lib{c,sys}: return wrapped syscall APIs to libc

These provide standard APIs, but are implemented using another system
call (e.g., pipe implemented in terms of pipe2) or are interposed by the
threading library to support cancelation.

After discussion with kib (see D44111), I've concluded that it is
better to keep most public interfaces in libc with as little
as possible in libsys.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D44241

lib/libc/Makefile

@@ -122,8 +122,7 @@ NOASM=
 .include "${LIBC_SRCTOP}/stdlib/Makefile.inc"
 .include "${LIBC_SRCTOP}/stdtime/Makefile.inc"
 .include "${LIBC_SRCTOP}/string/Makefile.inc"
-SHARED_CFLAGS+=	-D'_SYSCALL_BODY(name)='
-.include "${LIBSYS_SRCTOP}/Makefile.sys"
+.include "${LIBC_SRCTOP}/sys/Makefile.inc"
 .include "${LIBC_SRCTOP}/secure/Makefile.inc"
 .include "${LIBC_SRCTOP}/rpc/Makefile.inc"
 .include "${LIBC_SRCTOP}/uuid/Makefile.inc"

lib/libc/amd64/Symbol.map

@@ -6,6 +6,7 @@
 FBSD_1.0 {
 	.mcount;
 	__flt_rounds;
+	brk;
 	fpgetmask;
 	fpgetprec;
 	fpgetround;
@@ -13,6 +14,7 @@ FBSD_1.0 {
 	fpsetmask;
 	fpsetprec;
 	fpsetround;
+	sbrk;
 };
 
 /*
@@ -26,4 +28,5 @@ FBSDprivate_1.0 {
 	__signalcontext;
 	signalcontext;
 	__siglongjmp;
+	_brk;
 };

lib/libc/arm/Symbol.map

@@ -6,6 +6,8 @@
 FBSD_1.0 {
 	__mcount;
 	alloca;
+	brk;
+	sbrk;
 };
 
 FBSD_1.3 {
@@ -23,6 +25,7 @@ FBSD_1.6 {
 };
 
 FBSDprivate_1.0 {
+	_brk;
 	__aeabi_read_tp;
 	___longjmp;
 	__longjmp;

lib/libc/i386/Symbol.map

@@ -5,8 +5,10 @@
  */
 FBSD_1.0 {
 	.mcount;
+	brk;
 	__flt_rounds;
 	___tls_get_addr;
+	sbrk;
 };
 
 FBSDprivate_1.0 {
@@ -15,4 +17,5 @@ FBSDprivate_1.0 {
 	__signalcontext;
 	signalcontext;
 	__siglongjmp;
+	_brk;
 };

lib/libc/powerpc/Symbol.map

@@ -6,11 +6,13 @@
 FBSD_1.0 {
 	_mcount;
 	__flt_rounds;
+	brk;
 	fpgetmask;
 	fpgetround;
 	fpgetsticky;
 	fpsetmask;
 	fpsetround;
+	sbrk;
 };
 
 FBSD_1.3 {

lib/libc/powerpc64/Symbol.map

@@ -6,9 +6,11 @@
 FBSD_1.0 {
 	_mcount;
 	__flt_rounds;
+	brk;
 	fpgetmask;
 	fpgetround;
 	fpgetsticky;
 	fpsetmask;
 	fpsetround;
+	sbrk;
 };

lib/libc/sys/Makefile.inc

@@ -0,0 +1,38 @@
+# libc-specific portion of the system call interface
+
+.PATH: ${LIBC_SRCTOP}/sys
+
+# Most of the implementation is shared with libsys:
+.include "${LIBSYS_SRCTOP}/Makefile.sys"
+
+# emit empty assembly stubs for syscalls in dynamic libc
+SHARED_CFLAGS+=	-D'_SYSCALL_BODY(name)='
+
+SYM_MAPS+=	${LIBC_SRCTOP}/sys/Symbol.map
+
+# Add the interposer wrappers
+SRCS+=	${INTERPOSED:S/$/.c/}
+
+# Pseudo system calls implemented atop other interfaces.
+SRCS+= \
+	POSIX2x_Fork.c \
+	brk.c \
+	closefrom.c \
+	compat-stub.c \
+	creat.c \
+	getdents.c \
+	lockf.c \
+	lstat.c \
+	mknod.c \
+	pipe.c \
+	recv.c \
+	recvmmsg.c \
+	send.c \
+	sendmmsg.c \
+	shm_open.c \
+	stat.c \
+	vadvise.c \
+	wait.c \
+	wait3.c \
+	waitid.c \
+	waitpid.c

