1 # a waf tool to extract symbols from object files or libraries
2 # using nm, producing a set of exposed defined/undefined symbols
4 import os, re, subprocess
5 from waflib import Utils, Build, Options, Logs, Errors
6 from waflib.Logs import debug
7 from samba_utils import TO_LIST, LOCAL_CACHE, get_tgt_list, os_path_relpath
9 # these are the data structures used in symbols.py:
11 # bld.env.symbol_map : dictionary mapping public symbol names to list of
12 # subsystem names where that symbol exists
14 # t.in_library : list of libraries that t is in
16 # bld.env.public_symbols: set of public symbols for each subsystem
17 # bld.env.used_symbols : set of used symbols for each subsystem
19 # bld.env.syslib_symbols: dictionary mapping system library name to set of symbols
21 # bld.env.library_dict : dictionary mapping built library paths to subsystem names
23 # LOCAL_CACHE(bld, 'TARGET_TYPE') : dictionary mapping subsystem name to target type
26 def symbols_extract(bld, objfiles, dynamic=False):
27 '''extract symbols from objfile, returning a dictionary containing
28 the set of undefined and public symbols for each file'''
32 # see if we can get some results from the nm cache
33 if not bld.env.nm_cache:
36 objfiles = set(objfiles).copy()
40 if obj in bld.env.nm_cache:
41 ret[obj] = bld.env.nm_cache[obj].copy()
46 if len(objfiles) == 0:
51 # needed for some .so files
53 cmd.extend(list(objfiles))
55 nmpipe = subprocess.Popen(cmd, stdout=subprocess.PIPE).stdout
56 if len(objfiles) == 1:
57 filename = list(objfiles)[0]
58 ret[filename] = { "PUBLIC": set(), "UNDEFINED" : set()}
62 if line.endswith(b':'):
64 ret[filename] = { "PUBLIC": set(), "UNDEFINED" : set() }
66 cols = line.split(b" ")
69 # see if the line starts with an address
76 if symbol_type in b"BDGTRVWSi":
78 ret[filename]["PUBLIC"].add(symbol)
79 elif symbol_type in b"U":
80 ret[filename]["UNDEFINED"].add(symbol)
85 bld.env.nm_cache[obj] = ret[obj].copy()
87 bld.env.nm_cache[obj] = { "PUBLIC": set(), "UNDEFINED" : set() }
93 if name.find(".objlist") != -1:
98 def find_ldd_path(bld, libname, binary):
99 '''find the path to the syslib we will link against'''
101 if not bld.env.syslib_paths:
102 bld.env.syslib_paths = {}
103 if libname in bld.env.syslib_paths:
104 return bld.env.syslib_paths[libname]
106 lddpipe = subprocess.Popen(['ldd', binary], stdout=subprocess.PIPE).stdout
109 cols = line.split(b" ")
110 if len(cols) < 3 or cols[1] != b"=>":
112 if cols[0].startswith(b"libc."):
114 bld.env.libc_path = cols[2]
115 if cols[0].startswith(libname):
117 bld.env.syslib_paths[libname] = ret
121 # some regular expressions for parsing readelf output
122 re_sharedlib = re.compile(b'Shared library: \[(.*)\]')
123 re_rpath = re.compile(b'Library rpath: \[(.*)\]')
125 def get_libs(bld, binname):
126 '''find the list of linked libraries for any binary or library
127 binname is the path to the binary/library on disk
129 We do this using readelf instead of ldd as we need to avoid recursing
130 into system libraries
133 # see if we can get the result from the ldd cache
134 if not bld.env.lib_cache:
135 bld.env.lib_cache = {}
136 if binname in bld.env.lib_cache:
137 return bld.env.lib_cache[binname].copy()
142 elfpipe = subprocess.Popen(['readelf', '--dynamic', binname], stdout=subprocess.PIPE).stdout
144 m = re_sharedlib.search(line)
147 m = re_rpath.search(line)
149 # output from Popen is always bytestr even in py3
150 rpath.extend(m.group(1).split(b":"))
