[PATCH] lib: fwts_acpi_tables: load tables in deterministically

[Alex Hung]

On 06/20/2012 07:31 PM, Colin King wrote:
> From: Colin Ian King<colin.king at canonical.com>
>
> When loading a bunch of ACPI tables we should load them in
> some form of deterministic order rather that the random order
> that they appear in the directory.  So, load them in on
> filename alphasorted order.  This allows us to sanely check the
> tables using fwts-test with some sort of determinism.
>
> Signed-off-by: Colin Ian King<colin.king at canonical.com>
> ---
>   src/lib/src/fwts_acpi_tables.c |   24 +++++++++++++++---------
>   1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/src/lib/src/fwts_acpi_tables.c b/src/lib/src/fwts_acpi_tables.c
> index eabc2ea..513dfff 100644
> --- a/src/lib/src/fwts_acpi_tables.c
> +++ b/src/lib/src/fwts_acpi_tables.c
> @@ -444,29 +444,34 @@ static uint8_t *fwts_acpi_load_table_from_file(const int fd, size_t *length)
>
>   static int fwts_acpi_load_tables_from_file(fwts_framework *fw)
>   {
> -	DIR *dir;
> -	struct dirent *direntry;
> +	struct dirent **dir_entries;
>   	int count = 0;
> +	int i;
>
> -	if ((dir = opendir(fw->acpi_table_path)) == NULL) {
> +	/*
> + 	 * Read in directory in alphabetical name sorted order
> +	 * to ensure the tables are always loaded into memory
> +	 * in some form of deterministic order
> +	 */
> +	if ((count = scandir(fw->acpi_table_path,&dir_entries, 0, alphasort))<  0) {
>   		fwts_log_error(fw, "Cannot open directory '%s' to read ACPI tables.",
>   			fw->acpi_table_path);
>   		return FWTS_ERROR;
>   	}
>
> -	while ((direntry = readdir(dir)) != NULL) {
> -		if (strstr(direntry->d_name, ".dat")) {
> +	for (i = 0; i<  count; i++) {
> +		if (strstr(dir_entries[i]->d_name, ".dat")) {
>   			char path[PATH_MAX];
>   			int fd;
> +
>   			snprintf(path, sizeof(path), "%s/%s",
> -				fw->acpi_table_path, direntry->d_name);
> +				fw->acpi_table_path, dir_entries[i]->d_name);
>   			if ((fd = open(path, O_RDONLY))>= 0) {
>   				uint8_t *table;
>   				size_t length;
>   				char name[PATH_MAX];
>
> -				count++;
> -				strcpy(name, direntry->d_name);
> +				strcpy(name, dir_entries[i]->d_name);
>   				name[strlen(name)-4] = '\0';
>   				if ((table = fwts_acpi_load_table_from_file(fd,&length)) != NULL)
>   					fwts_acpi_add_table(name, table,
> @@ -475,8 +480,9 @@ static int fwts_acpi_load_tables_from_file(fwts_framework *fw)
>   			} else
>   				fwts_log_error(fw, "Cannot load ACPI table from file '%s'\n", path);
>   		}
> +		free(dir_entries[i]);
>   	}
> -	closedir(dir);
> +	free(dir_entries);
>
>   	if (count == 0) {
>   		fwts_log_error(fw, "Could not find any APCI tables in directory '%s'.\n", fw->acpi_table_path);

Acked-by: Alex Hung <alex.hung at canonical.com>