svn commit: r332119 - in head/lib/libc: amd64/sys gen i386/sys powerpc/sys powerpc64/sys sparc64/sys

[Brooks Davis]

Author: brooks
Date: Fri Apr  6 17:17:34 2018
New Revision: 332119
URL: https://svnweb.freebsd.org/changeset/base/332119

Log:
  Remove caching from getlogin(2).
  
  This caching has existed since the CSRG import, but serves no obvious
  purpose. Sure, setlogin() is called rarely, but calls to getlogin()
  should also be infrequent. The required invalidation was not
  implemented on aarch64, arm, mips, amd riscv so updates would never
  occur if getlogin() was called before setlogin().
  
  Reported by:	Ali Mashtizadeh <ali at mashtizadeh.com>
  Reviewed by:	kib
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D14965

Deleted:
  head/lib/libc/amd64/sys/setlogin.S
  head/lib/libc/i386/sys/setlogin.S
  head/lib/libc/powerpc/sys/setlogin.S
  head/lib/libc/powerpc64/sys/setlogin.S
  head/lib/libc/sparc64/sys/setlogin.S
Modified:
  head/lib/libc/amd64/sys/Makefile.inc
  head/lib/libc/gen/getlogin.c
  head/lib/libc/i386/sys/Makefile.inc
  head/lib/libc/powerpc/sys/Makefile.inc
  head/lib/libc/powerpc64/sys/Makefile.inc
  head/lib/libc/sparc64/sys/Makefile.inc

Modified: head/lib/libc/amd64/sys/Makefile.inc
==============================================================================
--- head/lib/libc/amd64/sys/Makefile.inc	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/amd64/sys/Makefile.inc	Fri Apr  6 17:17:34 2018	(r332119)
@@ -9,7 +9,7 @@ SRCS+=	\
 	amd64_set_gsbase.c
 
 MDASM=	vfork.S brk.S cerror.S exect.S getcontext.S \
-	sbrk.S setlogin.S
+	sbrk.S
 
 # Don't generate default code for these syscalls:
 NOASM+=	vfork.o

Modified: head/lib/libc/gen/getlogin.c
==============================================================================
--- head/lib/libc/gen/getlogin.c	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/gen/getlogin.c	Fri Apr  6 17:17:34 2018	(r332119)
@@ -47,62 +47,33 @@ __FBSDID("$FreeBSD$");
 
 #include "libc_private.h"
 
-#define	THREAD_LOCK()	if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
-#define	THREAD_UNLOCK()	if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
-
 extern int		_getlogin(char *, int);
 
-int			_logname_valid __hidden; /* known to setlogin() */
-static pthread_mutex_t	logname_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-static char *
-getlogin_basic(int *status)
-{
-	static char logname[MAXLOGNAME];
-
-	if (_logname_valid == 0) {
-		if (_getlogin(logname, sizeof(logname)) < 0) {
-			*status = errno;
-			return (NULL);
-		}
-		_logname_valid = 1;
-	}
-	*status = 0;
-	return (*logname ? logname : NULL);
-}
-
 char *
 getlogin(void)
 {
-	char	*result;
-	int	status;
+	static char logname[MAXLOGNAME];
 
-	THREAD_LOCK();
-	result = getlogin_basic(&status);
-	THREAD_UNLOCK();
-	return (result);
+	if (_getlogin(logname, sizeof(logname)) < 0)
+		return (NULL);
+	return (logname[0] != '\0' ? logname : NULL);
 }
 
 int
 getlogin_r(char *logname, int namelen)
 {
-	char	*result;
+	char tmpname[MAXLOGNAME];
 	int	len;
-	int	status;
 
 	if (namelen < 1)
 		return (ERANGE);
 	logname[0] = '\0';
 
-	THREAD_LOCK();
-	result = getlogin_basic(&status);
-	if (status == 0 && result != NULL) {
-		len = strlen(result) + 1;
-		if (len > namelen)
-			status = ERANGE;
-		else
-			strncpy(logname, result, len);
-	}
-	THREAD_UNLOCK();
-	return (status);
+	if (_getlogin(tmpname, sizeof(tmpname)) < 0)
+		return (errno);
+	len = strlen(tmpname) + 1;
+	if (len > namelen)
+		return (ERANGE);
+	strlcpy(logname, tmpname, len);
+	return (0);
 }

Modified: head/lib/libc/i386/sys/Makefile.inc
==============================================================================
--- head/lib/libc/i386/sys/Makefile.inc	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/i386/sys/Makefile.inc	Fri Apr  6 17:17:34 2018	(r332119)
@@ -8,7 +8,7 @@ SRCS+=	i386_get_fsbase.c i386_get_gsbase.c i386_get_io
 	i386_set_fsbase.c i386_set_gsbase.c i386_set_ioperm.c i386_set_ldt.c
 
 MDASM=	Ovfork.S brk.S cerror.S exect.S getcontext.S \
-	sbrk.S setlogin.S syscall.S
+	sbrk.S syscall.S
 
 NOASM+=	vfork.o
 

Modified: head/lib/libc/powerpc/sys/Makefile.inc
==============================================================================
--- head/lib/libc/powerpc/sys/Makefile.inc	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/powerpc/sys/Makefile.inc	Fri Apr  6 17:17:34 2018	(r332119)
@@ -1,3 +1,3 @@
 # $FreeBSD$
 
-MDASM+=	brk.S cerror.S exect.S sbrk.S setlogin.S
+MDASM+=	brk.S cerror.S exect.S sbrk.S

Modified: head/lib/libc/powerpc64/sys/Makefile.inc
==============================================================================
--- head/lib/libc/powerpc64/sys/Makefile.inc	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/powerpc64/sys/Makefile.inc	Fri Apr  6 17:17:34 2018	(r332119)
@@ -1,3 +1,3 @@
 # $FreeBSD$
 
-MDASM+=	brk.S cerror.S exect.S sbrk.S setlogin.S
+MDASM+=	brk.S cerror.S exect.S sbrk.S

Modified: head/lib/libc/sparc64/sys/Makefile.inc
==============================================================================
--- head/lib/libc/sparc64/sys/Makefile.inc	Fri Apr  6 17:16:50 2018	(r332118)
+++ head/lib/libc/sparc64/sys/Makefile.inc	Fri Apr  6 17:17:34 2018	(r332119)
@@ -12,4 +12,4 @@ SRCS+=	__sparc_sigtramp_setup.c \
 
 CFLAGS+= -I${LIBC_SRCTOP}/sparc64/fpu
 
-MDASM+=	brk.S cerror.S exect.S sbrk.S setlogin.S sigaction1.S
+MDASM+=	brk.S cerror.S exect.S sbrk.S sigaction1.S