Annotation of /tags/mkinitrd-6_1_12/busybox/scripts/trylink

#!/bin/sh

debug=false

# Linker flags used:
#
# Informational:
# --warn-common
# -Map $EXE.map
# --verbose
#
# Optimizations:
# --sort-common                 reduces padding
# --sort-section alignment      reduces padding
# --gc-sections                 throws out unused sections,
#                               does not work for shared libs
# -On                           Not used, maybe useful?
#
# List of files to link:
# $l_list                       == --start-group -llib1 -llib2 --end-group
# --start-group $O_FILES $A_FILES --end-group
#
# Shared library link:
# -shared                       self-explanatory
# -fPIC                         position-independent code
# --enable-new-dtags            ?
# -z,combreloc                  ?
# -soname="libbusybox.so.$BB_VER"
# --undefined=lbb_main          Seed name to start pulling from
#                               (otherwise we'll need --whole-archive)
# -static                       Not used, but may be useful! manpage:
#                               "... This option can be used with -shared.
#                               Doing so means that a shared library
#                               is being created but that all of the library's
#                               external references must be resolved by pulling
#                               in entries from static libraries."


try() {
    printf "%s\n" "Output of:" >$EXE.out
    printf "%s\n" "$*" >>$EXE.out
    printf "%s\n" "==========" >>$EXE.out
    $debug && echo "Trying: $*"
    $@ >>$EXE.out 2>&1
    return $?
}

check_cc() {
    local tempname="/tmp/temp.$$.$RANDOM"
    # Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :(
    # "-xc": C language. "/dev/null" is an empty source file.
    if $CC $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then
	echo "$1";
    else
	echo "$2";
    fi
    rm "$tempname".o 2>/dev/null
}

check_libc_is_glibc() {
    local tempname="/tmp/temp.$$.$RANDOM"
    echo "\
	#include <stdlib.h>
	/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
	#if defined(__GLIBC__) && !defined(__UCLIBC__)
	syntax error here
	#endif
	" >"$tempname".c
    if $CC "$tempname".c -c -o "$tempname".o >/dev/null 2>&1; then
	echo "$2";
    else
	echo "$1";
    fi
    rm "$tempname".c "$tempname".o 2>/dev/null
}

EXE="$1"
CC="$2"
CFLAGS="$3"
LDFLAGS="$4"
O_FILES="$5"
A_FILES="$6"
LDLIBS="$7"

# The --sort-section option is not supported by older versions of ld
SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""`

# Static linking against glibc produces buggy executables
# (glibc does not cope well with ld --gc-sections).
# See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
# Note that glibc is unsuitable for static linking anyway.
# We are removing -Wl,--gc-sections from link command line.
GC_SECTIONS=`(
. ./.config
if test x"$CONFIG_STATIC" = x"y"; then
    check_libc_is_glibc "" "-Wl,--gc-sections"
else
    echo "-Wl,--gc-sections"
fi
)`

# Sanitize lib list (dups, extra spaces etc)
LDLIBS=`echo "$LDLIBS" | xargs -n1 | sort | uniq | xargs`

# First link with all libs. If it fails, bail out
echo "Trying libraries: $LDLIBS"
# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
try $CC $CFLAGS $LDFLAGS \
	-o $EXE \
	-Wl,--sort-common \
	$SORT_SECTION \
	$GC_SECTIONS \
	-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
	$l_list \
|| {
    echo "Failed: $l_list"
    cat $EXE.out
    exit 1
}

# Now try to remove each lib and build without it.
# Stop when no lib can be removed.
while test "$LDLIBS"; do
    $debug && echo "Trying libraries: $LDLIBS"
    all_needed=true
    last_needed=false
    for one in $LDLIBS; do
	without_one=`echo " $LDLIBS " | sed "s/ $one / /g" | xargs`
	# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
	l_list=`echo "$without_one" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
	test x"$l_list" != x"" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
	$debug && echo "Trying -l options: '$l_list'"
	try $CC $CFLAGS $LDFLAGS \
		-o $EXE \
		-Wl,--sort-common \
		$SORT_SECTION \
		$GC_SECTIONS \
		-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
		$l_list
	if test $? = 0; then
	    echo " Library $one is not needed, excluding it"
	    LDLIBS="$without_one"
	    all_needed=false
	    last_needed=false
	else
	    echo " Library $one is needed, can't exclude it (yet)"
	    last_needed=true
	fi
    done
    # All libs were needed, can't remove any
    $all_needed && break
    # Optimization: was the last tried lib needed?
    if $last_needed; then
	# Was it the only one lib left? Don't test again then.
	{ echo "$LDLIBS" | grep -q ' '; } || break
    fi
done

