maint: generate ioctl entries without target architecture code execution

ioctls_sym.sh used to generate and invoke target architecture
executables that limited its applicability.
After this change, the generated code is just compiled to the target
architecture object files and all required information is obtained
from the dwarf sections.
This approach allows to generate ioctl entries for any target
architecture supported by compiler.

* maint/ioctls_sym.awk: New file.
* maint/ioctls_sym.sh (LC_ALL): Define to C and export.
(uname_m): Make configurable.
(CFLAGS): Add -gdwarf-2.
(LDFLAGS): Remove.
Do not use print_ioctlent.c.
Change asm-generic/ioctl.h and asm/ioctl.h hook.
Dump and process dwarf sections of generated object files.
* maint/print_ioctlent.c: Remove.

1 files changed, 32 insertions, 19 deletions

diff --git a/maint/ioctls_sym.sh b/maint/ioctls_sym.sh
index 124bbc41e..28ed105f7 100755
--- a/maint/ioctls_sym.sh
+++ b/maint/ioctls_sym.sh
@@ -27,6 +27,8 @@
 
 set -efu
 
+export LC_ALL=C
+
 # This script processes header files containing ioctl command definitions in
 # symbolic form, assuming that these definitions match the following regular
 # expressions:
@@ -37,7 +39,7 @@ r_io='\([A-Z]\+\)\?_S\?\(IO\|IOW\|IOR\|IOWR\|IOC\)'
 r_value='[[:space:]]\+'"$r_io"'[[:space:]]*([^)]'
 regexp="${r_define}${r_cmd_name}${r_value}"
 
-uname_m="$(uname -m)"
+: "${uname_m:=$(uname -m)}"
 me="${0##*/}"
 msg()
 {
@@ -89,19 +91,27 @@ failed=0
 CC="${CC:-gcc}"
 CPP="${CPP:-cpp}"
 CPPFLAGS="${CPPFLAGS-} -D__EXPORTED_HEADERS__"
-CFLAGS="${CFLAGS:--Wall -O2} -D__EXPORTED_HEADERS__"
-LDFLAGS="${LDFLAGS-}"
+CFLAGS="${CFLAGS:--Wall -O2} -gdwarf-2 -D__EXPORTED_HEADERS__"
 INCLUDES="-I$inc_dir/uapi -I$inc_dir ${INCLUDES-}"
 
-$CC $INCLUDES $CFLAGS -c -o "$tmpdir"/print_ioctlent.o "${0%/*}"/print_ioctlent.c
-
 # Hook onto <asm-generic/ioctl.h> and <asm/ioctl.h>
 for d in asm-generic asm; do
 	mkdir "$tmpdir/$d"
 	cat > "$tmpdir/$d"/ioctl.h <<__EOF__
 #include_next <$d/ioctl.h>
+#undef _IOC_NONE
+#define _IOC_NONE (2<<7)
+#undef _IOC_READ
+#define _IOC_READ (2<<8)
+#undef _IOC_WRITE
+#define _IOC_WRITE (2<<9)
 #undef _IOC
-#define _IOC(dir,type,nr,size) dir, type, nr, size
+#define _IOC(dir, type, nr, size) \
+	char \
+		d[1 + (dir)], \
+		n[1 + (((unsigned) (type) << _IOC_TYPESHIFT) | \
+			((unsigned) (nr) << _IOC_NRSHIFT))], \
+		s[1 + (size)]
 __EOF__
 done
 
@@ -158,15 +168,8 @@ typedef unsigned long long u64;
 
 #include "$f"
 
-void print_ioctlent(const char *, const char *, unsigned short, unsigned short, unsigned short, unsigned short);
-
-int main(void)
-{
-
 #include "defs.h"
 
-return 0;
-}
 __EOF__
 
 	# Soft pre-include workarounds for some processed files.  Fragile.
@@ -412,17 +415,27 @@ s/^\([[:space:]]\+[^),]\+)\),$/\1/' >> "$tmpdir/$f"
 	# Keep this in sync with $regexp by replacing $r_cmd_name with $r_local_names.
 	defs_regexp="${r_define}\($r_local_names\)${r_value}"
 
-	qf="$(echo "$prefix$f" | sed 's/[&\/]/\\&/g')"
 	# This outputs lines in the following format:
-	# print_ioctlent("filename.h", "IOCTL_CMD_NAME", IOCTL_CMD_NAME);
-	sed -n 's/'"$defs_regexp"'.*/print_ioctlent("'"$qf"'", "\1", \1);/p' \
+	# struct {IOCTL_CMD_NAME;} ioc_IOCTL_CMD_NAME;
+	sed -n 's/'"$defs_regexp"'.*/struct {\1;} ioc_\1;/p' \
 		< "$tmpdir"/header.out > "$tmpdir"/defs.h
 
 	# If something is wrong with the file, this will fail.
 	$CC $INCLUDES $CFLAGS -c -o "$tmpdir"/printents.o "$tmpdir"/printents.c
-	$CC $LDFLAGS -o "$tmpdir"/print_ioctlents \
-		"$tmpdir"/printents.o "$tmpdir"/print_ioctlent.o
-	"$tmpdir"/print_ioctlents > "$tmpdir"/ioctlents
+
+	readelf --wide --debug-dump=info "$tmpdir"/printents.o \
+		> "$tmpdir"/debug-dump
+
+	sed -r -n '
+		/^[[:space:]]*<1>/,/^[[:space:]]*<1><[^>]+>: Abbrev Number: 0/!d
+		/^[[:space:]]*<[^>]*><[^>]*>: Abbrev Number: 0/d
+		s/^[[:space:]]*<[[:xdigit:]]+>[[:space:]]+//
+		s/^[[:space:]]*((<[[:xdigit:]]+>){2}):[[:space:]]+/\1\n/
+		s/[[:space:]]+$//
+		p' "$tmpdir"/debug-dump > "$tmpdir"/debug-info
+	gawk -v HEADER_NAME="$prefix$f" -f "${0%/*}"/ioctls_sym.awk \
+		"$tmpdir"/debug-info > "$tmpdir"/ioctlents
+
 	cat "$tmpdir"/ioctlents
 	msg "$f: fetched $(grep -c '^{' "$tmpdir"/ioctlents) ioctl entries"
 }