Kernel environment access, preloaded module lookup.

1 files changed, 126 insertions, 0 deletions

diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
new file mode 100644
index 000000000000..400da455add5
--- /dev/null
+++ b/sys/kern/kern_environment.c
@@ -0,0 +1,126 @@
+/*-
+ * Copyright (c) 1998 Michael Smith
+ * 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.
+ *
+ *	$Id$
+
+/*
+ * The unified bootloader passes us a pointer to a preserved copy of
+ * bootstrap/kernel environment variables.
+ * We make these available using sysctl for both in-kernel and
+ * out-of-kernel consumers.
+ *
+ * Note that the current sysctl infrastructure doesn't allow 
+ * dynamic insertion or traversal through handled spaces.  Grr.
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/sysctl.h>
+#include <sys/libkern.h>
+#include <machine/bootinfo.h>
+
+char	*kern_envp;
+
+static char	*kernenv_next(char *cp);
+
+static void
+kernenv_init(void* arg)
+{
+    if (bootinfo.bi_envp != 0)
+	kern_envp = (char *)bootinfo.bi_envp;
+}
+
+SYSINIT(kernenv, SI_SUB_CONSOLE, SI_ORDER_FIRST, kernenv_init, 0);
+
+char *
+getenv(char *name)
+{
+    char	*cp, *ep;
+    int		len;
+    
+    for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
+	for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
+	    ;
+	len = ep - cp;
+	if (*ep = '=')
+	    ep++;
+	if (!strncmp(name, cp, len))
+	    return(ep);
+    }
+    return(NULL);
+}
+
+
+static int
+sysctl_kernenv SYSCTL_HANDLER_ARGS
+{
+    int		*name = (int *)arg1;
+    u_int	namelen = arg2;
+    char	*cp;
+    int		i, error;
+
+    if (kern_envp == NULL)
+	return(ENOENT);
+    
+    name++;
+    namelen--;
+    
+    if (namelen != 1)
+	return(EINVAL);
+
+    cp = kern_envp;
+    for (i = 0; i < name[0]; i++) {
+	cp = kernenv_next(cp);
+	if (cp == NULL)
+	    break;
+    }
+    
+    if (cp == NULL)
+	return(ENOENT);
+    
+    error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
+    return (error);
+}
+
+SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
+
+/*
+ * Find the next entry after the one which (cp) falls within, return a
+ * pointer to its start or NULL if there are no more.
+ */
+static char *
+kernenv_next(char *cp)
+{
+    if (cp != NULL) {
+	while (*cp != 0)
+	    cp++;
+	cp++;
+	if (*cp == 0)
+	    cp = NULL;
+    }
+    return(cp);
+}
+