BUG #4837: initdb segv's if getpwuid fails

The following bug has been logged online:

Bug reference: 4837
Logged by: David Vitek
Email address: dvitek(at)grammatech(dot)com
PostgreSQL version: 8.3
Operating system: Non-Windows
Description: initdb segv's if getpwuid fails
Details:

We've seen this happen in a deployment, and we are currently assuming the
user has some configuration problem. Here's a patch (ignore the
revisions):

Index: src/bin/initdb/initdb.c
===================================================================
--- src/bin/initdb/initdb.c (revision 48282)
+++ src/bin/initdb/initdb.c (working copy)
@@ -660,10 +660,18 @@
#ifndef WIN32

struct passwd *pw;
+ uid_t uid = geteuid();

- pw = getpwuid(geteuid());
+ errno = 0; /* getpwuid may not alter errno on failure */
+ pw = getpwuid(uid);
+ if( !pw )
+ {
+ fprintf(stderr, _("%s: getpwuid failed: %s\n"),
+ progname, strerror(errno));
+ exit(1);
+ }

- if (geteuid() == 0) /* 0 is root's uid */
+ if (uid == 0) /* 0 is root's uid */
{
fprintf(stderr,
_("%s: cannot be run as root\n"