HADOOP-10989. Work around buggy getgrouplist() implementations on Linux that return 0 on failure. Contributed by Chris Nauroth.
git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1619659 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 655df79..52fc3e0 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -686,6 +686,9 @@
HADOOP-10488. TestKeyProviderFactory fails randomly. (tucu)
+ HADOOP-10989. Work around buggy getgrouplist() implementations on Linux that
+ return 0 on failure. (cnauroth)
+
Release 2.5.0 - 2014-08-11
INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/security/hadoop_user_info.c b/hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/security/hadoop_user_info.c
index ca288ec..e2438b1 100644
--- a/hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/security/hadoop_user_info.c
+++ b/hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/security/hadoop_user_info.c
@@ -193,7 +193,17 @@
ngroups = uinfo->gids_size;
ret = getgrouplist(uinfo->pwd.pw_name, uinfo->pwd.pw_gid,
uinfo->gids, &ngroups);
+ // Return value is different on Linux vs. FreeBSD. Linux: the number of groups
+ // or -1 on error. FreeBSD: 0 on success or -1 on error. Unfortunately, we
+ // can't accept a 0 return on Linux, because buggy implementations have been
+ // observed to return 0 but leave the other out parameters in an indeterminate
+ // state. This deviates from the man page, but it has been observed in
+ // practice. See issue HADOOP-10989 for details.
+#ifdef __linux__
+ if (ret > 0) {
+#else
if (ret >= 0) {
+#endif
uinfo->num_gids = ngroups;
ret = put_primary_gid_first(uinfo);
if (ret) {
