xref: /openbsd-src/usr.bin/tmux/cmd-pipe-pane.c (revision ac9b4aacc1da35008afea06a5d23c2f2dea9b93e)
1 /* $OpenBSD: cmd-pipe-pane.c,v 1.22 2012/07/11 07:10:15 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_ctx *);
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 	NULL,
46 	cmd_pipe_pane_exec
47 };
48 
49 enum cmd_retval
50 cmd_pipe_pane_exec(struct cmd *self, struct cmd_ctx *ctx)
51 {
52 	struct args		*args = self->args;
53 	struct client		*c;
54 	struct window_pane	*wp;
55 	char			*command;
56 	int			 old_fd, pipe_fd[2], null_fd;
57 
58 	if (cmd_find_pane(ctx, args_get(args, 't'), NULL, &wp) == NULL)
59 		return (CMD_RETURN_ERROR);
60 	c = cmd_find_client(ctx, NULL);
61 
62 	/* Destroy the old pipe. */
63 	old_fd = wp->pipe_fd;
64 	if (wp->pipe_fd != -1) {
65 		bufferevent_free(wp->pipe_event);
66 		close(wp->pipe_fd);
67 		wp->pipe_fd = -1;
68 	}
69 
70 	/* If no pipe command, that is enough. */
71 	if (args->argc == 0 || *args->argv[0] == '\0')
72 		return (CMD_RETURN_NORMAL);
73 
74 	/*
75 	 * With -o, only open the new pipe if there was no previous one. This
76 	 * allows a pipe to be toggled with a single key, for example:
77 	 *
78 	 *	bind ^p pipep -o 'cat >>~/output'
79 	 */
80 	if (args_has(self->args, 'o') && old_fd != -1)
81 		return (CMD_RETURN_NORMAL);
82 
83 	/* Open the new pipe. */
84 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_fd) != 0) {
85 		ctx->error(ctx, "socketpair error: %s", strerror(errno));
86 		return (CMD_RETURN_ERROR);
87 	}
88 
89 	/* Fork the child. */
90 	switch (fork()) {
91 	case -1:
92 		ctx->error(ctx, "fork error: %s", strerror(errno));
93 		return (CMD_RETURN_ERROR);
94 	case 0:
95 		/* Child process. */
96 		close(pipe_fd[0]);
97 		clear_signals(1);
98 
99 		if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
100 			_exit(1);
101 		if (pipe_fd[1] != STDIN_FILENO)
102 			close(pipe_fd[1]);
103 
104 		null_fd = open(_PATH_DEVNULL, O_WRONLY, 0);
105 		if (dup2(null_fd, STDOUT_FILENO) == -1)
106 			_exit(1);
107 		if (dup2(null_fd, STDERR_FILENO) == -1)
108 			_exit(1);
109 		if (null_fd != STDOUT_FILENO && null_fd != STDERR_FILENO)
110 			close(null_fd);
111 
112 		closefrom(STDERR_FILENO + 1);
113 
114 		command = status_replace(
115 		    c, NULL, NULL, NULL, args->argv[0], time(NULL), 0);
116 		execl(_PATH_BSHELL, "sh", "-c", command, (char *) NULL);
117 		_exit(1);
118 	default:
119 		/* Parent process. */
120 		close(pipe_fd[1]);
121 
122 		wp->pipe_fd = pipe_fd[0];
123 		wp->pipe_off = EVBUFFER_LENGTH(wp->event->input);
124 
125 		wp->pipe_event = bufferevent_new(wp->pipe_fd,
126 		    NULL, NULL, cmd_pipe_pane_error_callback, wp);
127 		bufferevent_enable(wp->pipe_event, EV_WRITE);
128 
129 		setblocking(wp->pipe_fd, 0);
130 		return (CMD_RETURN_NORMAL);
131 	}
132 }
133 
134 /* ARGSUSED */
135 void
136 cmd_pipe_pane_error_callback(
137     unused struct bufferevent *bufev, unused short what, void *data)
138 {
139 	struct window_pane	*wp = data;
140 
141 	bufferevent_free(wp->pipe_event);
142 	close(wp->pipe_fd);
143 	wp->pipe_fd = -1;
144 }
145