1 /* $OpenBSD: cmd-pipe-pane.c,v 1.61 2024/02/13 08:03:50 nicm Exp $ */
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 <paths.h>
25 #include <signal.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <time.h>
29 #include <unistd.h>
30
31 #include "tmux.h"
32
33 /*
34 * Open pipe to redirect pane output. If already open, close first.
35 */
36
37 static enum cmd_retval cmd_pipe_pane_exec(struct cmd *, struct cmdq_item *);
38
39 static void cmd_pipe_pane_read_callback(struct bufferevent *, void *);
40 static void cmd_pipe_pane_write_callback(struct bufferevent *, void *);
41 static void cmd_pipe_pane_error_callback(struct bufferevent *, short, void *);
42
43 const struct cmd_entry cmd_pipe_pane_entry = {
44 .name = "pipe-pane",
45 .alias = "pipep",
46
47 .args = { "IOot:", 0, 1, NULL },
48 .usage = "[-IOo] " CMD_TARGET_PANE_USAGE " [shell-command]",
49
50 .target = { 't', CMD_FIND_PANE, 0 },
51
52 .flags = CMD_AFTERHOOK,
53 .exec = cmd_pipe_pane_exec
54 };
55
56 static enum cmd_retval
cmd_pipe_pane_exec(struct cmd * self,struct cmdq_item * item)57 cmd_pipe_pane_exec(struct cmd *self, struct cmdq_item *item)
58 {
59 struct args *args = cmd_get_args(self);
60 struct cmd_find_state *target = cmdq_get_target(item);
61 struct client *tc = cmdq_get_target_client(item);
62 struct window_pane *wp = target->wp;
63 struct session *s = target->s;
64 struct winlink *wl = target->wl;
65 struct window_pane_offset *wpo = &wp->pipe_offset;
66 char *cmd;
67 int old_fd, pipe_fd[2], null_fd, in, out;
68 struct format_tree *ft;
69 sigset_t set, oldset;
70
71 /* Do nothing if pane is dead. */
72 if (window_pane_exited(wp)) {
73 cmdq_error(item, "target pane has exited");
74 return (CMD_RETURN_ERROR);
75 }
76
77 /* Destroy the old pipe. */
78 old_fd = wp->pipe_fd;
79 if (wp->pipe_fd != -1) {
80 bufferevent_free(wp->pipe_event);
81 close(wp->pipe_fd);
82 wp->pipe_fd = -1;
83
84 if (window_pane_destroy_ready(wp)) {
85 server_destroy_pane(wp, 1);
86 return (CMD_RETURN_NORMAL);
87 }
88 }
89
90 /* If no pipe command, that is enough. */
91 if (args_count(args) == 0 || *args_string(args, 0) == '\0')
92 return (CMD_RETURN_NORMAL);
93
94 /*
95 * With -o, only open the new pipe if there was no previous one. This
96 * allows a pipe to be toggled with a single key, for example:
97 *
98 * bind ^p pipep -o 'cat >>~/output'
99 */
100 if (args_has(args, 'o') && old_fd != -1)
101 return (CMD_RETURN_NORMAL);
102
103 /* What do we want to do? Neither -I or -O is -O. */
104 if (args_has(args, 'I')) {
105 in = 1;
106 out = args_has(args, 'O');
107 } else {
108 in = 0;
109 out = 1;
110 }
111
112 /* Open the new pipe. */
113 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_fd) != 0) {
114 cmdq_error(item, "socketpair error: %s", strerror(errno));
115 return (CMD_RETURN_ERROR);
116 }
117
118 /* Expand the command. */
119 ft = format_create(cmdq_get_client(item), item, FORMAT_NONE, 0);
120 format_defaults(ft, tc, s, wl, wp);
121 cmd = format_expand_time(ft, args_string(args, 0));
122 format_free(ft);
123
