From e8c505a56d42871fcfbc77e3c1f4d0a60686bab7 Mon Sep 17 00:00:00 2001 From: ian Date: Sun, 27 Sep 1998 17:45:36 +0000 Subject: [PATCH] Various frameworks; ready for meat. --- src/adns-internal.h | 2 +- src/adns.c | 101 ++++++++++++++++++++++++++++++++++++++------ src/adns.h | 64 ++++++++++++++++------------ 3 files changed, 127 insertions(+), 40 deletions(-) diff --git a/src/adns-internal.h b/src/adns-internal.h index 8666614..05dd29c 100644 --- a/src/adns-internal.h +++ b/src/adns-internal.h @@ -16,7 +16,7 @@ struct adns__query { adns_query next, back; adns_query parent, child; adns_rrtype type; - struct adns_answer *answer; + adns_answer *answer; int flags, udpretries, server; struct timeval timeout; void *context; diff --git a/src/adns.c b/src/adns.c index 210c256..43a0dac 100644 --- a/src/adns.c +++ b/src/adns.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include @@ -60,13 +61,23 @@ static void diag(adns_state ads, const char *fmt, ...) { } static void addserver(adns_state ads, struct in_addr addr) { + int i; + + for (i=0; inservers; i++) { + if (ads->servers[i].addr.s_addr == addr.s_addr) { + debug(ads,"duplicate nameserver %s ignored",inet_ntoa(addr)); + return; + } + } + if (ads->nservers>=MAXSERVERS) { diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr)); - } else { - ads->servers[ads->nservers].addr= addr; - ads->servers[ads->nservers].tcpsocket= -1; - ads->nservers++; + return; } + + ads->servers[ads->nservers].addr= addr; + ads->servers[ads->nservers].tcpsocket= -1; + ads->nservers++; } static void configparseerr(adns_state ads, const char *fn, int lno, @@ -180,8 +191,8 @@ static const char *instrum_getenv(adns_state ads, const char *envvar) { const char *value; value= getenv(envvar); - if (!value) debug(ads,"environment variable `%s' not set",envvar); - else debug(ads,"environment variable `%s' set to `%s'",envvar,value); + if (!value) debug(ads,"environment variable %s not set",envvar); + else debug(ads,"environment variable %s set to `%s'",envvar,value); return value; } @@ -242,7 +253,7 @@ int adns_init(adns_state *ads_r, adns_initflags flags) { } static void query_fail(adns_state ads, adns_query qu, adns_status stat) { - struct adns_answer *ans; + adns_answer *ans; ans= qu->answer; if (!ans) ans= malloc(sizeof(*qu->answer)); @@ -256,12 +267,79 @@ static void query_fail(adns_state ads, adns_query qu, adns_status stat) { LIST_LINK_TAIL(ads->input,qu); } -void adns_interest(adns_state ads, +void adns_interest(adns_state ads, int *maxfd, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, - int *maxfd, struct timeval **tv_io, struct timeval *tvbuf) { + struct timeval **tv_io, struct timeval *tvbuf) { abort(); /* FIXME */ } +static void autosys(adns_state ads) { + if (ads->iflags & adns_if_noautosys) return; + adns_callback(ads,-1,0,0,0); +} + +void adns_cancel(adns_state ads, adns_query query) { + abort(); /* FIXME */ +} + +int adns_callback(adns_state ads, int maxfd, + const fd_set *readfds, const fd_set *writefds, + const fd_set *exceptfds) { + abort(); /* FIXME */ +} + +static int internal_check(adns_state ads, + adns_query *query_io, + adns_answer *answer, + void *context_r) { + abort(); /* FIXME */ +} + +int adns_wait(adns_state ads, + adns_query *query_io, + adns_answer *answer, + void *context_r) { + int r, maxfd, rsel, rcb; + fd_set readfds, writefds, exceptfds; + struct timeval tvbuf, *tvp; + + for (;;) { + r= internal_check(ads,query_io,answer,context_r); + if (r && r != EWOULDBLOCK) return r; + FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); + maxfd= 0; tvp= 0; + adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf); + rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp); + if (rsel==-1) return r; + rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds); + assert(rcb==rsel); + } +} + +int adns_check(adns_state ads, + adns_query *query_io, + adns_answer *answer, + void *context_r) { + autosys(ads); + return internal_check(ads,query_io,answer,context_r); +} + +int adns_synchronous(adns_state ads, + const char *owner, + adns_rrtype type, + int flags, + adns_answer *answer) { + adns_query qu; + int r; + + r= adns_submit(ads,owner,type,flags,0,&qu); + if (r) return r; + + r= adns_wait(ads,&qu,answer,0); + if (r) adns_cancel(ads,qu); + return r; +} + int adns_submit(adns_state ads, const char *owner, adns_rrtype type, @@ -289,9 +367,8 @@ int adns_submit(adns_state ads, query_fail(ads,qu,stat); } else { LIST_LINK_TAIL(ads->input,qu); - adns_interest(ads,0,0,0,0,0,0); + autosys(ads); } *query_r= qu; - - abort(); /* FIXME */ + return 0; } diff --git a/src/adns.h b/src/adns.h index fd4c8ee..69425ae 100644 --- a/src/adns.h +++ b/src/adns.h @@ -13,6 +13,7 @@ typedef enum { adns_if_noenv= 0x0001, /* do not