The posix_madvise(3) and posix_fadvise(2) should return error on

failure, same as posix_fallocate(2).

Noted by:	Bob Bishop <rb@gid.co.uk>
Discussed with:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

lib/libc/gen/pmadvise.c

@@ -8,9 +8,19 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/mman.h>
+#include <errno.h>
 
 int
 posix_madvise(void *address, size_t size, int how)
 {
-	return madvise(address, size, how);
+	int ret, saved_errno;
+
+	saved_errno = errno;
+	if (madvise(address, size, how) == -1) {
+		ret = errno;
+		errno = saved_errno;
+	} else {
+		ret = 0;
+	}
+	return (ret);
 }

lib/libc/sys/madvise.2

@@ -28,7 +28,7 @@
 .\"	@(#)madvise.2	8.1 (Berkeley) 6/9/93
 .\" $FreeBSD$
 .\"
-.Dd July 19, 1996
+.Dd January 30, 2014
 .Dt MADVISE 2
 .Os
 .Sh NAME
@@ -50,7 +50,10 @@ allows a process that has knowledge of its memory behavior
 to describe it to the system.
 The
 .Fn posix_madvise
-interface is identical and is provided for standards conformance.
+interface is identical, except it returns an error number on error and does
+not modify
+.Va errno ,
+and is provided for standards conformance.
 .Pp
 The known behaviors are:
 .Bl -tag -width MADV_SEQUENTIAL

lib/libc/sys/posix_fadvise.2

@@ -28,7 +28,7 @@
 .\"	@(#)madvise.2	8.1 (Berkeley) 6/9/93
 .\" $FreeBSD$
 .\"
-.Dd June 19, 2012
+.Dd January 30, 2014
 .Dt POSIX_FADVISE 2
 .Os
 .Sh NAME
@@ -93,7 +93,7 @@ Future access to this data may require a read operation.
 .Sh ERRORS
 The
 .Fn posix_fadvise
-system call will fail if:
+system call returns zero on success, and an error on failure:
 .Bl -tag -width Er
 .It Bq Er EBADF
 The

lib/libc/sys/posix_fallocate.2

@@ -83,9 +83,8 @@ that reduces the file size to a size smaller than
 If successful,
 .Fn posix_fallocate
 returns zero.
-It returns error number on failure, without setting
-.Va errno
-variable.
+It returns an error on failure, without setting
+.Va errno .
 .Sh ERRORS
 Possible failure conditions:
 .Bl -tag -width Er

sys/compat/freebsd32/freebsd32_misc.c

@@ -3005,8 +3005,10 @@ freebsd32_posix_fadvise(struct thread *td,
     struct freebsd32_posix_fadvise_args *uap)
 {
 
-	return (kern_posix_fadvise(td, uap->fd, PAIR32TO64(off_t, uap->offset),
-	    PAIR32TO64(off_t, uap->len), uap->advice));
+	td->td_retval[0] = kern_posix_fadvise(td, uap->fd,
+	    PAIR32TO64(off_t, uap->offset), PAIR32TO64(off_t, uap->len),
+	    uap->advice);
+	return (0);
 }
 
 int

sys/kern/vfs_syscalls.c

@@ -4725,6 +4725,7 @@ int
 sys_posix_fadvise(struct thread *td, struct posix_fadvise_args *uap)
 {
 
-	return (kern_posix_fadvise(td, uap->fd, uap->offset, uap->len,
-	    uap->advice));
+	td->td_retval[0] = kern_posix_fadvise(td, uap->fd, uap->offset,
+	    uap->len, uap->advice);
+	return (0);
 }