[PATCH] lib: fwts_acpi_tables: load tables in deterministically

[Keng-Yu Lin]

On Wed, Jun 20, 2012 at 7:31 PM, Colin King <colin.king at canonical.com> 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);
> --
> 1.7.10.4
>
good to have this fixed. :-)

Acked-by: Keng-Yu Lin <kengyu at canonical.com>