Re: kernel .config support?

Paul Rolland (rol@as2917.net)
Thu, 2 Jan 2003 19:37:56 +0100


Hello,

Following some advices from the list, here is my patch updated,
to embed the .config in the kernel and give access to a gzip'ed
copy thru /proc/config/config.gz

Regards,
Paul

diff -urN linux-2.5.53-orig/drivers/char/Kconfig
linux-2.5.53/drivers/char/Kconfig
--- linux-2.5.53-orig/drivers/char/Kconfig Tue Dec 24 06:19:26 2002
+++ linux-2.5.53/drivers/char/Kconfig Mon Dec 30 08:35:54 2002
@@ -4,6 +4,13 @@

menu "Character devices"

+config CONFIG
+ bool "Linux Kernel Configuration Driver"
+ ---help---
+ If you say Y here, and if you have /proc support enabled,
you'll find
+ a /proc/config directory that will contain a copy of the
.config used
+ to generate the running kernel.
+
config VT
bool "Virtual terminal"
---help---
diff -urN linux-2.5.53-orig/drivers/char/Makefile
linux-2.5.53/drivers/char/Makefile
--- linux-2.5.53-orig/drivers/char/Makefile Tue Dec 24 06:21:17 2002
+++ linux-2.5.53/drivers/char/Makefile Mon Dec 30 12:06:53 2002
@@ -7,6 +7,9 @@
#
FONTMAPFILE = cp437.uni

+EXTRA_TARGETS := config.h
+host-progs := dotHmaker
+
obj-y += mem.o tty_io.o n_tty.o tty_ioctl.o pty.o misc.o random.o

# All of the (potential) objects that export symbols.
@@ -16,6 +19,7 @@
ite_gpio.o keyboard.o misc.o nvram.o random.o
rtc.o \
selection.o sonypi.o sysrq.o tty_io.o
tty_ioctl.o

+obj-$(CONFIG_CONFIG) += config.o
obj-$(CONFIG_VT) += vt_ioctl.o vc_screen.o consolemap.o
consolemap_deftbl.o selection.o keyboard.o
obj-$(CONFIG_HW_CONSOLE) += vt.o defkeymap.o
obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o
@@ -85,7 +89,7 @@

# Files generated that shall be removed upon make clean
-clean-files := consolemap_deftbl.c defkeymap.c qtronixmap.c
+clean-files := consolemap_deftbl.c defkeymap.c qtronixmap.c dotHmaker
config.txt config.txt.gz config.h

$(obj)/consolemap_deftbl.c: $(src)/$(FONTMAPFILE)
$(call do_cmd,CONMK $@,$(objtree)/scripts/conmakehash $< > $@)
@@ -107,3 +111,13 @@
rm $@.tmp