lib/libc/sys/Symbol.map

@@ -0,0 +1,73 @@
+FBSD_1.0 {
+	accept;
+	aio_suspend;
+	close;
+	connect;
+	fcntl;
+	fork;
+	fsync;
+	msync;
+	nanosleep;
+	open;
+	pipe;
+	poll;
+	pselect;
+	ptrace;
+	read;
+	readv;
+	recvfrom;
+	recvmsg;
+	select;
+	sendmsg;
+	sendto;
+	shm_open;
+	sigaction;
+	sigprocmask;
+	sigsuspend;
+	sigtimedwait;
+	sigwait;
+	sigwaitinfo;
+	vadvise;
+	wait4;
+	write;
+	writev;
+};
+
+FBSD_1.1 {
+	closefrom;
+};
+
+FBSD_1.2 {
+	pdfork;
+};
+
+FBSD_1.3 {
+	accept4;
+	wait6;
+};
+
+FBSD_1.4 {
+	ppoll;
+	numa_setaffinity;
+	numa_getaffinity;
+	sendmmsg;
+	recvmmsg;
+};
+
+FBSD_1.5 {
+	clock_nanosleep;
+	fdatasync;
+	getdents;
+	kevent;
+	lstat;
+	mknod;
+	stat;
+};
+
+FBSD_1.6 {
+	shm_create_largepage;
+};
+
+FBSD_1.7 {
+	_Fork;
+};

lib/libsys/Makefile.sys

@@ -40,21 +40,6 @@ SRCS+=	\
 	interposing_table.c \
 	libsys_sigwait.c
 
-SRCS+= getdents.c lstat.c mknod.c stat.c
-
-SRCS+=	creat.c
-SRCS+=	lockf.c wait.c wait3.c waitpid.c waitid.c
-SRCS+=	recv.c recvmmsg.c send.c sendmmsg.c
-
-SRCS+= brk.c
-SRCS+= closefrom.c
-SRCS+= pipe.c
-SRCS+= shm_open.c
-SRCS+= vadvise.c
-SRCS+= POSIX2x_Fork.c
-
-SRCS+=	compat-stub.c
-
 .if ${LIB} == "c"
 # Trapping stubs in dynamic libc to be filtered by libsys.
 SOBJS+=	libc_stubs.pico
@@ -113,7 +98,6 @@ INTERPOSED = \
 	write \
 	writev
 
-SRCS+=	${INTERPOSED:S/$/.c/}
 PSEUDO+=	${INTERPOSED}
 
 # Add machine dependent asm sources:

lib/libsys/Symbol.sys.map

@@ -33,7 +33,6 @@ FBSD_1.0 {
 	_exit;
 	_umtx_op;
 	abort2;
-	accept;
 	access;
 	acct;
 	adjtime;
@@ -42,7 +41,6 @@ FBSD_1.0 {
 	aio_fsync;
 	aio_read;
 	aio_return;
-	aio_suspend;
 	aio_waitcomplete;
 	aio_write;
 	audit;
@@ -57,8 +55,6 @@ FBSD_1.0 {
 	clock_getres;
 	clock_gettime;
 	clock_settime;
-	close;
-	connect;
 	dup;
 	dup2;
 	eaccess;
@@ -81,12 +77,9 @@ FBSD_1.0 {
 	fchflags;
 	fchmod;
 	fchown;
-	fcntl;
 	fhopen;
 	flock;
-	fork;
 	fpathconf;
-	fsync;
 	futimes;
 	getaudit;
 	getaudit_addr;
@@ -173,32 +166,21 @@ FBSD_1.0 {
 	msgrcv;
 	msgsnd;
 	msgsys;
-	msync;
 	munlock;
 	munlockall;
 	munmap;
-	nanosleep;
 	nfssvc;
 	nmount;
 	ntp_adjtime;
 	ntp_gettime;
-	open;
 	pathconf;
-	pipe;
-	poll;
 	posix_openpt;
 	preadv;
 	profil;
-	pselect;
-	ptrace;
 	pwritev;
 	quotactl;
-	read;
 	readlink;
-	readv;
 	reboot;
-	recvfrom;
-	recvmsg;
 	rename;
 	revoke;
 	rfork;
@@ -213,13 +195,10 @@ FBSD_1.0 {
 	sched_setparam;
 	sched_setscheduler;
 	sched_yield;
-	select;
 	semget;
 	semop;
 	semsys;
 	sendfile;
-	sendmsg;
-	sendto;
 	setaudit;
 	setaudit_addr;
 	setauid;
@@ -240,23 +219,16 @@ FBSD_1.0 {
 	setsockopt;
 	settimeofday;
 	setuid;
-	shm_open;
 	shm_unlink;
 	shmat;
 	shmdt;
 	shmget;
 	shmsys;
 	shutdown;
-	sigaction;
 	sigaltstack;
 	sigpending;
-	sigprocmask;
 	sigqueue;
 	sigreturn;
-	sigsuspend;
-	sigtimedwait;
-	sigwait;
-	sigwaitinfo;
 	socket;
 	socketpair;
 	swapon;
@@ -285,11 +257,7 @@ FBSD_1.0 {
 	utimes;
 	utrace;
 	uuidgen;
-	vadvise;
 	vfork;
-	wait4;
-	write;
-	writev;
 