124 /* Fork the child. */
125 sigfillset(&set);
126 sigprocmask(SIG_BLOCK, &set, &oldset);
127 switch (fork()) {
128 case -1:
129 sigprocmask(SIG_SETMASK, &oldset, NULL);
130 cmdq_error(item, "fork error: %s", strerror(errno));
131
132 free(cmd);
133 return (CMD_RETURN_ERROR);
134 case 0:
135 /* Child process. */
136 proc_clear_signals(server_proc, 1);
137 sigprocmask(SIG_SETMASK, &oldset, NULL);
138 close(pipe_fd[0]);
139
140 null_fd = open(_PATH_DEVNULL, O_WRONLY);
141 if (out) {
142 if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
143 _exit(1);
144 } else {
145 if (dup2(null_fd, STDIN_FILENO) == -1)
146 _exit(1);
147 }
148 if (in) {
149 if (dup2(pipe_fd[1], STDOUT_FILENO) == -1)
150 _exit(1);
151 if (pipe_fd[1] != STDOUT_FILENO)
152 close(pipe_fd[1]);
153 } else {
154 if (dup2(null_fd, STDOUT_FILENO) == -1)
155 _exit(1);
156 }
157 if (dup2(null_fd, STDERR_FILENO) == -1)
158 _exit(1);
159 closefrom(STDERR_FILENO + 1);
160
161 execl(_PATH_BSHELL, "sh", "-c", cmd, (char *) NULL);
162 _exit(1);
163 default:
164 /* Parent process. */
165 sigprocmask(SIG_SETMASK, &oldset, NULL);
166 close(pipe_fd[1]);
167
168 wp->pipe_fd = pipe_fd[0];
169 memcpy(wpo, &wp->offset, sizeof *wpo);
170
171 setblocking(wp->pipe_fd, 0);
172 wp->pipe_event = bufferevent_new(wp->pipe_fd,
173 cmd_pipe_pane_read_callback,
174 cmd_pipe_pane_write_callback,
175 cmd_pipe_pane_error_callback,
176 wp);
177 if (wp->pipe_event == NULL)
178 fatalx("out of memory");
179 if (out)
180 bufferevent_enable(wp->pipe_event, EV_WRITE);
181 if (in)
182 bufferevent_enable(wp->pipe_event, EV_READ);
183
184 free(cmd);
185 return (CMD_RETURN_NORMAL);
186 }
187 }
188
189 static void
cmd_pipe_pane_read_callback(__unused struct bufferevent * bufev,void * data)190 cmd_pipe_pane_read_callback(__unused struct bufferevent *bufev, void *data)
191 {
192 struct window_pane *wp = data;
193 struct evbuffer *evb = wp->pipe_event->input;
194 size_t available;
195
196 available = EVBUFFER_LENGTH(evb);
197 log_debug("%%%u pipe read %zu", wp->id, available);
198
199 bufferevent_write(wp->event, EVBUFFER_DATA(evb), available);
200 evbuffer_drain(evb, available);
201
202 if (window_pane_destroy_ready(wp))
203 server_destroy_pane(wp, 1);
204 }
205
206 static void
cmd_pipe_pane_write_callback(__unused struct bufferevent * bufev,void * data)207 cmd_pipe_pane_write_callback(__unused struct bufferevent *bufev, void *data)
208 {
209 struct window_pane *wp = data;
210
211 log_debug("%%%u pipe empty", wp->id);
212
213 if (window_pane_destroy_ready(wp))
214 server_destroy_pane(wp, 1);
215 }
216
217 static void
cmd_pipe_pane_error_callback(__unused struct bufferevent * bufev,__unused short what,void * data)218 cmd_pipe_pane_error_callback(__unused struct bufferevent *bufev,
219 __unused short what, void *data)
220 {
221 struct window_pane *wp = data;
222
223 log_debug("%%%u pipe error", wp->id);
224
225 bufferevent_free(wp->pipe_event);
226 close(wp->pipe_fd);
227 wp->pipe_fd = -1;
228
229 if (window_pane_destroy_ready(wp))
230 server_destroy_pane(wp, 1);
231 }
232