From bfca3db41e9af78e56e7a9b7f30121df83b6af0a Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 17 May 2021 14:57:48 +0100 Subject: [cpio] Split out bzImage initrd CPIO header construction iPXE will construct CPIO headers for images that have a non-empty command line, thereby allowing raw images (without CPIO headers) to be injected into a dynamically constructed initrd. This feature is currently implemented within the BIOS-only bzImage format support. Split out the CPIO header construction logic to allow for reuse in other contexts such as in a UEFI build. Signed-off-by: Michael Brown --- src/arch/x86/image/bzimage.c | 52 ++------------------------ src/arch/x86/image/initrd.c | 1 + src/arch/x86/include/initrd.h | 7 ---- src/core/cpio.c | 85 +++++++++++++++++++++++++++++++++++++++++++ src/include/ipxe/cpio.h | 21 +++++++++++ 5 files changed, 110 insertions(+), 56 deletions(-) diff --git a/src/arch/x86/image/bzimage.c b/src/arch/x86/image/bzimage.c index 51498bf..a782127 100644 --- a/src/arch/x86/image/bzimage.c +++ b/src/arch/x86/image/bzimage.c @@ -327,32 +327,6 @@ static void bzimage_set_cmdline ( struct image *image, } /** - * Parse standalone image command line for cpio parameters - * - * @v image bzImage file - * @v cpio CPIO header - * @v cmdline Command line - */ -static void bzimage_parse_cpio_cmdline ( struct image *image, - struct cpio_header *cpio, - const char *cmdline ) { - char *arg; - char *end; - unsigned int mode; - - /* Look for "mode=" */ - if ( ( arg = strstr ( cmdline, "mode=" ) ) ) { - arg += 5; - mode = strtoul ( arg, &end, 8 /* Octal for file mode */ ); - if ( *end && ( *end != ' ' ) ) { - DBGC ( image, "bzImage %p strange \"mode=\"" - "terminator '%c'\n", image, *end ); - } - cpio_set_field ( cpio->c_mode, ( 0100000 | mode ) ); - } -} - -/** * Align initrd length * * @v len Length @@ -374,11 +348,9 @@ static inline size_t bzimage_align ( size_t len ) { static size_t bzimage_load_initrd ( struct image *image, struct image *initrd, userptr_t address ) { - char *filename = initrd->cmdline; - char *cmdline; + const char *filename = cpio_name ( initrd ); struct cpio_header cpio; size_t offset; - size_t name_len; size_t pad_len; /* Do not include kernel image itself as an initrd */ @@ -386,25 +358,7 @@ static size_t bzimage_load_initrd ( struct image *image, return 0; /* Create cpio header for non-prebuilt images */ - if ( filename && filename[0] ) { - cmdline = strchr ( filename, ' ' ); - name_len = ( ( cmdline ? ( ( size_t ) ( cmdline - filename ) ) - : strlen ( filename ) ) + 1 /* NUL */ ); - memset ( &cpio, '0', sizeof ( cpio ) ); - memcpy ( cpio.c_magic, CPIO_MAGIC, sizeof ( cpio.c_magic ) ); - cpio_set_field ( cpio.c_mode, 0100644 ); - cpio_set_field ( cpio.c_nlink, 1 ); - cpio_set_field ( cpio.c_filesize, initrd->len ); - cpio_set_field ( cpio.c_namesize, name_len ); - if ( cmdline ) { - bzimage_parse_cpio_cmdline ( image, &cpio, - ( cmdline + 1 /* ' ' */ )); - } - offset = ( ( sizeof ( cpio ) + name_len + 0x03 ) & ~0x03 ); - } else { - offset = 0; - name_len = 0; - } + offset = cpio_header ( initrd, &cpio ); /* Copy in initrd image body (and cpio header if applicable) */ if ( address ) { @@ -413,7 +367,7 @@ static size_t bzimage_load_initrd ( struct image *image, memset_user ( address, 0, 0, offset ); copy_to_user ( address, 0, &cpio, sizeof ( cpio ) ); copy_to_user ( address, sizeof ( cpio ), filename, - ( name_len - 1 /* NUL (or space) */ ) ); + cpio_name_len ( initrd ) ); } DBGC ( image, "bzImage %p initrd %p [%#08lx,%#08lx,%#08lx)" "%s%s\n", image, initrd, user_to_phys ( address, 0 ), diff --git a/src/arch/x86/image/initrd.c b/src/arch/x86/image/initrd.c index 49b959a..d7b1f57 100644 --- a/src/arch/x86/image/initrd.c +++ b/src/arch/x86/image/initrd.c @@ -29,6 +29,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include #include #include +#include /** @file * diff --git a/src/arch/x86/include/initrd.h b/src/arch/x86/include/initrd.h index ddb3e5a..2fb9d3d 