From 7eb4e8959784bd25892ca166a1ea07a920e9777b Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Sat, 11 Jun 2022 09:17:07 +0100
Subject: [PATCH] Allow non-POSIX features to be turned off at runtime

The -C option (GitHub PR #8) and enhanced treatment of the MAKE
macro (GitHub PR #10) should be turned off in POSIX mode.

The .POSIX special target doesn't work for these features as they're
processed before any makefiles are read.  Instead:

- Use the --posix command line option, which must be the first given.

- Set the environment variable PDPMAKE_POSIXLY_CORRECT.

In addition, if pdpmake is run with extensions enabled and a valid
.POSIX special target is present, then PDPMAKE_POSIXLY_CORRECT is
set in the environment.  Thus, recursive invocations of pdpmake
will have non-POSIX features disabled.
---
 input.c |  4 +++-
 main.c  | 50 ++++++++++++++++++++++++++++++++++++--------------
 make.h  | 17 +++++++++++++----
 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/input.c b/input.c
index c8542fa..1715f4c 100644
--- a/input.c
+++ b/input.c
@@ -984,8 +984,10 @@ input(FILE *fd)
 		free(copy);
 		free(expanded);
 #if ENABLE_FEATURE_MAKE_EXTENSIONS
-		if (first_line && findname(".POSIX"))
+		if (first_line && findname(".POSIX")) {
+			setenv("PDPMAKE_POSIXLY_CORRECT", "", 1);
 			posix = TRUE;
+		}
 		first_line = FALSE;
 #endif
 	}
diff --git a/main.c b/main.c
index 56e3640..2d1fc4f 100644
--- a/main.c
+++ b/main.c
@@ -1,7 +1,8 @@
 /*
- * make [-C path] [-f makefile] [-eiknpqrsSt] [macro=val ...] [target ...]
+ * make [--posix] [-C path] [-f makefile] [-eiknpqrsSt] [macro=val ...] [target ...]
  *
- *  -C  Change directory to path
+ *  --posix  Enforce POSIX mode (non-POSIX)
+ *  -C  Change directory to path (non-POSIX)
  *  -f  Makefile name
  *  -e  Environment variables override macros in makefiles
  *  -i  Ignore exit status
@@ -29,8 +30,11 @@ static void
 usage(void)
 {
 	fprintf(stderr,
-		"Usage: %s [-C path] [-f makefile] [-eiknpqrsSt] [macro=val ...]"
-		"[target ...]\n", myname);
+		"Usage: %s"
+		IF_FEATURE_MAKE_EXTENSIONS(" [--posix] [-C path]")
+		" [-f makefile] [-eiknpqrsSt] [macro=val ...]"
+		IF_FEATURE_MAKE_EXTENSIONS("\n\t")
+		" [target ...]\n", myname);
 	exit(2);
 }
 
@@ -46,14 +50,18 @@ process_options(int argc, char **argv, int from_env)
 
 	while ((opt = getopt(argc, argv, OPTSTR1 OPTSTR2)) != -1) {
 		switch(opt) {
+#if ENABLE_FEATURE_MAKE_EXTENSIONS
 		case 'C':
-			if (!from_env) {
+			if (!posix && !from_env) {
 				if (chdir(optarg) == -1) {
 					error("can't chdir to %s: %s", optarg, strerror(errno));
 				}
 				flags |= OPT_C;
+				break;
 			}
+			error("-C not allowed");
 			break;
+#endif
 		case 'f':	// Alternate file name
 			if (!from_env) {
 				makefiles = newcmd(optarg, makefiles);
@@ -302,7 +310,7 @@ int
 main(int argc, char **argv)
 {
 #if ENABLE_FEATURE_MAKE_EXTENSIONS
-	const char *path, *argv0;
+	const char *path, *newpath = NULL;
 #else
 	const char *path = "make";
 #endif
@@ -312,15 +320,30 @@ main(int argc, char **argv)
 	struct cmd *mp;
 
 	myname = basename(*argv);
+#if ENABLE_FEATURE_MAKE_EXTENSIONS
+	if (argv[1] && strcmp(argv[1], "--posix") == 0) {
+		argv[1] = argv[0];
+		++argv;
+		--argc;
+		setenv("PDPMAKE_POSIXLY_CORRECT", "", 1);
+		posix = TRUE;
+	} else {
+		posix = getenv("PDPMAKE_POSIXLY_CORRECT") != NULL;
+	}
+#endif
 
 #if ENABLE_FEATURE_MAKE_EXTENSIONS
-	path = argv0 = argv[0];
-	if (argv[0][0] != '/' && strchr(argv[0], '/')) {
-		// Make relative path absolute
-		path = realpath(argv[0], NULL);
-		if (!path) {
-			error("can't resolve path for %s: %s", argv[0], strerror(errno));
+	if (!posix) {
+		path = argv[0];
+		if (argv[0][0] != '/' && strchr(argv[0], '/')) {
+			// Make relative path absolute
+			path = newpath = realpath(argv[0], NULL);
+			if (!path) {
+				error("can't resolve path for %s: %s", argv[0], strerror(errno));
+			}
 		}
+	} else {
+		path = "make";
 	}
 #endif
 
@@ -371,8 +394,7 @@ main(int argc, char **argv)
 	setmacro("SHELL", "/bin/sh", 4);
 	setmacro("MAKE", path, 4);
 #if ENABLE_FEATURE_MAKE_EXTENSIONS
-	if (path != argv0)
-		free((void *)path);
+	free((void *)newpath);
 #endif
 
 #if ENABLE_FEATURE_MAKE_EXTENSIONS
diff --git a/make.h b/make.h
index ab3c675..2e90a7a 100644
--- a/make.h
+++ b/make.h
@@ -49,9 +49,18 @@ extern char **environ;
 #define MAX(a,b)	((a)>(b)?(a):(b))
 
 #define OPTSTR1 "eiknqrsSt"
+#if ENABLE_FEATURE_MAKE_EXTENSIONS
 #define OPTSTR2 "pf:C:"
+#else
+#define OPTSTR2 "pf:"
+#endif
 
 enum {
+	OPTBIT_p = 9,
+	OPTBIT_f,
+	IF_FEATURE_MAKE_EXTENSIONS(OPTBIT_C,)
+	OPTBIT_precious,
+
 	OPT_e = (1 << 0),
 	OPT_i = (1 << 1),
 	OPT_k = (1 << 2),
@@ -62,11 +71,11 @@ enum {
 	OPT_S = (1 << 7),
 	OPT_t = (1 << 8),
 	// These options aren't allowed in MAKEFLAGS
-	OPT_p = (1 << 9),
-	OPT_f = (1 << 10),
-	OPT_C = (1 << 11),
+	OPT_p = (1 << OPTBIT_p),
+	OPT_f = (1 << OPTBIT_f),
+	OPT_C = IF_FEATURE_MAKE_EXTENSIONS((1 << OPTBIT_C)) + 0,
 	// OPT_precious isn't a command line option and must be last
-	OPT_precious = (1 << 12),
+	OPT_precious = (1 << OPTBIT_precious),
 };
 
 // Options that aren't included in MAKEFLAGS
-- 
2.36.1