endif
+
+$(obj)/config.o: $(obj)/config.h
+
+$(obj)/config.h: $(obj)/config.txt.gz $(obj)/dotHmaker
+ $(obj)/dotHmaker < $< > $@
+
+$(obj)/config.txt.gz: .config FORCE
+ cp .config $(obj)/config.txt
+ $(call if_changed,gzip)
+
diff -urN linux-2.5.53-orig/drivers/char/config.c
linux-2.5.53/drivers/char/config.c
--- linux-2.5.53-orig/drivers/char/config.c Thu Jan 1 01:00:00 1970
+++ linux-2.5.53/drivers/char/config.c Mon Dec 30 08:33:48 2002
@@ -0,0 +1,149 @@
+/*
+ * Linux Configuration Driver
+ * (c) 2002 Paul Rolland
+ *
+ * This driver is intended to give access to the .config file that was
+ * used to compile the kernel.
+ * It does include a gzip'd copy of the file, which can be access thru
+ * /proc/config/config.gz
+ *
+ */
+
+#define DOT_CONFIG_VERSION "1.0"
+
+#include <linux/module.h>
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/smp_lock.h>
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/mc146818rtc.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#include "config.h"
+
+static int config_read_proc(char * page, char ** start, off_t off,
+ int count, int *eof, void *data);
+
+
+#ifndef CONFIG_PROC_FS
+#warn Attention
+static int config_read_proc( char *buffer, char **start, off_t offset,
+ int size, int *eof, void *data) { return 0;
+} #else
+
+/* This macro frees the machine specific function from bounds checking
+and
+ * this like that... */
+#define PRINT_PROC(fmt,args...)
\
+ do { \
+ *len += sprintf( buffer+*len, fmt, ##args ); \
+ if (*begin + *len > offset + size) \
+ return( 0 ); \
+ if (*begin + *len < offset) {
\
+ *begin += *len; \
+ *len = 0; \
+ } \
+ } while(0)
+
+
+static int config_version_infos(char *buffer, int *len, off_t *begin,
+ off_t offset, int size)
+{
+ PRINT_PROC("Linux Kernel Configuration driver version %s\n",
+DOT_CONFIG_VERSION);
+ PRINT_PROC("(c) P. Rolland - Dec 2002\n");
+
+ return(1);
+}
+
+static int config_gz_infos(char *buffer, int *len, off_t *begin, off_t
offset,
+ int size)
+{
+ int i;
+
+ for (i=0; i<DOT_CONFIG_GZ_SIZE; i++) {
+ PRINT_PROC("%c", config_gz[i]);
+ }
+
+ return(1);
+}
+
+static int config_read_proc( char *buffer, char **start, off_t offset,
+ int size, int *eof, void *data )
+{
+ int len = 0;
+ off_t begin = 0;
+
+ *eof = config_version_infos(buffer, &len, &begin, offset, size);
+
+ if (offset >= begin + len)
+ return(0);
+ *start = buffer + (offset - begin);
+ return( size < begin + len - offset ? size : begin + len - offset );
+}
+
+static int config_gz_read_proc( char *buffer, char **start, off_t
offset,
+ int size, int *eof, void *data ) {
+ int len = 0;
+ off_t begin = 0;
+
+ *eof = config_gz_infos(buffer, &len, &begin, offset, size);
+
+ if (offset >= begin + len)
+ return(0);
+ *start = buffer + (offset - begin);
+ return( size < begin + len - offset ? size : begin + len - offset );
+}
+
+static int __init config_init(void)
+{
+ struct proc_dir_entry * entry;
+ entry = create_proc_entry("config", S_IRUGO|S_IXUGO|S_IFDIR, NULL);
+ if (entry == NULL) {
+ printk(KERN_ERR "config: can't create /proc/config\n");
+ return(-ENOMEM);
+ }
+
+ if
(!create_proc_read_entry("config/version",0,0,config_read_proc,NULL)) {
+ printk(KERN_ERR "config: can't create /proc/config/version\n");
+ return(-ENOMEM);
+ }
+ if
(!create_proc_read_entry("config/config.gz",0,0,config_gz_read_proc,NULL
)) {
+ printk(KERN_ERR "config: can't create /proc/config/config.gz\n");
+ return(-ENOMEM);
+ }
+
+ printk(KERN_INFO "Linux Kernel Configuration driver v"
DOT_CONFIG_VERSION
+ " (c) Paul Rolland\n");
+
+ return( 0 );
+}
+
+static void __exit config_cleanup_module (void)
+{
+ remove_proc_entry( "config/version", 0 );
+ remove_proc_entry( "config/config.gz", 0 );
+ remove_proc_entry( "config", 0 );
+}
+
+module_init(config_init);
+module_exit(config_cleanup_module);
+
+#endif /* CONFIG_PROC_FS */
+
+MODULE_AUTHOR("Paul Rolland");
+MODULE_DESCRIPTION("Driver for accessing kernel configuration");
+MODULE_LICENSE("GPL");
+
diff -urN linux-2.5.53-orig/drivers/char/dotHmaker.c
linux-2.5.53/drivers/char/dotHmaker.c
--- linux-2.5.53-orig/drivers/char/dotHmaker.c Thu Jan 1 01:00:00 1970
+++ linux-2.5.53/drivers/char/dotHmaker.c Mon Dec 30 08:33:04 2002
@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+int main(void)
+{
+ FILE * in = stdin;
+ int i;
+ unsigned char buf;
+
+ int size = 0;
+
+ printf("/*\n");
+ printf(" * Automagically generated file, please don't edit !\n");
+ printf(" */\n"); printf("\n");
+ printf("static char config_gz[] = \\\n");
+
+ i = 0;
+
+ fread(&buf, sizeof(unsigned char), 1, in);
+ while (!feof(in)) {
+ if (i == 0) {
+ printf(" \"");
+ } /* endif */
+ printf("\\x%x", buf);
+ size ++;
+ i ++;
+ if (i == 10) {
+ i = 0;
+ printf("\"\\\n");
+ } /* endif */
+ fread(&buf, sizeof(unsigned char), 1, in);
+ } /* endwhile */
+
+ if (i != 0) {
+ printf(" ;\n");
+ } else {
+ printf("\";\n");
+ } /* endif */
+ printf("\n");
+ printf("#define DOT_CONFIG_GZ_SIZE %d\n\n", size);
+
+ exit(0);
+}
+

-
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