Reimplement in-place editing in a slightly less disgusting manner. Also,

make an effort to preserve the ownership and mode of the file we are
editing.

Sponsored by:	Registrar AS

3 files changed, 84 insertions, 91 deletions

diff --git a/usr.bin/sed/extern.h b/usr.bin/sed/extern.h
index df49f7e..8312d6a 100644
--- a/usr.bin/sed/extern.h
+++ b/usr.bin/sed/extern.h
@@ -45,7 +45,8 @@ extern size_t maxnsub;
 extern u_long linenum;
 extern int appendnum;
 extern int aflag, eflag, nflag;
-extern const char *fname;
+extern const char *fname, *outfname;
+extern FILE *infile, *outfile;
 extern int rflags;	/* regex flags to use */
 
 void	 cfclose(struct s_command *, struct s_command *);
diff --git a/usr.bin/sed/main.c b/usr.bin/sed/main.c
index 13f9de4..216cd42 100644
--- a/usr.bin/sed/main.c
+++ b/usr.bin/sed/main.c
@@ -96,7 +96,8 @@ struct s_flist {
  */
 static struct s_flist *files, **fl_nextp = &files;
 
-static FILE *curfile;		/* Current open file */
+FILE *infile;			/* Current input file */
+FILE *outfile;			/* Current output file */
 
 int aflag, eflag, nflag;
 int rflags = 0;
@@ -107,6 +108,9 @@ static int rval;		/* Exit status */
  * units, but span across input files.
  */
 const char *fname;		/* File name. */
+const char *outfname;		/* Output file name */
+static char oldfname[PATH_MAX];	/* Old file name (for in-place editing) */
+static char tmpfname[PATH_MAX];	/* Temporary file name (for in-place editing) */
 const char *inplace;		/* Inplace edit file extension. */
 u_long linenum;
 
@@ -292,66 +296,102 @@ again:
 int
 mf_fgets(SPACE *sp, enum e_spflag spflag)
 {
+	struct stat sb;
 	size_t len;
 	char *p;
 	int c;
 	static int firstfile;
 
-	if (curfile == NULL) {
+	if (infile == NULL) {
 		/* stdin? */
 		if (files->fname == NULL) {
 			if (inplace != NULL)
 				errx(1, "-i may not be used with stdin");
-			curfile = stdin;
+			infile = stdin;
 			fname = "stdin";
+			outfile = stdout;
+			outfname = "stdout";
 		}
 		firstfile = 1;
 	}
 
