From 3422fa769ae126d2d2dfc1471ac75f62aa676041 Mon Sep 17 00:00:00 2001
From: cheloha <cheloha@openbsd.org>
Date: Sat, 1 Jan 2022 02:20:38 +0000
Subject: [PATCH] uniq(1): freopen(3) stdin, stdout

uniq(1) defaults to stdin and stdout, has exactly one input and one
output, and permits the user to replace the default input and/or the
default output with a given file.

freopen(3) is the right idiom in this context.  Get rid of file() and
the extra FILE pointers.  Switch from fprintf(3) to printf(3).

While here, const the "str" argument to show().

Thread: https://marc.info/?l=openbsd-tech&m=164078603312936&w=2

ok millert@
---
 usr.bin/uniq/uniq.c | 58 +++++++++++++++------------------------------
 1 file changed, 19 insertions(+), 39 deletions(-)

diff --git a/usr.bin/uniq/uniq.c b/usr.bin/uniq/uniq.c
index fa2b0e7ebaa..72474bfd1e7 100644
--- a/usr.bin/uniq/uniq.c
+++ b/usr.bin/uniq/uniq.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uniq.c,v 1.30 2021/12/24 17:59:28 cheloha Exp $	*/
+/*	$OpenBSD: uniq.c,v 1.31 2022/01/01 02:20:38 cheloha Exp $	*/
 /*	$NetBSD: uniq.c,v 1.7 1995/08/31 22:03:48 jtc Exp $	*/
 
 /*
@@ -48,8 +48,7 @@
 int cflag, dflag, iflag, uflag;
 int numchars, numfields, repeats;
 
-FILE	*file(char *, char *);
-void	 show(FILE *, char *);
+void	 show(const char *);
 char	*skip(char *);
 void	 obsolete(char *[]);
 __dead void	usage(void);
@@ -58,7 +57,6 @@ int
 main(int argc, char *argv[])
 {
 	char *p, *prevline, *t, *thisline, *tmp;
-	FILE *ifp = NULL, *ofp = NULL;
 	size_t prevsize, thissize, tmpsize;
 	ssize_t len;
 	int ch;
@@ -112,21 +110,15 @@ main(int argc, char *argv[])
 	if (!dflag && !uflag)
 		dflag = uflag = 1;
 
-	switch (argc) {
-	case 0:
-		ifp = stdin;
-		ofp = stdout;
-		break;
-	case 1:
-		ifp = file(argv[0], "r");
-		ofp = stdout;
-		break;
-	case 2:
-		ifp = file(argv[0], "r");
-		ofp = file(argv[1], "w");
-		break;
-	default:
+	if (argc > 2)
 		usage();
+	if (argc >= 1 && strcmp(argv[0], "-") != 0) {
+		if (freopen(argv[0], "r", stdin) == NULL)
+			err(1, "%s", argv[0]);
+	}
+	if (argc == 2 && strcmp(argv[1], "-") != 0) {
+		if (freopen(argv[1], "w", stdout) == NULL)
+			err(1, "%s", argv[1]);
 	}
 
 	if (pledge("stdio", NULL) == -1)
@@ -134,9 +126,9 @@ main(int argc, char *argv[])
 
 	prevsize = 0;
 	prevline = NULL;
-	if ((len = getline(&prevline, &prevsize, ifp)) == -1) {
+	if ((len = getline(&prevline, &prevsize, stdin)) == -1) {
 		free(prevline);
-		if (ferror(ifp))
+		if (ferror(stdin))
 			err(1, "getline");
 		exit(0);
 	}
@@ -149,7 +141,7 @@ main(int argc, char *argv[])
 	
 	thissize = 0;
 	thisline = NULL;
-	while ((len = getline(&thisline, &thissize, ifp)) != -1) {
+	while ((len = getline(&thisline, &thissize, stdin)) != -1) {
 		if (thisline[len - 1] == '\n')
 			thisline[len - 1] = '\0';
 
@@ -161,7 +153,7 @@ main(int argc, char *argv[])
 
 		/* If different, print; set previous to new value. */
 		if ((iflag ? strcasecmp : strcmp)(p, t)) {
-			show(ofp, prevline);
+			show(prevline);
 			tmp = prevline;
 			prevline = thisline;
 			thisline = tmp;
@@ -176,10 +168,10 @@ main(int argc, char *argv[])
 			++repeats;
 	}
 	free(thisline);
-	if (ferror(ifp))
+	if (ferror(stdin))
 		err(1, "getline");
 
-	show(ofp, prevline);
+	show(prevline);
 	free(prevline);
 
 	exit(0);
@@ -191,13 +183,13 @@ main(int argc, char *argv[])
  *	of the line.
  */
 void
-show(FILE *ofp, char *str)
+show(const char *str)
 {
 	if ((dflag && repeats) || (uflag && !repeats)) {
 		if (cflag)
-			fprintf(ofp, "%4d %s\n", repeats + 1, str);
+			printf("%4d %s\n", repeats + 1, str);
 		else
-			fprintf(ofp, "%s\n", str);
+			printf("%s\n", str);
 	}
 }
 
@@ -233,18 +225,6 @@ skip(char *str)
 	return (str);
 }
 
-FILE *
-file(char *name, char *mode)
-{
-	FILE *fp;
-
-	if (strcmp(name, "-") == 0)
-		return(*mode == 'r' ? stdin : stdout);
-	if ((fp = fopen(name, mode)) == NULL)
-		err(1, "%s", name);
-	return (fp);
-}
-
 void
 obsolete(char *argv[])
 {
-- 
2.20.1