xref: /netbsd-src/external/bsd/tmux/dist/cmd-pipe-pane.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1 /* $OpenBSD$ */
2 
3 /*
4  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
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 <signal.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <time.h>
28 #include <unistd.h>
29 
30 #include "tmux.h"
31 
32 /*
33  * Open pipe to redirect pane output. If already open, close first.
34  */
35 
36 static enum cmd_retval	cmd_pipe_pane_exec(struct cmd *, struct cmdq_item *);
37 
38 static void cmd_pipe_pane_read_callback(struct bufferevent *, void *);
39 static void cmd_pipe_pane_write_callback(struct bufferevent *, void *);
40 static void cmd_pipe_pane_error_callback(struct bufferevent *, short, void *);
41 
42 const struct cmd_entry cmd_pipe_pane_entry = {
43 	.name = "pipe-pane",
44 	.alias = "pipep",
45 
46 	.args = { "IOot:", 0, 1 },
47 	.usage = "[-IOo] " CMD_TARGET_PANE_USAGE " [command]",
48 
49 	.target = { 't', CMD_FIND_PANE, 0 },
50 
51 	.flags = CMD_AFTERHOOK,
52 	.exec = cmd_pipe_pane_exec
53 };
54 
55 static enum cmd_retval
56 cmd_pipe_pane_exec(struct cmd *self, struct cmdq_item *item)
57 {
58 	struct args		*args = self->args;
59 	struct client		*c = cmd_find_client(item, NULL, 1);
60 	struct window_pane	*wp = item->target.wp;
61 	struct session		*s = item->target.s;
62 	struct winlink		*wl = item->target.wl;
63 	char			*cmd;
64 	int			 old_fd, pipe_fd[2], null_fd, in, out;
65 	struct format_tree	*ft;
66 	sigset_t		 set, oldset;
67 
68 	/* Destroy the old pipe. */
69 	old_fd = wp->pipe_fd;
70 	if (wp->pipe_fd != -1) {
71 		bufferevent_free(wp->pipe_event);
72 		close(wp->pipe_fd);
73 		wp->pipe_fd = -1;
74 
75 		if (window_pane_destroy_ready(wp)) {
76 			server_destroy_pane(wp, 1);
77 			return (CMD_RETURN_NORMAL);
78 		}
79 	}
80 
81 	/* If no pipe command, that is enough. */
82 	if (args->argc == 0 || *args->argv[0] == '\0')
83 		return (CMD_RETURN_NORMAL);
84 
85 	/*
86 	 * With -o, only open the new pipe if there was no previous one. This
87 	 * allows a pipe to be toggled with a single key, for example:
88 	 *
89 	 *	bind ^p pipep -o 'cat >>~/output'
90 	 */
91 	if (args_has(self->args, 'o') && old_fd != -1)
92 		return (CMD_RETURN_NORMAL);
93 
94 	/* What do we want to do? Neither -I or -O is -O. */
95 	if (args_has(self->args, 'I')) {
96 		in = 1;
97 		out = args_has(self->args, 'O');
98 	} else {
99 		in = 0;
100 		out = 1;
101 	}
102 
103 	/* Open the new pipe. */
104 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_fd) != 0) {
105 		cmdq_error(item, "socketpair error: %s", strerror(errno));
106 		return (CMD_RETURN_ERROR);
107 	}
108 
109 	/* Expand the command. */
110 	ft = format_create(item->client, item, FORMAT_NONE, 0);
111 	format_defaults(ft, c, s, wl, wp);
112 	cmd = format_expand_time(ft, args->argv[0]);
113 	format_free(ft);
114 
115 	/* Fork the child. */
116 	sigfillset(&set);
117 	sigprocmask(SIG_BLOCK, &set, &oldset);
