3d7896c72a
* kdump-avoid-endless-loop-on-EAI_AGAIN.patch: Avoid an endless
loop when resolving a hostname fails with EAI_AGAIN.
* kdump-install-real-resolv.conf.patch: Install /etc/resolv.conf
using its resolved path.
OBS-URL: https://build.opensuse.org/package/show/Kernel:kdump/kdump?expand=0&rev=211
103 lines
3.4 KiB
Diff
103 lines
3.4 KiB
Diff
From: Petr Pavlu <petr.pavlu@suse.com>
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Date: Thu Mar 25 12:48:54 2021 +0100
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Subject: Avoid an endless loop when resolving a hostname fails with EAI_AGAIN
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References: bsc#1183070
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Upstream: merged
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Git-commit: 716883423f45acf3271c200353dce074d6ffc5be
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Method Routable::resolve() invokes function getaddrinfo() to obtain a
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network address for a given hostname. This operation can fail with the
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error code EAI_AGAIN to indicate that the name server encountered a
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temporary failure. Routable::resolve() reacts to this situation by
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calling getaddrinfo() again which can result in an endless loop if the
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function continues to return this error code. It is not guaranteed that
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the underlying reason for EAI_AGAIN will go away in some bounded time.
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The patch removes the EAI_AGAIN loop in Routable::resolve() and updates
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the retry code in Routable::check() to repeatedly attempt resolving a
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hostname until it succeeds or a specified timeout for network operations
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is reached.
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---
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kdumptool/routable.cc | 38 ++++++++++++++++++++++++++++++--------
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1 file changed, 30 insertions(+), 8 deletions(-)
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--- a/kdumptool/routable.cc
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+++ b/kdumptool/routable.cc
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@@ -17,6 +17,7 @@
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* 02110-1301, USA.
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*/
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+#include <algorithm>
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#include <string.h>
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#include <unistd.h>
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@@ -36,6 +37,8 @@
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#include "stringutil.h"
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#include "debug.h"
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+using std::min;
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+
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//{{{ NetLink ------------------------------------------------------------------
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#define NETLINK_DEF_RECV_MAX 1024
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@@ -470,9 +473,7 @@ bool Routable::resolve(void)
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memset(&hints, 0, sizeof hints);
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hints.ai_family = AF_UNSPEC;
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hints.ai_socktype = SOCK_RAW;
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- do {
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- res = getaddrinfo(raw_host.c_str(), NULL, &hints, &m_ai);
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- } while (res == EAI_AGAIN);
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+ res = getaddrinfo(raw_host.c_str(), NULL, &hints, &m_ai);
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if (res == 0)
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return true;
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@@ -480,7 +481,8 @@ bool Routable::resolve(void)
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if (res == EAI_SYSTEM)
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throw KSystemError("Name resolution failed", errno);
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- if (res != EAI_NONAME && res != EAI_FAIL && res != EAI_NODATA)
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+ if (res != EAI_NONAME && res != EAI_FAIL && res != EAI_NODATA &&
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+ res != EAI_AGAIN)
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throw KGaiError("Name resolution failed", res);
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return false;
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@@ -489,13 +491,33 @@ bool Routable::resolve(void)
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// -----------------------------------------------------------------------------
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bool Routable::check(int timeout)
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{
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+ // Resolve the target hostname. An attempt is made regularly until the
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+ // hostname can be resolved or a specified timeout for network operations
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+ // is reached.
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+ struct timespec tstop;
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+ clock_gettime(CLOCK_MONOTONIC, &tstop);
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+ tstop.tv_sec += timeout;
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+
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+ while (!resolve()) {
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+ struct timespec tsnow;
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+ clock_gettime(CLOCK_MONOTONIC, &tsnow);
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+ int interval = (tstop.tv_sec - tsnow.tv_sec) * 1000;
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+ interval += (tstop.tv_nsec - tsnow.tv_nsec) / 1000000L;
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+ if (interval <= 0)
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+ return false;
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+
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+ // Sleep, at most for 1 second.
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+ struct timespec wait_period;
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+ interval = min(interval, 1000);
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+ wait_period.tv_sec = interval / 1000;
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+ wait_period.tv_nsec = (interval % 1000) * 1000 * 1000;
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+ nanosleep(&wait_period, NULL);
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+ }
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+
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+ // Check there is an existing route.
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NetLink nl(RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE);
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nl.setTimeout(timeout);
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- while (!resolve())
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- if (nl.waitRouteChange() != 0)
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- return false;
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-
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while (!hasRoute())
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if (nl.waitRouteChange() != 0)
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return false;
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