Posted upstream at:

  https://sourceware.org/ml/libc-alpha/2017-04/msg00082.html

sysdeps/unix/sysv/linux/syscall-names.list is stored as a separate patch

(glibc-rh1439165-syscall-names.patch) in the source RPM for easier

updates.

Author: Florian Weimer <fweimer@redhat.com>

    <bits/syscall.h>: Use an arch-independent system call list on Linux

    This commit changes the way the list of SYS_* system call macros

    is created on Linux.  glibc now contains a list of all known system

    calls, and the generated <bits/syscall.h> file defines the SYS_

    macro only if the correspnding __NR_ macro is defined by the kernel

    headers.

    As a result, there glibc does not have to be rebuilt to pick up

    system calls if the glibc sources already know about them.  This

    means that glibc can be built with older kernel headers, and if

    the installed kernel headers are upgraded afterwards, additional

    SYS_ macros become available as long as glibc has a record for

    those system calls.

The explicit system call list for system call management was not

accepted upstream.

Fedora bug: https://bugzilla.redhat.com/show_bug.cgi?id=1484729

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile

index 366b1d7..95cff0e 100644

--- a/sysdeps/unix/sysv/linux/Makefile

+++ b/sysdeps/unix/sysv/linux/Makefile

@@ -39,75 +39,46 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \

 tests += tst-clone

-# Generate the list of SYS_* macros for the system calls (__NR_* macros).

-

-# If there is more than one syscall list for different architecture

-# variants, the CPU/Makefile defines abi-variants to be a list of names

-# for those variants (e.g. 32 64), and, for each variant, defines

-# abi-$(variant)-options to be compiler options to cause <asm/unistd.h>

-# to define the desired list of syscalls and abi-$(variant)-condition to

-# be the condition for those options to use in a C #if condition.

-# abi-includes may be defined to a list of headers to include

-# in the generated header, if the default does not suffice.

-#

-# The generated header is compiled with `-ffreestanding' to avoid any

-# circular dependencies against the installed implementation headers.

-# Such a dependency would require the implementation header to be

-# installed before the generated header could be built (See bug 15711).

-# In current practice the generated header dependencies do not include

-# any of the implementation headers removed by the use of `-ffreestanding'.

-

-$(objpfx)bits/syscall%h $(objpfx)bits/syscall%d: ../sysdeps/unix/sysv/linux/sys/syscall.h

+# Generate the list of SYS_* macros for the system calls (__NR_*

+# macros).  The file syscall-names.list contains all possible system

+# call names, and the generated header file produces SYS_* macros for

+# the __NR_* macros which are actually defined.

+

+generated += bits/syscall.h

+$(objpfx)bits/syscall.h: \

+  ../sysdeps/unix/sysv/linux/gen-syscall-h.awk \

+  ../sysdeps/unix/sysv/linux/syscall-names.list

 	$(make-target-directory)

-	{ \

-	 echo '/* Generated at libc build time from kernel syscall list.  */';\

-	 echo ''; \

-	 echo '#ifndef _SYSCALL_H'; \

-	 echo '# error "Never use <bits/syscall.h> directly; include <sys/syscall.h> instead."'; \

-	 echo '#endif'; \

-	 echo ''; \

-	 $(foreach h,$(abi-includes), echo '#include <$(h)>';) \

-	 echo ''; \

-	 $(if $(abi-variants), \

-	 $(foreach v,$(abi-variants),\

-	 $(CC) -ffreestanding -E -MD -MP -MF $(@:.h=.d)-t$(v) -MT '$(@:.d=.h) $(@:.h=.d)' \

-	       -x c $(sysincludes) $< $(abi-$(v)-options) \

-	       -D_LIBC -dM | \

-	 sed -n 's@^#define __NR_\([^ ]*\) .*$$@#define SYS_\1 __NR_\1@p' | \

-	 LC_ALL=C sort > $(@:.d=.h).new$(v); \

-	 $(if $(abi-$(v)-condition),\

-	 echo '#if $(abi-$(v)-condition)';) \

-	 cat $(@:.d=.h).new$(v); \

-	 $(if $(abi-$(v)-condition),echo '#endif';) \

-	 rm -f $(@:.d=.h).new$(v); \

-	 ), \

-	 $(CC) -ffreestanding -E -MD -MP -MF $(@:.h=.d)-t$(v) -MT '$(@:.d=.h) $(@:.h=.d)' \

-	       -x c $(sysincludes) $< \

-	       -D_LIBC -dM | \

-	 sed -n 's@^#define __NR_\([^ ]*\) .*$$@#define SYS_\1 __NR_\1@p' | \

-	 LC_ALL=C sort;) \

-	} > $(@:.d=.h).new

-	mv -f $(@:.d=.h).new $(@:.d=.h)

