INDEX:
+		if (data->drv->is_ptmx) {
+			xasprintf(str, "%d", data->tty_index);
+			return true;
+		}
+		return false;
 	default:
 		return false;
 	}
 }
 
+static int cdev_tty_handle_fdinfo(struct cdev *cdev, const char *key, const char *val)
+{
+	struct ttydata *data = cdev->cdev_data;
+
+	if (!data->drv->is_ptmx)
+		return 0;
+
+	if (strcmp(key, "tty-index") == 0) {
+		errno = 0;
+		data->tty_index = (int)strtol(val, NULL, 10);
+		if (errno) {
+			data->tty_index = NO_TTY_INDEX;
+			return 0;
+		}
+		return 1;
+	}
+
+	return 0;
+}
+
 static struct cdev_ops cdev_tty_ops = {
 	.parent = &cdev_generic_ops,
 	.probe = cdev_tty_probe,
 	.free = cdev_tty_free,
+	.get_name = cdev_tty_get_name,
 	.fill_column = cdev_tty_fill_column,
+	.handle_fdinfo = cdev_tty_handle_fdinfo,
 };
 
 static const struct cdev_ops *cdev_ops[] = {
diff --git a/misc-utils/lsfd.1.adoc b/misc-utils/lsfd.1.adoc
index 1f7e889d46c..1e9d6acb76e 100644
--- a/misc-utils/lsfd.1.adoc
+++ b/misc-utils/lsfd.1.adoc
@@ -304,6 +304,12 @@ state=_SOCK.STATE_[ id=_PING.ID_][ laddr=_INET.LADDR_ [ raddr=_INET.RADDR_]]
 PINGv6:::
 state=_SOCK.STATE_[ id=_PING.ID_][ laddr=_INET6.LADDR_ [ raddr=_INET6.RADDR_]]
 +
+ptmx:::
+tty-index=_PTMX.TTY-INDEX_
++
+*lsfd* extracts _PTMX.TTY-INDEX_ from
+``/proc/``_pid_``/fdinfo/``_fd_.
++
 RAW:::
 state=_SOCK.STATE_[ protocol=_RAW.PROTOCOL_ [ laddr=_INET.LADDR_ [ raddr=_INET.RADDR_]]]
 +
@@ -484,6 +490,9 @@ Interval.
 TIMERFD.REMAINING <``number``>::
 Remaining time.
 
+PTMX.TTY-INDEX <``number``>::
+TTY index of the counterpart.
+
 TUN.IFACE <``string``>::
 Network intrface behind the tun device.
 
diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index 0bb02e28210..76e0e66e179 100644
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -275,6 +275,9 @@ static const struct colinfo infos[] = {
 	[COL_POS]              = { "POS",
 				   5,   SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER,
 				   N_("file position") },
+	[COL_PTMX_TTY_INDEX]   = { "PTMX.TTY-INDEX",
+				   0,   SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER,
+				   N_("tty index of the counterpart") },
 	[COL_RAW_PROTOCOL]     = { "RAW.PROTOCOL",
 				   0,   SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER,
 				   N_("protocol number of the raw socket") },
diff --git a/misc-utils/lsfd.h b/misc-utils/lsfd.h
index c9c975392fc..a819e65096c 100644
--- a/misc-utils/lsfd.h
+++ b/misc-utils/lsfd.h
@@ -92,6 +92,7 @@ enum {
 	COL_PIDFD_PID,
 	COL_PING_ID,
 	COL_POS,
+	COL_PTMX_TTY_INDEX,
 	COL_RAW_PROTOCOL,
 	COL_RDEV,
 	COL_SIGNALFD_MASK,

From 036a12d4888289579f324e32ebffd94c2827a506 Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Thu, 2 Nov 2023 02:42:27 +0900
Subject: [PATCH 4/7] lsfd: add attach_xinfo and get_ipc_class methods to
 cdev_ops

