When running set[ug]id, don't check the environment.

Idea from OpenBSD, but made a bit more generic to handle uncivilized lands
that do not define issetugid.

svn:r1529

ChangeLog

@@ -6,6 +6,7 @@ Changes in 1.4.13-stable:
  o Rename our replacement compat/sys/_time.h header to avoid build a conflict on HPUX; reported by Kathryn Hogg.
  o Build kqueue.c correctly on GNU/kFreeBSD platforms. Patch pulled upstream from Debian.
  o Fix a problem with excessive memory allocation when using multiple event priorities.
+ o When running set[ug]id, don't check the environment. Based on a patch from OpenBSD.
 
 
 Changes in 1.4.12-stable:

configure.in

@@ -136,7 +136,7 @@ AC_C_INLINE
 AC_HEADER_TIME
 
 dnl Checks for library functions.
-AC_CHECK_FUNCS(gettimeofday vasprintf fcntl clock_gettime strtok_r strsep getaddrinfo getnameinfo strlcpy inet_ntop signal sigaction strtoll)
+AC_CHECK_FUNCS(gettimeofday vasprintf fcntl clock_gettime strtok_r strsep getaddrinfo getnameinfo strlcpy inet_ntop signal sigaction strtoll issetugid geteuid getegid)
 
 AC_CHECK_SIZEOF(long)
 

devpoll.c

@@ -131,7 +131,7 @@ devpoll_init(struct event_base *base)
 	struct devpollop *devpollop;
 
 	/* Disable devpoll when this environment variable is set */
-	if (getenv("EVENT_NODEVPOLL"))
+	if (evutil_getenv("EVENT_NODEVPOLL"))
 		return (NULL);
 
 	if (!(devpollop = calloc(1, sizeof(struct devpollop))))

epoll.c

@@ -113,7 +113,7 @@ epoll_init(struct event_base *base)
 	struct epollop *epollop;
 
 	/* Disable epollueue when this environment variable is set */
-	if (getenv("EVENT_NOEPOLL"))
+	if (evutil_getenv("EVENT_NOEPOLL"))
 		return (NULL);
 
 	/* Initalize the kernel queue */

event-internal.h

@@ -91,6 +91,9 @@ int _evsignal_set_handler(struct event_base *base, int evsignal,
 			  void (*fn)(int));
 int _evsignal_restore_handler(struct event_base *base, int evsignal);
 
+/* defined in evutil.c */
+const char *evutil_getenv(const char *varname);
+
 #ifdef __cplusplus
 }
 #endif

event.c

@@ -193,7 +193,7 @@ event_base_new(void)
 	if (base->evbase == NULL)
 		event_errx(1, "%s: no event mechanism available", __func__);
 
-	if (getenv("EVENT_SHOW_METHOD")) 
+	if (evutil_getenv("EVENT_SHOW_METHOD")) 
 		event_msgx("libevent using: %s\n",
 			   base->evsel->name);
 

evport.c

@@ -143,7 +143,7 @@ evport_init(struct event_base *base)
 	/*
 	 * Disable event ports when this environment variable is set 
 	 */
-	if (getenv("EVENT_NOEVPORT"))
+	if (evutil_getenv("EVENT_NOEVPORT"))
 		return (NULL);
 
 	if (!(evpd = calloc(1, sizeof(struct evport_data))))

evutil.c

@@ -54,6 +54,9 @@
 #endif
 #include <stdio.h>
 
+#include <sys/queue.h>
+#include "event.h"
+#include "event-internal.h"
 #include "evutil.h"
 #include "log.h"
 
@@ -243,3 +246,31 @@ evutil_vsnprintf(char *buf, size_t buflen, const char *format, va_list ap)
 	return r;
 #endif
 }
+
+static int
+evutil_issetugid(void)
+{
+#ifdef _EVENT_HAVE_ISSETUGID
+	return issetugid();
+#else
+
+#ifdef _EVENT_HAVE_GETEUID
+	if (getuid() != geteuid())
+		return 1;
+#endif
+#ifdef _EVENT_HAVE_GETEGID
+	if (getgid() != getegid())
+		return 1;
+#endif
+	return 0;
+#endif
+}
+
+const char *
+evutil_getenv(const char *varname)
+{
+	if (evutil_issetugid())
+		return NULL;
+
+	return getenv(varname);
+}

kqueue.c

@@ -63,7 +63,6 @@
 #include "event.h"
 #include "event-internal.h"
 #include "log.h"
-#include "event-internal.h"
 
 #define EVLIST_X_KQINKERNEL	0x1000
 
@@ -103,7 +102,7 @@ kq_init(struct event_base *base)
 	struct kqop *kqueueop;
 
 	/* Disable kqueue when this environment variable is set */
-	if (getenv("EVENT_NOKQUEUE"))
+	if (evutil_getenv("EVENT_NOKQUEUE"))
 		return (NULL);
 
 	if (!(kqueueop = calloc(1, sizeof(struct kqop))))

poll.c

@@ -87,7 +87,7 @@ poll_init(struct event_base *base)
 	struct pollop *pollop;
 
 	/* Disable poll when this environment variable is set */
-	if (getenv("EVENT_NOPOLL"))
+	if (evutil_getenv("EVENT_NOPOLL"))
 		return (NULL);
 
 	if (!(pollop = calloc(1, sizeof(struct pollop))))

select.c

@@ -102,7 +102,7 @@ select_init(struct event_base *base)
 	struct selectop *sop;
 
 	/* Disable select when this environment variable is set */
-	if (getenv("EVENT_NOSELECT"))
+	if (evutil_getenv("EVENT_NOSELECT"))
 		return (NULL);
 
 	if (!(sop = calloc(1, sizeof(struct selectop))))