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/* $OpenBSD: edit.c,v 1.10 2006/02/02 19:30:23 claudio 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 <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "extern.h"
__dead static void cleanup(const char *);
static void edit(const char *);
static char *xmktemp(const char *);
static void
cleanup(const char *filename)
{
if (unlink(filename))
err(2, "could not delete: %s", filename);
exit(2);
}
/*
* Takes the name of a file and opens it with an editor.
*/
static void
edit(const char *filename)
{
int status;
pid_t pid;
const char *editor;
editor = getenv("VISUAL");
if (editor == NULL)
editor = getenv("EDITOR");
if (editor == NULL)
editor = "vi";
/* Start editor on temporary file. */
switch (pid = fork()) {
case 0:
/* child */
execlp(editor, editor, filename, (void *)NULL);
warn("could not execute editor: %s", editor);
cleanup(filename);
/* NOTREACHED */
case -1:
warn("could not fork");
cleanup(filename);
/* NOTREACHED */
}
/* parent */
/* Wait for editor to exit. */
if (waitpid(pid, &status, 0) == -1) {
warn("waitpid");
cleanup(filename);
/* NOTREACHED */
}
/* Check that editor terminated normally. */
if (!WIFEXITED(status)) {
warn("%s terminated abnormally", editor);
cleanup(filename);
/* NOTREACHED */
}
}
/*
* Creates and returns the name of a temporary file. Takes a string
* (or NULL) is written to the temporary file. The returned string
* needs to be freed.
*/
static char *
xmktemp(const char *s)
{
FILE *file;
int fd;
const char *tmpdir;
char *filename;
/* If TMPDIR is set, use it; otherwise use /tmp. */
if (!(tmpdir = getenv("TMPDIR")))
tmpdir = "/tmp";
if (asprintf(&filename, "%s/sdiff.XXXXXXXXXX", tmpdir) == -1)
err(2, "xmktemp");
/* Create temp file. */
if ((fd = mkstemp(filename)) == -1)
err(2, "could not create temporary file");
/* If we don't write anything to the file, just close. */
if (s == NULL) {
close(fd);
return (filename);
}
/* Open temp file for writing. */
if ((file = fdopen(fd, "w")) == NULL) {
warn("could not open %s", filename);
cleanup(filename);
/* NOTREACHED */
}
/* Write to file. */
if (fputs(s, file)) {
warn("could not write to %s", filename);
cleanup(filename);
/* NOTREACHED */
}
/* Close temp file. */
fclose(file);
return (filename);
}
/*
* 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, nwritten;
const 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. */
filename = xmktemp(text);
/* text is no longer used. */
free(text);
/* Edit temp file. */
edit(filename);
/* Open temporary file. */
if (!(file = fopen(filename, "r"))) {
warn("could not open edited file: %s", filename);
cleanup(filename);
/* NOTREACHED */
}
/* Copy temporary file contents to output file. */
for (nread = sizeof(buf); nread == sizeof(buf);) {
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);
/* NOTREACHED */
}
/*
* 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);
/* NOTREACHED */
}
}
/* We've reached the end of the temporary file, so remove it. */
if (unlink(filename))
warn("could not delete: %s", filename);
fclose(file);
/* filename was malloc()ed in xmktemp(). */
free((void *)filename);
return (0);
}
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