156 path = os.path.join(r, lib)
157 if os.path.exists(path):
158 ret.add(os.path.realpath(path))
162 # we didn't find this lib using rpath. It is probably a system
163 # library, so to find the path to it we either need to use ldd
164 # or we need to start parsing /etc/ld.so.conf* ourselves. We'll
165 # use ldd for now, even though it is slow
166 path = find_ldd_path(bld, lib, binname)
168 ret.add(os.path.realpath(path))
170 bld.env.lib_cache[binname] = ret.copy()
175 def get_libs_recursive(bld, binname, seen):
176 '''find the recursive list of linked libraries for any binary or library
177 binname is the path to the binary/library on disk. seen is a set used
182 ret = get_libs(bld, binname)
185 # we don't want to recurse into system libraries. If a system
186 # library that we use (eg. libcups) happens to use another library
187 # (such as libkrb5) which contains common symbols with our own
188 # libraries, then that is not an error
189 if lib in bld.env.library_dict:
190 ret = ret.union(get_libs_recursive(bld, lib, seen))
195 def find_syslib_path(bld, libname, deps):
196 '''find the path to the syslib we will link against'''
197 # the strategy is to use the targets that depend on the library, and run ldd
198 # on it to find the real location of the library that is used
200 linkpath = deps[0].link_task.outputs[0].abspath(bld.env)
202 if libname == "python":
203 libname += bld.env.PYTHON_VERSION
205 return find_ldd_path(bld, "lib%s" % libname.lower(), linkpath)
208 def build_symbol_sets(bld, tgt_list):
209 '''build the public_symbols and undefined_symbols attributes for each target'''
211 if bld.env.public_symbols:
214 objlist = [] # list of object file
215 objmap = {} # map from object filename to target (subsystem) name
218 t.public_symbols = set()
219 t.undefined_symbols = set()
220 t.used_symbols = set()
221 for tsk in getattr(t, 'compiled_tasks', []):
222 for output in tsk.outputs:
223 objpath = output.abspath(bld.env)
224 objlist.append(objpath)
227 symbols = symbols_extract(bld, objlist)
230 t.public_symbols = t.public_symbols.union(symbols[obj]["PUBLIC"])
231 t.undefined_symbols = t.undefined_symbols.union(symbols[obj]["UNDEFINED"])
232 t.used_symbols = t.used_symbols.union(symbols[obj]["UNDEFINED"])
234 t.undefined_symbols = t.undefined_symbols.difference(t.public_symbols)
236 # and the reverse map of public symbols to subsystem name
237 bld.env.symbol_map = {}
240 for s in t.public_symbols:
241 if not s in bld.env.symbol_map:
242 bld.env.symbol_map[s] = []
243 bld.env.symbol_map[s].append(real_name(t.sname))
245 targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
247 bld.env.public_symbols = {}
249 name = real_name(t.sname)
250 if name in bld.env.public_symbols:
251 bld.env.public_symbols[name] = bld.env.public_symbols[name].union(t.public_symbols)
253 bld.env.public_symbols[name] = t.public_symbols
254 if t.samba_type == 'LIBRARY':
255 for dep in t.add_objects:
256 t2 = bld.get_tgen_by_name(dep)
257 bld.ASSERT(t2 is not None, "Library '%s' has unknown dependency '%s'" % (name, dep))
258 bld.env.public_symbols[name] = bld.env.public_symbols[name].union(t2.public_symbols)
260 bld.env.used_symbols = {}
262 name = real_name(t.sname)
263 if name in bld.env.used_symbols:
264 bld.env.used_symbols[name] = bld.env.used_symbols[name].union(t.used_symbols)
266 bld.env.used_symbols[name] = t.used_symbols
267 if t.samba_type == 'LIBRARY':
268 for dep in t.add_objects:
