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" ""`

START_GROUP="-Wl,--start-group"
END_GROUP="-Wl,--end-group"
INFO_OPTS="-Wl,--warn-common -Wl,-Map,$EXE.map -Wl,--verbose"

# gold may not support --sort-common (yet)
SORT_COMMON=`check_cc "-Wl,--sort-common" ""`

# 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="$START_GROUP $l_list $END_GROUP"
try $CC $CFLAGS $LDFLAGS \
	-o $EXE \
	$SORT_COMMON \
	$SORT_SECTION \
	$GC_SECTIONS \
	$START_GROUP $O_FILES $A_FILES $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="$START_GROUP $l_list $END_GROUP"
	$debug && echo "Trying -l options: '$l_list'"
	try $CC $CFLAGS $LDFLAGS \
		-o $EXE \
		$SORT_COMMON \
		$SORT_SECTION \
		$GC_SECTIONS \
		$START_GROUP $O_FILES $A_FILES $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="$START_GROUP $l_list $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 \
	    $SORT_COMMON \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    $START_GROUP $O_FILES $A_FILES $END_GROUP \
	    $l_list \
	    $INFO_OPTS \
    || {
	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 \
	    $SORT_COMMON \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    -Wl,-T,busybox_ldscript \
	    $START_GROUP $O_FILES $A_FILES $END_GROUP \
	    $l_list \
	    $INFO_OPTS \
    || {
	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 \
	    $SORT_COMMON \
	    $SORT_SECTION \
	    $START_GROUP $A_FILES $END_GROUP \
	    $l_list \
	    $INFO_OPTS \
    || {
	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 \
	    $SORT_COMMON \
	    $SORT_SECTION \
	    $GC_SECTIONS \
	    $START_GROUP $O_FILES $END_GROUP \
	    -L"$sharedlib_dir" -lbusybox \
	    $INFO_OPTS \
    || {
	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 \
		$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="$7"
84
85	# The --sort-section option is not supported by older versions of ld
86	SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""`
87
88	START_GROUP="-Wl,--start-group"
89	END_GROUP="-Wl,--end-group"
90	INFO_OPTS="-Wl,--warn-common -Wl,-Map,$EXE.map -Wl,--verbose"
91
92	# gold may not support --sort-common (yet)
93	SORT_COMMON=`check_cc "-Wl,--sort-common" ""`
94
95	# Static linking against glibc produces buggy executables
96	# (glibc does not cope well with ld --gc-sections).
97	# See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
98	# Note that glibc is unsuitable for static linking anyway.
99	# We are removing -Wl,--gc-sections from link command line.
100	GC_SECTIONS=`(
101	. ./.config
102	if test x"$CONFIG_STATIC" = x"y"; then
103	check_libc_is_glibc "" "-Wl,--gc-sections"
104	else
105	echo "-Wl,--gc-sections"
106	fi
107	)`
108
109	# The --gc-sections option is not supported by older versions of ld
110	if test -n "$GC_SECTIONS"; then
111	GC_SECTIONS=`check_cc "$GC_SECTIONS" ""`
112	fi
113
114	# Sanitize lib list (dups, extra spaces etc)
115	LDLIBS=`echo "$LDLIBS" \| xargs -n1 \| sort \| uniq \| xargs`
116
117	# First link with all libs. If it fails, bail out
118	echo "Trying libraries: $LDLIBS"
119	# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
120	l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
121	test "x$l_list" != "x" && l_list="$START_GROUP $l_list $END_GROUP"
122	try $CC $CFLAGS $LDFLAGS \
123	-o $EXE \
124	$SORT_COMMON \
125	$SORT_SECTION \
126	$GC_SECTIONS \
127	$START_GROUP $O_FILES $A_FILES $END_GROUP \
128	$l_list \
129	\|\| {
130	echo "Failed: $l_list"
131	cat $EXE.out
132	exit 1
133	}
134
135	# Now try to remove each lib and build without it.
136	# Stop when no lib can be removed.
137	while test "$LDLIBS"; do
138	$debug && echo "Trying libraries: $LDLIBS"
139	all_needed=true
140	last_needed=false
141	for one in $LDLIBS; do
142	without_one=`echo " $LDLIBS " \| sed "s/ $one / /g" \| xargs`
143	# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
144	l_list=`echo "$without_one" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
145	test x"$l_list" != x"" && l_list="$START_GROUP $l_list $END_GROUP"
146	$debug && echo "Trying -l options: '$l_list'"
147	try $CC $CFLAGS $LDFLAGS \
148	-o $EXE \
149	$SORT_COMMON \
150	$SORT_SECTION \
151	$GC_SECTIONS \
152	$START_GROUP $O_FILES $A_FILES $END_GROUP \
153	$l_list
154	if test $? = 0; then
155	echo " Library $one is not needed, excluding it"
156	LDLIBS="$without_one"
157	all_needed=false
158	last_needed=false
