summaryrefslogtreecommitdiff
path: root/usr.bin/sdiff/edit.c
blob: 47a222f5a42c0bd0080a5117b83fc5658c900abd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
/*	$OpenBSD: edit.c,v 1.18 2007/10/17 20:02:33 deraadt Exp $ */

/*
 * Written by Raymond Lai <ray@cyth.net>.
 * Public domain.
 */

#include <sys/types.h>
#include <sys/wait.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "extern.h"

int editit(const char *);

/*
 * Execute an editor on the specified pathname, which is interpreted
 * from the shell.  This means flags may be included.
 *
 * Returns -1 on error, or the exit value on success.
 */
int
editit(const char *pathname)
{
	char *argp[] = {"sh", "-c", NULL, NULL}, *ed, *p;
	sig_t sighup, sigint, sigquit, sigchld;
	pid_t pid;
	int saved_errno, st, ret = -1;

	ed = getenv("VISUAL");
	if (ed == NULL || ed[0] == '\0')
		ed = getenv("EDITOR");
	if (ed == NULL || ed[0] == '\0')
		ed = _PATH_VI;
	if (asprintf(&p, "%s %s", ed, pathname) == -1)
		return (-1);
	argp[2] = p;

	sighup = signal(SIGHUP, SIG_IGN);
	sigint = signal(SIGINT, SIG_IGN);
	sigquit = signal(SIGQUIT, SIG_IGN);
	sigchld = signal(SIGCHLD, SIG_DFL);
	if ((pid = fork()) == -1)
		goto fail;
	if (pid == 0) {
		execv(_PATH_BSHELL, argp);
		_exit(127);
	}
	while (waitpid(pid, &st, 0) == -1)
		if (errno != EINTR)
			goto fail;
	if (!WIFEXITED(st))
		errno = EINTR;
	else
		ret = WEXITSTATUS(st);

 fail:
	saved_errno = errno;
	(void)signal(SIGHUP, sighup);
	(void)signal(SIGINT, sigint);
	(void)signal(SIGQUIT, sigquit);
	(void)signal(SIGCHLD, sigchld);
	free(p);
	errno = saved_errno;
	return (ret);
}

/*
 * Parse edit command.  Returns 0 on success, -1 on error.
 */
int
eparse(const char *cmd, const char *left, const char *right)
{
	FILE *file;
	size_t nread;
	int fd;
	char *filename;
	char buf[BUFSIZ], *text;

	/* Skip whitespace. */
	while (isspace(*cmd))
		++cmd;

	text = NULL;
	switch (*cmd) {
	case '\0':
		/* Edit empty file. */
		break;

	case 'b':
		/* Both strings. */
		if (left == NULL)
			goto RIGHT;
		if (right == NULL)
			goto LEFT;

		/* Neither column is blank, so print both. */
		if (asprintf(&text, "%s\n%s\n", left, right) == -1)
			err(2, "could not allocate memory");
		break;

	case 'l':
LEFT:
		/* Skip if there is no left column. */
		if (left == NULL)
			break;

		if (asprintf(&text, "%s\n", left) == -1)
			err(2, "could not allocate memory");

		break;

	case 'r':
RIGHT:
		/* Skip if there is no right column. */
		if (right == NULL)
			break;

		if (asprintf(&text, "%s\n", right) == -1)
			err(2, "could not allocate memory");

		break;

	default:
		return (-1);
	}

	/* Create temp file. */
	if (asprintf(&filename, "%s/sdiff.XXXXXXXXXX", tmpdir) == -1)
		err(2, "asprintf");
	if ((fd = mkstemp(filename)) == -1)
		err(2, "mkstemp");
	if (text != NULL) {
		size_t len;
		ssize_t nwritten;

		len = strlen(text);
		if ((nwritten = write(fd, text, len)) == -1 ||
		    nwritten != len) {
			warn("error writing to temp file");
			cleanup(filename);
		}
	}
	close(fd);

	/* text is no longer used. */
	free(text);

	/* Edit temp file. */
	if (editit(filename) == -1) {
		warn("error editing %s", filename);
		cleanup(filename);
	}

	/* Open temporary file. */
	if (!(file = fopen(filename, "r"))) {
		warn("could not open edited file: %s", filename);
		cleanup(filename);
	}

	/* Copy temporary file contents to output file. */
	for (nread = sizeof(buf); nread == sizeof(buf);) {
		size_t nwritten;

		nread = fread(buf, sizeof(*buf), sizeof(buf), file);
		/* Test for error or end of file. */
		if (nread != sizeof(buf) &&
		    (ferror(file) || !feof(file))) {
			warnx("error reading edited file: %s", filename);
			cleanup(filename);
		}

		/*
		 * If we have nothing to read, break out of loop
		 * instead of writing nothing.
		 */
		if (!nread)
			break;

		/* Write data we just read. */
		nwritten = fwrite(buf, sizeof(*buf), nread, outfile);
		if (nwritten != nread) {
			warnx("error writing to output file");
			cleanup(filename);
		}
	}

	/* We've reached the end of the temporary file, so remove it. */
	if (unlink(filename))
		warn("could not delete: %s", filename);
	fclose(file);

	free(filename);

	return (0);
}