1/*	$OpenBSD: util.c,v 1.46 2021/10/24 21:24:17 deraadt Exp $	*/
2
3/*
4 * patch - a program to apply diffs to original files
5 *
6 * Copyright 1986, Larry Wall
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following condition is met:
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this condition and the following disclaimer.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
17 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
19 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
20 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * -C option added in 1998, original code by Marc Espie, based on FreeBSD
26 * behaviour
27 */
28
29#include <sys/stat.h>
30
31#include <ctype.h>
32#include <errno.h>
33#include <fcntl.h>
34#include <paths.h>
35#include <signal.h>
36#include <stdarg.h>
37#include <stdlib.h>
38#include <stdio.h>
39#include <string.h>
40#include <unistd.h>
41
42#include "common.h"
43#include "util.h"
44#include "backupfile.h"
45
46/* Rename a file, copying it if necessary. */
47
48int
49move_file(const char *from, const char *to)
50{
51	int	fromfd;
52	ssize_t	i;
53
54	/* to stdout? */
55
56	if (strEQ(to, "-")) {
57#ifdef DEBUGGING
58		if (debug & 4)
59			say("Moving %s to stdout.\n", from);
60#endif
61		fromfd = open(from, O_RDONLY);
62		if (fromfd == -1)
63			pfatal("internal error, can't reopen %s", from);
64		while ((i = read(fromfd, buf, bufsz)) > 0)
65			if (write(STDOUT_FILENO, buf, i) != i)
66				pfatal("write failed");
67		close(fromfd);
68		return 0;
69	}
70	if (backup_file(to) < 0) {
71		say("Can't backup %s, output is in %s: %s\n", to, from,
72		    strerror(errno));
73		return -1;
74	}
75#ifdef DEBUGGING
76	if (debug & 4)
77		say("Moving %s to %s.\n", from, to);
78#endif
79	if (rename(from, to) == -1) {
80		if (errno != EXDEV || copy_file(from, to) < 0) {
81			say("Can't create %s, output is in %s: %s\n",
82			    to, from, strerror(errno));
83			return -1;
84		}
85	}
86	return 0;
87}
88
89/* Backup the original file.  */
90
91int
92backup_file(const char *orig)
93{
94	struct stat	filestat;
95	char		bakname[PATH_MAX], *s, *simplename;
96	dev_t		orig_device;
97	ino_t		orig_inode;
98
99	if (backup_type == none || stat(orig, &filestat) != 0)
100		return 0;			/* nothing to do */
101	orig_device = filestat.st_dev;
102	orig_inode = filestat.st_ino;
103
104	if (origprae) {
105		if (strlcpy(bakname, origprae, sizeof(bakname)) >= sizeof(bakname) ||
106		    strlcat(bakname, orig, sizeof(bakname)) >= sizeof(bakname))
107			fatal("filename %s too long for buffer\n", origprae);
108	} else {
109		if ((s = find_backup_file_name(orig)) == NULL)
110			fatal("out of memory\n");
111		if (strlcpy(bakname, s, sizeof(bakname)) >= sizeof(bakname))
112			fatal("filename %s too long for buffer\n", s);
113		free(s);
114	}
115
116	if ((simplename = strrchr(bakname, '/')) != NULL)
117		simplename = simplename + 1;
118	else
119		simplename = bakname;
120
121	/*
122	 * Find a backup name that is not the same file. Change the
123	 * first lowercase char into uppercase; if that isn't
124	 * sufficient, chop off the first char and try again.
125	 */
126	while (stat(bakname, &filestat) == 0 &&
127	    orig_device == filestat.st_dev && orig_inode == filestat.st_ino) {
128		/* Skip initial non-lowercase chars.  */
129		for (s = simplename; *s && !islower((unsigned char)*s); s++)
130			;
131		if (*s)
132			*s = toupper((unsigned char)*s);
133		else
134			memmove(simplename, simplename + 1,
135			    strlen(simplename + 1) + 1);
136	}
137#ifdef DEBUGGING
138	if (debug & 4)
139		say("Moving %s to %s.\n", orig, bakname);
140#endif
141	if (rename(orig, bakname) == -1) {
142		if (errno != EXDEV || copy_file(orig, bakname) < 0)
143			return -1;
144	}
145	return 0;
146}
147
148/*
149 * Copy a file.
