Rework the kernel environment subsystem. We now convert the static

environment needed at boot time to a dynamic subsystem when VM is
up.  The dynamic kernel environment is protected by an sx lock.

This adds some new functions to manipulate the kernel environment :
freeenv(), setenv(), unsetenv() and testenv().  freeenv() has to be
called after every getenv() when you have finished using the string.
testenv() only tests if an environment variable is present, and
doesn't require a freeenv() call. setenv() and unsetenv() are self
explanatory.

The kenv(2) syscall exports these new functionalities to userland,
mainly for kenv(1).

Reviewed by:	peter

5 files changed, 63 insertions, 2 deletions

diff --git a/sys/sys/kenv.h b/sys/sys/kenv.h
new file mode 100644
index 0000000..0a30ddb
--- /dev/null
+++ b/sys/sys/kenv.h
@@ -0,0 +1,43 @@
+/*-
+ * Copyright (c) 2002 Maxime Henrion <mux@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_KENV_H_
+#define _SYS_KENV_H_
+
+/*
+ * Constants for the kenv(2) syscall
+ */
+#define KENV_GET	0
+#define KENV_SET	1
+#define KENV_UNSET	2
+#define KENV_DUMP	3
+
+#define KENV_MNAMELEN	128	/* Maximum name length (for the syscall) */
+#define KENV_MVALLEN	128	/* Maximum value length (for the syscall) */
+
+#endif /* !_SYS_KENV_H_ */
diff --git a/sys/sys/syscall.h b/sys/sys/syscall.h
index fb693c6..c336453 100644
--- a/sys/sys/syscall.h
+++ b/sys/sys/syscall.h
@@ -303,4 +303,5 @@
 #define	SYS_kse_new	381
 #define	SYS_thread_wakeup	382
 #define	SYS_kse_yield	383
-#define	SYS_MAXSYSCALL	390
+#define	SYS_kenv	390
+#define	SYS_MAXSYSCALL	391
diff --git a/sys/sys/syscall.mk b/sys/sys/syscall.mk
index 3d67b4e..4c25a9e 100644
--- a/sys/sys/syscall.mk
+++ b/sys/sys/syscall.mk
@@ -252,4 +252,5 @@ MIASM =  \
 	kse_wakeup.o \
 	kse_new.o \
 	thread_wakeup.o \
-	kse_yield.o
+	kse_yield.o \
+	kenv.o
diff --git a/sys/sys/sysproto.h b/sys/sys/sysproto.h
index 1f4b987..80385c0 100644
--- a/sys/sys/sysproto.h
+++ b/sys/sys/sysproto.h
@@ -1105,6 +1105,12 @@ struct thread_wakeup_args {
 struct kse_yield_args {
 	register_t dummy;
 };
+struct kenv_args {
+	char what_l_[PADL_(int)]; int what; char what_r_[PADR_(int)];
+	char name_l_[PADL_(const char *)]; const char * name; char name_r_[PADR_(const char *)];
+	char value_l_[PADL_(char *)]; char * value; char value_r_[PADR_(char *)];
+	char len_l_[PADL_(int)]; int len; char len_r_[PADR_(int)];
+};
 int	nosys(struct thread *, struct nosys_args *);
 void	sys_exit(struct thread *, struct sys_exit_args *);
 int	fork(struct thread *, struct fork_args *);
@@ -1354,6 +1360,7 @@ int	kse_wakeup(struct thread *, struct kse_wakeup_args *);
 int	kse_new(struct thread *, struct kse_new_args *);
 int	thread_wakeup(struct thread *, struct thread_wakeup_args *);
 int	kse_yield(struct thread *, struct kse_yield_args *);
+int	kenv(struct thread *, struct kenv_args *);
 
 #ifdef COMPAT_43
 
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index e3d3602..1bcbf79 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -45,6 +45,7 @@
 #include <machine/atomic.h>
 #include <machine/cpufunc.h>
 #include <sys/callout.h>
+#include <sys/queue.h>
 
 extern int securelevel;		/* system security level (see init(8)) */
 extern int suser_enabled;	/* suser() is permitted to return 0 */
@@ -90,10 +91,14 @@ extern int maxusers;		/* system tune hint */
  */
 extern int envmode;
 extern int hintmode;		/* 0 = off. 1 = config, 2 = fallback */
+extern int dynamic_kenv;
+extern struct sx kenv_lock;
 extern char *kern_envp;
 extern char static_env[];
 extern char static_hints[];	/* by config for now */
 
+extern char **kenvp;
+
 /*
  * General function declarations.
  */
@@ -201,9 +206,13 @@ int	cr_cansee(struct ucred *u1, struct ucred *u2);
 int	cr_canseesocket(struct ucred *cred, struct socket *so);
 
 char	*getenv(const char *name);
+void	freeenv(char *env);
 int	getenv_int(const char *name, int *data);
 int	getenv_string(const char *name, char *data, int size);
 int	getenv_quad(const char *name, quad_t *data);
+void	setenv(const char *name, const char *value);
+int	unsetenv(const char *name);
+int	testenv(const char *name);
 
 #ifdef APM_FIXUP_CALLTODO 
 struct timeval;