From 833d85cdfebda1a68898dd0b713a501551739080 Mon Sep 17 00:00:00 2001 From: ache Date: Sat, 3 Sep 2016 01:09:22 +0000 Subject: MFC r305133 Apply the same qsort() usage fix as in r304911 getaddrinfo.c qsort() can't be stabilized with just return(-1) alone. --- lib/libc/net/name6.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'lib/libc/net/name6.c') diff --git a/lib/libc/net/name6.c b/lib/libc/net/name6.c index 90b4562..7e52a51 100644 --- a/lib/libc/net/name6.c +++ b/lib/libc/net/name6.c @@ -185,6 +185,7 @@ struct hp_order { #define aio_sa aio_un.aiou_sa int aio_matchlen; char *aio_h_addr; + int aio_initial_sequence; }; static struct hostent *_hpcopy(struct hostent *, int *); @@ -711,6 +712,7 @@ _hpreorder(struct hostent *hp) aio[i].aio_dstscope = gai_addr2scopetype(sa); aio[i].aio_dstpolicy = match_addrselectpolicy(sa, &policyhead); set_source(&aio[i], &policyhead); + aio[i].aio_initial_sequence = i; } /* perform sorting. */ @@ -1045,6 +1047,23 @@ comp_dst(const void *arg1, const void *arg2) } /* Rule 10: Otherwise, leave the order unchanged. */ + + /* + * Note that qsort is unstable; so, we can't return zero and + * expect the order to be unchanged. + * That also means we can't depend on the current position of + * dst2 being after dst1. We must enforce the initial order + * with an explicit compare on the original position. + * The qsort specification requires that "When the same objects + * (consisting of width bytes, irrespective of their current + * positions in the array) are passed more than once to the + * comparison function, the results shall be consistent with one + * another." + * In other words, If A < B, then we must also return B > A. + */ + if (dst2->aio_initial_sequence < dst1->aio_initial_sequence) + return(1); + return(-1); } -- cgit v1.1