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When calling initgroups(), set a flag that the segfault handler checks

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in order to output a special warning about a particular case of segfaults
due to a mix of static binaries, NSS, and LDAP. (Bug #4872)
This commit is contained in:
jimw@mysql.com
2005-02-16 11:58:35 -08:00
parent c4ff270284
commit 9df24e5ebd
1 changed files with 22 additions and 0 deletions
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22
sql/mysqld.cc
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@ -308,6 +308,9 @@ my_bool opt_readonly = 0, opt_sync_bdb_logs, opt_sync_frm;
volatile bool mqh_used = 0;
FILE *bootstrap_file=0;
int segfaulted = 0; // ensure we do not enter SIGSEGV handler twice
#ifdef HAVE_INITGROUPS
static bool calling_initgroups= FALSE; /* Used in SIGSEGV handler. */
#endif
/*
If sql_bin_update is true, SQL_LOG_UPDATE and SQL_LOG_BIN are kept in sync,
@ -1086,7 +1089,15 @@ static void set_user(const char *user, struct passwd *user_info)
#if !defined(__WIN__) && !defined(OS2) && !defined(__NETWARE__)
DBUG_ASSERT(user_info);
#ifdef HAVE_INITGROUPS
/*
We can get a SIGSEGV when calling initgroups() on some systems when NSS
is configured to use LDAP and the server is statically linked. We set
calling_initgroups as a flag to the SIGSEGV handler that is then used to
output a specific message to help the user resolve this problem.
*/
calling_initgroups= TRUE;
initgroups((char*) user, user_info->pw_gid);
calling_initgroups= FALSE;
#endif
if (setgid(user_info->pw_gid) == -1)
{
@ -1807,6 +1818,17 @@ information that should help you find out what is causing the crash.\n");
fflush(stderr);
#endif /* HAVE_STACKTRACE */
#ifdef HAVE_INITGROUPS
if (calling_initgroups)
fprintf(stderr, "\n\
This crash occured while the server was calling initgroups(). This is\n\
often due to the use of a mysqld that is statically linked against glibc\n\
and configured to use LDAP in /etc/nsswitch.conf. You will need to either\n\
upgrade to a version of glibc that does not have this problem (2.3.4 or\n\
later when used with nscd), disable LDAP in your nsswitch.conf, or use a\n\
mysqld that is not statically linked.\n");
#endif
if (test_flags & TEST_CORE_ON_SIGNAL)
{
fprintf(stderr, "Writing a core file\n");