ping and a short question: would it make more sense to put the parsing
code into smbios.c and unconditionally compile it?
Am Mi., 7. Okt. 2020 um 14:33 Uhr schrieb Christian Gmeiner
<christian.gmei...@gmail.com>:
>
> Add an very simple API to be able to access SMBIOS strings
> like vendor, model and bios version.
>
> Signed-off-by: Christian Gmeiner <christian.gmei...@gmail.com>
> ---
> include/smbios.h | 27 +++++++++++++
> lib/Kconfig | 6 +++
> lib/Makefile | 1 +
> lib/smbios-parser.c | 96 +++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 130 insertions(+)
> create mode 100644 lib/smbios-parser.c
>
> diff --git a/include/smbios.h b/include/smbios.h
> index 97b9ddce23..ed60c00fae 100644
> --- a/include/smbios.h
> +++ b/include/smbios.h
> @@ -237,4 +237,31 @@ typedef int (*smbios_write_type)(ulong *addr, int
> handle);
> */
> ulong write_smbios_table(ulong addr);
>
> +/**
> + * smbios_entry() - Get a vaild struct smbios_entry pointer
> + *
> + * @address: address where smbios tables is located
> + * @size: size of smbios table
> + * @return: NULL or a valid pointer to a struct smbios_entry
> + */
> +const struct smbios_entry *smbios_entry(u64 address, u32 size);
> +
> +/**
> + * smbios_header() - Search for SMBIOS header type
> + *
> + * @entry: pointer to a struct smbios_entry
> + * @type: SMBIOS type
> + * @return: NULL or a valid pointer to a struct smbios_header
> + */
> +const struct smbios_header *smbios_header(const struct smbios_entry *entry,
> int type);
> +
> +/**
> + * smbios_string() - Return string from SMBIOS
> + *
> + * @header: pointer to struct smbios_header
> + * @index: string index
> + * @return: NULL or a valid const char pointer
> + */
> +const char *smbios_string(const struct smbios_header *header, int index);
> +
> #endif /* _SMBIOS_H_ */
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 8efb154f73..c92131b7bc 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -667,6 +667,12 @@ config OID_REGISTRY
> help
> Enable fast lookup object identifier registry.
>
> +config SMBIOS_PARSER
> + bool "SMBIOS parser"
> + default n
> + help
> + A simple parser for SMBIOS data.
> +
> source lib/efi/Kconfig
> source lib/efi_loader/Kconfig
> source lib/optee/Kconfig
> diff --git a/lib/Makefile b/lib/Makefile
> index 0cd7bea282..0383fddf2c 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_FIT) += fdtdec_common.o
> obj-$(CONFIG_TEST_FDTDEC) += fdtdec_test.o
> obj-$(CONFIG_GZIP_COMPRESSED) += gzip.o
> obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += smbios.o
> +obj-$(CONFIG_SMBIOS_PARSER) += smbios-parser.o
> obj-$(CONFIG_IMAGE_SPARSE) += image-sparse.o
> obj-y += ldiv.o
> obj-$(CONFIG_XXHASH) += xxhash.o
> diff --git a/lib/smbios-parser.c b/lib/smbios-parser.c
> new file mode 100644
> index 0000000000..b89f988ef9
> --- /dev/null
> +++ b/lib/smbios-parser.c
> @@ -0,0 +1,96 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020, Bachmann electronic GmbH
> + */
> +
> +#include <common.h>
> +#include <smbios.h>
> +
> +static inline int verify_checksum(const struct smbios_entry *e)
> +{
> + /*
> + * Checksums for SMBIOS tables are calculated to have a value, so that
> + * the sum over all bytes yields zero (using unsigned 8 bit
> arithmetic).
> + */
> + u8 *byte = (u8 *)e;
> + u8 sum = 0;
> +
> + for (int i = 0; i < e->length; i++)
> + sum += byte[i];
> +
> + return sum;
> +}
> +
> +const struct smbios_entry *smbios_entry(u64 address, u32 size)
> +{
> + const struct smbios_entry *entry = (struct smbios_entry
> *)(uintptr_t)address;
> +
> + if (!address | !size)
> + return NULL;
> +
> + if (memcmp(entry->anchor, "_SM_", 4))
> + return NULL;
> +
> + if (verify_checksum(entry))
> + return NULL;
> +
> + return entry;
> +}
> +
> +static const struct smbios_header *next_header(const struct smbios_header
> *curr)
> +{
> + u8 *pos = ((u8 *)curr) + curr->length;
> +
> + /* search for _double_ NULL bytes */
> + while (!((*pos == 0) && (*(pos + 1) == 0)))
> + pos++;
> +
> + /* step behind the double NULL bytes */
> + pos += 2;
> +
> + return (struct smbios_header *)pos;
> +}
> +
> +const struct smbios_header *smbios_header(const struct smbios_entry *entry,
> int type)
> +{
> + const unsigned int num_header = entry->struct_count;
> + const struct smbios_header *header = (struct smbios_header
> *)entry->struct_table_address;
> +
> + for (unsigned int i = 0; i < num_header; i++) {
> + if (header->type == type)
> + return header;
> +
> + header = next_header(header);
> + }
> +
> + return NULL;
> +}
> +
> +static const char *string_from_smbios_table(const struct smbios_header
> *header,
> + int idx)
> +{
> + unsigned int i = 1;
> + u8 *pos;
> +
> + if (!header)
> + return NULL;
> +
> + pos = ((u8 *)header) + header->length;
> +
> + while (i < idx) {
> + if (*pos == 0x0)
> + i++;
> +
> + pos++;
> + }
> +
> + return (const char *)pos;
> +}
> +
> +const char *smbios_string(const struct smbios_header *header, int index)
> +{
> + if (!header)
> + return NULL;
> +
> + return string_from_smbios_table(header, index);
> +}
> --
> 2.28.0
>
--
greets
--
Christian Gmeiner, MSc
https://christian-gmeiner.info/privacypolicy