150 */
151int
152copy_file(const char *from, const char *to)
153{
154	int	tofd, fromfd;
155	ssize_t	i;
156
157	tofd = open(to, O_CREAT|O_TRUNC|O_WRONLY, 0666);
158	if (tofd == -1)
159		return -1;
160	fromfd = open(from, O_RDONLY);
161	if (fromfd == -1)
162		pfatal("internal error, can't reopen %s", from);
163	while ((i = read(fromfd, buf, bufsz)) > 0)
164		if (write(tofd, buf, i) != i)
165			pfatal("write to %s failed", to);
166	close(fromfd);
167	close(tofd);
168	return 0;
169}
170
171/*
172 * Allocate a unique area for a string.
173 */
174char *
175savestr(const char *s)
176{
177	char	*rv;
178
179	if (!s)
180		s = "Oops";
181	rv = strdup(s);
182	if (rv == NULL) {
183		if (using_plan_a)
184			out_of_mem = true;
185		else
186			fatal("out of memory\n");
187	}
188	return rv;
189}
190
191/*
192 * Allocate a unique area for a string.  Call fatal if out of memory.
193 */
194char *
195xstrdup(const char *s)
196{
197	char	*rv;
198
199	if (!s)
200		s = "Oops";
201	rv = strdup(s);
202	if (rv == NULL)
203		fatal("out of memory\n");
204	return rv;
205}
206
207/*
208 * Vanilla terminal output (buffered).
209 */
210void
211say(const char *fmt, ...)
212{
213	va_list	ap;
214
215	va_start(ap, fmt);
216	vfprintf(stdout, fmt, ap);
217	va_end(ap);
218	fflush(stdout);
219}
220
221/*
222 * Terminal output, pun intended.
223 */
224void
225fatal(const char *fmt, ...)
226{
227	va_list	ap;
228
229	va_start(ap, fmt);
230	fprintf(stderr, "patch: **** ");
231	vfprintf(stderr, fmt, ap);
232	va_end(ap);
233	my_exit(2);
234}
235
236/*
237 * Say something from patch, something from the system, then silence . . .
238 */
239void
240pfatal(const char *fmt, ...)
241{
242	va_list	ap;
243	int	errnum = errno;
244
245	fprintf(stderr, "patch: **** ");
246	va_start(ap, fmt);
247	vfprintf(stderr, fmt, ap);
248	va_end(ap);
249	fprintf(stderr, ": %s\n", strerror(errnum));
250	my_exit(2);
251}
252
253/*
254 * Get a response from the user via /dev/tty
255 */
256void
257ask(const char *fmt, ...)
258{
259	va_list	ap;
260	ssize_t	nr;
261	static	int ttyfd = -1;
262
263	va_start(ap, fmt);
264	vfprintf(stdout, fmt, ap);
265	va_end(ap);
266	fflush(stdout);
267	if (ttyfd < 0)
268		ttyfd = open(_PATH_TTY, O_RDONLY);
269	if (ttyfd >= 0) {
270		if ((nr = read(ttyfd, buf, bufsz)) > 0 &&
271		    buf[nr - 1] == '\n')
272			buf[nr - 1] = '\0';
273	}
274	if (ttyfd == -1 || nr <= 0) {
275		/* no tty or error reading, pretend user entered 'return' */
276		putchar('\n');
277		buf[0] = '\0';
278	}
279}
280
281/*
282 * How to handle certain events when not in a critical region.
