xref: /openbsd/usr.bin/tmux/cmd-pipe-pane.c (revision 404b540a)
1 /* $OpenBSD: cmd-pipe-pane.c,v 1.1 2009/10/11 10:04:27 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 
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <paths.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 #include "tmux.h"
28 
29 /*
30  * Open pipe to redirect pane output. If already open, close first.
31  */
32 
33 int	cmd_pipe_pane_exec(struct cmd *, struct cmd_ctx *);
34 
35 const struct cmd_entry cmd_pipe_pane_entry = {
36 	"pipe-pane", "pipep",
37 	CMD_TARGET_PANE_USAGE "[-o] [command]",
38 	CMD_ARG01, CMD_CHFLAG('o'),
39 	cmd_target_init,
40 	cmd_target_parse,
41 	cmd_pipe_pane_exec,
42 	cmd_target_free,
43 	cmd_target_print
44 };
45 
46 int
47 cmd_pipe_pane_exec(struct cmd *self, struct cmd_ctx *ctx)
48 {
49 	struct cmd_target_data	*data = self->data;
50 	struct winlink		*wl;
51 	struct window_pane	*wp;
52 	int			 old_fd, pipe_fd[2], null_fd, mode;
53 
54 	if ((wl = cmd_find_pane(ctx, data->target, NULL, &wp)) == NULL)
55 		return (-1);
56 
57 	/* Destroy the old pipe. */
58 	old_fd = wp->pipe_fd;
59 	if (wp->pipe_fd != -1) {
60 		buffer_destroy(wp->pipe_buf);
61 		close(wp->pipe_fd);
62 		wp->pipe_fd = -1;
63 	}
64 
65 	/* If no pipe command, that is enough. */
66 	if (data->arg == NULL || *data->arg == '\0')
67 		return (0);
68 
69 	/*
70 	 * With -o, only open the new pipe if there was no previous one. This
71 	 * allows a pipe to be toggled with a single key, for example:
72 	 *
73 	 *	bind ^p pipep -o 'cat >>~/output'
74 	 */
75 	if (data->chflags & CMD_CHFLAG('o') && old_fd != -1)
76 		return (0);
77 
78 	/* Open the new pipe. */
79 	if (pipe(pipe_fd) != 0) {
80 		ctx->error(ctx, "pipe error: %s", strerror(errno));
81 		return (-1);
82 	}
83 
84 	/* Fork the child. */
85 	switch (fork()) {
86 	case -1:
87 		ctx->error(ctx, "fork error: %s", strerror(errno));
88 		return (-1);
89 	case 0:
90 		/* Child process. */
91 		close(pipe_fd[0]);
92 		sigreset();
93 
94 		if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
95 			_exit(1);
96 		if (pipe_fd[1] != STDIN_FILENO)
97 			close(pipe_fd[1]);
98 
99 		null_fd = open(_PATH_DEVNULL, O_WRONLY, 0);
100 		if (dup2(null_fd, STDOUT_FILENO) == -1)
101 			_exit(1);
102 		if (dup2(null_fd, STDERR_FILENO) == -1)
103 			_exit(1);
104 		if (null_fd != STDOUT_FILENO && null_fd != STDERR_FILENO)
105 			close(null_fd);
106 
107 		execl(_PATH_BSHELL, "sh", "-c", data->arg, (char *) NULL);
108 		_exit(1);
109 	default:
110 		/* Parent process. */
111 		close(pipe_fd[1]);
112 
113 		wp->pipe_fd = pipe_fd[0];
114 		wp->pipe_buf = buffer_create(BUFSIZ);
115 		wp->pipe_off = BUFFER_USED(wp->in);
116 
117 		if ((mode = fcntl(wp->pipe_fd, F_GETFL)) == -1)
118 			fatal("fcntl failed");
119 		if (fcntl(wp->pipe_fd, F_SETFL, mode|O_NONBLOCK) == -1)
120 			fatal("fcntl failed");
121 		if (fcntl(wp->pipe_fd, F_SETFD, FD_CLOEXEC) == -1)
122 			fatal("fcntl failed");
123 		return (0);
124 	}
125 
126 	return (0);
127 }
128