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 misc-utils/lsfd-cdev.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/misc-utils/lsfd-cdev.c b/misc-utils/lsfd-cdev.c
index 9bcbea35332..0f47169f834 100644
--- a/misc-utils/lsfd-cdev.c
+++ b/misc-utils/lsfd-cdev.c
@@ -57,7 +57,9 @@ struct cdev_ops {
 			    char **);
 	void (*init)(const struct cdev *);
 	void (*free)(const struct cdev *);
+	void (*attach_xinfo)(struct cdev *);
 	int (*handle_fdinfo)(struct cdev *, const char *, const char *);
+	const struct ipc_class * (*get_ipc_class)(struct cdev *);
 };
 
 static bool cdev_fill_column(struct proc *proc __attribute__((__unused__)),
@@ -575,6 +577,14 @@ static void free_cdev_content(struct file *file)
 		cdev->cdev_ops->free(cdev);
 }
 
+static void cdev_attach_xinfo(struct file *file)
+{
+	struct cdev *cdev = (struct cdev *)file;
+
+	if (cdev->cdev_ops->attach_xinfo)
+		cdev->cdev_ops->attach_xinfo(cdev);
+}
+
 static int cdev_handle_fdinfo(struct file *file, const char *key, const char *value)
 {
 	struct cdev *cdev = (struct cdev *)file;
@@ -584,6 +594,15 @@ static int cdev_handle_fdinfo(struct file *file, const char *key, const char *va
 	return 0;		/* Should be handled in parents */
 }
 
+static const struct ipc_class *cdev_get_ipc_class(struct file *file)
+{
+	struct cdev *cdev = (struct cdev *)file;
+
+	if (cdev->cdev_ops->get_ipc_class)
+		return cdev->cdev_ops->get_ipc_class(cdev);
+	return NULL;
+}
+
 const struct file_class cdev_class = {
 	.super = &file_class,
 	.size = sizeof(struct cdev),
@@ -592,5 +611,7 @@ const struct file_class cdev_class = {
 	.fill_column = cdev_fill_column,
 	.initialize_content = init_cdev_content,
 	.free_content = free_cdev_content,
+	.attach_xinfo = cdev_attach_xinfo,
 	.handle_fdinfo = cdev_handle_fdinfo,
+	.get_ipc_class = cdev_get_ipc_class,
 };

From 52e94d61b09a05f7ee5ef0dddf75e9c69b3f0368 Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Thu, 2 Nov 2023 02:47:35 +0900
Subject: [PATCH 5/7] lsfd: fill ENDPOINTS column for pty devices

An example output:

  $ ./lsfd -o+ENDPOINTS -Q '(COMMAND =~ "tmux") and ((SOURCE == "ptmx") or (SOURCE =~ "pts:.*"))'
  COMMAND          PID   USER ASSOC  XMODE TYPE SOURCE MNTID INODE NAME         ENDPOINTS
  tmux: client 3717086 yamato     0 rw----  CHR  pts:9    27    12 /dev/pts/9   2143274,xfce4-terminal,34rw
  tmux: client 3717086 yamato     1 rw----  CHR  pts:9    27    12 /dev/pts/9   2143274,xfce4-terminal,34rw
  tmux: client 3717086 yamato     2 rw----  CHR  pts:9    27    12 /dev/pts/9   2143274,xfce4-terminal,34rw
  tmux: server 3717088 yamato     5 rw---m  CHR  pts:9    27    12 /dev/pts/9   2143274,xfce4-terminal,34rw
  tmux: server 3717088 yamato     8 rw---m  CHR   ptmx    24   208 tty-index=16 3717089,zsh,0rw
                                                                                3717089,zsh,1rw
                                                                                3717089,zsh,2rw
                                                                                3717089,zsh,10rw

  $ ./lsfd -o+ENDPOINTS -Q '(PID == 3717089) and (FD == 0)'
  COMMAND     PID   USER ASSOC  XMODE TYPE SOURCE MNTID INODE NAME        ENDPOINTS
  zsh     3717089 yamato     0 rw----  CHR pts:16    27    19 /dev/pts/16 3717088,tmux: server,8rw

