Use pgrp of pty fd not pid of immediate child when recovering current working

directory (like current process). From Marcel Partap.

cmd.c

@@ -1297,7 +1297,7 @@ cmd_get_default_path(struct cmd_ctx *ctx, const char *cwd)
 		if (ctx->cmdclient != NULL && ctx->cmdclient->cwd != NULL)
 			root = ctx->cmdclient->cwd;
 		else if (ctx->curclient != NULL && s->curw != NULL)
-			root = osdep_get_cwd(s->curw->window->active->pid);
+			root = osdep_get_cwd(s->curw->window->active->fd);
 		else
 			return (s->cwd);
 		skip = 0;

format.c

@@ -391,7 +391,7 @@ format_window_pane(struct format_tree *ft, struct window_pane *wp)
 		format_add(ft, "pane_start_command", "%s", wp->cmd);
 	if (wp->cwd != NULL)
 		format_add(ft, "pane_start_path", "%s", wp->cwd);
-	format_add(ft, "pane_current_path", "%s", osdep_get_cwd(wp->pid));
+	format_add(ft, "pane_current_path", "%s", osdep_get_cwd(wp->fd));
 	format_add(ft, "pane_pid", "%ld", (long) wp->pid);
 	format_add(ft, "pane_tty", "%s", wp->tty);
 }

osdep-aix.c

@@ -29,7 +29,7 @@ osdep_get_name(unused int fd, unused char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(unused int fd)
 {
 	return (NULL);
 }

osdep-darwin.c

@@ -26,7 +26,7 @@
 #include <unistd.h>
 
 char			*osdep_get_name(int, char *);
-char			*osdep_get_cwd(pid_t);
+char			*osdep_get_cwd(int);
 struct event_base	*osdep_event_init(void);
 
 #define unused __attribute__ ((unused))
@@ -51,14 +51,18 @@ osdep_get_name(int fd, unused char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	static char 			wd[PATH_MAX];
 	struct proc_vnodepathinfo	pathinfo;
+	pid_t				pgrp;
 	int				ret;
 
+	if ((pgrp = tcgetpgrp(fd)) == -1)
+		return (NULL);
+
 	ret = proc_pidinfo(
-	    pid, PROC_PIDVNODEPATHINFO, 0, &pathinfo, sizeof pathinfo);
+	    pgrp, PROC_PIDVNODEPATHINFO, 0, &pathinfo, sizeof pathinfo);
 	if (ret == sizeof pathinfo) {
 		strlcpy(wd, pathinfo.pvi_cdir.vip_path, sizeof wd);
 		return (wd);

osdep-dragonfly.c

@@ -31,7 +31,7 @@
 
 struct kinfo_proc	*cmp_procs(struct kinfo_proc *, struct kinfo_proc *);
 char			*osdep_get_name(int, char *);
-char			*osdep_get_cwd(pid_t);
+char			*osdep_get_cwd(int);
 struct event_base	*osdep_event_init(void);
 
 #ifndef nitems
@@ -121,7 +121,7 @@ error:
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	return (NULL);
 }

osdep-freebsd.c

@@ -33,7 +33,7 @@
 
 struct kinfo_proc	*cmp_procs(struct kinfo_proc *, struct kinfo_proc *);
 char			*osdep_get_name(int, char *);
-char			*osdep_get_cwd(pid_t);
+char			*osdep_get_cwd(int);
 struct event_base	*osdep_event_init(void);
 
 #ifndef nitems
@@ -133,13 +133,17 @@ error:
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	static char		 wd[PATH_MAX];
 	struct kinfo_file	*info = NULL;
+	pid_t			 pgrp;
 	int			 nrecords, i;
 
-	if ((info = kinfo_getfile(pid, &nrecords)) == NULL)
+	if ((pgrp = tcgetpgrp(fd)) == -1)
+		return (NULL);
+
+	if ((info = kinfo_getfile(pgrp, &nrecords)) == NULL)
 		return (NULL);
 
 	for (i = 0; i < nrecords; i++) {

osdep-hpux.c

@@ -29,7 +29,7 @@ osdep_get_name(unused int fd, unused char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(unused int fd)
 {
 	return (NULL);
 }

osdep-linux.c

@@ -61,13 +61,17 @@ osdep_get_name(int fd, unused char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	static char	 target[MAXPATHLEN + 1];
 	char		*path;
+	pid_t		 pgrp;
 	ssize_t		 n;
 
-	xasprintf(&path, "/proc/%d/cwd", pid);
+	if ((pgrp = tcgetpgrp(fd)) == -1)
+		return (NULL);
+
+	xasprintf(&path, "/proc/%lld/cwd", (long long) pgrp);
 	n = readlink(path, target, MAXPATHLEN);
 	free(path);
 	if (n > 0) {

osdep-netbsd.c

@@ -34,7 +34,7 @@
 
 struct kinfo_proc2	*cmp_procs(struct kinfo_proc2 *, struct kinfo_proc2 *);
 char			*osdep_get_name(int, char *);
-char			*osdep_get_cwd(pid_t);
+char			*osdep_get_cwd(int);
 struct event_base	*osdep_event_init(void);
 
 struct kinfo_proc2 *
@@ -125,7 +125,7 @@ error:
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	return (NULL);
 }

osdep-openbsd.c

@@ -37,7 +37,7 @@
 
 struct kinfo_proc	*cmp_procs(struct kinfo_proc *, struct kinfo_proc *);
 char			*osdep_get_name(int, char *);
-char			*osdep_get_cwd(pid_t);
+char			*osdep_get_cwd(int);
 struct event_base	*osdep_event_init(void);
 
 struct kinfo_proc *
@@ -135,12 +135,14 @@ error:
 }
 
 char*
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
-	int		name[] = { CTL_KERN, KERN_PROC_CWD, (int)pid };
+	int		name[] = { CTL_KERN, KERN_PROC_CWD, 0 };
 	static char	path[MAXPATHLEN];
 	size_t		pathlen = sizeof path;
 
+	if ((name[2] = tcgetpgrp(fd)) == -1)
+		return (NULL);
 	if (sysctl(name, 3, path, &pathlen, NULL, 0) != 0)
 		return (NULL);
 	return (path);

osdep-sunos.c

@@ -65,13 +65,17 @@ osdep_get_name(int fd, char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	static char	 target[MAXPATHLEN + 1];
 	char		*path;
 	ssize_t		 n;
+	pid_t		 pgrp;
 
-	xasprintf(&path, "/proc/%u/path/cwd", (u_int) pid);
+	if ((pgrp = tcgetpgrp(fd)) == -1)
+		return (NULL);
+
+	xasprintf(&path, "/proc/%u/path/cwd", (u_int) pgrp);
 	n = readlink(path, target, MAXPATHLEN);
 	free(path);
 	if (n > 0) {

osdep-unknown.c

@@ -29,7 +29,7 @@ osdep_get_name(unused int fd, unused char *tty)
 }
 
 char *
-osdep_get_cwd(pid_t pid)
+osdep_get_cwd(int fd)
 {
 	return (NULL);
 }

tmux.h

@@ -2273,7 +2273,7 @@ u_int	utf8_split2(u_int, u_char *);
 
 /* osdep-*.c */
 char		*osdep_get_name(int, char *);
-char		*osdep_get_cwd(pid_t);
+char		*osdep_get_cwd(int);
 struct event_base *osdep_event_init(void);
 
 /* log.c */