 	__error;
 	ftruncate;
@@ -302,7 +270,6 @@ FBSD_1.0 {
 
 FBSD_1.1 {
 	__semctl;
-	closefrom;
 	cpuset;
 	cpuset_getid;
 	cpuset_setid;
@@ -334,7 +301,6 @@ FBSD_1.2 {
 	cap_getmode;
 	getloginclass;
 	getpagesizes;
-	pdfork;
 	pdgetpid;
 	pdkill;
 	posix_fallocate;
@@ -347,7 +313,6 @@ FBSD_1.2 {
 };
 
 FBSD_1.3 {
-	accept4;
 	aio_mlock;
 	bindat;
 	cap_fcntls_get;
@@ -365,37 +330,24 @@ FBSD_1.3 {
 	pipe2;
 	posix_fadvise;
 	procctl;
-	wait6;
 };
 
 FBSD_1.4 {
 	futimens;
-	ppoll;
 	utimensat;
-	numa_setaffinity;
-	numa_getaffinity;
-	sendmmsg;
-	recvmmsg;
 };
 
 FBSD_1.5 {
-	clock_nanosleep;
 	elf_aux_info;
-	fdatasync;
 	fhstat;
 	fhstatfs;
 	fstat;
 	fstatat;
 	fstatfs;
-	getdents;
 	getdirentries;
 	getfsstat;
 	getrandom;
-	kevent;
-	lstat;
-	mknod;
 	mknodat;
-	stat;
 	statfs;
 	cpuset_getdomain;
 	cpuset_setdomain;
@@ -412,12 +364,10 @@ FBSD_1.6 {
 	fhreadlink;
 	getfhat;
 	funlinkat;
-	shm_create_largepage;
 	shm_rename;
 };
 
 FBSD_1.7 {
-	_Fork;
 	fspacectl;
 	kqueuex;
 	membarrier;

lib/libsys/amd64/Symbol.sys.map

@@ -4,8 +4,6 @@ FBSD_1.0 {
 	amd64_get_gsbase;
 	amd64_set_fsbase;
 	amd64_set_gsbase;
-	brk;
-	sbrk;
 };
 
 FBSD_1.6 {
@@ -15,12 +13,6 @@ FBSD_1.6 {
 	 x86_pkru_unprotect_range;
 };
 
-/*
- *
- * FreeBSD private ABI
- *
- */
 FBSDprivate_1.0 {
-	_brk;
 	_vfork;
 };

lib/libsys/arm/Symbol.sys.map

@@ -1,10 +1,3 @@
-FBSD_1.0 {
-	brk;
-	sbrk;
-};
-
 FBSDprivate_1.0 {
 	_vfork;
-	_brk;
-	_sbrk;
 };

lib/libsys/i386/Symbol.sys.map

@@ -1,6 +1,5 @@
 FBSD_1.0 {
 	rfork_thread;
-	brk;
 	i386_clr_watch;
 	i386_get_fsbase;
 	i386_get_gsbase;
@@ -12,7 +11,6 @@ FBSD_1.0 {
 	i386_set_ldt;
 	i386_set_watch;
 	i386_vm86;
-	sbrk;
 };
 
 FBSD_1.6 {
@@ -24,5 +22,4 @@ FBSD_1.6 {
 
 FBSDprivate_1.0 {
 	_vfork;
-	_brk;
 };

lib/libsys/powerpc/Symbol.sys.map

@@ -1,4 +0,0 @@
-FBSD_1.0 {
-	brk;
-	sbrk;
-};

lib/libsys/powerpc64/Symbol.sys.map

@@ -1,4 +0,0 @@
-FBSD_1.0 {
-	brk;
-	sbrk;
-};