Contents of /tags/mkinitrd-6_1_0/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	#!/bin/sh
2
3	debug=false
4
5	# 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	}
47
48	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