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Message-Id: <1400525957-11525-2-git-send-email-bp@alien8.de>
Date: Mon, 19 May 2014 20:59:16 +0200
From: Borislav Petkov <bp@...en8.de>
To: X86 ML <x86@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...e.de>
Subject: [PATCH 1/2] x86: Carve out cmdline parsing function
From: Borislav Petkov <bp@...e.de>
into .../lib/cmdline.c to use by kernel proper too.
Adapted from arch/x86/boot/cmdline.c.
Signed-off-by: Borislav Petkov <bp@...e.de>
---
arch/x86/include/asm/cmdline.h | 6 +++
arch/x86/lib/Makefile | 2 +-
arch/x86/lib/cmdline.c | 84 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 91 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/include/asm/cmdline.h
create mode 100644 arch/x86/lib/cmdline.c
diff --git a/arch/x86/include/asm/cmdline.h b/arch/x86/include/asm/cmdline.h
new file mode 100644
index 000000000000..e01f7f7ccb0c
--- /dev/null
+++ b/arch/x86/include/asm/cmdline.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_CMDLINE_H
+#define _ASM_X86_CMDLINE_H
+
+int cmdline_find_option_bool(const char *cmdline_ptr, const char *option);
+
+#endif /* _ASM_X86_CMDLINE_H */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index eabcb6e6a900..4d4f96a27638 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -16,7 +16,7 @@ clean-files := inat-tables.c
obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
-lib-y := delay.o misc.o
+lib-y := delay.o misc.o cmdline.o
lib-y += thunk_$(BITS).o
lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c
new file mode 100644
index 000000000000..422db000d727
--- /dev/null
+++ b/arch/x86/lib/cmdline.c
@@ -0,0 +1,84 @@
+/*
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ *
+ * Misc librarized functions for cmdline poking.
+ */
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <asm/setup.h>
+
+static inline int myisspace(u8 c)
+{
+ return c <= ' '; /* Close enough approximation */
+}
+
+/**
+ * Find a boolean option (like quiet,noapic,nosmp....)
+ *
+ * @cmdline: the cmdline string
+ * @option: option string to look for
+ *
+ * Returns the position of that @option (starts counting with 1)
+ * or 0 on not found.
+ */
+int cmdline_find_option_bool(const char *cmdline, const char *option)
+{
+ char c;
+ int len, pos = 0, wstart = 0;
+ const char *opptr = NULL;
+ enum {
+ st_wordstart = 0, /* Start of word/after whitespace */
+ st_wordcmp, /* Comparing this word */
+ st_wordskip, /* Miscompare, skip */
+ } state = st_wordstart;
+
+ if (!cmdline)
+ return -1; /* No command line */
+
+ len = min_t(int, strlen(cmdline), COMMAND_LINE_SIZE);
+ if (!len)
+ return 0;
+
+ while (len--) {
+ c = *(char *)cmdline++;
+ pos++;
+
+ switch (state) {
+ case st_wordstart:
+ if (!c)
+ return 0;
+ else if (myisspace(c))
+ break;
+
+ state = st_wordcmp;
+ opptr = option;
+ wstart = pos;
+ /* fall through */
+
+ case st_wordcmp:
+ if (!*opptr)
+ if (!c || myisspace(c))
+ return wstart;
+ else
+ state = st_wordskip;
+ else if (!c)
+ return 0;
+ else if (c != *opptr++)
+ state = st_wordskip;
+ else if (!len) /* last word and is matching */
+ return wstart;
+ break;
+
+ case st_wordskip:
+ if (!c)
+ return 0;
+ else if (myisspace(c))
+ state = st_wordstart;
+ break;
+ }
+ }
+
+ return 0; /* Buffer overrun */
+}
--
1.9.0
--
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