269 t2 = bld.get_tgen_by_name(dep)
270 bld.ASSERT(t2 is not None, "Library '%s' has unknown dependency '%s'" % (name, dep))
271 bld.env.used_symbols[name] = bld.env.used_symbols[name].union(t2.used_symbols)
274 def build_library_dict(bld, tgt_list):
275 '''build the library_dict dictionary'''
277 if bld.env.library_dict:
280 bld.env.library_dict = {}
283 if t.samba_type in [ 'LIBRARY', 'PYTHON' ]:
284 linkpath = os.path.realpath(t.link_task.outputs[0].abspath(bld.env))
285 bld.env.library_dict[linkpath] = t.sname
288 def build_syslib_sets(bld, tgt_list):
289 '''build the public_symbols for all syslibs'''
291 if bld.env.syslib_symbols:
294 # work out what syslibs we depend on, and what targets those are used in
298 if getattr(t, 'uselib', []) and t.samba_type in [ 'LIBRARY', 'BINARY', 'PYTHON' ]:
300 if lib in ['PYEMBED', 'PYEXT']:
302 if not lib in syslibs:
304 syslibs[lib].append(t)
306 # work out the paths to each syslib
309 path = find_syslib_path(bld, lib, syslibs[lib])
311 Logs.warn("Unable to find syslib path for %s" % lib)
313 syslib_paths.append(path)
314 objmap[path] = lib.lower()
317 syslib_paths.append(bld.env.libc_path)
318 objmap[bld.env.libc_path] = 'c'
320 symbols = symbols_extract(bld, syslib_paths, dynamic=True)
322 # keep a map of syslib names to public symbols
323 bld.env.syslib_symbols = {}
325 bld.env.syslib_symbols[lib] = symbols[lib]["PUBLIC"]
327 # add to the map of symbols to dependencies
329 for sym in symbols[lib]["PUBLIC"]:
330 if not sym in bld.env.symbol_map:
331 bld.env.symbol_map[sym] = []
332 bld.env.symbol_map[sym].append(objmap[lib])
334 # keep the libc symbols as well, as these are useful for some of the
336 bld.env.libc_symbols = symbols[bld.env.libc_path]["PUBLIC"]
338 # add to the combined map of dependency name to public_symbols
339 for lib in bld.env.syslib_symbols:
340 bld.env.public_symbols[objmap[lib]] = bld.env.syslib_symbols[lib]
343 def build_autodeps(bld, t):
344 '''build the set of dependencies for a target'''
346 name = real_name(t.sname)
348 targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
350 for sym in t.undefined_symbols:
351 if sym in t.public_symbols:
353 if sym in bld.env.symbol_map:
354 depname = bld.env.symbol_map[sym]
355 if depname == [ name ]:
356 # self dependencies aren't interesting
358 if t.in_library == depname:
359 # no need to depend on the library we are part of
361 if depname[0] in ['c', 'python']:
362 # these don't go into autodeps
364 if targets[depname[0]] in [ 'SYSLIB' ]:
367 t2 = bld.get_tgen_by_name(depname[0])
368 if len(t2.in_library) != 1:
371 if t2.in_library == t.in_library:
372 # if we're part of the same library, we don't need to autodep
374 deps.add(t2.in_library[0])
378 def build_library_names(bld, tgt_list):
379 '''add a in_library attribute to all targets that are part of a library'''
381 if bld.env.done_build_library_names:
388 if t.samba_type in [ 'LIBRARY' ]:
389 for obj in t.samba_deps_extended:
390 t2 = bld.get_tgen_by_name(obj)
391 if t2 and t2.samba_type in [ 'SUBSYSTEM', 'ASN1' ]:
392 if not t.sname in t2.in_library:
393 t2.in_library.append(t.sname)
394 bld.env.done_build_library_names = True
397 def check_library_deps(bld, t):
398 '''check that all the autodeps that have mutual dependency of this
399 target are in the same library as the target'''
401 name = real_name(t.sname)
403 if len(t.in_library) > 1:
404 Logs.warn("WARNING: Target '%s' in multiple libraries: %s" % (t.sname, t.in_library))
