aboutsummaryrefslogtreecommitdiff
path: root/scripts/generate_BUFSIZ.sh
blob: 750fedbef8c7072ea860868dadbe6b67b8dcba1b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
#!/bin/sh
# Called from top-level directory a-la
#
# scripts/generate_BUFSIZ.sh include/common_bufsiz.h

. ./.config || exit 1

debug=false

postcompile=false
test x"$1" = x"--post" && { postcompile=true; shift; }

common_bufsiz_h=$1

test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm"
test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc"

exitcmd="exit 0"

regenerate() {
	cat >"$1.$$"
	test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return
	mv "$1.$$" "$1"
}

generate_std_and_exit() {
	$debug && echo "Configuring: bb_common_bufsiz1[] in bss"
	{
	echo "enum { COMMON_BUFSIZE = 1024 };"
	echo "extern char bb_common_bufsiz1[];"
	echo "#define setup_common_bufsiz() ((void)0)"
	} | regenerate "$common_bufsiz_h"
	echo "std" >"$common_bufsiz_h.method"
	$exitcmd
}

generate_big_and_exit() {
	$debug && echo "Configuring: bb_common_bufsiz1[] in _end[], COMMON_BUFSIZE = $1"
	{
	echo "enum { COMMON_BUFSIZE = $1 };"
	echo "extern char _end[]; /* linker-provided label */"
	echo "#define bb_common_bufsiz1 _end"
	echo "#define setup_common_bufsiz() ((void)0)"
	} | regenerate "$common_bufsiz_h"
	echo "$2" >"$common_bufsiz_h.method"
	$exitcmd
}

generate_1k_and_exit() {
	generate_big_and_exit 1024 "1k"
}


generate_malloc_and_exit() {
	$debug && echo "Configuring: bb_common_bufsiz1[] is malloced"
	{
	echo "enum { COMMON_BUFSIZE = 1024 };"
	echo "extern char *const bb_common_bufsiz1;"
	echo "void setup_common_bufsiz(void);"
	} | regenerate "$common_bufsiz_h"
	echo "malloc" >"$common_bufsiz_h.method"
	$exitcmd
}

# User does not want any funky stuff?
test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit

# The script is run two times: before compilation, when it needs to
# (re)generate $common_bufsiz_h, and directly after successful build,
# when it needs to assess whether the build is ok to use at all (not buggy),
# and (re)generate $common_bufsiz_h for a future build.

if $postcompile; then
	# Postcompile needs to create/delete OK/FAIL files

	test -f busybox_unstripped || exit 1
	test -f "$common_bufsiz_h.method" || exit 1

	# How the build was done?
	method=`cat -- "$common_bufsiz_h.method"`

	# Get _end address
	END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
	test x"$END" = x"" && generate_std_and_exit
	$debug && echo "END:0x$END $((0x$END))"
	END=$((0x$END))

	# Get PAGE_SIZE
	{
	echo "#include <sys/user.h>"
	echo "#if defined(PAGE_SIZE) && PAGE_SIZE > 0"
	echo "char page_size[PAGE_SIZE];"
	echo "#endif"
	} >page_size_$$.c
	$CC -c "page_size_$$.c" || exit 1
	PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
	rm "page_size_$$.c" "page_size_$$.o"
	test x"$PAGE_SIZE" = x"" && exit 1
	$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
	PAGE_SIZE=$((0x$PAGE_SIZE))
	test $PAGE_SIZE -lt 512 && exit 1

	# How much space between _end[] and next page?
	PAGE_MASK=$((PAGE_SIZE-1))
	COMMON_BUFSIZE=$(( (-END) & PAGE_MASK ))
	echo "COMMON_BUFSIZE = $COMMON_BUFSIZE bytes"

	if test x"$method" != x"malloc"; then
		if test $COMMON_BUFSIZE -lt 1024; then
			# _end[] has no enough space for bb_common_bufsiz1[]
			rm -- "$common_bufsiz_h.1k.OK" 2>/dev/null
			{ md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config; } >"$common_bufsiz_h.1k.FAIL"
			echo "Warning! Space in _end[] is too small ($COMMON_BUFSIZE bytes)!"
			echo "Rerun make to build a binary which doesn't use it!"
			rm busybox_unstripped busybox
			exitcmd="exit 1"
		else
			rm -- "$common_bufsiz_h.1k.FAIL" 2>/dev/null
			echo $COMMON_BUFSIZE >"$common_bufsiz_h.1k.OK"
			test $COMMON_BUFSIZE -gt $((1024+32)) && echo "Rerun make to use larger COMMON_BUFSIZE"
		fi
	fi
fi

# Based on past success/fail of 1k build, decide next build type

if test -f "$common_bufsiz_h.1k.OK"; then
	# Previous build succeeded fitting 1k into _end[].
	# Try bigger COMMON_BUFSIZE if possible.
	COMMON_BUFSIZE=`cat -- "$common_bufsiz_h.1k.OK"`
	# Round down a bit
	COMMON_BUFSIZE=$(( (COMMON_BUFSIZE-32) & 0xfffffe0 ))
	COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
	test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
	generate_big_and_exit $COMMON_BUFSIZE "big"
fi
if test -f "$common_bufsiz_h.1k.FAIL"; then
	# Previous build FAILED to fit 1k into _end[].
	# Was it with same .config?
	oldcfg=`cat -- "$common_bufsiz_h.1k.FAIL"`
	curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
	# If yes, then build a "malloced" version
	if test x"$oldcfg" = x"$curcfg"; then
		echo "Will not try 1k build, it failed before. Touch .config to override"
		generate_malloc_and_exit
	fi
	# else: try 1k version
	echo "New .config, will try 1k build"
	rm -- "$common_bufsiz_h.1k.FAIL"
	generate_1k_and_exit
fi
# There was no 1k build yet. Try it.
generate_1k_and_exit