config(8): Make 'env' files consistent with other file-accepting options

Previously, only one 'env' file could be specified. Later 'env' directives
would overwrite earlier 'env' directives. This is inconsistent with every
other file-accepting directives which process files in order, including
hints.

A caveat applies to both hints and env that isn't mentioned: they're
concatenated in the order of appearance, so they're not actually applied in
the way one might think by supplying:

hints x
hints y

Hints in x will take precedence over same-name hints in y due to how
the kernel processes them, stopping at the first line that matches the hint
we're searching for. Future work will flip the order of concatenation so
that later files may still properly override earlier files.

In practice, this likely doesn't matter at all due to the nature of the
beast.

usr.sbin/config/config.5

@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 22, 2018
+.Dd June 26, 2018
 .Dt CONFIG 5
 .Os
 .Sh NAME
@@ -124,6 +124,18 @@ the compiled-in environment instead, unless the boot environment contains
 This directive is useful for setting kernel tunables in
 embedded environments that do not start from
 .Xr loader 8 .
+.Pp
+All
+.Ic env
+and
+.Ic envvar
+directives will be processed and added to the staitc environment in the order of
+appearance.
+Note that within
+.Ar filename ,
+the first appearance of a given variable will be the first one seen by the
+kernel, effectively shadowing any later appearances of the same variable within
+.Ar filename .
 .\" -------- ENVVAR --------
 .Pp
 .It Ic envvar Ar setting
@@ -133,11 +145,13 @@ compiled-in environment.
 must be of the form
 .Dq Va name=value .
 Optional quotes are supported in both name and value.
-All environment variables specified with
-.Ic envvar
-will be set after any
+.Pp
+All
 .Ic env
-files are included.
+and
+.Ic envvar
+directives will be processed and added to the staitc environment in the order of
+appearance.
 .\" -------- FILES --------
 .Pp
 .It Ic files Ar filename

usr.sbin/config/config.h

@@ -37,6 +37,7 @@
  */
 #include <sys/types.h>
 #include <sys/queue.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -142,6 +143,7 @@ SLIST_HEAD(, opt_list) otab;
 
 struct envvar {
 	char	*env_str;
+	bool	env_is_file;
 	STAILQ_ENTRY(envvar) envvar_next;
 };
 
@@ -175,7 +177,6 @@ SLIST_HEAD(, includepath) includepath;
 #define OPT_AUTOGEN	"CONFIG_AUTOGENERATED"
 
 extern char	*ident;
-extern char	*env;
 extern char	kernconfstr[];
 extern int	do_trace;
 extern int	envmode;

usr.sbin/config/config.y

@@ -82,7 +82,6 @@
 
 struct	device_head dtab;
 char	*ident;
-char	*env;
 int	envmode;
 int	hintmode;
 int	yyline;
@@ -99,6 +98,7 @@ int yywrap(void);
 
 static void newdev(char *name);
 static void newfile(char *name);
+static void newenvvar(char *name, bool is_file);
 static void rmdev_schedule(struct device_head *dh, char *name);
 static void newopt(struct opt_head *list, char *name, char *value, int append);
 static void rmopt_schedule(struct opt_head *list, char *name);
@@ -191,20 +191,8 @@ Config_spec:
 		|
 	MAXUSERS NUMBER { maxusers = $2; } |
 	PROFILE NUMBER { profiling = $2; } |
-	ENV ID {
-		env = $2;
-		envmode = 1;
-		} |
-	ENVVAR ENVLINE {
-		struct envvar *envvar;
-
-		envvar = (struct envvar *)calloc(1, sizeof (struct envvar));
-		if (envvar == NULL)
-			err(EXIT_FAILURE, "calloc");
-		envvar->env_str = $2;
-		STAILQ_INSERT_TAIL(&envvars, envvar, envvar_next);
-		envmode = 1;
-	        } |
+	ENV ID { newenvvar($2, true); } |
+	ENVVAR ENVLINE { newenvvar($2, false); } |
 	HINTS ID {
 		struct hint *hint;
 
@@ -361,7 +349,21 @@ newfile(char *name)
 	nl->f_name = name;
 	STAILQ_INSERT_TAIL(&fntab, nl, f_next);
 }
-	
+
+static void
+newenvvar(char *name, bool is_file)
+{
+	struct envvar *envvar;
+
+	envvar = (struct envvar *)calloc(1, sizeof (struct envvar));
+	if (envvar == NULL)
+		err(EXIT_FAILURE, "calloc");
+	envvar->env_str = name;
+	envvar->env_is_file = is_file;
+	STAILQ_INSERT_TAIL(&envvars, envvar, envvar_next);
+	envmode = 1;
+}
+
 /*
  * Find a device in the list of devices.
  */

usr.sbin/config/mkmakefile.c

@@ -306,13 +306,6 @@ makeenv(void)
 	char line[BUFSIZ], result[BUFSIZ], *linep;
 	struct envvar *envvar;
 
-	if (env) {
-		ifp = fopen(env, "r");
-		if (ifp == NULL)
-			err(1, "%s", env);
-	} else {
-		ifp = NULL;
-	}
 	ofp = fopen(path("env.c.new"), "w");
 	if (ofp == NULL)
 		err(1, "%s", path("env.c.new"));
@@ -321,22 +314,27 @@ makeenv(void)
 	fprintf(ofp, "\n");
 	fprintf(ofp, "int envmode = %d;\n", envmode);
 	fprintf(ofp, "char static_env[] = {\n");
-	if (ifp) {
-		while (fgets(line, BUFSIZ, ifp) != NULL) {
-			sanitize_envline(result, line);
-			/* anything left? */
+	STAILQ_FOREACH(envvar, &envvars, envvar_next) {
+		if (envvar->env_is_file) {
+			ifp = fopen(envvar->env_str, "r");
+			if (ifp == NULL)
+				err(1, "%s", envvar->env_str);
+			while (fgets(line, BUFSIZ, ifp) != NULL) {
+				sanitize_envline(result, line);
+				/* anything left? */
+				if (*result == '\0')
+					continue;
+				fprintf(ofp, "\"%s\\0\"\n", result);
+			}
+			fclose(ifp);
+		} else {
+			linep = envvar->env_str;
+			sanitize_envline(result, linep);
 			if (*result == '\0')
 				continue;
 			fprintf(ofp, "\"%s\\0\"\n", result);
 		}
 	}
-	STAILQ_FOREACH(envvar, &envvars, envvar_next) {
-		linep = envvar->env_str;
-		sanitize_envline(result, linep);
-		if (*result == '\0')
-			continue;
-		fprintf(ofp, "\"%s\\0\"\n", result);
-	}
 	fprintf(ofp, "\"\\0\"\n};\n");
 	if (ifp)
 		fclose(ifp);