# Make the binary with final, minimal list of libs
echo "Final link with: ${LDLIBS:-<none>}"
l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
# --verbose gives us gobs of info to stdout (e.g. linker script used)
if ! test -f busybox_ldscript; then
    try $CC $CFLAGS $LDFLAGS \
	    -o $EXE \
	    -Wl,--sort-common \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
	    $l_list \
	    -Wl,--warn-common \
	    -Wl,-Map,$EXE.map \
	    -Wl,--verbose \
    || {
	cat $EXE.out
	exit 1
    }
else
    echo "Custom linker script 'busybox_ldscript' found, using it"
    # Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
    #  .rodata         : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) }
    #  *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*)
    #  *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*)
    # This will eliminate most of the padding (~3kb).
    # Hmm, "ld --sort-section alignment" should do it too.
    try $CC $CFLAGS $LDFLAGS \
	    -o $EXE \
	    -Wl,--sort-common \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    -Wl,-T,busybox_ldscript \
	    -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
	    $l_list \
	    -Wl,--warn-common \
	    -Wl,-Map,$EXE.map \
	    -Wl,--verbose \
    || {
	cat $EXE.out
	exit 1
    }
fi

. ./.config

sharedlib_dir="0_lib"

if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
    mkdir "$sharedlib_dir" 2>/dev/null
    test -d "$sharedlib_dir" || {
	echo "Cannot make directory $sharedlib_dir"
	exit 1
    }
    ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null

    EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
    try $CC $CFLAGS $LDFLAGS \
	    -o $EXE \
	    -shared -fPIC \
	    -Wl,--enable-new-dtags \
	    -Wl,-z,combreloc \
	    -Wl,-soname="libbusybox.so.$BB_VER" \
	    -Wl,--undefined=lbb_main \
	    -Wl,--sort-common \
	    $SORT_SECTION \
	    -Wl,--start-group $A_FILES -Wl,--end-group \
	    $l_list \
	    -Wl,--warn-common \
	    -Wl,-Map,$EXE.map \
	    -Wl,--verbose \
    || {
	echo "Linking $EXE failed"
	cat $EXE.out
	exit 1
    }
    $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
    chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
    echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
fi

if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
    EXE="$sharedlib_dir/busybox_unstripped"
    try $CC $CFLAGS $LDFLAGS \
	    -o $EXE \
	    -Wl,--sort-common \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    -Wl,--start-group $O_FILES -Wl,--end-group \
	    -L"$sharedlib_dir" -lbusybox \
	    -Wl,--warn-common \
	    -Wl,-Map,$EXE.map \
	    -Wl,--verbose \
    || {
	echo "Linking $EXE failed"
	cat $EXE.out
	exit 1
    }
    $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
    echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
fi

if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
    echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
    gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
    | grep -v "^#" \
    | grep -v "^$" \
    > applet_lst.tmp
    while read name main junk; do

	echo "\
void lbb_prepare(const char *applet, char **argv);
int $main(int argc, char **argv);

int main(int argc, char **argv)
{
	lbb_prepare(\"$name\", argv);
	return $main(argc, argv);
}
" >"$sharedlib_dir/applet.c"

	EXE="$sharedlib_dir/$name"
	try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
		-o $EXE \
		-Wl,--sort-common \
		$SORT_SECTION \
		$GC_SECTIONS \
		-L"$sharedlib_dir" -lbusybox \
		-Wl,--warn-common \
	|| {
	    echo "Linking $EXE failed"
	    cat $EXE.out
	    exit 1
	}
	rm -- "$sharedlib_dir/applet.c" $EXE.out
	$STRIP -s --remove-section=.note --remove-section=.comment $EXE

