m2-internship/dwarf-assembly
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Refactor python shared snippets

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This commit is contained in:
Théophile Bastian 2018-05-09 17:55:57 +02:00
parent 066f1f06c1
commit 789e79613c
4 changed files with 126 additions and 96 deletions
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1
.gitignore vendored
View file

@ -32,3 +32,4 @@
*.app
dwarf-assembly
__pycache__

6
compare_sizes.py
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@ -9,7 +9,7 @@ import os
import subprocess
from collections import namedtuple
from generate_eh_elf import elf_so_deps
from shared_python import elf_so_deps
''' An ELF object, including the path to the ELF itself, and the path to its
@ -41,11 +41,11 @@ def section_size(elf_loc, section_name):
except subprocess.CalledProcessError as exn:
raise Exception(("Cannot obtain section {} size for {}: objdump "
"terminated with exit code {}.").format(
section_name, elf_loc))
section_name, elf_loc, exn.returncode))
for line in objdump_out.split('\n'):
line = line.strip()
if not line or not ('0' <= line[0] <= '9'): # not a section line
if not line or not '0' <= line[0] <= '9': # not a section line
continue
spl = line.split()

99
generate_eh_elf.py
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@ -9,10 +9,10 @@ all the shared objects it depends upon.
import os
import sys
import subprocess
import re
import tempfile
import argparse
from collections import namedtuple
from shared_python import elf_so_deps, do_remote, is_newer
DWARF_ASSEMBLY_BIN = os.path.join(
@ -23,33 +23,6 @@ C_BIN = (
else os.environ['C'])
def elf_so_deps(path):
''' Get the list of shared objects dependencies of the given ELF object.
This is obtained by running `ldd`. '''
deps_list = []
try:
ldd_output = subprocess.check_output(['/usr/bin/ldd', path]) \
.decode('utf-8')
ldd_re = re.compile(r'^.* => (.*) \(0x[0-9a-fA-F]*\)$')
ldd_lines = ldd_output.strip().split('\n')
for line in ldd_lines:
line = line.strip()
match = ldd_re.match(line)
if match is None:
continue # Just ignore that line — it might be eg. linux-vdso
deps_list.append(match.group(1))
return deps_list
except subprocess.CalledProcessError as e:
raise Exception(
("Cannot get dependencies for {}: ldd terminated with exit code "
"{}.").format(path, e.returncode))
def gen_dw_asm_c(obj_path, out_path, dwarf_assembly_args):
''' Generate the C code produced by dwarf-assembly from `obj_path`, saving
it as `out_path` '''
@ -61,66 +34,13 @@ def gen_dw_asm_c(obj_path, out_path, dwarf_assembly_args):
[DWARF_ASSEMBLY_BIN, obj_path] + dwarf_assembly_args) \
.decode('utf-8')
out_handle.write(dw_asm_output)
except subprocess.CalledProcessError as e:
except subprocess.CalledProcessError as exn:
raise Exception(
("Cannot generate C code from object file {} using {}: process "
"terminated with exit code {}.").format(
obj_path,
DWARF_ASSEMBLY_BIN,
e.returncode))
def do_remote(remote, command, send_files=None, retr_files=None):
def ssh_do(cmd_args, working_directory=None):
try:
cmd = ['ssh', remote]
if working_directory:
cmd += ['cd', working_directory, '&&']
cmd += cmd_args
return subprocess.check_output(cmd).decode('utf-8').strip()
except subprocess.CalledProcessError as e:
return None
def ssh_copy(what, where, is_upload):
if is_upload:
where = '{}:{}'.format(remote, where)
else:
what = '{}:{}'.format(remote, what)
subprocess.check_output(['scp', what, where])
TransferredFile = namedtuple('TransferredFile', 'local remote')
def interpret_transferred_file(descr):
if type(descr) == type(''):
return TransferredFile(descr, descr)
if os.path.isdir(descr[1]):
to = os.path.join(descr[1], descr[0])
else:
to = descr[1]
return TransferredFile(descr[0], to)
# Create temp dir
tmp_dir = ssh_do(['mktemp', '-d'])
# Upload `send_files`
for f in send_files:
dest = tmp_dir+'/'
ssh_copy(f, dest, is_upload=True)
# Do whatever must be done
output = ssh_do(command, working_directory=tmp_dir)
# Download `retr_files`
for f in map(interpret_transferred_file, retr_files):
src = os.path.join(tmp_dir, f.local)
ssh_copy(src, f.remote, is_upload=False)
# Remove temp dir
ssh_do(['rm', '-rf', tmp_dir])
return output
exn.returncode))
def gen_eh_elf(obj_path, args, dwarf_assembly_args=None):
@ -141,15 +61,8 @@ def gen_eh_elf(obj_path, args, dwarf_assembly_args=None):
out_base_name = os.path.basename(obj_path) + '.eh_elf'
out_so_path = os.path.join(out_dir, (out_base_name + '.so'))
try:
so_mtime = os.path.getmtime(out_so_path)
obj_mtime = os.path.getmtime(obj_path)
if obj_mtime < so_mtime:
return # The object is recent enough, no need to recreate it
except OSError:
pass
if is_newer(out_so_path, obj_path):
return # The object is recent enough, no need to recreate it
with tempfile.TemporaryDirectory() as compile_dir:
# Generate the C source file