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 misc-utils/lsfd-cdev.c | 120 +++++++++++++++++++++++++++++++++++++++--
 misc-utils/lsfd.1.adoc |   1 +
 2 files changed, 118 insertions(+), 3 deletions(-)

diff --git a/misc-utils/lsfd-cdev.c b/misc-utils/lsfd-cdev.c
index 0f47169f834..63f95ed516b 100644
--- a/misc-utils/lsfd-cdev.c
+++ b/misc-utils/lsfd-cdev.c
@@ -35,7 +35,8 @@ struct ttydrv {
 	unsigned long major;
 	unsigned long minor_start, minor_end;
 	char *name;
-	bool is_ptmx;
+	unsigned int is_ptmx: 1;
+	unsigned int is_pts: 1;
 };
 
 struct cdev {
@@ -164,9 +165,12 @@ static struct ttydrv *new_ttydrv(unsigned int major,
 	ttydrv->minor_start = minor_start;
 	ttydrv->minor_end = minor_end;
 	ttydrv->name = xstrdup(name);
-	ttydrv->is_ptmx = false;
+	ttydrv->is_ptmx = 0;
 	if (strcmp(name, "ptmx") == 0)
-		ttydrv->is_ptmx = true;
+		ttydrv->is_ptmx = 1;
+	ttydrv->is_pts = 0;
+	if (strcmp(name, "pts") == 0)
+		ttydrv->is_pts = 1;
 
 	return ttydrv;
 }
@@ -177,6 +181,11 @@ static void free_ttydrv(struct ttydrv *ttydrv)
 	free(ttydrv);
 }
 
+static bool is_pty(const struct ttydrv *ttydrv)
+{
+	return ttydrv->is_ptmx || ttydrv->is_pts;
+}
+
 static struct ttydrv *read_ttydrv(const char *line)
 {
 	const char *p;
@@ -435,9 +444,11 @@ static struct cdev_ops cdev_tun_ops = {
  * tty devices
  */
 struct ttydata {
+	struct cdev *cdev;
 	const struct ttydrv *drv;
 #define NO_TTY_INDEX -1
 	int tty_index;		/* used only in ptmx devices */
+	struct ipc_endpoint endpoint;
 };
 
 static bool cdev_tty_probe(struct cdev *cdev) {
@@ -449,6 +460,7 @@ static bool cdev_tty_probe(struct cdev *cdev) {
 		return false;
 
 	data = xmalloc(sizeof(struct ttydata));
+	data->cdev = cdev;
 	data->drv = ttydrv;
 	data->tty_index = NO_TTY_INDEX;
 	cdev->cdev_data = data;
@@ -477,6 +489,16 @@ static char * cdev_tty_get_name(struct cdev *cdev)
 	return str;
 }
 
+static inline char *cdev_tty_xstrendpoint(struct file *file)
+{
+	char *str = NULL;
+	xasprintf(&str, "%d,%s,%d%c%c",
+		  file->proc->pid, file->proc->command, file->association,
+		  (file->mode & S_IRUSR)? 'r': '-',
+		  (file->mode & S_IWUSR)? 'w': '-');
+	return str;
+}
+
 static bool cdev_tty_fill_column(struct proc *proc  __attribute__((__unused__)),
 				 struct cdev *cdev,
 				 struct libscols_line *ln __attribute__((__unused__)),
@@ -501,6 +523,30 @@ static bool cdev_tty_fill_column(struct proc *proc  __attribute__((__unused__)),
 			return true;
 		}
 		return false;
+	case COL_ENDPOINTS:
+		if (is_pty(data->drv)) {
+			struct ttydata *this = data;
+			struct list_head *e;
+			foreach_endpoint(e, data->endpoint) {
+				char *estr;
+				struct ttydata *other = list_entry(e, struct ttydata, endpoint.endpoints);
+				if (this == other)
+					continue;
+
+				if ((this->drv->is_ptmx && !other->drv->is_pts)
+				    || (this->drv->is_pts && !other->drv->is_ptmx))
+					continue;
+
+				if (*str)
+					xstrputc(str, '\n');
+				estr = cdev_tty_xstrendpoint(&other->cdev->file);
+				xstrappend(str, estr);
+				free(estr);
+			}
+			if (*str)
+				return true;
+		}
+		return false;
 	default:
 		return false;
 	}
@@ -526,13 +572,81 @@ static int cdev_tty_handle_fdinfo(struct cdev *cdev, const char *key, const char
 	return 0;
 }
 
