Commit 5edc77be authored by unknown's avatar unknown
Browse files

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

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)


sql/mysqld.cc:
  Add code to output a special message when we get a segfault when calling
  initgroups() to explain the problem.
parent c7b57735

sql/mysqld.cc

+22 −0
Original line number Diff line number Diff line
@@ -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");