Contents of /trunk/mkinitrd-magellan/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
)`

# The --gc-sections option is not supported by older versions of ld
if test -n "$GC_SECTIONS"; then
    GC_SECTIONS=`check_cc "$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	# The --gc-sections option is not supported by older versions of ld
103	if test -n "$GC_SECTIONS"; then
104	GC_SECTIONS=`check_cc "$GC_SECTIONS" ""`
105	fi
106
107	# Sanitize lib list (dups, extra spaces etc)
108	LDLIBS=`echo "$LDLIBS" \| xargs -n1 \| sort \| uniq \| xargs`
109
110	# First link with all libs. If it fails, bail out
111	echo "Trying libraries: $LDLIBS"
112	# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
113	l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
114	test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
115	try $CC $CFLAGS $LDFLAGS \
116	-o $EXE \
117	-Wl,--sort-common \
118	$SORT_SECTION \
119	$GC_SECTIONS \
120	-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
121	$l_list \
122	\|\| {
123	echo "Failed: $l_list"
124	cat $EXE.out
125	exit 1
126	}
127
128	# Now try to remove each lib and build without it.
129	# Stop when no lib can be removed.
130	while test "$LDLIBS"; do
131	$debug && echo "Trying libraries: $LDLIBS"
132	all_needed=true
133	last_needed=false
134	for one in $LDLIBS; do
135	without_one=`echo " $LDLIBS " \| sed "s/ $one / /g" \| xargs`
136	# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
137	l_list=`echo "$without_one" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
138	test x"$l_list" != x"" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
139	$debug && echo "Trying -l options: '$l_list'"
140	try $CC $CFLAGS $LDFLAGS \
141	-o $EXE \
142	-Wl,--sort-common \
143	$SORT_SECTION \
144	$GC_SECTIONS \
145	-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
146	$l_list
147	if test $? = 0; then
148	echo " Library $one is not needed, excluding it"
149	LDLIBS="$without_one"
150	all_needed=false
151	last_needed=false
152	else
153	echo " Library $one is needed, can't exclude it (yet)"
154	last_needed=true
155	fi
156	done
157	# All libs were needed, can't remove any
158	$all_needed && break
159	# Optimization: was the last tried lib needed?
160	if $last_needed; then
161	# Was it the only one lib left? Don't test again then.
162	{ echo "$LDLIBS" \| grep -q ' '; } \|\| break
163	fi
164	done
165
166	# Make the binary with final, minimal list of libs
167	echo "Final link with: ${LDLIBS:-<none>}"
168	l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
169	test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
170	# --verbose gives us gobs of info to stdout (e.g. linker script used)
171	if ! test -f busybox_ldscript; then
172	try $CC $CFLAGS $LDFLAGS \
173	-o $EXE \
174	-Wl,--sort-common \
175	$SORT_SECTION \
176	$GC_SECTIONS \
177	-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
178	$l_list \
179	-Wl,--warn-common \
180	-Wl,-Map,$EXE.map \
181	-Wl,--verbose \
182	\|\| {
183	cat $EXE.out
184	exit 1
185	}
186	else
187	echo "Custom linker script 'busybox_ldscript' found, using it"
188	# Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
189	# .rodata : { (.rodata SORT_BY_ALIGNMENT(.rodata.) .gnu.linkonce.r.*) }
190	# (.data SORT_BY_ALIGNMENT(.data.) .gnu.linkonce.d.*)
191	# (.bss SORT_BY_ALIGNMENT(.bss.) .gnu.linkonce.b.*)
192	# This will eliminate most of the padding (~3kb).
193	# Hmm, "ld --sort-section alignment" should do it too.
194	try $CC $CFLAGS $LDFLAGS \
195	-o $EXE \
196	-Wl,--sort-common \
197	$SORT_SECTION \
198	$GC_SECTIONS \
199	-Wl,-T,busybox_ldscript \
200	-Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
201	$l_list \
202	-Wl,--warn-common \
203	-Wl,-Map,$EXE.map \
204	-Wl,--verbose \
205	\|\| {
206	cat $EXE.out
207	exit 1
208	}
209	fi
210
211	. ./.config
212
213	sharedlib_dir="0_lib"
214
215	if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
216	mkdir "$sharedlib_dir" 2>/dev/null
217	test -d "$sharedlib_dir" \|\| {
218	echo "Cannot make directory $sharedlib_dir"
219	exit 1
220	}
221	ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
222
223	EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
224	try $CC $CFLAGS $LDFLAGS \
225	-o $EXE \
226	-shared -fPIC \
227	-Wl,--enable-new-dtags \
228	-Wl,-z,combreloc \
229	-Wl,-soname="libbusybox.so.$BB_VER" \
230	-Wl,--undefined=lbb_main \
231	-Wl,--sort-common \
232	$SORT_SECTION \
233	-Wl,--start-group $A_FILES -Wl,--end-group \
234	$l_list \
235	-Wl,--warn-common \
236	-Wl,-Map,$EXE.map \
237	-Wl,--verbose \
238	\|\| {
239	echo "Linking $EXE failed"
240	cat $EXE.out
241	exit 1
242	}
243	$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
244	chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
245	echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
246	fi
247
248	if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
249	EXE="$sharedlib_dir/busybox_unstripped"
250	try $CC $CFLAGS $LDFLAGS \
251	-o $EXE \
252	-Wl,--sort-common \
253	$SORT_SECTION \
254	$GC_SECTIONS \
255	-Wl,--start-group $O_FILES -Wl,--end-group \
256	-L"$sharedlib_dir" -lbusybox \
257	-Wl,--warn-common \
258	-Wl,-Map,$EXE.map \
259	-Wl,--verbose \
260	\|\| {
261	echo "Linking $EXE failed"
262	cat $EXE.out
263	exit 1
264	}
265	$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
266	echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
267	fi
268
269	if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
270	echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
271	gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
272	\| grep -v "^#" \
273	\| grep -v "^$" \
274	> applet_lst.tmp
275	while read name main junk; do
276
277	echo "\
278	void lbb_prepare(const char applet, char *argv);
279	int $main(int argc, char **argv);
280
281	int main(int argc, char **argv)
282	{
283	lbb_prepare(\"$name\", argv);
284	return $main(argc, argv);
285	}
286	" >"$sharedlib_dir/applet.c"
287
288	EXE="$sharedlib_dir/$name"
289	try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
290	-o $EXE \
291	-Wl,--sort-common \
292	$SORT_SECTION \
293	$GC_SECTIONS \
294	-L"$sharedlib_dir" -lbusybox \
295	-Wl,--warn-common \
296	\|\| {
297	echo "Linking $EXE failed"
298	cat $EXE.out
299	exit 1
300	}
301	rm -- "$sharedlib_dir/applet.c" $EXE.out
302	$STRIP -s --remove-section=.note --remove-section=.comment $EXE
303
304	done <applet_lst.tmp
305	fi
306
307	# libbusybox.so is needed only for -lbusybox at link time,
308	# it is not needed at runtime. Deleting to reduce confusion.
309	rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
310	exit 0 # or else we may confuse make