Remove HAVE_SYS_PRCTL_H check as the prctl() system call was introduced in Linux 2.1.57.

bin/named/unix/os.c

@@ -59,49 +59,6 @@ static int singletonfd = -1;
 #define ISC_FACILITY LOG_DAEMON
 #endif
 
-/*
- * If there's no <sys/capability.h>, we don't care about <sys/prctl.h>
- */
-#ifndef HAVE_SYS_CAPABILITY_H
-#undef HAVE_SYS_PRCTL_H
-#endif
-
-/*
- * Linux defines:
- *	(C) HAVE_SYS_CAPABILITY_H
- *	(P) HAVE_SYS_PRCTL_H
- * The possible cases are:
- *	none:	setuid() normally
- *	T:	no setuid()
- *	C:	setuid() normally, drop caps (keep CAP_SETUID)
- *	T+C:	no setuid(), drop caps (don't keep CAP_SETUID)
- *	T+C+P:	setuid() early, drop caps (keep CAP_SETUID)
- *	C+P:	setuid() normally, drop caps (keep CAP_SETUID)
- *	P:	not possible
- *	T+P:	not possible
- *
- * if (C)
- *	caps = BIND_SERVICE + CHROOT + SETGID
- *	if ((T && C && P) || !T)
- *		caps += SETUID
- *	endif
- *	capset(caps)
- * endif
- * if (T && C && P && -u)
- *	setuid()
- * else if (T && -u)
- *	fail
- * --> start threads
- * if (!T && -u)
- *	setuid()
- * if (C && (P || !-u))
- *	caps = BIND_SERVICE
- *	capset(caps)
- * endif
- *
- * It will be nice when Linux threads work properly with setuid().
- */
-
 static struct passwd *runas_pw = NULL;
 static bool done_setuid = false;
 static int dfd[2] = { -1, -1 };
@@ -112,10 +69,7 @@ static bool non_root = false;
 static bool non_root_caps = false;
 
 #include <sys/capability.h>
-
+#include <sys/prctl.h>
-#ifdef HAVE_SYS_PRCTL_H
-#include <sys/prctl.h>		/* Required for prctl(). */
-#endif /* HAVE_SYS_PRCTL_H */
 
 static void
 linux_setcaps(cap_t caps) {
@@ -196,15 +150,11 @@ linux_initialprivs(void) {
 	 */
 	SET_CAP(CAP_SYS_CHROOT);
 
-#if defined(HAVE_SYS_PRCTL_H)
 	/*
-	 * We can setuid() only if either the kernel supports keeping
+	 * We need setuid() as the kernel supports keeping capabilities after
-	 * capabilities after setuid() (which we don't know until we've
+	 * setuid().
-	 * tried) or we're not using threads.  If either of these is
-	 * true, we want the setuid capability.
 	 */
 	SET_CAP(CAP_SETUID);
-#endif
 
 	/*
 	 * Since we call initgroups, we need this.
@@ -270,7 +220,6 @@ linux_minprivs(void) {
 	FREE_CAP;
 }
 
-#ifdef HAVE_SYS_PRCTL_H
 static void
 linux_keepcaps(void) {
 	char strbuf[ISC_STRERRORSIZE];
@@ -290,11 +239,9 @@ linux_keepcaps(void) {
 			non_root = true;
 	}
 }
-#endif
 
 #endif	/* HAVE_SYS_CAPABILITY_H */
 
-
 static void
 setup_syslog(const char *progname) {
 	int options;
@@ -497,7 +444,7 @@ named_os_changeuser(void) {
 		named_main_earlyfatal("setuid(): %s", strbuf);
 	}
 
-#if defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_DUMPABLE)
+#if defined(PR_SET_DUMPABLE)
 	/*
 	 * Restore the ability of named to drop core after the setuid()
 	 * call has disabled it.
@@ -540,11 +487,8 @@ named_os_adjustnofile(void) {
 
 void
 named_os_minprivs(void) {
-#ifdef HAVE_SYS_PRCTL_H
-	linux_keepcaps();
-#endif
-
 #if defined(HAVE_SYS_CAPABILITY_H)
+	linux_keepcaps();
 	linux_minprivs();
 #endif
 }

config.h.in

@@ -363,9 +363,6 @@
 /* Define to 1 if you have the <sys/param.h> header file. */
 #undef HAVE_SYS_PARAM_H
 
-/* Define to 1 if you have the <sys/prctl.h> header file. */
-#undef HAVE_SYS_PRCTL_H
-
 /* Define to 1 if you have the <sys/select.h> header file. */
 #undef HAVE_SYS_SELECT_H
 

configure

@@ -17709,19 +17709,6 @@ $as_echo "no" >&6; }
 fi
 
 
-for ac_header in sys/prctl.h
-do :
-  ac_fn_c_check_header_mongrel "$LINENO" "sys/prctl.h" "ac_cv_header_sys_prctl_h" "$ac_includes_default"
-if test "x$ac_cv_header_sys_prctl_h" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_SYS_PRCTL_H 1
-_ACEOF
-
-fi
-
-done
-
-
 for ac_header in sys/un.h
 do :
   ac_fn_c_check_header_mongrel "$LINENO" "sys/un.h" "ac_cv_header_sys_un_h" "$ac_includes_default"

configure.in

@@ -1891,8 +1891,6 @@ AS_IF([test "$enable_linux_caps" = "yes"],
       [AC_MSG_RESULT([no])])
 AC_SUBST([LIBCAP_LIBS])
 
-AC_CHECK_HEADERS(sys/prctl.h)
-
 AC_CHECK_HEADERS(sys/un.h,
 ISC_PLATFORM_HAVESYSUNH="#define ISC_PLATFORM_HAVESYSUNH 1"
 ,