283 */
284void
285set_signals(int reset)
286{
287	static sig_t	hupval, intval;
288
289	if (!reset) {
290		hupval = signal(SIGHUP, SIG_IGN);
291		if (hupval != SIG_IGN)
292			hupval = my_sigexit;
293		intval = signal(SIGINT, SIG_IGN);
294		if (intval != SIG_IGN)
295			intval = my_sigexit;
296	}
297	signal(SIGHUP, hupval);
298	signal(SIGINT, intval);
299}
300
301/*
302 * How to handle certain events when in a critical region.
303 */
304void
305ignore_signals(void)
306{
307	signal(SIGHUP, SIG_IGN);
308	signal(SIGINT, SIG_IGN);
309}
310
311/*
312 * Make sure we'll have the directories to create a file. If `striplast' is
313 * true, ignore the last element of `filename'.
314 */
315
316void
317makedirs(const char *filename, bool striplast)
318{
319	char	*tmpbuf;
320
321	if ((tmpbuf = strdup(filename)) == NULL)
322		fatal("out of memory\n");
323
324	if (striplast) {
325		char	*s = strrchr(tmpbuf, '/');
326		if (s == NULL) {
327			free(tmpbuf);
328			return;	/* nothing to be done */
329		}
330		*s = '\0';
331	}
332	if (mkpath(tmpbuf) != 0)
333		pfatal("creation of %s failed", tmpbuf);
334	free(tmpbuf);
335}
336
337/*
338 * Make filenames more reasonable.
339 */
340char *
341fetchname(const char *at, bool *exists, int strip_leading)
342{
343	char		*fullname, *name, *t;
344	int		sleading, tab;
345	struct stat	filestat;
346
347	if (at == NULL || *at == '\0')
348		return NULL;
349	while (isspace((unsigned char)*at))
350		at++;
351#ifdef DEBUGGING
352	if (debug & 128)
353		say("fetchname %s %d\n", at, strip_leading);
354#endif
355	/* So files can be created by diffing against /dev/null.  */
356	if (strnEQ(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
357		return NULL;
358	name = fullname = t = savestr(at);
359
360	tab = strchr(t, '\t') != NULL;
361	/* Strip off up to `strip_leading' path components and NUL terminate. */
362	for (sleading = strip_leading; *t != '\0' && ((tab && *t != '\t') ||
363	    !isspace((unsigned char)*t)); t++) {
364		if (t[0] == '/' && t[1] != '/' && t[1] != '\0')
365			if (--sleading >= 0)
366				name = t + 1;
367	}
368	*t = '\0';
369
370	/*
371	 * If no -p option was given (957 is the default value!), we were
372	 * given a relative pathname, and the leading directories that we
373	 * just stripped off all exist, put them back on.
374	 */
375	if (strip_leading == 957 && name != fullname && *fullname != '/') {
376		name[-1] = '\0';
377		if (stat(fullname, &filestat) == 0 && S_ISDIR(filestat.st_mode)) {
378			name[-1] = '/';
379			name = fullname;
380		}
381	}
382	name = savestr(name);
383	free(fullname);
384
385	*exists = stat(name, &filestat) == 0;
386	return name;
387}
388
389void
390version(void)
391{
392	fprintf(stderr, "Patch version 2.0-12u8-OpenBSD\n");
393	my_exit(EXIT_SUCCESS);
394}
395
396void
397my_cleanup(void)
398{
399	unlink(TMPINNAME);
400	if (!toutkeep)
401		unlink(TMPOUTNAME);
402	if (!trejkeep)
403		unlink(TMPREJNAME);
404	unlink(TMPPATNAME);
405}
406
407/*
408 * Exit with cleanup.
409 */
410void
411my_exit(int status)
412{
413	my_cleanup();
414	exit(status);
415}
416
417/*
418 * Exit with cleanup, from a signal handler.
419 */
420void
421my_sigexit(int signo)
422{
423	my_cleanup();
424	_exit(2);
425}
426