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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: will@kernel.org, danielwa@cisco.com, robh@kernel.org,
	daniel@gimpelevich.san-francisco.ca.us
Cc: linux-arch@vger.kernel.org, devicetree@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	linux-arm-kernel@lists.infradead.org,
	microblaze <monstr@monstr.eu>,
	linux-mips@vger.kernel.org, nios2 <ley.foon.tan@intel.com>,
	openrisc@lists.librecores.org, linux-hexagon@vger.kernel.org,
	linux-riscv@lists.infradead.org, x86@kernel.org,
	linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org,
	sparclinux@vger.kernel.org
Subject: [PATCH v3 01/17] cmdline: Add generic function to build command line.
Date: Fri, 26 Mar 2021 13:44:48 +0000 (UTC)
Message-ID: <878228ad88df38f8914c7aa25dede3ed05c50f48.1616765869.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1616765869.git.christophe.leroy@csgroup.eu>

This code provides architectures with a way to build command line
based on what is built in the kernel and what is handed over by the
bootloader, based on selected compile-time options.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3:
- Addressed comments from Will
- Added capability to have src == dst
---
 include/linux/cmdline.h | 57 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 include/linux/cmdline.h

diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
new file mode 100644
index 000000000000..dea87edd41be
--- /dev/null
+++ b/include/linux/cmdline.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_CMDLINE_H
+#define _LINUX_CMDLINE_H
+
+#include <linux/string.h>
+
+/* Allow architectures to override strlcat, powerpc can't use strings so early */
+#ifndef cmdline_strlcat
+#define cmdline_strlcat strlcat
+#endif
+
+/*
+ * This function will append or prepend a builtin command line to the command
+ * line provided by the bootloader. Kconfig options can be used to alter
+ * the behavior of this builtin command line.
+ * @dst: The destination of the final appended/prepended string.
+ * @src: The starting string or NULL if there isn't one.
+ * @len: the length of dest buffer.
+ */
+static __always_inline void __cmdline_build(char *dst, const char *src, size_t len)
+{
+	if (!len || src == dst)
+		return;
+
+	if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !src) {
+		dst[0] = 0;
+		cmdline_strlcat(dst, CONFIG_CMDLINE, len);
+		return;
+	}
+
+	if (dst != src)
+		dst[0] = 0;
+
+	if (IS_ENABLED(CONFIG_CMDLINE_PREPEND))
+		cmdline_strlcat(dst, CONFIG_CMDLINE " ", len);
+
+	cmdline_strlcat(dst, src, len);
+
+	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND))
+		cmdline_strlcat(dst, " " CONFIG_CMDLINE, len);
+}
+
+#define cmdline_build(dst, src, len) do {				\
+	char *__c_dst = (dst);						\
+	const char *__c_src = (src);					\
+									\
+	if (__c_src == __c_dst) {					\
+		static char __c_tmp[COMMAND_LINE_SIZE] __initdata = "";	\
+									\
+		cmdline_strlcat(__c_tmp, __c_src, COMMAND_LINE_SIZE);	\
+		__cmdline_build(__c_dst, __c_tmp, (len));		\
+	} else {							\
+		__cmdline_build(__c_dst, __c_src, (len));		\
+	}								\
+} while (0)
+
+#endif /* _LINUX_CMDLINE_H */
-- 
2.25.0


  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 13:44 [PATCH v3 00/17] Implement GENERIC_CMDLINE Christophe Leroy
2021-03-26 13:44 ` Christophe Leroy [this message]
2021-03-26 15:42   ` [PATCH v3 01/17] cmdline: Add generic function to build command line Rob Herring
2021-03-26 15:55     ` Christophe Leroy
2021-04-02 15:23     ` Christophe Leroy
2021-03-30 17:27   ` Daniel Walker
2021-03-30 18:07     ` H. Nikolaus Schaller
2021-03-30 18:23       ` Daniel Walker
2021-04-02 15:33     ` Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 02/17] drivers: of: use cmdline building function Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 03/17] cmdline: Gives architectures opportunity to use generically defined boot cmdline manipulation Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 04/17] powerpc: Convert to GENERIC_CMDLINE Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 05/17] arm: " Christophe Leroy
2021-03-26 15:47   ` Rob Herring
2021-03-26 15:49     ` Christophe Leroy
2021-03-26 18:22       ` Rob Herring
2021-04-02 15:19     ` Christophe Leroy
2021-04-02 15:24     ` Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 06/17] arm64: " Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 07/17] hexagon: " Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 08/17] microblaze: " Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 09/17] nios2: " Christophe Leroy
2021-03-29  1:35   ` Tan, Ley Foon
2021-04-02 15:33     ` Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 10/17] openrisc: " Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 11/17] riscv: " Christophe Leroy
2021-03-26 14:08   ` Andreas Schwab
2021-03-26 14:20     ` Christophe Leroy
2021-03-26 15:26       ` Rob Herring
2021-03-30  0:52         ` Nick Kossifidis
2021-04-02 15:21         ` Christophe Leroy
2021-03-26 13:44 ` [PATCH v3 12/17] sh: " Christophe Leroy
2021-04-02 15:36   ` Christophe Leroy
2021-03-26 13:45 ` [PATCH v3 13/17] sparc: " Christophe Leroy
2021-03-26 13:45 ` [PATCH v3 14/17] xtensa: " Christophe Leroy
2021-03-26 13:45 ` [PATCH v3 15/17] x86: " Christophe Leroy
2021-03-26 13:45 ` [PATCH v3 16/17] mips: " Christophe Leroy
2021-03-26 13:45 ` [PATCH v3 17/17] cmdline: Remove CONFIG_CMDLINE_EXTEND Christophe Leroy
2021-03-26 15:04 ` [PATCH v3 00/17] Implement GENERIC_CMDLINE Rob Herring
2021-04-02 15:20   ` Christophe Leroy

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