Date: Wed, 8 May 2019 16:07:43 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r347353 - stable/11/usr.sbin/rtadvd Message-ID: <201905081607.x48G7hTZ026117@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: markj Date: Wed May 8 16:07:43 2019 New Revision: 347353 URL: https://svnweb.freebsd.org/changeset/base/347353 Log: MFC r346960: Retry upon NET_RT_IFLIST sysctl failure. PR: 195191 Modified: stable/11/usr.sbin/rtadvd/if.c Directory Properties: stable/11/ (props changed) Modified: stable/11/usr.sbin/rtadvd/if.c ============================================================================== --- stable/11/usr.sbin/rtadvd/if.c Wed May 8 16:07:01 2019 (r347352) +++ stable/11/usr.sbin/rtadvd/if.c Wed May 8 16:07:43 2019 (r347353) @@ -406,6 +406,8 @@ update_ifinfo_nd_flags(struct ifinfo *ifi) return (0); } +#define MAX_SYSCTL_TRY 5 + struct ifinfo * update_ifinfo(struct ifilist_head_t *ifi_head, int ifindex) { @@ -417,26 +419,43 @@ update_ifinfo(struct ifilist_head_t *ifi_head, int ifi size_t len; char *lim; int mib[] = { CTL_NET, PF_ROUTE, 0, AF_INET6, NET_RT_IFLIST, 0 }; - int error; + int error, ntry; syslog(LOG_DEBUG, "<%s> enter", __func__); - if (sysctl(mib, sizeof(mib)/sizeof(mib[0]), NULL, &len, NULL, 0) < - 0) { - syslog(LOG_ERR, - "<%s> sysctl: NET_RT_IFLIST size get failed", __func__); - exit(1); - } - if ((msg = malloc(len)) == NULL) { - syslog(LOG_ERR, "<%s> malloc failed", __func__); - exit(1); - } - if (sysctl(mib, sizeof(mib)/sizeof(mib[0]), msg, &len, NULL, 0) < - 0) { - syslog(LOG_ERR, - "<%s> sysctl: NET_RT_IFLIST get failed", __func__); - exit(1); - } + ntry = 0; + do { + /* + * We'll try to get addresses several times in case that + * the number of addresses is unexpectedly increased during + * the two sysctl calls. This should rarely happen. + * Portability note: since FreeBSD does not add margin of + * memory at the first sysctl, the possibility of failure on + * the second sysctl call is a bit higher. + */ + + if (sysctl(mib, nitems(mib), NULL, &len, NULL, 0) < 0) { + syslog(LOG_ERR, + "<%s> sysctl: NET_RT_IFLIST size get failed", + __func__); + exit(1); + } + if ((msg = malloc(len)) == NULL) { + syslog(LOG_ERR, "<%s> malloc failed", __func__); + exit(1); + } + if (sysctl(mib, nitems(mib), msg, &len, NULL, 0) < 0) { + if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) { + free(msg); + syslog(LOG_ERR, + "<%s> sysctl: NET_RT_IFLIST get failed", + __func__); + exit(1); + } + free(msg); + msg = NULL; + } + } while (msg == NULL); lim = msg + len; for (ifm = (struct if_msghdr *)msg;
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201905081607.x48G7hTZ026117>