100644 --- a/src/arch/x86/include/initrd.h +++ b/src/arch/x86/include/initrd.h @@ -11,13 +11,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include -/** Minimum alignment for initrds - * - * Some versions of Linux complain about initrds that are not - * page-aligned. - */ -#define INITRD_ALIGN 4096 - /** Minimum free space required to reshuffle initrds * * Chosen to avoid absurdly long reshuffling times diff --git a/src/core/cpio.c b/src/core/cpio.c index 080c72d..27aee75 100644 --- a/src/core/cpio.c +++ b/src/core/cpio.c @@ -30,6 +30,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); */ #include +#include #include #include @@ -45,3 +46,87 @@ void cpio_set_field ( char *field, unsigned long value ) { snprintf ( buf, sizeof ( buf ), "%08lx", value ); memcpy ( field, buf, 8 ); } + +/** + * Get CPIO image filename + * + * @v image Image + * @ret len CPIO filename length (0 for no filename) + */ +size_t cpio_name_len ( struct image *image ) { + const char *name = cpio_name ( image ); + char *sep; + size_t len; + + /* Check for existence of CPIO filename */ + if ( ! name ) + return 0; + + /* Locate separator (if any) */ + sep = strchr ( name, ' ' ); + len = ( sep ? ( ( size_t ) ( sep - name ) ) : strlen ( name ) ); + + return len; +} + +/** + * Parse CPIO image parameters + * + * @v image Image + * @v cpio CPIO header to fill in + */ +static void cpio_parse_cmdline ( struct image *image, + struct cpio_header *cpio ) { + const char *cmdline; + char *arg; + char *end; + unsigned int mode; + + /* Skip image filename */ + cmdline = ( cpio_name ( image ) + cpio_name_len ( image ) ); + + /* Look for "mode=" */ + if ( ( arg = strstr ( cmdline, "mode=" ) ) ) { + arg += 5; + mode = strtoul ( arg, &end, 8 /* Octal for file mode */ ); + if ( *end && ( *end != ' ' ) ) { + DBGC ( image, "CPIO %p strange \"mode=\" " + "terminator '%c'\n", image, *end ); + } + cpio_set_field ( cpio->c_mode, ( 0100000 | mode ) ); + } +} + +/** + * Construct CPIO header for image, if applicable + * + * @v image Image + * @v cpio CPIO header to fill in + * @ret len Length of magic CPIO header (including filename) + */ +size_t cpio_header ( struct image *image, struct cpio_header *cpio ) { + size_t name_len; + size_t len; + + /* Get filename length */ + name_len = cpio_name_len ( image ); + + /* Images with no filename are assumed to already be CPIO archives */ + if ( ! name_len ) + return 0; + + /* Construct CPIO header */ + memset ( cpio, '0', sizeof ( *cpio ) ); + memcpy ( cpio->c_magic, CPIO_MAGIC, sizeof ( cpio->c_magic ) ); + cpio_set_field ( cpio->c_mode, 0100644 ); + cpio_set_field ( cpio->c_nlink, 1 ); + cpio_set_field ( cpio->c_filesize, image->len ); + cpio_set_field ( cpio->c_namesize, ( name_len + 1 /* NUL */ ) ); + cpio_parse_cmdline ( image, cpio ); + + /* Calculate total length */ + len = ( ( sizeof ( *cpio ) + name_len + 1 /* NUL */ + CPIO_ALIGN - 1 ) + & ~( CPIO_ALIGN - 1 ) ); + + return len; +} diff --git a/src/include/ipxe/cpio.h b/src/include/ipxe/cpio.h index 0637c53..9c5e22d 100644 --- a/src/include/ipxe/cpio.h +++ b/src/include/ipxe/cpio.h @@ -9,6 +9,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); +#include + /** A CPIO archive header * * All field are hexadecimal ASCII numbers padded with '0' on the @@ -48,6 +50,25 @@ struct cpio_header { /** CPIO magic */ #define CPIO_MAGIC "070701" +/** CPIO header length alignment */ +#define CPIO_ALIGN 4 + +/** Alignment for CPIO archives within an initrd */ +#define INITRD_ALIGN 4096 + +/** + * Get CPIO image name + * + * @v image Image + * @ret name Image name (not NUL terminated) + */ +static inline __attribute__ (( always_inline )) const char * +cpio_name ( struct image *image ) { + return image->cmdline; +} + extern void cpio_set_field ( char *field, unsigned long value ); +extern size_t cpio_name_len ( struct image *image ); +extern size_t cpio_header ( struct image *image, struct cpio_header *cpio ); #endif /* _IPXE_CPIO_H */ -- cgit v1.1