 	for (;;) {
-		if (curfile != NULL && (c = getc(curfile)) != EOF) {
-			(void)ungetc(c, curfile);
+		if (infile != NULL && (c = getc(infile)) != EOF) {
+			(void)ungetc(c, infile);
 			break;
 		}
 		/* If we are here then either eof or no files are open yet */
-		if (curfile == stdin) {
+		if (infile == stdin) {
 			sp->len = 0;
 			return (0);
 		}
-		if (curfile != NULL) {
-			fclose(curfile);
+		if (infile != NULL) {
+			fclose(infile);
+			if (*oldfname != '\0' &&
+			    rename(fname, oldfname) != 0) {
+				warn("rename()");
+				unlink(tmpfname);
+				exit(1);
+			}
+			if (*tmpfname != '\0')
+				rename(tmpfname, fname);
+			*tmpfname = *oldfname = '\0';
+			outfname = NULL;
 		}
-		if (firstfile == 0) {
+		if (firstfile == 0)
 			files = files->next;
-		} else
+		else
 			firstfile = 0;
 		if (files == NULL) {
 			sp->len = 0;
 			return (0);
 		}
+		fname = files->fname;
 		if (inplace != NULL) {
-			if (inplace_edit(&files->fname) == -1)
-				continue;
+			if (lstat(fname, &sb) != 0)
+				err(1, "%s", fname);
+			if (!(sb.st_mode & S_IFREG))
+				errx(1, "%s: %s %s", fname,
+				    "in-place editing only",
+				    "works for regular files");
+			if (*inplace != '\0') {
+				strlcpy(oldfname, fname,
+				    sizeof(oldfname));
+				len = strlcat(oldfname, inplace,
+				    sizeof(oldfname));
+				if (len > sizeof(oldfname))
+					errx(1, "%s: name too long", fname);
+			}
+			len = snprintf(tmpfname, sizeof(tmpfname),
+			    ".!%ld!%s", (long)getpid(), fname);
+			if (len >= sizeof(tmpfname))
+				errx(1, "%s: name too long", fname);
+			unlink(tmpfname);
+			if ((outfile = fopen(tmpfname, "w")) == NULL)
+				err(1, "%s", fname);
+			fchown(fileno(outfile), sb.st_uid, sb.st_gid);
+			fchmod(fileno(outfile), sb.st_mode & ALLPERMS);
+			outfname = tmpfname;
+		} else {
+			outfile = stdout;
+			outfname = "stdout";
 		}
-		fname = files->fname;
-		if ((curfile = fopen(fname, "r")) == NULL) {
+		if ((infile = fopen(fname, "r")) == NULL) {
 			warn("%s", fname);
 			rval = 1;
 			continue;
 		}
-		if (inplace != NULL && *inplace == '\0')
-			unlink(fname);
 	}
 	/*
-	 * We are here only when curfile is open and we still have something
+	 * We are here only when infile is open and we still have something
 	 * to read from it.
 	 *
 	 * Use fgetln so that we can handle essentially infinite input data.
 	 * Can't use the pointer into the stdio buffer as the process space
 	 * because the ungetc() can cause it to move.
 	 */
-	p = fgetln(curfile, &len);
-	if (ferror(curfile))
+	p = fgetln(infile, &len);
+	if (ferror(infile))
 		errx(1, "%s: %s", fname, strerror(errno ? errno : EIO));
 	if (len != 0 && p[len - 1] == '\n')
 		len--;
@@ -395,56 +435,6 @@ add_file(char *s)
 	fl_nextp = &fp->next;
 }
 
-/*
- * Modify a pointer to a filename for inplace editing and reopen stdout
- */
-static int
-inplace_edit(char **filename)
-{
-	struct stat orig;
-	char backup[MAXPATHLEN];
-
-	if (lstat(*filename, &orig) == -1)
-		err(1, "lstat");
-	if ((orig.st_mode & S_IFREG) == 0) {
-		warnx("cannot inplace edit %s, not a regular file", *filename);
-		return (-1);
-	}
-
-	if (*inplace == '\0') {
-		/*
-		 * This is a bit of a hack: we use mkstemp() to avoid the
-		 * mktemp() link-time warning, although mktemp() would fit in
-		 * this context much better. We're only interested in getting
-		 * a name for use in the rename(); there aren't any security
-		 * issues here that don't already exist in relation to the
-		 * original file and its directory.
-		 */
-		int fd;
-		strlcpy(backup, *filename, sizeof(backup));
-		strlcat(backup, ".XXXXXXXXXX", sizeof(backup));
-		fd = mkstemp(backup);
-		if (fd == -1)
-			errx(1, "could not create backup of %s", *filename);
-		else
-			close(fd);
-	} else {
-		strlcpy(backup, *filename, sizeof(backup));
-		strlcat(backup, inplace, sizeof(backup));
-	}
-
-	if (rename(*filename, backup) == -1)
-		err(1, "rename(\"%s\", \"%s\")", *filename, backup);
-	if (freopen(*filename, "w", stdout) == NULL)
-		err(1, "open(\"%s\")", *filename);
-	if (fchmod(fileno(stdout), orig.st_mode) == -1)
-		err(1, "chmod(\"%s\")", *filename);
-	*filename = strdup(backup);
-	if (*filename == NULL)
-		err(1, "malloc");
-	return (0);
-}
-
 int
 lastline(void)
 {
@@ -452,8 +442,8 @@ lastline(void)
 
 	if (files->next != NULL)
 		return (0);
-	if ((ch = getc(curfile)) == EOF)
+	if ((ch = getc(infile)) == EOF)
 		return (1);
-	ungetc(ch, curfile);
+	ungetc(ch, infile);
 	return (0);
 }
diff --git a/usr.bin/sed/process.c b/usr.bin/sed/process.c
index 5baed7a..772fd0b 100644
--- a/usr.bin/sed/process.c
+++ b/usr.bin/sed/process.c
@@ -86,7 +86,7 @@ static regex_t *defpreg;
 size_t maxnsub;
 regmatch_t *match;
 
