[systemd-devel] [RFC 18/25] sd-ipv4all: fall back to random if no random_r

[Tom Gundersen]

No, this actually breaks the behaviour, so we absolutely cannot do
this. Again, I suggest adding the missing features to your libc.

Cheers,

Tom

On Thu, Sep 18, 2014 at 3:24 PM, Emil Renner Berthing <systemd at esmil.dk> wrote:
> ---
>  configure.ac                       |  1 +
>  src/libsystemd-network/sd-ipv4ll.c | 25 +++++++++++++++++++++----
>  2 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 397521e..9cd4c05 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -301,6 +301,7 @@ RT_LIBS="$LIBS"
>  AC_SUBST(RT_LIBS)
>  LIBS="$save_LIBS"
>
> +AC_CHECK_FUNCS([random_r])
>  AC_CHECK_FUNCS([fanotify_init fanotify_mark])
>  AC_CHECK_FUNCS([__secure_getenv secure_getenv])
>  AC_CHECK_DECLS([gettid, pivot_root, canonicalize_file_name, strndupa, name_to_handle_at, setns, LO_FLAGS_PARTSCAN],
> diff --git a/src/libsystemd-network/sd-ipv4ll.c b/src/libsystemd-network/sd-ipv4ll.c
> index 8b24331..5712350 100644
> --- a/src/libsystemd-network/sd-ipv4ll.c
> +++ b/src/libsystemd-network/sd-ipv4ll.c
> @@ -81,8 +81,10 @@ struct sd_ipv4ll {
>          usec_t defend_window;
>          int next_wakeup_valid;
>          be32_t address;
> +#ifdef HAVE_RANDOM_R
>          struct random_data *random_data;
>          char *random_data_state;
> +#endif
>          /* External */
>          be32_t claimed_address;
>          struct ether_addr mac_addr;
> @@ -141,18 +143,24 @@ static sd_ipv4ll *ipv4ll_stop(sd_ipv4ll *ll, int event) {
>
>  static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) {
>          be32_t addr;
> -        int r;
> -        int32_t random;
>
>          assert(ll);
>          assert(address);
> +#ifdef HAVE_RANDOM_R
>          assert(ll->random_data);
> +#endif
>
>          do {
> -                r = random_r(ll->random_data, &random);
> +#ifdef HAVE_RANDOM_R
> +                int32_t value;
> +                int r = random_r(ll->random_data, &value);
> +
>                  if (r < 0)
>                          return r;
> -                addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK);
> +#else
> +                long int value = random();
> +#endif
> +                addr = htonl((value & 0x0000FFFF) | IPV4LL_NETWORK);
>          } while (addr == ll->address ||
>                  (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
>                  (ntohl(addr) & 0x0000FF00) == 0x0000 ||
> @@ -481,6 +489,7 @@ int sd_ipv4ll_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) {
>
>          entropy = *seed;
>
> +#ifdef HAVE_RANDOM_R
>          free(ll->random_data);
>          free(ll->random_data_state);
>
> @@ -503,6 +512,10 @@ error:
>                  ll->random_data = NULL;
>                  ll->random_data_state = NULL;
>          }
> +#else
> +        srandom(entropy);
> +        r = 0;
> +#endif
>          return r;
>  }
>
> @@ -535,6 +548,7 @@ int sd_ipv4ll_start (sd_ipv4ll *ll) {
>          ll->defend_window = 0;
>          ll->claimed_address = 0;
>
> +#ifdef HAVE_RANDOM_R
>          if (!ll->random_data) {
>                  uint8_t seed[8];
>
> @@ -546,6 +560,7 @@ int sd_ipv4ll_start (sd_ipv4ll *ll) {
>                  if (r < 0)
>                          goto out;
>          }
> +#endif
>
>          if (ll->address == 0) {
>                  r = ipv4ll_pick_address(ll, &ll->address);
> @@ -614,8 +629,10 @@ sd_ipv4ll *sd_ipv4ll_unref(sd_ipv4ll *ll) {
>
>                  sd_ipv4ll_detach_event(ll);
>
> +#ifdef HAVE_RANDOM_R
>                  free(ll->random_data);
>                  free(ll->random_data_state);
> +#endif
>                  free(ll);
>
>                  return NULL;
> --
> 2.1.0
>
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