look at environment */ adns_if_noerrprint= 0x0002, /* never print output to stderr */ adns_if_debug= 0x0004, /* print debugging output to stderr */ + adns_if_noautosys= 0x0008, /* do not do full flow-of-control whenever we can */ } adns_initflags; typedef enum { @@ -75,7 +76,7 @@ typedef enum { * used. */ -struct adns_answer { +typedef struct { adns_status status; char *cname; /* always NULL if query was for CNAME records */ adns_rrtype type; @@ -93,7 +94,7 @@ struct adns_answer { } soa[1]; /* soa, soa_raw */ /* NULL is empty */ } rrs; -}; +} adns_answer; /* Memory management: * adns_state and adns_query are actually pointers to malloc'd state; @@ -111,10 +112,10 @@ struct adns_answer { * are returned in the status field of the answer. If status is * nonzero then nrrs will be 0, otherwise it will be >0. * type will always be the type requested; - * If no (appropriate) requests are done adns_query returns EWOULDBLOCK; - * If no requests are outstanding adns_query and adns_wait return ESRCH; + * If no (appropriate) requests are done adns_check returns EWOULDBLOCK; + * If no (appropriate) requests are outstanding adns_query and adns_wait return ESRCH; * If malloc failure occurs during internal allocation or processing - * ands_query, _wait and _answer set *answer to 0. + * ands_check and _wait set *answer to 0. */ int adns_init(adns_state *newstate_r, adns_initflags flags); @@ -123,7 +124,12 @@ int adns_synchronous(adns_state ads, const char *owner, adns_rrtype type, int flags, - struct adns_answer *answer); + adns_answer *answer); + +/* NB: if you set adns_if_noautosys then _submit and _check do not + * make any system calls; you must use adns_callback (possibly after + * adns_interest) to actually get things to happen. + */ int adns_submit(adns_state ads, const char *owner, @@ -134,34 +140,38 @@ int adns_submit(adns_state ads, int adns_check(adns_state ads, adns_query *query_io, - struct adns_answer *answer, + adns_answer *answer, void *context_r); int adns_wait(adns_state ads, adns_query *query_io, - struct adns_answer *answer, + adns_answer *answer, void *context_r); -int adns_cancel(adns_state ads, adns_query query); +void adns_cancel(adns_state ads, adns_query query); int adns_finish(adns_state); -void adns_interest(adns_state, fd_set *readfds_mod, - fd_set *writefds_mod, fd_set *exceptfds_mod, - int *maxfd_mod, struct timeval **tv_mod, struct timeval *tv_buf); -/* You may call this with *_mod=0 to allow adns to have flow-of-control - * briefly, or with *fds_mod=*maxfd_mod=0 but tv_mod!=0 if you are - * not going to sleep, or with all !=0 if you are going to sleep. - * If tv_mod!=0 and *tv_mod=0 then tv_buf must be !0 and *tv_buf is irrelevant - * and may be overwritten (and *tv_mod set to tv_buf); otherwise tv_buf is ignored. +int adns_callback(adns_state, int maxfd, const fd_set *readfds, const fd_set *writefds, + const fd_set *exceptfds); +/* Gives adns flow-of-control for a bit. This will never block. + * If maxfd == -1 then adns will check (make nonblocking system calls on) + * all of its own filedescriptors; otherwise it will only use those + * < maxfd and specified in the fd_set's, as if select had returned them. + * Other fd's may be in the fd_sets, and will be ignored. + * _callback returns how many adns fd's were in the various sets, so + * you can tell if your select handling code has missed something and is going awol. */ -int adns_callback(adns_state, fd_set readfds, fd_set writefds, - fd_set exceptfds, int maxfd); -/* For select-driven programs, this allows adns to know which fd's are relevant, - * so that it doesn't need to make syscalls on others of its fd's. It's a kind - * of limited flow-of-control allowance. It will return how many adns fd's were - * in the set, so you can tell if your select handling code is missing things. +void adns_interest(adns_state, int *maxfd_io, fd_set *readfds_io, + fd_set *writefds_io, fd_set *exceptfds_io, + struct timeval **tv_mod, struct timeval *tv_buf); +/* Find out file descriptors adns is interested in, and when it + * would like the opportunity to time something out. If you do not plan to + * block then tv_mod may be 0. Otherwise, tv_mod may point to 0 meaning + * you have no timeout of your own, in which case tv_buf must be non-null and + * _interest may fill it in and set *tv_mod=tv_buf. + * readfds, writefds, exceptfds and maxfd may not be 0. */ /* Example expected/legal calling sequences: @@ -176,14 +186,14 @@ int adns_callback(adns_state, fd_set readfds, fd_set writefds, * .... * adns_finish * - * adns_init - * adns_submit ... + * adns_init _noautosys * loop { - * adns_check * adns_interest * select * adns_callback - * other things + * ... + * adns_submit / adns_check + * ... * } */ -- 2.30.2