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comparison io.c @ 19:5c6155c8e9b6

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Handle signals Handled signals are generally blocked and only unblocked when doing blocking I/O, i.e. either when reading commands or printing results. A (possibly queued) signal will then interrupt I/O and can be dealt with in the main loop.
author Guido Berhoerster <guido+pwm@berhoerster.name>
date Fri, 01 Sep 2017 22:33:41 +0200
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children ec01c579024a
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18:1e39a251cbe9 19:5c6155c8e9b6
1 /*
2 * Copyright (C) 2017 Guido Berhoerster <guido+pwm@berhoerster.name>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included
13 * in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #include "compat.h"
25
26 #ifdef HAVE_ERR_H
27 #include <err.h>
28 #endif /* HAVE_ERR_H */
29 #include <errno.h>
30 #include <setjmp.h>
31 #include <signal.h>
32 #include <stdarg.h>
33 #include <stdio.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <unistd.h>
37
38 #include "io.h"
39 #include "util.h"
40 #include "pwm.h"
41
42 static sigjmp_buf signal_env;
43
44 static void
45 signal_handler(int signal_no)
46 {
47 siglongjmp(signal_env, signal_no);
48 }
49
50 int
51 io_gl_complete_nothing(WordCompletion *cpl, void *data, const char *line,
52 int word_end)
53 {
54 return (0);
55 }
56
57 enum io_status
58 io_get_char(const char *prompt, int *cp)
59 {
60 enum io_status retval = IO_OK;
61 GetLine *gl = NULL;
62
63 gl = new_GetLine(16, 0);
64 if (gl== NULL) {
65 err(1, "new_GetLine");
66 }
67 gl_catch_blocked(gl);
68
69 /* prompt with echo off */
70 gl_echo_mode(gl, 0);
71 if ((*cp = gl_query_char(gl, prompt, '\0')) == EOF) {
72 switch (gl_return_status(gl)) {
73 case GLR_SIGNAL:
74 retval = IO_SIGNAL;
75 break;
76 case GLR_ERROR:
77 errx(1, "gl_get_line: %s",
78 gl_error_message(gl, NULL, 0));
79 default:
80 errx(1, "unknown error in gl_get_line");
81 }
82 }
83
84 /* erase prompt */
85 if (io_printf("\r%*s\r", (int)strlen(prompt), "") == IO_SIGNAL) {
86 retval = IO_SIGNAL;
87 }
88
89 del_GetLine(gl);
90
91 return (retval);
92 }
93
94 enum io_status
95 io_get_line(GetLine *gl, const char *prompt, int with_history,
96 const char *start_line, int start_pos, size_t buf_size, char *buf)
97 {
98 enum io_status retval = IO_OK;
99 GetLine *gl_private = NULL;
100 GlHistoryState state;
101 char *line;
102
103 if (gl == NULL) {
104 gl = gl_private = new_GetLine(buf_size - 1, 0);
105 if (gl_private == NULL) {
106 err(1, "new_GetLine");
107 }
108 gl_catch_blocked(gl_private);
109 }
110
111 gl_state_of_history(gl, &state);
112 gl_toggle_history(gl, with_history);
113
114 line = gl_get_line(gl, prompt, start_line, start_pos);
115 if (line == NULL) {
116 switch (gl_return_status(gl)) {
117 case GLR_BLOCKED:
118 break;
119 case GLR_SIGNAL:
120 retval = IO_SIGNAL;
121 goto out;
122 case GLR_EOF:
123 retval = IO_EOF;
124 goto out;
125 case GLR_ERROR:
126 errx(1, "gl_get_line: %s",
127 gl_error_message(gl, NULL, 0));
128 default:
129 errx(1, "unknown error in gl_get_line");
130 }
131 }
132
133 if (snprintf(buf, buf_size, "%s", line) >= (int)buf_size) {
134 retval = IO_TRUNCATED;
135 }
136
137 out:
138 if (gl != NULL) {
139 gl_toggle_history(gl, state.enabled);
140 }
141 del_GetLine(gl_private);
142
143 return (retval);
144 }
145
146 enum io_status
147 io_get_password(const char *prompt, const char *confirm_prompt,
148 size_t buf_size, char *buf)
149 {
150 enum io_status retval = IO_OK;
151 GetLine *gl = NULL;
152 size_t len;
153 char *password_buf = NULL;
154 char *confirm_buf = NULL;
155