116
shared_python.py Normal file
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@ -0,0 +1,116 @@
""" Shared snippets between the various python scripts of this project """
import subprocess
import re
import os
from collections import namedtuple
def is_newer(file1, file2):
''' Returns True iff file1 is newer than file2 '''
try:
f1_mtime = os.path.getmtime(file1)
f2_mtime = os.path.getmtime(file2)
if f1_mtime > f2_mtime:
return True
except OSError:
pass
return False
def elf_so_deps(path):
''' Get the list of shared objects dependencies of the given ELF object.
This is obtained by running `ldd`. '''
deps_list = []
try:
ldd_output = subprocess.check_output(['/usr/bin/ldd', path]) \
.decode('utf-8')
ldd_re = re.compile(r'^.* => (.*) \(0x[0-9a-fA-F]*\)$')
ldd_lines = ldd_output.strip().split('\n')
for line in ldd_lines:
line = line.strip()
match = ldd_re.match(line)
if match is None:
continue # Just ignore that line — it might be eg. linux-vdso
deps_list.append(match.group(1))
return deps_list
except subprocess.CalledProcessError as exn:
raise Exception(
("Cannot get dependencies for {}: ldd terminated with exit code "
"{}.").format(path, exn.returncode))
def do_remote(remote, command, send_files=None, retr_files=None):
''' Execute remotely (via ssh) a given command
The command is executed on the machine described by `remote` (see ssh(1)).
send_files is a list of file paths that must be first copied at the root of
a temporary directory on `remote` before running the command. Consider
yourself jailed in that directory.
retr_files is a list of files that will be copied to the local machine
after the command is executed. Each list item can either be a string, which
is both the path on the remote and the local machine; or a pair
`(file_name, local_path)`. In the latter case, `file_name` is copied as
`local_path/file_name` if `local_path` is a directory, or as `local_path`
otherwise, on the local machine.
'''
def ssh_do(cmd_args, working_directory=None):
try:
cmd = ['ssh', remote]
if working_directory:
cmd += ['cd', working_directory, '&&']
cmd += cmd_args
return subprocess.check_output(cmd).decode('utf-8').strip()
except subprocess.CalledProcessError as e:
return None
def ssh_copy(what, where, is_upload):
if is_upload:
where = '{}:{}'.format(remote, where)
else:
what = '{}:{}'.format(remote, what)
subprocess.check_output(['scp', what, where])
TransferredFile = namedtuple('TransferredFile', 'local remote')
def interpret_transferred_file(descr):
if isinstance(descr, type('')):
return TransferredFile(descr, descr)
if os.path.isdir(descr[1]):
to = os.path.join(descr[1], descr[0])
else:
to = descr[1]
return TransferredFile(descr[0], to)
# Create temp dir
tmp_dir = ssh_do(['mktemp', '-d'])
# Upload `send_files`
for f in send_files:
dest = tmp_dir+'/'
ssh_copy(f, dest, is_upload=True)
# Do whatever must be done
output = ssh_do(command, working_directory=tmp_dir)
# Download `retr_files`
for f in map(interpret_transferred_file, retr_files):
src = os.path.join(tmp_dir, f.local)
ssh_copy(src, f.remote, is_upload=False)
# Remove temp dir
ssh_do(['rm', '-rf', tmp_dir])
return output