406 for dep in t.autodeps:
407 t2 = bld.get_tgen_by_name(dep)
410 for dep2 in t2.autodeps:
411 if dep2 == name and t.in_library != t2.in_library:
412 Logs.warn("WARNING: mutual dependency %s <=> %s" % (name, real_name(t2.sname)))
413 Logs.warn("Libraries should match. %s != %s" % (t.in_library, t2.in_library))
414 # raise Errors.WafError("illegal mutual dependency")
417 def check_syslib_collisions(bld, tgt_list):
418 '''check if a target has any symbol collisions with a syslib
420 We do not want any code in Samba to use a symbol name from a
421 system library. The chance of that causing problems is just too
422 high. Note that libreplace uses a rep_XX approach of renaming
428 for lib in bld.env.syslib_symbols:
429 common = t.public_symbols.intersection(bld.env.syslib_symbols[lib])
431 Logs.error("ERROR: Target '%s' has symbols '%s' which is also in syslib '%s'" % (t.sname, common, lib))
434 raise Errors.WafError("symbols in common with system libraries")
437 def check_dependencies(bld, t):
438 '''check for depenencies that should be changed'''
440 if bld.get_tgen_by_name(t.sname + ".objlist"):
443 targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
445 remaining = t.undefined_symbols.copy()
446 remaining = remaining.difference(t.public_symbols)
448 sname = real_name(t.sname)
450 deps = set(t.samba_deps)
451 for d in t.samba_deps:
452 if targets[d] in [ 'EMPTY', 'DISABLED', 'SYSLIB', 'GENERATOR' ]:
454 bld.ASSERT(d in bld.env.public_symbols, "Failed to find symbol list for dependency '%s'" % d)
455 diff = remaining.intersection(bld.env.public_symbols[d])
456 if not diff and targets[sname] != 'LIBRARY':
457 Logs.info("Target '%s' has no dependency on %s" % (sname, d))
459 remaining = remaining.difference(diff)
461 t.unsatisfied_symbols = set()
463 for sym in remaining:
464 if sym in bld.env.symbol_map:
465 dep = bld.env.symbol_map[sym]
466 if not dep[0] in needed:
467 needed[dep[0]] = set()
468 needed[dep[0]].add(sym)
470 t.unsatisfied_symbols.add(sym)
473 Logs.info("Target '%s' should add dep '%s' for symbols %s" % (sname, dep, " ".join(needed[dep])))
477 def check_syslib_dependencies(bld, t):
478 '''check for syslib depenencies'''
480 if bld.get_tgen_by_name(t.sname + ".objlist"):
483 sname = real_name(t.sname)
487 features = TO_LIST(t.features)
488 if 'pyembed' in features or 'pyext' in features:
489 if 'python' in bld.env.public_symbols:
490 t.unsatisfied_symbols = t.unsatisfied_symbols.difference(bld.env.public_symbols['python'])
493 for sym in t.unsatisfied_symbols:
494 if sym in bld.env.symbol_map:
495 dep = bld.env.symbol_map[sym][0]
498 if not dep in needed:
505 Logs.info("Target '%s' should add syslib dep '%s' for symbols %s" % (sname, dep, " ".join(needed[dep])))
508 debug("deps: Target '%s' has unsatisfied symbols: %s" % (sname, " ".join(remaining)))
512 def symbols_symbolcheck(task):
513 '''check the internal dependency lists'''
515 tgt_list = get_tgt_list(bld)
517 build_symbol_sets(bld, tgt_list)
518 build_library_names(bld, tgt_list)
522 if getattr(t, 'source', ''):
523 build_autodeps(bld, t)
526 check_dependencies(bld, t)
529 check_library_deps(bld, t)
531 def symbols_syslibcheck(task):
532 '''check the syslib dependencies'''
534 tgt_list = get_tgt_list(bld)
536 build_syslib_sets(bld, tgt_list)
537 check_syslib_collisions(bld, tgt_list)
540 check_syslib_dependencies(bld, t)
543 def symbols_whyneeded(task):
544 """check why 'target' needs to link to 'subsystem'"""