+struct cdev_pty_ipc {
+	struct ipc ipc;
+	int tty_index;
+};
+
+static unsigned int cdev_pty_get_hash(struct file *file)
+{
+	struct cdev *cdev = (struct cdev *)file;
+	struct ttydata *data = cdev->cdev_data;
+
+	return data->drv->is_ptmx?
+		(unsigned int)data->tty_index:
+		(unsigned int)minor(file->stat.st_rdev);
+}
+
+static bool cdev_pty_is_suitable_ipc(struct ipc *ipc, struct file *file)
+{
+	struct cdev *cdev = (struct cdev *)file;
+	struct ttydata *data = cdev->cdev_data;
+	struct cdev_pty_ipc *cdev_pty_ipc = (struct cdev_pty_ipc *)ipc;
+
+	return (data->drv->is_ptmx)?
+		cdev_pty_ipc->tty_index == (int)data->tty_index:
+		cdev_pty_ipc->tty_index == (int)minor(file->stat.st_rdev);
+}
+
+static const struct ipc_class *cdev_tty_get_ipc_class(struct cdev *cdev)
+{
+	static const struct ipc_class cdev_pty_ipc_class = {
+		.size = sizeof(struct cdev_pty_ipc),
+		.get_hash = cdev_pty_get_hash,
+		.is_suitable_ipc = cdev_pty_is_suitable_ipc,
+	};
+
+	struct ttydata *data = cdev->cdev_data;
+
+	if (is_pty(data->drv))
+		return &cdev_pty_ipc_class;
+
+	return NULL;
+}
+
+static void cdev_tty_attach_xinfo(struct cdev *cdev)
+{
+	struct ttydata *data = cdev->cdev_data;
+	struct ipc *ipc;
+	unsigned int hash;
+
+
+	if (! is_pty(data->drv))
+		return;
+
+	init_endpoint(&data->endpoint);
+	ipc = get_ipc(&cdev->file);
+	if (ipc)
+		goto link;
+
+	ipc = new_ipc(cdev_tty_get_ipc_class(cdev));
+	hash = cdev_pty_get_hash(&cdev->file);
+	((struct cdev_pty_ipc *)ipc)->tty_index = (int)hash;
+
+	add_ipc(ipc, hash);
+ link:
+	add_endpoint(&data->endpoint, ipc);
+}
+
 static struct cdev_ops cdev_tty_ops = {
 	.parent = &cdev_generic_ops,
 	.probe = cdev_tty_probe,
 	.free = cdev_tty_free,
 	.get_name = cdev_tty_get_name,
 	.fill_column = cdev_tty_fill_column,
+	.attach_xinfo  = cdev_tty_attach_xinfo,
 	.handle_fdinfo = cdev_tty_handle_fdinfo,
+	.get_ipc_class = cdev_tty_get_ipc_class,
 };
 
 static const struct cdev_ops *cdev_ops[] = {
diff --git a/misc-utils/lsfd.1.adoc b/misc-utils/lsfd.1.adoc
index 1e9d6acb76e..aef76ec5e3f 100644
--- a/misc-utils/lsfd.1.adoc
+++ b/misc-utils/lsfd.1.adoc
@@ -180,6 +180,7 @@ with the fd:
 
 FIFO type:::
 mqueue type:::
+ptmx and pts sources:::
 _PID_,_COMMAND_,_ASSOC_[-r][-w]
 +
 The last characters ([-r][-w]) represents the read and/or

From a76ea60adab8b1562a5ccb2d9b497e72be500b9f Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Sat, 4 Nov 2023 04:38:52 +0900
Subject: [PATCH 6/7] tests: (test_mkfds::pty) add a new factory

