xref: /openbsd-src/usr.bin/tmux/cmd-pipe-pane.c (revision 91f110e064cd7c194e59e019b83bb7496c1c84d4)
1 /* $OpenBSD: cmd-pipe-pane.c,v 1.26 2013/10/10 12:00:21 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <paths.h>
25 #include <string.h>
26 #include <time.h>
27 #include <unistd.h>
28 
29 #include "tmux.h"
30 
31 /*
32  * Open pipe to redirect pane output. If already open, close first.
33  */
34 
35 enum cmd_retval	 cmd_pipe_pane_exec(struct cmd *, struct cmd_q *);
36 
37 void	cmd_pipe_pane_error_callback(struct bufferevent *, short, void *);
38 
39 const struct cmd_entry cmd_pipe_pane_entry = {
40 	"pipe-pane", "pipep",
41 	"ot:", 0, 1,
42 	"[-o] " CMD_TARGET_PANE_USAGE " [command]",
43 	0,
44 	NULL,
45 	cmd_pipe_pane_exec
46 };
47 
48 enum cmd_retval
49 cmd_pipe_pane_exec(struct cmd *self, struct cmd_q *cmdq)
50 {
51 	struct args		*args = self->args;
52 	struct client		*c;
53 	struct window_pane	*wp;
54 	char			*command;
55 	int			 old_fd, pipe_fd[2], null_fd;
56 
57 	if (cmd_find_pane(cmdq, args_get(args, 't'), NULL, &wp) == NULL)
58 		return (CMD_RETURN_ERROR);
59 	c = cmd_find_client(cmdq, NULL, 1);
60 
61 	/* Destroy the old pipe. */
62 	old_fd = wp->pipe_fd;
63 	if (wp->pipe_fd != -1) {
64 		bufferevent_free(wp->pipe_event);
65 		close(wp->pipe_fd);
66 		wp->pipe_fd = -1;
67 	}
68 
69 	/* If no pipe command, that is enough. */
70 	if (args->argc == 0 || *args->argv[0] == '\0')
71 		return (CMD_RETURN_NORMAL);
72 
73 	/*
74 	 * With -o, only open the new pipe if there was no previous one. This
75 	 * allows a pipe to be toggled with a single key, for example:
76 	 *
77 	 *	bind ^p pipep -o 'cat >>~/output'
78 	 */
79 	if (args_has(self->args, 'o') && old_fd != -1)
80 		return (CMD_RETURN_NORMAL);
81 
82 	/* Open the new pipe. */
83 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_fd) != 0) {
84 		cmdq_error(cmdq, "socketpair error: %s", strerror(errno));
85 		return (CMD_RETURN_ERROR);
86 	}
87 
88 	/* Fork the child. */
89 	switch (fork()) {
90 	case -1:
91 		cmdq_error(cmdq, "fork error: %s", strerror(errno));
92 		return (CMD_RETURN_ERROR);
93 	case 0:
94 		/* Child process. */
95 		close(pipe_fd[0]);
96 		clear_signals(1);
97 
98 		if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
99 			_exit(1);
100 		if (pipe_fd[1] != STDIN_FILENO)
101 			close(pipe_fd[1]);
102 
103 		null_fd = open(_PATH_DEVNULL, O_WRONLY, 0);
104 		if (dup2(null_fd, STDOUT_FILENO) == -1)
105 			_exit(1);
106 		if (dup2(null_fd, STDERR_FILENO) == -1)
107 			_exit(1);
108 		if (null_fd != STDOUT_FILENO && null_fd != STDERR_FILENO)
109 			close(null_fd);
110 
111 		closefrom(STDERR_FILENO + 1);
112 
113 		command = status_replace(
114 		    c, NULL, NULL, NULL, args->argv[0], time(NULL), 0);
115 		execl(_PATH_BSHELL, "sh", "-c", command, (char *) NULL);
116 		_exit(1);
117 	default:
118 		/* Parent process. */
119 		close(pipe_fd[1]);
120 
121 		wp->pipe_fd = pipe_fd[0];
122 		wp->pipe_off = EVBUFFER_LENGTH(wp->event->input);
123 
124 		wp->pipe_event = bufferevent_new(wp->pipe_fd,
125 		    NULL, NULL, cmd_pipe_pane_error_callback, wp);
126 		bufferevent_enable(wp->pipe_event, EV_WRITE);
127 
128 		setblocking(wp->pipe_fd, 0);
129 		return (CMD_RETURN_NORMAL);
130 	}
131 }
132 
133 void
134 cmd_pipe_pane_error_callback(
135     unused struct bufferevent *bufev, unused short what, void *data)
136 {
137 	struct window_pane	*wp = data;
138 
139 	bufferevent_free(wp->pipe_event);
140 	close(wp->pipe_fd);
141 	wp->pipe_fd = -1;
142 }
143