-ifdef abi-variants

-ifneq (,$(objpfx))

-	sed $(sed-remove-objpfx) \

-	 $(foreach v,$(abi-variants),$(@:.h=.d)-t$(v)) > $(@:.h=.d)-t3

-else

-	cat $(foreach v,$(abi-variants),$(@:.h=.d)-t$(v)) \

-	 > $(@:.h=.d)-t3

-endif

-	rm -f $(foreach v,$(abi-variants),$(@:.h=.d)-t$(v))

-	mv -f $(@:.h=.d)-t3 $(@:.h=.d)

-else

-	mv -f $(@:.h=.d)-t $(@:.h=.d)

-endif

-

-ifndef no_deps

-# Get the generated list of dependencies (probably /usr/include/asm/unistd.h).

--include $(objpfx)bits/syscall.d

-endif

-generated += bits/syscall.h bits/syscall.d

-endif

+	$(AWK) -f $^ > $@-tmp

+	$(move-if-change) $@-tmp $@

+

+# All macros defined by <sys/syscall.h>.  Include <bits/syscall.h>

+# explicitly because <sys/sycall.h> skips it if _LIBC is defined.

+$(objpfx)tst-syscall-list-macros.list: \

+  $(objpfx)bits/syscall.h ../sysdeps/unix/sysv/linux/sys/syscall.h

+	printf '#include <sys/syscall.h>\n#include <bits/syscall.h>\n' | \

+	  $(CC) -E -o $@-tmp $(CFLAGS) $(CPPFLAGS) -x c - -dM

+	$(move-if-change) $@-tmp $@

+

+# __NR_* system call names.  Used by the test below.

+$(objpfx)tst-syscall-list-nr.list: \

+  ../sysdeps/unix/sysv/linux/filter-nr-syscalls.awk \

+  $(objpfx)tst-syscall-list-macros.list

+	$(AWK) -f $^ > $@-tmp

+	$(move-if-change) $@-tmp $@

+

+# SYS_* system call names.  Used by the test below.

+$(objpfx)tst-syscall-list-sys.list: $(objpfx)tst-syscall-list-macros.list

+	$(AWK) '/^#define SYS_/ { print substr($$2, 5) }' $< > $@-tmp

+	$(move-if-change) $@-tmp $@

+

+tests: $(objpfx)tst-syscall-list.out

+$(objpfx)tst-syscall-list.out: \

+  ../sysdeps/unix/sysv/linux/tst-syscall-list.sh \

+  $(objpfx)tst-syscall-list-nr.list $(objpfx)tst-syscall-list-sys.list

+	$(BASH) $^ > $@

+

+endif # $(subdir) == misc

 ifeq ($(subdir),time)

 sysdep_headers += sys/timex.h bits/timex.h

diff --git a/sysdeps/unix/sysv/linux/filter-nr-syscalls.awk b/sysdeps/unix/sysv/linux/filter-nr-syscalls.awk

new file mode 100644

index 0000000..15b052a

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/filter-nr-syscalls.awk

@@ -0,0 +1,35 @@

+# Filter preprocessor __NR_* macros and extract system call names.

+# Copyright (C) 2017 Free Software Foundation, Inc.

+# This file is part of the GNU C Library.

+#

+# The GNU C Library is free software; you can redistribute it and/or

+# modify it under the terms of the GNU Lesser General Public

+# License as published by the Free Software Foundation; either

+# version 2.1 of the License, or (at your option) any later version.

+#

+# The GNU C Library is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+# Lesser General Public License for more details.

+#

+# You should have received a copy of the GNU Lesser General Public

+# License along with the GNU C Library; if not, see

+# <http://www.gnu.org/licenses/>.

+

+# Skip reserved system calls.

+/^#define __NR_(unused|reserved)[0-9]+ / {

+    next;

+}

+

+# Skip pseudo-system calls which describe ranges.

+/^#define __NR_(syscalls|arch_specific_syscall|(OABI_)?SYSCALL_BASE) / {

+    next;

+}

+/^#define __NR_(|64_|[NO]32_)Linux(_syscalls)? / {

+    next;

+}

+

+# Print the remaining _NR_* macros as system call names.

+/^#define __NR_/ {

+    print substr($2, 6);

+}

diff --git a/sysdeps/unix/sysv/linux/gen-syscall-h.awk b/sysdeps/unix/sysv/linux/gen-syscall-h.awk

new file mode 100644

index 0000000..0a27b3c

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/gen-syscall-h.awk

@@ -0,0 +1,75 @@

+# Generate SYS_* macros from a list in a text file.

+# Copyright (C) 2017 Free Software Foundation, Inc.