546 tgt_list = get_tgt_list(bld)
548 why = Options.options.WHYNEEDED.split(":")
550 raise Errors.WafError("usage: WHYNEEDED=TARGET:DEPENDENCY")
554 build_symbol_sets(bld, tgt_list)
555 build_library_names(bld, tgt_list)
556 build_syslib_sets(bld, tgt_list)
558 Logs.info("Checking why %s needs to link to %s" % (target, subsystem))
559 if not target in bld.env.used_symbols:
560 Logs.warn("unable to find target '%s' in used_symbols dict" % target)
562 if not subsystem in bld.env.public_symbols:
563 Logs.warn("unable to find subsystem '%s' in public_symbols dict" % subsystem)
565 overlap = bld.env.used_symbols[target].intersection(bld.env.public_symbols[subsystem])
567 Logs.info("target '%s' doesn't use any public symbols from '%s'" % (target, subsystem))
569 Logs.info("target '%s' uses symbols %s from '%s'" % (target, overlap, subsystem))
572 def report_duplicate(bld, binname, sym, libs, fail_on_error):
573 '''report duplicated symbols'''
574 if sym in ['_init', '_fini', '_edata', '_end', '__bss_start']:
578 if lib in bld.env.library_dict:
579 libnames.append(bld.env.library_dict[lib])
583 raise Errors.WafError("%s: Symbol %s linked in multiple libraries %s" % (binname, sym, libnames))
585 print("%s: Symbol %s linked in multiple libraries %s" % (binname, sym, libnames))
588 def symbols_dupcheck_binary(bld, binname, fail_on_error):
589 '''check for duplicated symbols in one binary'''
591 libs = get_libs_recursive(bld, binname, set())
592 symlist = symbols_extract(bld, libs, dynamic=True)
595 for libpath in symlist:
596 for sym in symlist[libpath]['PUBLIC']:
597 if sym == '_GLOBAL_OFFSET_TABLE_':
599 if not sym in symmap:
601 symmap[sym].add(libpath)
603 if len(symmap[sym]) > 1:
604 for libpath in symmap[sym]:
605 if libpath in bld.env.library_dict:
606 report_duplicate(bld, binname, sym, symmap[sym], fail_on_error)
609 def symbols_dupcheck(task, fail_on_error=False):
610 '''check for symbols defined in two different subsystems'''
612 tgt_list = get_tgt_list(bld)
614 targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
616 build_library_dict(bld, tgt_list)
618 if t.samba_type == 'BINARY':
619 binname = os_path_relpath(t.link_task.outputs[0].abspath(bld.env), os.getcwd())
620 symbols_dupcheck_binary(bld, binname, fail_on_error)
623 def symbols_dupcheck_fatal(task):
624 '''check for symbols defined in two different subsystems (and fail if duplicates are found)'''
625 symbols_dupcheck(task, fail_on_error=True)
628 def SYMBOL_CHECK(bld):
629 '''check our dependency lists'''
630 if Options.options.SYMBOLCHECK:
631 bld.SET_BUILD_GROUP('symbolcheck')
632 task = bld(rule=symbols_symbolcheck, always=True, name='symbol checking')
635 bld.SET_BUILD_GROUP('syslibcheck')
636 task = bld(rule=symbols_syslibcheck, always=True, name='syslib checking')
639 bld.SET_BUILD_GROUP('syslibcheck')
640 task = bld(rule=symbols_dupcheck, always=True, name='symbol duplicate checking')
643 if Options.options.WHYNEEDED:
644 bld.SET_BUILD_GROUP('syslibcheck')
645 task = bld(rule=symbols_whyneeded, always=True, name='check why a dependency is needed')
649 Build.BuildContext.SYMBOL_CHECK = SYMBOL_CHECK
651 def DUP_SYMBOL_CHECK(bld):
652 if Options.options.DUP_SYMBOLCHECK and bld.env.DEVELOPER:
653 '''check for duplicate symbols'''
654 bld.SET_BUILD_GROUP('syslibcheck')
655 task = bld(rule=symbols_dupcheck_fatal, always=True, name='symbol duplicate checking')
658 Build.BuildContext.DUP_SYMBOL_CHECK = DUP_SYMBOL_CHECK