From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [RFC PATCH 1/2] efi/libstub: refactor load option command line processing for reuse Date: Wed, 4 Jul 2018 17:49:18 +0200 Message-ID: <20180704154919.18564-2-ard.biesheuvel@linaro.org> References: <20180704154919.18564-1-ard.biesheuvel@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180704154919.18564-1-ard.biesheuvel@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: linux-efi@vger.kernel.org Cc: mark.rutland@arm.com, Lorenzo Pieralisi , Ard Biesheuvel , Geoff Levand , catalin.marinas@arm.com, Riku Voipio , Sudeep Holla , will.deacon@arm.com, leif.lindholm@linaro.org, linux-acpi@vger.kernel.org, James Morse , Hanjun Guo , Mark Salter , linux-arm-kernel@lists.infradead.org, Ian Campbell List-Id: linux-acpi@vger.kernel.org As a preparatory step towards adding support for extra kernel command line arguments passed via a UEFI variable, do a slight refactor of the existing code so we can extend it more cleanly in a subsequent patch. No change is functionality is intended. Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/libstub/efi-stub-helper.c | 43 ++++++++++++-------- 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 50a9cab5a834..97a2423782af 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -726,6 +726,22 @@ static int efi_utf8_bytes(u16 c) return 1 + (c >= 0x80) + (c >= 0x800); } +/* + * Get an upper bound for the number of UTF-8 bytes corresponding + * to a \n or \0 terminated UTF-16 string. + */ +static int count_utf8_bytes(const u16 *s, int max_chars, int *num_chars) +{ + int ret = 0; + + while (*s != '\0' && *s != '\n' && --max_chars >= 0) { + ret += efi_utf8_bytes(*s++); + ++*num_chars; + } + + return ret; +} + /* * Convert an UTF-16 string, not necessarily null terminated, to UTF-8. */ @@ -779,44 +795,35 @@ char *efi_convert_cmdline(efi_system_table_t *sys_table_arg, efi_loaded_image_t *image, int *cmd_line_len) { - const u16 *s2; - u8 *s1 = NULL; + u8 *s1; unsigned long cmdline_addr = 0; int load_options_chars = image->load_options_size / 2; /* UTF-16 */ const u16 *options = image->load_options; - int options_bytes = 0; /* UTF-8 bytes */ + int cmd_line_bytes = 0; /* UTF-8 bytes */ int options_chars = 0; /* UTF-16 chars */ efi_status_t status; u16 zero = 0; - if (options) { - s2 = options; - while (*s2 && *s2 != '\n' - && options_chars < load_options_chars) { - options_bytes += efi_utf8_bytes(*s2++); - options_chars++; - } - } + if (options) + cmd_line_bytes = count_utf8_bytes(options, load_options_chars, + &options_chars); if (!options_chars) { /* No command line options, so return empty string*/ options = &zero; } - options_bytes++; /* NUL termination */ + cmd_line_bytes++; /* NUL termination */ - status = efi_high_alloc(sys_table_arg, options_bytes, 0, + status = efi_high_alloc(sys_table_arg, cmd_line_bytes, 0, &cmdline_addr, MAX_CMDLINE_ADDRESS); if (status != EFI_SUCCESS) return NULL; - s1 = (u8 *)cmdline_addr; - s2 = (const u16 *)options; - - s1 = efi_utf16_to_utf8(s1, s2, options_chars); + s1 = efi_utf16_to_utf8((u8 *)cmdline_addr, options, options_chars); *s1 = '\0'; - *cmd_line_len = options_bytes; + *cmd_line_len = cmd_line_bytes; return (char *)cmdline_addr; } -- 2.17.1