| From e505371dd83963caae1a37ead9524e8d997341be Mon Sep 17 00:00:00 2001 |
| From: Tom Lendacky <thomas.lendacky@amd.com> |
| Date: Mon, 17 Jul 2017 16:10:33 -0500 |
| Subject: x86/boot: Add early cmdline parsing for options with arguments |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Tom Lendacky <thomas.lendacky@amd.com> |
| |
| commit e505371dd83963caae1a37ead9524e8d997341be upstream. |
| |
| Add a cmdline_find_option() function to look for cmdline options that |
| take arguments. The argument is returned in a supplied buffer and the |
| argument length (regardless of whether it fits in the supplied buffer) |
| is returned, with -1 indicating not found. |
| |
| Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> |
| Reviewed-by: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Alexander Potapenko <glider@google.com> |
| Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> |
| Cc: Andy Lutomirski <luto@kernel.org> |
| Cc: Arnd Bergmann <arnd@arndb.de> |
| Cc: Borislav Petkov <bp@alien8.de> |
| Cc: Brijesh Singh <brijesh.singh@amd.com> |
| Cc: Dave Young <dyoung@redhat.com> |
| Cc: Dmitry Vyukov <dvyukov@google.com> |
| Cc: Jonathan Corbet <corbet@lwn.net> |
| Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| Cc: Larry Woodman <lwoodman@redhat.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Matt Fleming <matt@codeblueprint.co.uk> |
| Cc: Michael S. Tsirkin <mst@redhat.com> |
| Cc: Paolo Bonzini <pbonzini@redhat.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Radim Krčmář <rkrcmar@redhat.com> |
| Cc: Rik van Riel <riel@redhat.com> |
| Cc: Toshimitsu Kani <toshi.kani@hpe.com> |
| Cc: kasan-dev@googlegroups.com |
| Cc: kvm@vger.kernel.org |
| Cc: linux-arch@vger.kernel.org |
| Cc: linux-doc@vger.kernel.org |
| Cc: linux-efi@vger.kernel.org |
| Cc: linux-mm@kvack.org |
| Link: http://lkml.kernel.org/r/36b5f97492a9745dce27682305f990fc20e5cf8a.1500319216.git.thomas.lendacky@amd.com |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/include/asm/cmdline.h | 2 |
| arch/x86/lib/cmdline.c | 105 +++++++++++++++++++++++++++++++++++++++++ |
| 2 files changed, 107 insertions(+) |
| |
| --- a/arch/x86/include/asm/cmdline.h |
| +++ b/arch/x86/include/asm/cmdline.h |
| @@ -2,5 +2,7 @@ |
| #define _ASM_X86_CMDLINE_H |
| |
| int cmdline_find_option_bool(const char *cmdline_ptr, const char *option); |
| +int cmdline_find_option(const char *cmdline_ptr, const char *option, |
| + char *buffer, int bufsize); |
| |
| #endif /* _ASM_X86_CMDLINE_H */ |
| --- a/arch/x86/lib/cmdline.c |
| +++ b/arch/x86/lib/cmdline.c |
| @@ -104,7 +104,112 @@ __cmdline_find_option_bool(const char *c |
| return 0; /* Buffer overrun */ |
| } |
| |
| +/* |
| + * Find a non-boolean option (i.e. option=argument). In accordance with |
| + * standard Linux practice, if this option is repeated, this returns the |
| + * last instance on the command line. |
| + * |
| + * @cmdline: the cmdline string |
| + * @max_cmdline_size: the maximum size of cmdline |
| + * @option: option string to look for |
| + * @buffer: memory buffer to return the option argument |
| + * @bufsize: size of the supplied memory buffer |
| + * |
| + * Returns the length of the argument (regardless of if it was |
| + * truncated to fit in the buffer), or -1 on not found. |
| + */ |
| +static int |
| +__cmdline_find_option(const char *cmdline, int max_cmdline_size, |
| + const char *option, char *buffer, int bufsize) |
| +{ |
| + char c; |
| + int pos = 0, len = -1; |
| + const char *opptr = NULL; |
| + char *bufptr = buffer; |
| + enum { |
| + st_wordstart = 0, /* Start of word/after whitespace */ |
| + st_wordcmp, /* Comparing this word */ |
| + st_wordskip, /* Miscompare, skip */ |
| + st_bufcpy, /* Copying this to buffer */ |
| + } state = st_wordstart; |
| + |
| + if (!cmdline) |
| + return -1; /* No command line */ |
| + |
| + /* |
| + * This 'pos' check ensures we do not overrun |
| + * a non-NULL-terminated 'cmdline' |
| + */ |
| + while (pos++ < max_cmdline_size) { |
| + c = *(char *)cmdline++; |
| + if (!c) |
| + break; |
| + |
| + switch (state) { |
| + case st_wordstart: |
| + if (myisspace(c)) |
| + break; |
| + |
| + state = st_wordcmp; |
| + opptr = option; |
| + /* fall through */ |
| + |
| + case st_wordcmp: |
| + if ((c == '=') && !*opptr) { |
| + /* |
| + * We matched all the way to the end of the |
| + * option we were looking for, prepare to |
| + * copy the argument. |
| + */ |
| + len = 0; |
| + bufptr = buffer; |
| + state = st_bufcpy; |
| + break; |
| + } else if (c == *opptr++) { |
| + /* |
| + * We are currently matching, so continue |
| + * to the next character on the cmdline. |
| + */ |
| + break; |
| + } |
| + state = st_wordskip; |
| + /* fall through */ |
| + |
| + case st_wordskip: |
| + if (myisspace(c)) |
| + state = st_wordstart; |
| + break; |
| + |
| + case st_bufcpy: |
| + if (myisspace(c)) { |
| + state = st_wordstart; |
| + } else { |
| + /* |
| + * Increment len, but don't overrun the |
| + * supplied buffer and leave room for the |
| + * NULL terminator. |
| + */ |
| + if (++len < bufsize) |
| + *bufptr++ = c; |
| + } |
| + break; |
| + } |
| + } |
| + |
| + if (bufsize) |
| + *bufptr = '\0'; |
| + |
| + return len; |
| +} |
| + |
| int cmdline_find_option_bool(const char *cmdline, const char *option) |
| { |
| return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option); |
| } |
| + |
| +int cmdline_find_option(const char *cmdline, const char *option, char *buffer, |
| + int bufsize) |
| +{ |
| + return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, |
| + buffer, bufsize); |
| +} |