From: Masatake YAMATO <yamato@redhat.com>
Date: Wed, 1 Nov 2023 15:44:20 +0000 (+0900)
Subject: lsfd: add PTMX.TTY-INDEX column
X-Git-Tag: v2.40-rc1~165^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6919acfff864d36f84d84b5509133377b2f051b5;p=thirdparty%2Futil-linux.git

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>
---

diff --git a/misc-utils/lsfd-cdev.c b/misc-utils/lsfd-cdev.c
index 3cb133fb08..9bcbea3533 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 1f7e889d46..1e9d6acb76 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 0bb02e2821..76e0e66e17 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 c9c975392f..a819e65096 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,