Re: [PATCH 5/7] smbios: if a string value is unknown, use string number 0

On Mon, 29 Jan 2024 at 23:05, Heinrich Schuchardt heinrich.schuchardt@canonical.com wrote:

The SMBIOS specification describes: "If a string field references no string, a null (0) is placed in that string field."

Accordingly we should avoid writing a string "Unknown" to the SMBIOS table.

dmidecode displays 'Not Specified' if the string number is 0.

Commit 00a871d34e2f ("smbios: empty strings in smbios_add_string()") correctly identified that strings may not have length 0 as two consecutive NULs indentify the end of the string list. But the suggested solution did not match the intent of the SMBIOS specification.

Fixes: 00a871d34e2f ("smbios: empty strings in smbios_add_string()") Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

---

lib/smbios.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/lib/smbios.c b/lib/smbios.c index 81908e89610..50072adb4e8 100644 --- a/lib/smbios.c +++ b/lib/smbios.c @@ -135,13 +135,16 @@ static const struct map_sysinfo *convert_sysinfo_to_dt(const char *node, const c

• @ctx: SMBIOS context
• @str: string to add

• • Return: string number in the string area (1 or more)

• • Return: string number in the string area. 0 if str is NULL.
  */

static int smbios_add_string(struct smbios_ctx *ctx, const char *str) { int i = 1; char *p = ctx->eos;

•   if (!str)
  

•           return 0;
  

•   for (;;) {
            if (!*p) {
                    ctx->last_str = p;
  

@@ -216,7 +219,7 @@ static int smbios_add_prop_si(struct smbios_ctx *ctx, const char *prop, int ret;

    if (!dval || !*dval)

•           dval = "Unknown";
  

•           dval = NULL;
  
    if (!prop)
            return smbios_add_string(ctx, dval);
  

@@ -378,19 +381,19 @@ static int smbios_write_type1(ulong *current, int handle, memset(t, 0, sizeof(struct smbios_type1)); fill_smbios_header(t, SMBIOS_SYSTEM_INFORMATION, len, handle); smbios_set_eos(ctx, t->eos);

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", "Unknown");
  

•   t->product_name = smbios_add_prop(ctx, "product", "Unknown");
  

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", NULL);
  

•   t->product_name = smbios_add_prop(ctx, "product", NULL);
    t->version = smbios_add_prop_si(ctx, "version",
                                    SYSINFO_ID_SMBIOS_SYSTEM_VERSION,
  

•                                   "Unknown");
  

•                                   NULL);
    if (serial_str) {
            t->serial_number = smbios_add_prop(ctx, NULL, serial_str);
            strncpy((char *)t->uuid, serial_str, sizeof(t->uuid));
    } else {
  

•           t->serial_number = smbios_add_prop(ctx, "serial", "Unknown");
  

•           t->serial_number = smbios_add_prop(ctx, "serial", NULL);
    }
  

•   t->sku_number = smbios_add_prop(ctx, "sku", "Unknown");
  

•   t->family = smbios_add_prop(ctx, "family", "Unknown");
  

•   t->sku_number = smbios_add_prop(ctx, "sku", NULL);
  

•   t->family = smbios_add_prop(ctx, "family", NULL);
  
    len = t->length + smbios_string_table_len(ctx);
    *current += len;
  

@@ -409,12 +412,12 @@ static int smbios_write_type2(ulong *current, int handle, memset(t, 0, sizeof(struct smbios_type2)); fill_smbios_header(t, SMBIOS_BOARD_INFORMATION, len, handle); smbios_set_eos(ctx, t->eos);

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", "Unknown");
  

•   t->product_name = smbios_add_prop(ctx, "product", "Unknown");
  

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", NULL);
  

•   t->product_name = smbios_add_prop(ctx, "product", NULL);
    t->version = smbios_add_prop_si(ctx, "version",
                                    SYSINFO_ID_SMBIOS_BASEBOARD_VERSION,
  

•                                   "Unknown");
  

•   t->asset_tag_number = smbios_add_prop(ctx, "asset-tag", "Unknown");
  

•                                   NULL);
  

•   t->asset_tag_number = smbios_add_prop(ctx, "asset-tag", NULL);
    t->feature_flags = SMBIOS_BOARD_FEATURE_HOSTING;
    t->board_type = SMBIOS_BOARD_MOTHERBOARD;
  
  

@@ -435,7 +438,7 @@ static int smbios_write_type3(ulong *current, int handle, memset(t, 0, sizeof(struct smbios_type3)); fill_smbios_header(t, SMBIOS_SYSTEM_ENCLOSURE, len, handle); smbios_set_eos(ctx, t->eos);

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", "Unknown");
  

•   t->manufacturer = smbios_add_prop(ctx, "manufacturer", NULL);
    t->chassis_type = SMBIOS_ENCLOSURE_DESKTOP;
    t->bootup_state = SMBIOS_STATE_SAFE;
    t->power_supply_state = SMBIOS_STATE_SAFE;
  

@@ -453,8 +456,8 @@ static void smbios_write_type4_dm(struct smbios_type4 *t, struct smbios_ctx *ctx) { u16 processor_family = SMBIOS_PROCESSOR_FAMILY_UNKNOWN;

•   const char *vendor = "Unknown";
  

•   const char *name = "Unknown";
  

•   const char *vendor = NULL;
  

•   const char *name = NULL;
  
  

#ifdef CONFIG_CPU char processor_name[49]; -- 2.43.0

Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org