-#define OUT(s) { fwrite(s, sizeof(u_char), psl, stdout); putchar('\n'); }
+#define OUT(s) { fwrite(s, sizeof(u_char), psl, outfile); fputc('\n', outfile); }
 
 void
 process(void)
@@ -130,7 +130,7 @@ redirect:
 				pd = 1;
 				psl = 0;
 				if (cp->a2 == NULL || lastaddr)
-					(void)printf("%s", cp->t);
+					(void)fprintf(outfile, "%s", cp->t);
 				break;
 			case 'd':
 				pd = 1;
@@ -162,7 +162,7 @@ redirect:
 				cspace(&HS, ps, psl, 0);
 				break;
 			case 'i':
-				(void)printf("%s", cp->t);
+				(void)fprintf(outfile, "%s", cp->t);
 				break;
 			case 'l':
 				lputs(ps);
@@ -252,7 +252,7 @@ redirect:
 			case '}':
 				break;
 			case '=':
-				(void)printf("%lu\n", linenum);
+				(void)fprintf(outfile, "%lu\n", linenum);
 			}
 			cp = cp->next;
 		} /* for all cp */
@@ -438,7 +438,7 @@ flush_appends(void)
 		switch (appends[i].type) {
 		case AP_STRING:
 			fwrite(appends[i].s, sizeof(char), appends[i].len,
-			    stdout);
+			    outfile);
 			break;
 		case AP_FILE:
 			/*
@@ -452,12 +452,12 @@ flush_appends(void)
 			if ((f = fopen(appends[i].s, "r")) == NULL)
 				break;
 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
-				(void)fwrite(buf, sizeof(char), count, stdout);
+				(void)fwrite(buf, sizeof(char), count, outfile);
 			(void)fclose(f);
 			break;
 		}
-	if (ferror(stdout))
-		errx(1, "stdout: %s", strerror(errno ? errno : EIO));
+	if (ferror(outfile))
+		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 	appendx = sdone = 0;
 }
 
@@ -470,6 +470,8 @@ lputs(char *s)
 	struct winsize win;
 	static int termwidth = -1;
 
+	if (outfile != stdout)
+		termwidth = 60;
 	if (termwidth == -1) {
 		if ((p = getenv("COLUMNS")) && *p != '\0')
 			termwidth = atoi(p);
@@ -482,32 +484,32 @@ lputs(char *s)
 
 	for (count = 0; *s; ++s) {
 		if (count + 5 >= termwidth) {
-			(void)printf("\\\n");
+			(void)fprintf(outfile, "\\\n");
 			count = 0;
 		}
 		if (isprint((unsigned char)*s) && *s != '\\') {
-			(void)putchar(*s);
+			(void)fputc(*s, outfile);
 			count++;
 		} else if (*s == '\n') {
-			(void)putchar('$');
-			(void)putchar('\n');
+			(void)fputc('$', outfile);
+			(void)fputc('\n', outfile);
 			count = 0;
 		} else {
 			escapes = "\\\a\b\f\r\t\v";
-			(void)putchar('\\');
+			(void)fputc('\\', outfile);
 			if ((p = strchr(escapes, *s))) {
-				(void)putchar("\\abfrtv"[p - escapes]);
+				(void)fputc("\\abfrtv"[p - escapes], outfile);
 				count += 2;
 			} else {
-				(void)printf("%03o", *(u_char *)s);
+				(void)fprintf(outfile, "%03o", *(u_char *)s);
 				count += 4;
 			}
 		}
 	}
-	(void)putchar('$');
-	(void)putchar('\n');
-	if (ferror(stdout))
-		errx(1, "stdout: %s", strerror(errno ? errno : EIO));
+	(void)fputc('$', outfile);
+	(void)fputc('\n', outfile);
+	if (ferror(outfile))
+		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 }
 
 static __inline int