xref: /netbsd-src/external/bsd/tmux/dist/cmd-pipe-pane.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /* $OpenBSD$ */
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 <stdlib.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 	cmd_pipe_pane_exec
45 };
46 
47 enum cmd_retval
48 cmd_pipe_pane_exec(struct cmd *self, struct cmd_q *cmdq)
49 {
50 	struct args		*args = self->args;
51 	struct client		*c;
52 	struct session		*s;
53 	struct winlink		*wl;
54 	struct window_pane	*wp;
55 	char			*cmd;
56 	int			 old_fd, pipe_fd[2], null_fd;
57 	struct format_tree	*ft;
58 
59 	if ((wl = cmd_find_pane(cmdq, args_get(args, 't'), &s, &wp)) == NULL)
60 		return (CMD_RETURN_ERROR);
61 	c = cmd_find_client(cmdq, NULL, 1);
62 
63 	/* Destroy the old pipe. */
64 	old_fd = wp->pipe_fd;
65 	if (wp->pipe_fd != -1) {
66 		bufferevent_free(wp->pipe_event);
67 		close(wp->pipe_fd);
68 		wp->pipe_fd = -1;
69 	}
70 
71 	/* If no pipe command, that is enough. */
72 	if (args->argc == 0 || *args->argv[0] == '\0')
73 		return (CMD_RETURN_NORMAL);
74 
75 	/*
76 	 * With -o, only open the new pipe if there was no previous one. This
77 	 * allows a pipe to be toggled with a single key, for example:
78 	 *
79 	 *	bind ^p pipep -o 'cat >>~/output'
80 	 */
81 	if (args_has(self->args, 'o') && old_fd != -1)
82 		return (CMD_RETURN_NORMAL);
83 
84 	/* Open the new pipe. */
85 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_fd) != 0) {
86 		cmdq_error(cmdq, "socketpair error: %s", strerror(errno));
87 		return (CMD_RETURN_ERROR);
88 	}
89 
90 	/* Expand the command. */
91 	ft = format_create();
92 	format_defaults(ft, c, s, wl, wp);
93 	cmd = format_expand_time(ft, args->argv[0], time(NULL));
94 	format_free(ft);
95 
96 	/* Fork the child. */
97 	switch (fork()) {
98 	case -1:
99 		cmdq_error(cmdq, "fork error: %s", strerror(errno));
100 
101 		free(cmd);
102 		return (CMD_RETURN_ERROR);
103 	case 0:
104 		/* Child process. */
105 		close(pipe_fd[0]);
106 		clear_signals(1);
107 
108 		if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
109 			_exit(1);
110 		if (pipe_fd[1] != STDIN_FILENO)
111 			close(pipe_fd[1]);
112 
113 		null_fd = open(_PATH_DEVNULL, O_WRONLY, 0);
114 		if (dup2(null_fd, STDOUT_FILENO) == -1)
115 			_exit(1);
116 		if (dup2(null_fd, STDERR_FILENO) == -1)
117 			_exit(1);
118 		if (null_fd != STDOUT_FILENO && null_fd != STDERR_FILENO)
119 			close(null_fd);
120 
121 		closefrom(STDERR_FILENO + 1);
122 
123 		execl(_PATH_BSHELL, "sh", "-c", cmd, (char *) NULL);
124 		_exit(1);
125 	default:
126 		/* Parent process. */
127 		close(pipe_fd[1]);
128 
129 		wp->pipe_fd = pipe_fd[0];
130 		wp->pipe_off = EVBUFFER_LENGTH(wp->event->input);
131 
132 		wp->pipe_event = bufferevent_new(wp->pipe_fd,
133 		    NULL, NULL, cmd_pipe_pane_error_callback, wp);
134 		bufferevent_enable(wp->pipe_event, EV_WRITE);
135 
136 		setblocking(wp->pipe_fd, 0);
137 
138 		free(cmd);
139 		return (CMD_RETURN_NORMAL);
140 	}
141 }
142 
143 void
144 cmd_pipe_pane_error_callback(
145     unused struct bufferevent *bufev, unused short what, void *data)
146 {
147 	struct window_pane	*wp = data;
148 
149 	bufferevent_free(wp->pipe_event);
150 	close(wp->pipe_fd);
151 	wp->pipe_fd = -1;
152 }
153