$ python evil_linker_torture.py 2000 50 100 2000000
ok so it's pretty basic, and arguments of "2000 50 10 1000000"
resulted in around a 10-15 second linker phase, which top showed to be
getting up to around the 2-3GB resident memory range. "2000 50 100
2000000" should start to make even a system with 64GB RAM start to
feel the pain.
evil_linker_torture.py N M O P generates N files with M functions
calling O randomly-selected functions where each file contains a
static char of size P that is *deliberately* put into the code segment
by being initialised with a non-zero value, exactly and precisely as
you should never do because... surpriiise! it adversely impacts the
binary size.
i'm just running the above, will hit "send" now in case i can't hit
ctrl-c in time on the linker phase... goodbye world... :)
l.
#!/usr/bin/env python
import sys
import random
maketemplate = """\
CC := gcc
CFILES:=$(shell ls | grep "\.c")
OBJS:=$(CFILES:%.c=%.o)
DEPS := $(CFILES:%.c=%.d)
CFLAGS := -g -g -g
LDFLAGS := -g -g -g
%.d: %.c
$(CC) $(CFLAGS) -MM -o $@ $<
%.o: %.c
$(CC) $(CFLAGS) -o $@ -c $<
# $(CC) $(CFLAGS) -include $(DEPS) -o $@ $<
main: $(OBJS)
$(CC) $(OBJS) $(LDFLAGS) -o main
"""
def gen_makefile():
with open("Makefile", "w") as f:
f.write(maketemplate)
def gen_headers(num_files, num_fns):
for fnum in range(num_files):
with open("hdr{}.h".format(fnum), "w") as f:
for fn_num in range(num_fns):
f.write("extern int fn_{}_{}(int arg1);\n".format(fnum, fn_num))
def gen_c_code(num_files, num_fns, num_calls, static_sz):
for fnum in range(num_files):
with open("src{}.c".format(fnum), "w") as f:
for hfnum in range(num_files):
f.write('#include "hdr{}.h"\n'.format(hfnum))
f.write('static char data[%d] = {1};\n' % static_sz)
for fn_num in range(num_fns):
f.write("int fn_%d_%d(int arg1)\n{\n" % (fnum, fn_num))
f.write("\tint arg = arg1 + 1;\n")
for nc in range(num_calls):
cnum = random.randint(0, num_fns-1)
cfile = random.randint(0, num_files-1)
f.write("\targ += fn_{}_{}(arg);\n".format(cfile, cnum))
f.write("\treturn arg;\n")
f.write("}\n")
if fnum != 0:
continue
f.write("int main(int argc, char *argv[])\n{\n")
f.write("\tint arg = 0;\n")
for nc in range(num_calls):
cnum = random.randint(0, num_fns-1)
cfile = random.randint(0, num_files-1)
f.write("\targ += fn_{}_{}(arg);\n".format(cfile, cnum))
f.write("\treturn 0;\n")
f.write("}\n")
if __name__ == '__main__':
num_files = int(sys.argv[1])
num_fns = int(sys.argv[2])
num_calls = int(sys.argv[3])
static_sz = int(sys.argv[4])
gen_makefile()
gen_headers(num_files, num_fns)
gen_c_code(num_files, num_fns, num_calls, static_sz)