118 	switch (fork()) {
119 	case -1:
120 		sigprocmask(SIG_SETMASK, &oldset, NULL);
121 		cmdq_error(item, "fork error: %s", strerror(errno));
122 
123 		free(cmd);
124 		return (CMD_RETURN_ERROR);
125 	case 0:
126 		/* Child process. */
127 		proc_clear_signals(server_proc, 1);
128 		sigprocmask(SIG_SETMASK, &oldset, NULL);
129 		close(pipe_fd[0]);
130 
131 		null_fd = open(_PATH_DEVNULL, O_WRONLY, 0);
132 		if (out) {
133 			if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
134 				_exit(1);
135 		} else {
136 			if (dup2(null_fd, STDIN_FILENO) == -1)
137 				_exit(1);
138 		}
139 		if (in) {
140 			if (dup2(pipe_fd[1], STDOUT_FILENO) == -1)
141 				_exit(1);
142 			if (pipe_fd[1] != STDOUT_FILENO)
143 				close(pipe_fd[1]);
144 		} else {
145 			if (dup2(null_fd, STDOUT_FILENO) == -1)
146 				_exit(1);
147 		}
148 		if (dup2(null_fd, STDERR_FILENO) == -1)
149 			_exit(1);
150 		closefrom(STDERR_FILENO + 1);
151 
152 		execl(_PATH_BSHELL, "sh", "-c", cmd, (char *) NULL);
153 		_exit(1);
154 	default:
155 		/* Parent process. */
156 		sigprocmask(SIG_SETMASK, &oldset, NULL);
157 		close(pipe_fd[1]);
158 
159 		wp->pipe_fd = pipe_fd[0];
160 		if (wp->fd != -1)
161 			wp->pipe_off = EVBUFFER_LENGTH(wp->event->input);
162 		else
163 			wp->pipe_off = 0;
164 
165 		setblocking(wp->pipe_fd, 0);
166 		wp->pipe_event = bufferevent_new(wp->pipe_fd,
167 		    cmd_pipe_pane_read_callback,
168 		    cmd_pipe_pane_write_callback,
169 		    cmd_pipe_pane_error_callback,
170 		    wp);
171 		if (wp->pipe_event == NULL)
172 			fatalx("out of memory");
173 		if (out)
174 			bufferevent_enable(wp->pipe_event, EV_WRITE);
175 		if (in)
176 			bufferevent_enable(wp->pipe_event, EV_READ);
177 
178 		free(cmd);
179 		return (CMD_RETURN_NORMAL);
180 	}
181 }
182 
183 static void
184 cmd_pipe_pane_read_callback(__unused struct bufferevent *bufev, void *data)
185 {
186 	struct window_pane	*wp = data;
187 	struct evbuffer		*evb = wp->pipe_event->input;
188 	size_t			 available;
189 
190 	available = EVBUFFER_LENGTH(evb);
191 	log_debug("%%%u pipe read %zu", wp->id, available);
192 
193 	bufferevent_write(wp->event, EVBUFFER_DATA(evb), available);
194 	evbuffer_drain(evb, available);
195 
196 	if (window_pane_destroy_ready(wp))
197 		server_destroy_pane(wp, 1);
198 }
199 
200 static void
201 cmd_pipe_pane_write_callback(__unused struct bufferevent *bufev, void *data)
202 {
203 	struct window_pane	*wp = data;
204 
205 	log_debug("%%%u pipe empty", wp->id);
206 
207 	if (window_pane_destroy_ready(wp))
208 		server_destroy_pane(wp, 1);
209 }
210 
211 static void
212 cmd_pipe_pane_error_callback(__unused struct bufferevent *bufev,
213     __unused short what, void *data)
214 {
215 	struct window_pane	*wp = data;
216 
217 	log_debug("%%%u pipe error", wp->id);
218 
219 	bufferevent_free(wp->pipe_event);
220 	close(wp->pipe_fd);
221 	wp->pipe_fd = -1;
222 
223 	if (window_pane_destroy_ready(wp))
224 		server_destroy_pane(wp, 1);
225 }
226