1 /* $OpenBSD: edit.c,v 1.8 2021/07/10 07:10:31 anton Exp $ */
2 /*
3 * Copyright (c) 2017 Anton Lindqvist <anton@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/wait.h>
19
20 #include <err.h>
21 #include <errno.h>
22 #include <poll.h>
23 #include <signal.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <termios.h>
28 #include <unistd.h>
29 #include <util.h>
30
31 #define WRTIM 50 /* input write timeout */
32 #define PRTIM 5000 /* prompt read timeout */
33
34 static size_t findprompt(const char *, const char *);
35 static void sighandler(int);
36 static void __dead usage(void);
37
38 static volatile sig_atomic_t gotsig;
39
40 int
main(int argc,char * argv[])41 main(int argc, char *argv[])
42 {
43 const char *linefeed = "\003\004\n\r";
44 const char *prompt = "";
45 char in[BUFSIZ], out[BUFSIZ];
46 struct pollfd pfd;
47 struct winsize ws;
48 pid_t pid;
49 ssize_t n;
50 size_t nin, nprompt, nread, nwrite;
51 int c, nready, ptyfd, readprompt, ret, status, timeout;
52
53 while ((c = getopt(argc, argv, "p:")) != -1) {
54 switch (c) {
55 case 'p':
56 prompt = optarg;
57 break;
58 default:
59 usage();
60 }
61 }
62 argc -= optind;
63 argv += optind;
64 if (argc == 0 || strlen(prompt) == 0)
65 usage();
66
67 nin = 0;
68 for (;;) {
69 if (nin == sizeof(in))
70 errx(1, "input buffer too small");
71
72 n = read(0, in + nin, sizeof(in) - nin);
73 if (n == -1)
74 err(1, "read");
75 if (n == 0)
76 break;
77
78 nin += n;
79 }
80
81 if (signal(SIGCHLD, sighandler) == SIG_ERR)
82 err(1, "signal: SIGCHLD");
83 if (signal(SIGINT, sighandler) == SIG_ERR)
84 err(1, "signal: SIGINT");
85
86 memset(&ws, 0, sizeof(ws));
87 ws.ws_col = 80;
88 ws.ws_row = 24;
89
90 pid = forkpty(&ptyfd, NULL, NULL, &ws);
91 if (pid == -1)
92 err(1, "forkpty");
93 if (pid == 0) {
94 execvp(*argv, argv);
95 err(1, "%s", *argv);
96 }
97
98 nprompt = nread = nwrite = ret = 0;
99 readprompt = 1;
100 while (!gotsig) {
101 pfd.fd = ptyfd;
102 if (!readprompt && nwrite < nin)
103 pfd.events = POLLOUT;
104 else
105 pfd.events = POLLIN;
106 timeout = readprompt ? PRTIM : WRTIM;
107 nready = poll(&pfd, 1, timeout);
108 if (nready == -1) {
109 if (errno == EINTR)
110 continue;
111 err(1, "poll");
112 }
113 if (nready == 0) {
114 if (timeout == PRTIM) {
115 warnx("timeout waiting from prompt");
116 ret = 1;
117 }
118 break;
119 }
120 if (pfd.revents & (POLLERR | POLLNVAL))
121 errc(1, EBADF, NULL);
122
123 if (pfd.revents & (POLLIN | POLLHUP)) {
124 if (nread == sizeof(out))
125 errx(1, "output buffer too small");
126
127 n = read(ptyfd, out + nread, sizeof(out) - 1 - nread);
128 if (n == -1)
129 err(1, "read");
130 nread += n;
131 out[nread] = '\0';
132
133 if (readprompt &&
134 (n = findprompt(out + nprompt, prompt)) > 0) {
135 nprompt += n;
136 readprompt = 0;
137 }
138 } else if (pfd.revents & POLLOUT) {
139 if (strchr(linefeed, in[nwrite]) != NULL)
140 readprompt = 1;
141
142 n = write(ptyfd, in + nwrite, 1);
143 if (n == -1)
144 err(1, "write");
145 nwrite += n;
146 }
147 }
148 close(ptyfd);
149 while (waitpid(pid, &status, 0) == -1)
150 if (errno != EINTR)
151 err(1, "waitpid");
152 if (WIFSIGNALED(status) && WTERMSIG(status) != SIGHUP) {
153 warnx("%s: terminated by signal %d", *argv, WTERMSIG(status));
154 ret = 128 + WTERMSIG(status);
155 }
156
157 printf("%.*s", (int)nread, out);
158
159 return ret;
160 }
161
162 static size_t
findprompt(const char * str,const char * prompt)163 findprompt(const char *str, const char *prompt)
164 {
165 char *cp;
166 size_t len;
167
168 if ((cp = strstr(str, prompt)) == NULL)
169 return 0;
170 len = strlen(prompt);
171
172 return (cp - str) + len;
173 }
174
175 static void
sighandler(int sig)176 sighandler(int sig)
177 {
178 gotsig = sig;
179 }
180
181 static void __dead
usage(void)182 usage(void)
183 {
184 fprintf(stderr, "usage: edit -p prompt command [args]\n");
185 exit(1);
186 }
187