diff options
Diffstat (limited to 'resolv/res_query.c')
| -rw-r--r-- | resolv/res_query.c | 119 |
1 files changed, 88 insertions, 31 deletions
diff --git a/resolv/res_query.c b/resolv/res_query.c index 968ba8b4e8..ab4e02a559 100644 --- a/resolv/res_query.c +++ b/resolv/res_query.c @@ -91,6 +91,13 @@ static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vix #define MAXPACKET 65536 #endif +#define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1) + +static int +__libc_res_nquerydomain(res_state statp, const char *name, const char *domain, + int class, int type, u_char *answer, int anslen, + u_char **answerp); + /* * Formulate a normal query, send, and await answer. * Returned answer is placed in supplied buffer "answer". @@ -102,11 +109,12 @@ static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vix * Caller must parse answer and determine whether it answers the question. */ int -res_nquery(res_state statp, - const char *name, /* domain name */ - int class, int type, /* class and type of query */ - u_char *answer, /* buffer to put answer */ - int anslen) /* size of answer buffer */ +__libc_res_nquery(res_state statp, + const char *name, /* domain name */ + int class, int type, /* class and type of query */ + u_char *answer, /* buffer to put answer */ + int anslen, /* size of answer buffer */ + u_char **answerp) /* if buffer needs to be enlarged */ { u_char *buf; HEADER *hp = (HEADER *) answer; @@ -114,15 +122,7 @@ res_nquery(res_state statp, hp->rcode = NOERROR; /* default */ - if (!__libc_use_alloca (MAXPACKET)) { - buf = malloc (MAXPACKET); - if (buf == NULL) { - __set_h_errno (NETDB_INTERNAL); - return -1; - } - use_malloc = 1; - } else - buf = alloca (MAXPACKET); + buf = alloca (QUERYSIZE); #ifdef DEBUG if (statp->options & RES_DEBUG) @@ -130,8 +130,18 @@ res_nquery(res_state statp, #endif n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL, - buf, MAXPACKET); - if (n <= 0) { + buf, QUERYSIZE); + if (__builtin_expect (n <= 0, 0)) { + /* Retry just in case res_nmkquery failed because of too + short buffer. Shouldn't happen. */ + buf = malloc (MAXPACKET); + if (buf != NULL) { + use_malloc = 1; + n = res_nmkquery(statp, QUERY, name, class, type, NULL, + 0, NULL, buf, MAXPACKET); + } + } + if (__builtin_expect (n <= 0, 0)) { #ifdef DEBUG if (statp->options & RES_DEBUG) printf(";; res_query: mkquery failed\n"); @@ -141,7 +151,7 @@ res_nquery(res_state statp, free (buf); return (n); } - n = res_nsend(statp, buf, n, answer, anslen); + n = __libc_res_nsend(statp, buf, n, answer, anslen, answerp); if (use_malloc) free (buf); if (n < 0) { @@ -181,6 +191,17 @@ res_nquery(res_state statp, return (n); } +int +res_nquery(res_state statp, + const char *name, /* domain name */ + int class, int type, /* class and type of query */ + u_char *answer, /* buffer to put answer */ + int anslen) /* size of answer buffer */ +{ + return __libc_res_nquery(statp, name, class, type, answer, anslen, + NULL); +} + /* * Formulate a normal query, send, and retrieve answer in supplied buffer. * Return the size of the response on success, -1 on error. @@ -188,11 +209,12 @@ res_nquery(res_state statp, * is detected. Error code, if any, is left in H_ERRNO. */ int -res_nsearch(res_state statp, +__libc_res_nsearch(res_state statp, const char *name, /* domain name */ int class, int type, /* class and type of query */ u_char *answer, /* buffer to put answer */ - int anslen) /* size of answer */ + int anslen, /* size of answer */ + u_char **answerp) { const char *cp, * const *domain; HEADER *hp = (HEADER *) answer; @@ -214,7 +236,8 @@ res_nsearch(res_state statp, /* If there aren't any dots, it could be a user-level alias. */ if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL) - return (res_nquery(statp, cp, class, type, answer, anslen)); + return (__libc_res_nquery(statp, cp, class, type, answer, + anslen, answerp)); /* * If there are enough dots in the name, let's just give it a @@ -223,12 +246,16 @@ res_nsearch(res_state statp, */ saved_herrno = -1; if (dots >= statp->ndots || trailing_dot) { - ret = res_nquerydomain(statp, name, NULL, class, type, - answer, anslen); + ret = __libc_res_nquerydomain(statp, name, NULL, class, type, + answer, anslen, answerp); if (ret > 0 || trailing_dot) return (ret); saved_herrno = h_errno; tried_as_is++; + if (answerp && *answerp != answer) { + answer = *answerp; + anslen = MAXPACKET; + } } /* @@ -249,12 +276,17 @@ res_nsearch(res_state statp, (domain[0][0] == '.' && domain[0][1] == '\0')) root_on_list++; - ret = res_nquerydomain(statp, name, *domain, - class, type, - answer, anslen); + ret = __libc_res_nquerydomain(statp, name, *domain, + class, type, + answer, anslen, answerp); if (ret > 0) return (ret); + if (answerp && *answerp != answer) { + answer = *answerp; + anslen = MAXPACKET; + } + /* * If no server present, give up. * If name isn't found in this domain, @@ -306,8 +338,8 @@ res_nsearch(res_state statp, * query now. */ if (statp->ndots && !(tried_as_is || root_on_list)) { - ret = res_nquerydomain(statp, name, NULL, class, type, - answer, anslen); + ret = __libc_res_nquerydomain(statp, name, NULL, class, type, + answer, anslen, answerp); if (ret > 0) return (ret); } @@ -328,17 +360,29 @@ res_nsearch(res_state statp, return (-1); } +int +res_nsearch(res_state statp, + const char *name, /* domain name */ + int class, int type, /* class and type of query */ + u_char *answer, /* buffer to put answer */ + int anslen) /* size of answer */ +{ + return __libc_res_nsearch(statp, name, class, type, answer, + anslen, NULL); +} + /* * Perform a call on res_query on the concatenation of name and domain, * removing a trailing dot from name if domain is NULL. */ -int -res_nquerydomain(res_state statp, +static int +__libc_res_nquerydomain(res_state statp, const char *name, const char *domain, int class, int type, /* class and type of query */ u_char *answer, /* buffer to put answer */ - int anslen) /* size of answer */ + int anslen, /* size of answer */ + u_char **answerp) { char nbuf[MAXDNAME]; const char *longname = nbuf; @@ -374,7 +418,20 @@ res_nquerydomain(res_state statp, } sprintf(nbuf, "%s.%s", name, domain); } - return (res_nquery(statp, longname, class, type, answer, anslen)); + return (__libc_res_nquery(statp, longname, class, type, answer, + anslen, answerp)); +} + +int +res_nquerydomain(res_state statp, + const char *name, + const char *domain, + int class, int type, /* class and type of query */ + u_char *answer, /* buffer to put answer */ + int anslen) /* size of answer */ +{ + return __libc_res_nquerydomain(statp, name, domain, class, type, + answer, anslen, NULL); } const char * |