159	else
160	echo " Library $one is needed, can't exclude it (yet)"
161	last_needed=true
162	fi
163	done
164	# All libs were needed, can't remove any
165	$all_needed && break
166	# Optimization: was the last tried lib needed?
167	if $last_needed; then
168	# Was it the only one lib left? Don't test again then.
169	{ echo "$LDLIBS" \| grep -q ' '; } \|\| break
170	fi
171	done
172
173	# Make the binary with final, minimal list of libs
174	echo "Final link with: ${LDLIBS:-<none>}"
175	l_list=`echo "$LDLIBS" \| sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
176	test "x$l_list" != "x" && l_list="$START_GROUP $l_list $END_GROUP"
177	# --verbose gives us gobs of info to stdout (e.g. linker script used)
178	if ! test -f busybox_ldscript; then
179	try $CC $CFLAGS $LDFLAGS \
180	-o $EXE \
181	$SORT_COMMON \
182	$SORT_SECTION \
183	$GC_SECTIONS \
184	$START_GROUP $O_FILES $A_FILES $END_GROUP \
185	$l_list \
186	$INFO_OPTS \
187	\|\| {
188	cat $EXE.out
189	exit 1
190	}
191	else
192	echo "Custom linker script 'busybox_ldscript' found, using it"
193	# Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
194	# .rodata : { (.rodata SORT_BY_ALIGNMENT(.rodata.) .gnu.linkonce.r.*) }
195	# (.data SORT_BY_ALIGNMENT(.data.) .gnu.linkonce.d.*)
196	# (.bss SORT_BY_ALIGNMENT(.bss.) .gnu.linkonce.b.*)
197	# This will eliminate most of the padding (~3kb).
198	# Hmm, "ld --sort-section alignment" should do it too.
199	try $CC $CFLAGS $LDFLAGS \
200	-o $EXE \
201	$SORT_COMMON \
202	$SORT_SECTION \
203	$GC_SECTIONS \
204	-Wl,-T,busybox_ldscript \
205	$START_GROUP $O_FILES $A_FILES $END_GROUP \
206	$l_list \
207	$INFO_OPTS \
208	\|\| {
209	cat $EXE.out
210	exit 1
211	}
212	fi
213
214	. ./.config
215
216	sharedlib_dir="0_lib"
217
218	if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
219	mkdir "$sharedlib_dir" 2>/dev/null
220	test -d "$sharedlib_dir" \|\| {
221	echo "Cannot make directory $sharedlib_dir"
222	exit 1
223	}
224	ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
225
226	EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
227	try $CC $CFLAGS $LDFLAGS \
228	-o $EXE \
229	-shared -fPIC \
230	-Wl,--enable-new-dtags \
231	-Wl,-z,combreloc \
232	-Wl,-soname="libbusybox.so.$BB_VER" \
233	-Wl,--undefined=lbb_main \
234	$SORT_COMMON \
235	$SORT_SECTION \
236	$START_GROUP $A_FILES $END_GROUP \
237	$l_list \
238	$INFO_OPTS \
239	\|\| {
240	echo "Linking $EXE failed"
241	cat $EXE.out
242	exit 1
243	}
244	$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
245	chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
246	echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
247	fi
248
249	if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
250	EXE="$sharedlib_dir/busybox_unstripped"
251	try $CC $CFLAGS $LDFLAGS \
252	-o $EXE \
253	$SORT_COMMON \
254	$SORT_SECTION \
255	$GC_SECTIONS \
256	$START_GROUP $O_FILES $END_GROUP \
257	-L"$sharedlib_dir" -lbusybox \
258	$INFO_OPTS \
259	\|\| {
260	echo "Linking $EXE failed"
261	cat $EXE.out
262	exit 1
263	}
264	$STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
265	echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
266	fi
267
268	if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
269	echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
270	gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
271	\| grep -v "^#" \
272	\| grep -v "^$" \
273	> applet_lst.tmp
274	while read name main junk; do
275
276	echo "\
277	void lbb_prepare(const char applet, char *argv);
278	int $main(int argc, char **argv);
279
280	int main(int argc, char **argv)
281	{
282	lbb_prepare(\"$name\", argv);
283	return $main(argc, argv);
284	}
285	" >"$sharedlib_dir/applet.c"
286
287	EXE="$sharedlib_dir/$name"
288	try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
289	-o $EXE \
290	$SORT_COMMON \
291	$SORT_SECTION \
292	$GC_SECTIONS \
293	-L"$sharedlib_dir" -lbusybox \
294	-Wl,--warn-common \
295	\|\| {
296	echo "Linking $EXE failed"
297	cat $EXE.out
298	exit 1
299	}
300	rm -- "$sharedlib_dir/applet.c" $EXE.out
301	$STRIP -s --remove-section=.note --remove-section=.comment $EXE
302
303	done <applet_lst.tmp
304	fi
305
306	# libbusybox.so is needed only for -lbusybox at link time,
307	# it is not needed at runtime. Deleting to reduce confusion.
308	rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
309	exit 0 # or else we may confuse make