156 gl = new_GetLine(buf_size - 1, 0);
157 if (gl == NULL) {
158 err(1, "new_GetLine");
159 }
160 /* disable default filename completion */
161 gl_customize_completion(gl, NULL, io_gl_complete_nothing);
162 gl_echo_mode(gl, 0);
163
164 password_buf = xmalloc(buf_size);
165
166 if (io_get_line(gl, prompt, 0, NULL, 0, buf_size, password_buf) ==
167 IO_SIGNAL) {
168 retval = IO_SIGNAL;
169 goto out;
170 }
171 len = strlen(password_buf);
172 /* strip trailing newline */
173 if ((len > 0) && (password_buf[len - 1] == '\n')) {
174 password_buf[--len] = '\0';
175 }
176 if (len == 0) {
177 retval = IO_PASSWORD_EMPTY;
178 goto out;
179 }
180
181 if (confirm_prompt != NULL) {
182 if (io_printf("\n") == IO_SIGNAL) {
183 retval = IO_SIGNAL;
184 goto out;
185 }
186
187 /* confirm new password */
188 confirm_buf = xmalloc(buf_size);
189 if (io_get_line(gl, confirm_prompt, 0, NULL, 0,
190 buf_size, confirm_buf) == IO_SIGNAL) {
191 retval = IO_SIGNAL;
192 goto out;
193 }
194 len = strlen(confirm_buf);
195 /* strip trailing newline */
196 if ((len > 0) && (confirm_buf[len - 1] == '\n')) {
197 confirm_buf[--len] = '\0';
198 }
199 if (strcmp(password_buf, confirm_buf) != 0) {
200 retval = IO_PASSWORD_MISMATCH;
201 goto out;
202 }
203 }
204
205 strcpy(buf, password_buf);
206
207 out:
208 if (io_printf("\n") == IO_SIGNAL) {
209 retval = IO_SIGNAL;
210 goto out;
211 }
212 free(password_buf);
213 free(confirm_buf);
214 del_GetLine(gl);
215
216 return (retval);
217 }
218
219 enum io_status
220 io_dputs(int fd, const char *s)
221 {
222 struct sigaction action;
223 struct sigaction oaction;
224 int signal_no = 0;
225 const char *p = s;
226 size_t remaining;
227 ssize_t n;
228
229 /* install signal handlers */
230 action.sa_handler = signal_handler;
231 action.sa_flags = 0;
232 sigemptyset(&action.sa_mask);
233 sigaddset(&action.sa_mask, SIGINT);
234 sigaddset(&action.sa_mask, SIGTERM);
235 sigaddset(&action.sa_mask, SIGHUP);
236 sigaddset(&action.sa_mask, SIGQUIT);
237 if ((sigaction(SIGINT, &action, &oaction) != 0) ||
238 (sigaction(SIGTERM, &action, &oaction) != 0) ||
239 (sigaction(SIGHUP, &action, &oaction) != 0) ||
240 (sigaction(SIGQUIT, &action, &oaction) != 0)) {
241 err(1, "sigaction");
242 }
243
244 if ((signal_no = sigsetjmp(signal_env, 1)) != 0) {
245 /* signal received, signal mask has been restored */
246 goto out;
247 }
248
249 remaining = strlen(s);
250 while (remaining > 0) {
251 pwm_unblock_signals();
252 n = write(fd, p, remaining);
253 if ((n < (int)remaining) && (errno != EINTR)) {
254 err(1, "write");
255 }
256 pwm_block_signals();
257 remaining -= MAX(n, 0);
258 p += MAX(n, 0);
259 }
260
261 out:
262 /* restore signal handlers */
263 if ((sigaction(SIGINT, &oaction, NULL) != 0) ||
264 (sigaction(SIGTERM, &oaction, NULL) != 0) ||
265 (sigaction(SIGHUP, &oaction, NULL) != 0) ||
266 (sigaction(SIGQUIT, &oaction, NULL) != 0)) {
267 err(1, "sigaction");
268 }
269
270 return ((signal_no == 0) ? IO_OK : IO_SIGNAL);
271 }
272
273 enum io_status
274 io_vdprintf(int fd, const char *fmt, va_list args)
275 {
276 enum io_status retval;
277 char *buf;
278
279 xvasprintf(&buf, fmt, args);
280 retval = io_dputs(fd, buf);
281 free(buf);
282
283 return (retval);
284 }
285
286 enum io_status
287 io_dprintf(int fd, const char *fmt, ...)
288 {
289 enum io_status retval;
290 va_list args;
291
292 va_start(args, fmt);
293 retval = io_vdprintf(fd, fmt, args);
294 va_end(args);
295
296 return (retval);
297 }
298
299 enum io_status
300 io_printf(const char *fmt, ...)
301 {
302 enum io_status retval;
303 va_list args;
304
305 va_start(args, fmt);
306 retval = io_vdprintf(STDOUT_FILENO, fmt, args);
307 va_end(args);
308
309 return (retval);
310 }