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 tests/helpers/test_mkfds.c | 108 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 1 deletion(-)

diff --git a/tests/helpers/test_mkfds.c b/tests/helpers/test_mkfds.c
index 8a1388adff4..cd5379bc2b7 100644
--- a/tests/helpers/test_mkfds.c
+++ b/tests/helpers/test_mkfds.c
@@ -3020,6 +3020,99 @@ static void *make_bpf_map(const struct factory *factory, struct fdesc fdescs[],
 	return NULL;
 }
 
+static void *make_pty(const struct factory *factory _U_, struct fdesc fdescs[],
+		      int argc _U_, char ** argv _U_)
+{
+	int index, *indexp;
+	char *pts;
+	int pts_fd;
+	int ptmx_fd = posix_openpt(O_RDWR);
+	if (ptmx_fd < 0)
+		err(EXIT_FAILURE, "failed in opening /dev/ptmx");
+
+	if (unlockpt(ptmx_fd) < 0) {
+		int e = errno;
+		close(ptmx_fd);
+		errno = e;
+		err(EXIT_FAILURE, "failed in unlockpt()");
+	}
+
+	if (ioctl(ptmx_fd, TIOCGPTN, &index) < 0) {
+		int e = errno;
+		close(ptmx_fd);
+		errno = e;
+		err(EXIT_FAILURE, "failed in ioctl(TIOCGPTN)");
+	}
+
+	pts = ptsname(ptmx_fd);
+	if (pts == NULL) {
+		int e = errno;
+		close(ptmx_fd);
+		errno = e;
+		err(EXIT_FAILURE, "failed in ptsname()");
+	}
+
+	if (ptmx_fd != fdescs[0].fd) {
+		if (dup2(ptmx_fd, fdescs[0].fd) < 0) {
+			int e = errno;
+			close(ptmx_fd);
+			errno = e;
+			err(EXIT_FAILURE, "failed to dup %d -> %d", ptmx_fd, fdescs[0].fd);
+		}
+		close(ptmx_fd);
+		ptmx_fd = fdescs[0].fd;
+	}
+
+	pts_fd = open(pts, O_RDONLY);
+	if (pts_fd < 0) {
+		int e = errno;
+		close(ptmx_fd);
+		errno = e;
+		err(EXIT_FAILURE, "failed in opening %s", pts);
+	}
+
+	if (pts_fd != fdescs[1].fd) {
+		if (dup2(pts_fd, fdescs[1].fd) < 0) {
+			int e = errno;
+			close(pts_fd);
+			close(ptmx_fd);
+			errno = e;
+			err(EXIT_FAILURE, "failed to dup %d -> %d", pts_fd, fdescs[1].fd);
+		}
+		close(pts_fd);
+		pts_fd = fdescs[1].fd;
+	}
+
+	fdescs[0] = (struct fdesc){
+		.fd    = fdescs[0].fd,
+		.close = close_fdesc,
+		.data  = NULL
+	};
+	fdescs[1] = (struct fdesc){
+		.fd    = fdescs[1].fd,
+		.close = close_fdesc,
+		.data  = NULL
+	};
+
+	indexp = xmalloc(sizeof(index));
+	*indexp = index;
+	return indexp;
+}
+
+static void report_pty(const struct factory *factory _U_,
+		       int nth, void *data, FILE *fp)
+{
+	if (nth == 0) {
+		int *index = data;
+		fprintf(fp, "%d", *index);
+	}
+}
+
+static void free_pty(const struct factory * factory _U_, void *data)
+{
+	free(data);
+}
+
 #define PARAM_END { .name = NULL, }
 static const struct factory factories[] = {
 	{
@@ -3817,7 +3910,20 @@ static const struct factory factories[] = {
 			PARAM_END
 		}
 	},
-
+	{
+		.name = "pty",
+		.desc = "make a pair of ptmx and pts",
+		.priv = false,
+		.N = 2,
+		.EX_N = 0,
+		.EX_R = 1,
+		.make = make_pty,
+		.report = report_pty,
+		.free = free_pty,
+		.params = (struct parameter []) {
+			PARAM_END
+		}
+	},
 };
 
 static int count_parameters(const struct factory *factory)