+# This file is part of the GNU C Library.

+#

+# The GNU C Library is free software; you can redistribute it and/or

+# modify it under the terms of the GNU Lesser General Public

+# License as published by the Free Software Foundation; either

+# version 2.1 of the License, or (at your option) any later version.

+#

+# The GNU C Library is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+# Lesser General Public License for more details.

+#

+# You should have received a copy of the GNU Lesser General Public

+# License along with the GNU C Library; if not, see

+# <http://www.gnu.org/licenses/>.

+

+# Emit a conditional definition for SYS_NAME.

+function emit(name) {

+    print "#ifdef __NR_" name;

+    print "# define SYS_" name " __NR_" name;

+    print "#endif";

+    print "";

+}

+

+# Bail out with an error.

+function fatal(message) {

+    print FILENAME ":" FNR ": " message > "/dev/stderr";

+    exit 1;

+}

+

+BEGIN {

+    name = "";

+    kernel = "";

+}

+

+# Skip empty lines and comments.

+/^\s*(|#.*)$/ {

+    next;

+}

+

+# Kernel version.  Used for documentation purposes only.

+/^kernel [0-9.]+$/ {

+    if (kernel != "") {

+        fatal("duplicate kernel directive");

+    }

+    kernel = $2;

+    print "/* Generated at libc build time from syscall list.  */";

+    print "/* The system call list corresponds to kernel " kernel ".  */";

+    print "";

+    print "#ifndef _SYSCALL_H"

+    print "# error \"Never use <bits/syscall.h> directly; include <sys/syscall.h> instead.\"";

+    print "#endif";

+    print "";

+    next;

+}

+

+# If there is just one word, it is a system call.

+/^[a-zA-Z_][a-zA-Z0-9_]+$/ {

+    if (kernel == "") {

+        fatal("expected kernel directive before this line");

+    }

+    if ($1 <= name) {

+        fatal("name " name " violates ordering");

+    }

+    emit($1);

+    name = $1;

+    next;

+}

+

+# The rest has to be syntax errors.

+// {

+    fatal("unrecognized syntax");

+}

diff --git a/sysdeps/unix/sysv/linux/tst-syscall-list.sh b/sysdeps/unix/sysv/linux/tst-syscall-list.sh

new file mode 100644

index 0000000..f48b7cd

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/tst-syscall-list.sh

@@ -0,0 +1,72 @@

+#!/bin/bash

+# Consistency checks for the system call list

+# Copyright (C) 2017 Free Software Foundation, Inc.

+# This file is part of the GNU C Library.

+#

+# The GNU C Library is free software; you can redistribute it and/or

+# modify it under the terms of the GNU Lesser General Public

+# License as published by the Free Software Foundation; either

+# version 2.1 of the License, or (at your option) any later version.

+#

+# The GNU C Library is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+# Lesser General Public License for more details.

+#

+# You should have received a copy of the GNU Lesser General Public

+# License along with the GNU C Library; if not, see

+# <http://www.gnu.org/licenses/>.

+

+export LC_ALL=C

+set -e

+set -o pipefail

+

+if test $# != 2 ; then

+    echo "error: wrong number of arguments: $#"

+    exit 1

+fi

+

+list_nr="$1"

+list_sys="$2"

+

+errors=0

+

+# Use getpid as a system call which is expected to be always defined.

+# alpha uses getxpid instead, so it is permitted as an alternative.

+if ! grep -E -q '^getx?pid$' -- "$list_nr" ; then

+    echo "error: __NR_getpid not defined"

+    errors=1

+fi

+if ! grep -E -q '^getx?pid$' -- "$list_sys" ; then

+    echo "error: SYS_getpid not defined"

+    errors=1

+fi

+

+comm_1="$(mktemp)"

+comm_2="$(mktemp)"

+comm_result="$(mktemp)"

+cleanup () {

+    rm -f -- "$comm_1" "$comm_2" "$comm_result"

+}

+trap cleanup 0

+

+sort -o "$comm_1" -- "$list_nr"

+sort -o "$comm_2" -- "$list_sys"

+

+# Check for missing SYS_* macros.

+comm --check-order -2 -3 -- "$comm_1" "$comm_2" > "$comm_result"

+if test -s "$comm_result"; then

+    echo "error: These system calls need to be added to syscall-names.list:"

+    cat -- "$comm_result"

+    errors=1

+fi

+

+# Check for additional SYS_* macros.

+comm --check-order -1 -3 -- "$comm_1" "$comm_2" > "$comm_result"

+if test -s "$comm_result"; then

+    echo "error: The following system calls have unexpected SYS_* macros:"

+    cat -- "$comm_result"

+    errors=1

+fi

+

+exit "$errors"