efi-pstore: Read and write to the 'compressed' flag of pstore

In pstore write, Efi will add a character 'C'(compressed) or
D'(decompressed) in its header while writing to persistent store.
In pstore read, read the header and update the 'compressed' flag
accordingly.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 9a5425f3f88592da00c6e3fdda194061c48c16f0..5002d50e37817314d1fe3e449ad991ade1969f6b 100644 (file)
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -35,6 +35,7 @@ struct pstore_read_data {
        enum pstore_type_id *type;
        int *count;
        struct timespec *timespec;
+       bool *compressed;
        char **buf;
 };
 
@@ -42,7 +43,7 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
 {
        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
        struct pstore_read_data *cb_data = data;
-       char name[DUMP_NAME_LEN];
+       char name[DUMP_NAME_LEN], data_type;
        int i;
        int cnt;
        unsigned int part;
@@ -54,12 +55,23 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
        for (i = 0; i < DUMP_NAME_LEN; i++)
                name[i] = entry->var.VariableName[i];
 
-       if (sscanf(name, "dump-type%u-%u-%d-%lu",
+       if (sscanf(name, "dump-type%u-%u-%d-%lu-%c",
+                  cb_data->type, &part, &cnt, &time, &data_type) == 5) {
+               *cb_data->id = part;
+               *cb_data->count = cnt;
+               cb_data->timespec->tv_sec = time;
+               cb_data->timespec->tv_nsec = 0;
+               if (data_type == 'C')
+                       *cb_data->compressed = true;
+               else
+                       *cb_data->compressed = false;
+       } else if (sscanf(name, "dump-type%u-%u-%d-%lu",
                   cb_data->type, &part, &cnt, &time) == 4) {
                *cb_data->id = part;
                *cb_data->count = cnt;
                cb_data->timespec->tv_sec = time;
                cb_data->timespec->tv_nsec = 0;
+               *cb_data->compressed = false;
        } else if (sscanf(name, "dump-type%u-%u-%lu",
                          cb_data->type, &part, &time) == 3) {
                /*
@@ -71,6 +83,7 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
                *cb_data->count = 0;
                cb_data->timespec->tv_sec = time;
                cb_data->timespec->tv_nsec = 0;
+               *cb_data->compressed = false;
        } else
                return 0;
 
@@ -96,6 +109,7 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
        data.type = type;
        data.count = count;
        data.timespec = timespec;
+       data.compressed = compressed;
        data.buf = buf;
 
        return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
@@ -112,8 +126,8 @@ static int efi_pstore_write(enum pstore_type_id type,
        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
        int i, ret = 0;
 
-       sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
-               get_seconds());
+       sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count,
+               get_seconds(), compressed ? 'C' : 'D');
 
        for (i = 0; i < DUMP_NAME_LEN; i++)
                efi_name[i] = name[i];