    done <applet_lst.tmp
fi

# libbusybox.so is needed only for -lbusybox at link time,
# it is not needed at runtime. Deleting to reduce confusion.
rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
exit 0 # or else we may confuse make
1	niro	532	#!/bin/sh
2
3			debug=false
4
5	niro	816	# Linker flags used:
6			#
7			# Informational:
8			# --warn-common
9			# -Map $EXE.map
10			# --verbose
11			#
12			# Optimizations:
13			# --sort-common reduces padding
14			# --sort-section alignment reduces padding
15			# --gc-sections throws out unused sections,
16			# does not work for shared libs
17			# -On Not used, maybe useful?
18			#
19			# List of files to link:
20			# $l_list == --start-group -llib1 -llib2 --end-group
21			# --start-group $O_FILES $A_FILES --end-group
22			#
23			# Shared library link:
24			# -shared self-explanatory
25			# -fPIC position-independent code
26			# --enable-new-dtags ?
27			# -z,combreloc ?
28			# -soname="libbusybox.so.$BB_VER"
29			# --undefined=lbb_main Seed name to start pulling from
30			# (otherwise we'll need --whole-archive)
31			# -static Not used, but may be useful! manpage:
32			# "... This option can be used with -shared.
33			# Doing so means that a shared library
34			# is being created but that all of the library's
35			# external references must be resolved by pulling
36			# in entries from static libraries."
37
38
39			try() {
40			printf "%s\n" "Output of:" >$EXE.out
41			printf "%s\n" "$*" >>$EXE.out
42			printf "%s\n" "==========" >>$EXE.out
43			$debug && echo "Trying: $*"
44			$@ >>$EXE.out 2>&1
45			return $?
46	niro	532	}
47
48	niro	816	check_cc() {
49			local tempname="/tmp/temp.$$.$RANDOM"
50			# Can use "-o /dev/null", but older gcc tend to unlink it on failure! :(
51			# "-xc": C language. "/dev/null" is an empty source file.
52			if $CC $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then
53			echo "$1";
54			else
55			echo "$2";
56			fi
57			rm "$tempname".o 2>/dev/null
58			}
59
60			check_libc_is_glibc() {
61			local tempname="/tmp/temp.$$.$RANDOM"
62			echo "\
63			#include <stdlib.h>
64			/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
65			#if defined(__GLIBC__) && !defined(__UCLIBC__)
66			syntax error here
67			#endif
68			" >"$tempname".c
69			if $CC "$tempname".c -c -o "$tempname".o >/dev/null 2>&1; then
70			echo "$2";
71			else
72			echo "$1";
73			fi
74			rm "$tempname".c "$tempname".o 2>/dev/null
75			}
76
77			EXE="$1"
78			CC="$2"
79			CFLAGS="$3"
80			LDFLAGS="$4"
81			O_FILES="$5"
82			A_FILES="$6"
83			LDLIBS="$7"
84
85			# The --sort-section option is not supported by older versions of ld
86			SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""`
87
88			# Static linking against glibc produces buggy executables
89			# (glibc does not cope well with ld --gc-sections).
90			# See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
91			# Note that glibc is unsuitable for static linking anyway.
92			# We are removing -Wl,--gc-sections from link command line.
93			GC_SECTIONS=`(
94			. ./.config
95			if test x"$CONFIG_STATIC" = x"y"; then
96			check_libc_is_glibc "" "-Wl,--gc-sections"
97			else
98			echo "-Wl,--gc-sections"
99			fi
100			)`
101
102			# Sanitize lib list (dups, extra spaces etc)
103			LDLIBS=`echo "$LDLIBS" \| xargs -n1 \| sort \| uniq \| xargs`
104
105			# First link with all libs. If it fails, bail out
106			echo "Trying libraries: $LDLIBS"
107			# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
108			l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
109			test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
110			try $CC $CFLAGS $LDFLAGS \
111			-o $EXE \
112			-Wl,--sort-common \
113			$SORT_SECTION \
114			$GC_SECTIONS \
115			-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
116			$l_list \
117			\|\| {
118			echo "Failed: $l_list"
119			cat $EXE.out
120			exit 1
121			}
122
123			# Now try to remove each lib and build without it.
124			# Stop when no lib can be removed.
125			while test "$LDLIBS"; do
126			$debug && echo "Trying libraries: $LDLIBS"
127			all_needed=true
128			last_needed=false
129			for one in $LDLIBS; do
130			without_one=`echo " $LDLIBS " \| sed "s/ $one / /g" \| xargs`
131			# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
132			l_list=`echo "$without_one" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
133			test x"$l_list" != x"" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
134			$debug && echo "Trying -l options: '$l_list'"
135			try $CC $CFLAGS $LDFLAGS \
136			-o $EXE \
137			-Wl,--sort-common \
138			$SORT_SECTION \
139			$GC_SECTIONS \
140			-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
141			$l_list
142			if test $? = 0; then
143			echo " Library $one is not needed, excluding it"
144			LDLIBS="$without_one"
145			all_needed=false
146			last_needed=false
147			else
