diff options
Diffstat (limited to 'resolv/res_libc.c')
| -rw-r--r-- | resolv/res_libc.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/resolv/res_libc.c b/resolv/res_libc.c index 94bb2fdca6..b1047f009b 100644 --- a/resolv/res_libc.c +++ b/resolv/res_libc.c @@ -15,16 +15,31 @@ * SOFTWARE. */ +#include <limits.h> #include <sys/types.h> #include <netinet/in.h> #include <arpa/nameser.h> #include <resolv.h> +#include <bits/libc-lock.h> /* The following bit is copied from res_data.c (where it is #ifdef'ed out) since res_init() should go into libc.so but the rest of that file should not. */ +unsigned long long int __res_initstamp attribute_hidden; +/* We have atomic increment operations on 64-bit platforms. */ +#if __WORDSIZE == 64 +# define atomicinclock(lock) (void) 0 +# define atomicincunlock(lock) (void) 0 +# define atomicinc(var) atomic_increment (&(var)) +#else +__libc_lock_define_initialized (static, lock); +# define atomicinclock(lock) __libc_lock_lock (lock) +# define atomicincunlock(lock) __libc_lock_unlock (lock) +# define atomicinc(var) ++var +#endif + int res_init(void) { extern int __res_vinit(res_state, int); @@ -70,8 +85,45 @@ res_init(void) { if (!_res.id) _res.id = res_randomid(); + atomicinclock (lock); + /* Request all threads to re-initialize their resolver states, + resolv.conf might have changed. */ + atomicinc (__res_initstamp); + atomicincunlock (lock); + return (__res_vinit(&_res, 1)); } + +/* Initialize resp if RES_INIT is not yet set or if res_init in some other + thread requested re-initializing. */ +int +__res_maybe_init (res_state resp, int preinit) +{ + if (resp->options & RES_INIT) { + if (__res_initstamp != resp->_u._ext.initstamp) { + if (resp->nscount > 0) { + __res_nclose (resp); + for (int ns = 0; ns < MAXNS; ns++) { + free (resp->_u._ext.nsaddrs[ns]); + resp->_u._ext.nsaddrs[ns] = NULL; + } + return __res_vinit (resp, 1); + } + } + return 0; + } else if (preinit) { + if (!resp->retrans) + resp->retrans = RES_TIMEOUT; + if (!resp->retry) + resp->retry = 4; + resp->options = RES_DEFAULT; + if (!resp->id) + resp->id = res_randomid (); + return __res_vinit (resp, 1); + } else + return __res_ninit (resp); +} +libc_hidden_def (__res_maybe_init) /* This needs to be after the use of _res in res_init, above. */ #undef _res |