From bedfc7dd72ed7a50758c6290600b51fd8db656dd Mon Sep 17 00:00:00 2001
From: Masatake YAMATO <yamato@redhat.com>
Date: Sat, 4 Nov 2023 05:22:21 +0900
Subject: [PATCH 7/7] tests: (lsfd) add a case testing NAME, SOURCE, ENDPOINTS,
 and PTMX.TTY-INDEX columns of pts fds

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
 tests/expected/lsfd/mkfds-pty | 10 +++++
 tests/ts/lsfd/mkfds-pty       | 73 +++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 tests/expected/lsfd/mkfds-pty
 create mode 100755 tests/ts/lsfd/mkfds-pty

diff --git a/tests/expected/lsfd/mkfds-pty b/tests/expected/lsfd/mkfds-pty
new file mode 100644
index 00000000000..ac38fc974b7
--- /dev/null
+++ b/tests/expected/lsfd/mkfds-pty
@@ -0,0 +1,10 @@
+5 rw- CHR ptmx
+ASSOC,MODE,TYPE,SOURCE: 0
+NAME: 0
+ENDPOINTS: 0
+PTMX.TTY-INDEX: 0
+6 r-- CHR
+ASSOC,MODE,TYPE: 0
+SOURCE: 0
+NAME: 0
+ENDPOINTS: 0
diff --git a/tests/ts/lsfd/mkfds-pty b/tests/ts/lsfd/mkfds-pty
new file mode 100755
index 00000000000..cc781ebe1e7
--- /dev/null
+++ b/tests/ts/lsfd/mkfds-pty
@@ -0,0 +1,73 @@
+#!/bin/bash
+#
+# Copyright (C) 2023 Masatake YAMATO <yamato@redhat.com>
+#
+# This file is part of util-linux.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+TS_TOPDIR="${0%/*}/../.."
+TS_DESC="ptmx and associated pts"
+
+. "$TS_TOPDIR"/functions.sh
+ts_init "$*"
+
+ts_check_test_command "$TS_CMD_LSFD"
+ts_check_test_command "$TS_HELPER_MKFDS"
+
+ts_cd "$TS_OUTDIR"
+
+PID=
+FD0=5
+FD1=6
+INDEX=
+
+col_test()
+{
+    local col=$1
+    local expected=$2
+    local output
+
+    output=$(${TS_CMD_LSFD} -p "${PID}" -n --raw -o "$col" -Q "${EXPR}")
+    echo "$col": $?
+    if [[ "$output" != "$expected" ]]; then
+	echo "expected ${col} -Q ${EXPR}: ${expected}"
+	echo "output ${col} -Q ${EXPR}: ${output}"
+    fi
+}
+
+{
+    coproc MKFDS { "$TS_HELPER_MKFDS" pty $FD0 $FD1 ; }
+    if read -u ${MKFDS[0]} PID INDEX; then
+	EXPR='(FD == '$FD0')'
+	columns=ASSOC,MODE,TYPE,SOURCE
+	${TS_CMD_LSFD} -p "${PID}" -n -r -o "$columns" -Q "${EXPR}"
+	echo "$columns": $?
+
+	col_test NAME "tty-index=${INDEX}"
+	col_test ENDPOINTS "${PID},test_mkfds,${FD1}r-"
+	col_test PTMX.TTY-INDEX "$INDEX"
+
+	EXPR='(FD == '$FD1')'
+	columns=ASSOC,MODE,TYPE
+	${TS_CMD_LSFD} -p "${PID}" -n -r -o "$columns" -Q "${EXPR}"
+	echo "$columns": $?
+
+	col_test SOURCE "pts:${INDEX}"
+	col_test NAME "/dev/pts/${INDEX}"
+	col_test ENDPOINTS "${PID},test_mkfds,${FD0}rw"
+
+	echo DONE >&"${MKFDS[1]}"
+    fi
+    wait ${MKFDS_PID}
+} > $TS_OUTPUT 2>&1
+
+ts_finalize