148			echo " Library $one is needed, can't exclude it (yet)"
149			last_needed=true
150			fi
151			done
152			# All libs were needed, can't remove any
153			$all_needed && break
154			# Optimization: was the last tried lib needed?
155			if $last_needed; then
156			# Was it the only one lib left? Don't test again then.
157			{ echo "$LDLIBS" \| grep -q ' '; } \|\| break
158			fi
159			done
160
161			# Make the binary with final, minimal list of libs
162			echo "Final link with: ${LDLIBS:-<none>}"
163			l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
164			test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
165			# --verbose gives us gobs of info to stdout (e.g. linker script used)
166			if ! test -f busybox_ldscript; then
167			try $CC $CFLAGS $LDFLAGS \
168			-o $EXE \
169			-Wl,--sort-common \
170			$SORT_SECTION \
171			$GC_SECTIONS \
172			-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
173			$l_list \
174			-Wl,--warn-common \
175			-Wl,-Map,$EXE.map \
176			-Wl,--verbose \
177			\|\| {
178			cat $EXE.out
179			exit 1
180			}
181			else
182			echo "Custom linker script 'busybox_ldscript' found, using it"
183			# Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
184			# .rodata : { (.rodata SORT_BY_ALIGNMENT(.rodata.) .gnu.linkonce.r.*) }
185			# (.data SORT_BY_ALIGNMENT(.data.) .gnu.linkonce.d.*)
186			# (.bss SORT_BY_ALIGNMENT(.bss.) .gnu.linkonce.b.*)
187			# This will eliminate most of the padding (~3kb).
188			# Hmm, "ld --sort-section alignment" should do it too.
189			try $CC $CFLAGS $LDFLAGS \
190			-o $EXE \
191			-Wl,--sort-common \
192			$SORT_SECTION \
193			$GC_SECTIONS \
194			-Wl,-T,busybox_ldscript \
195			-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
196			$l_list \
197			-Wl,--warn-common \
198			-Wl,-Map,$EXE.map \
199			-Wl,--verbose \
200			\|\| {
201			cat $EXE.out
202			exit 1
203			}
204			fi
205
206			. ./.config
207
208			sharedlib_dir="0_lib"
209
210			if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
211			mkdir "$sharedlib_dir" 2>/dev/null
212			test -d "$sharedlib_dir" \|\| {
213			echo "Cannot make directory $sharedlib_dir"
214			exit 1
215			}
216			ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
217
218			EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
219			try $CC $CFLAGS $LDFLAGS \
220			-o $EXE \
221			-shared -fPIC \
222			-Wl,--enable-new-dtags \
223			-Wl,-z,combreloc \
224			-Wl,-soname="libbusybox.so.$BB_VER" \
225			-Wl,--undefined=lbb_main \
226			-Wl,--sort-common \
227			$SORT_SECTION \
228			-Wl,--start-group $A_FILES -Wl,--end-group \
229			$l_list \
230			-Wl,--warn-common \
231			-Wl,-Map,$EXE.map \
232			-Wl,--verbose \
233			\|\| {
234			echo "Linking $EXE failed"
235			cat $EXE.out
236			exit 1
237			}
238			$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
239			chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
240			echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
241			fi
242
243			if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
244			EXE="$sharedlib_dir/busybox_unstripped"
245			try $CC $CFLAGS $LDFLAGS \
246			-o $EXE \
247			-Wl,--sort-common \
248			$SORT_SECTION \
249			$GC_SECTIONS \
250			-Wl,--start-group $O_FILES -Wl,--end-group \
251			-L"$sharedlib_dir" -lbusybox \
252			-Wl,--warn-common \
253			-Wl,-Map,$EXE.map \
254			-Wl,--verbose \
255			\|\| {
256			echo "Linking $EXE failed"
257			cat $EXE.out
258			exit 1
259			}
260			$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
261			echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
262			fi
263
264			if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
265			echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
266			gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
267			\| grep -v "^#" \
268			\| grep -v "^$" \
269			> applet_lst.tmp
270			while read name main junk; do
271
272			echo "\
273			void lbb_prepare(const char applet, char *argv);
274			int $main(int argc, char **argv);
275
276			int main(int argc, char **argv)
277			{
278			lbb_prepare(\"$name\", argv);
279			return $main(argc, argv);
280			}
281			" >"$sharedlib_dir/applet.c"
282
283			EXE="$sharedlib_dir/$name"
284			try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
285			-o $EXE \
286			-Wl,--sort-common \
287			$SORT_SECTION \
288			$GC_SECTIONS \
289			-L"$sharedlib_dir" -lbusybox \
290			-Wl,--warn-common \
291			\|\| {
292			echo "Linking $EXE failed"
293			cat $EXE.out
294			exit 1
295			}
296			rm -- "$sharedlib_dir/applet.c" $EXE.out
297			$STRIP -s --remove-section=.note --remove-section=.comment $EXE
298
299			done <applet_lst.tmp
300			fi
301
302			# libbusybox.so is needed only for -lbusybox at link time,
303			# it is not needed at runtime. Deleting to reduce confusion.
304			rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
305			exit 0 # or else we may confuse make