1 files changed, 659 insertions, 0 deletions
diff --git a/buildtools/wafsamba/symbols.py b/buildtools/wafsamba/symbols.py
new file mode 100644
index 0000000..5fbc072
--- /dev/null
+++ b/buildtools/wafsamba/symbols.py
@@ -0,0 +1,659 @@
+# a waf tool to extract symbols from object files or libraries
+# using nm, producing a set of exposed defined/undefined symbols
+
+import os, re, subprocess
+from waflib import Utils, Build, Options, Logs, Errors
+from waflib.Logs import debug
+from samba_utils import TO_LIST, LOCAL_CACHE, get_tgt_list
+
+# these are the data structures used in symbols.py:
+#
+# bld.env.symbol_map : dictionary mapping public symbol names to list of
+#                      subsystem names where that symbol exists
+#
+# t.in_library       : list of libraries that t is in
+#
+# bld.env.public_symbols: set of public symbols for each subsystem
+# bld.env.used_symbols  : set of used symbols for each subsystem
+#
+# bld.env.syslib_symbols: dictionary mapping system library name to set of symbols
+#                         for that library
+# bld.env.library_dict  : dictionary mapping built library paths to subsystem names
+#
+# LOCAL_CACHE(bld, 'TARGET_TYPE') : dictionary mapping subsystem name to target type
+
+
+def symbols_extract(bld, objfiles, dynamic=False):
+    '''extract symbols from objfile, returning a dictionary containing
+       the set of undefined and public symbols for each file'''
+
+    ret = {}
+
+    # see if we can get some results from the nm cache
+    if not bld.env.nm_cache:
+        bld.env.nm_cache = {}
+
+    objfiles = set(objfiles).copy()
+
+    remaining = set()
+    for obj in objfiles:
+        if obj in bld.env.nm_cache:
+            ret[obj] = bld.env.nm_cache[obj].copy()
+        else:
+            remaining.add(obj)
+    objfiles = remaining
+
+    if len(objfiles) == 0:
+        return ret
+
+    cmd = ["nm"]
+    if dynamic:
+        # needed for some .so files
+        cmd.append("-D")
+    cmd.extend(list(objfiles))
+
+    nmpipe = subprocess.Popen(cmd, stdout=subprocess.PIPE).stdout
+    if len(objfiles) == 1:
+        filename = list(objfiles)[0]
+        ret[filename] = { "PUBLIC": set(), "UNDEFINED" : set()}
+
+    for line in nmpipe:
+        line = line.strip()
+        if line.endswith(b':'):
+            filename = line[:-1]
+            ret[filename] = { "PUBLIC": set(), "UNDEFINED" : set() }
+            continue
+        cols = line.split(b" ")
+        if cols == [b'']:
+            continue
+        # see if the line starts with an address
+        if len(cols) == 3:
+            symbol_type = cols[1]
+            symbol = cols[2]
+        else:
+            symbol_type = cols[0]
+            symbol = cols[1]
+        if symbol_type in b"BDGTRVWSi":
+            # its a public symbol
+            ret[filename]["PUBLIC"].add(symbol)
+        elif symbol_type in b"U":
+            ret[filename]["UNDEFINED"].add(symbol)
+
+    # add to the cache
+    for obj in objfiles:
+        if obj in ret:
+            bld.env.nm_cache[obj] = ret[obj].copy()
+        else:
+            bld.env.nm_cache[obj] = { "PUBLIC": set(), "UNDEFINED" : set() }
+
+    return ret
+
+
+def real_name(name):
+    if name.find(".objlist") != -1:
+        name = name[:-8]
+    return name
+
+
+def find_ldd_path(bld, libname, binary):
+    '''find the path to the syslib we will link against'''
+    ret = None
+    if not bld.env.syslib_paths:
+        bld.env.syslib_paths = {}
+    if libname in bld.env.syslib_paths:
+        return bld.env.syslib_paths[libname]
+
+    lddpipe = subprocess.Popen(['ldd', binary], stdout=subprocess.PIPE).stdout
+    for line in lddpipe:
+        line = line.strip()
+        cols = line.split(b" ")
+        if len(cols) < 3 or cols[1] != b"=>":
+            continue
+        if cols[0].startswith(b"libc."):
+            # save this one too
+            bld.env.libc_path = cols[2]
+        if cols[0].startswith(libname):
+            ret = cols[2]
+    bld.env.syslib_paths[libname] = ret
+    return ret
+
+
+# some regular expressions for parsing readelf output
+re_sharedlib = re.compile(rb'Shared library: \[(.*)\]')
+# output from readelf could be `Library rpath` or `Libray runpath`
+re_rpath     = re.compile(rb'Library (rpath|runpath): \[(.*)\]')
+
+def get_libs(bld, binname):
+    '''find the list of linked libraries for any binary or library
+    binname is the path to the binary/library on disk
+
+    We do this using readelf instead of ldd as we need to avoid recursing
+    into system libraries
+    '''
+
+    # see if we can get the result from the ldd cache
+    if not bld.env.lib_cache:
+        bld.env.lib_cache = {}
+    if binname in bld.env.lib_cache:
+        return bld.env.lib_cache[binname].copy()
+
+    rpath = []
+    libs = set()
+
+    elfpipe = subprocess.Popen(['readelf', '--dynamic', binname], stdout=subprocess.PIPE).stdout
+    for line in elfpipe:
+        m = re_sharedlib.search(line)
+        if m:
+            libs.add(m.group(1))
+        m = re_rpath.search(line)
+        if m:
+            # output from Popen is always bytestr even in py3
+            rpath.extend(m.group(2).split(b":"))
+
+    ret = set()
+    for lib in libs:
+        found = False
+        for r in rpath:
+            path = os.path.join(r, lib)
+            if os.path.exists(path):
+                ret.add(os.path.realpath(path))
+                found = True
+                break
+        if not found:
+            # we didn't find this lib using rpath. It is probably a system
+            # library, so to find the path to it we either need to use ldd
+            # or we need to start parsing /etc/ld.so.conf* ourselves. We'll
+            # use ldd for now, even though it is slow
+            path = find_ldd_path(bld, lib, binname)
+            if path:
+                ret.add(os.path.realpath(path))
+
+    bld.env.lib_cache[binname] = ret.copy()
+
+    return ret
+
+
+def get_libs_recursive(bld, binname, seen):
+    '''find the recursive list of linked libraries for any binary or library
+    binname is the path to the binary/library on disk. seen is a set used
+    to prevent loops
+    '''
+    if binname in seen:
+        return set()
+    ret = get_libs(bld, binname)
+    seen.add(binname)
+    for lib in ret:
+        # we don't want to recurse into system libraries. If a system
+        # library that we use (eg. libcups) happens to use another library
+        # (such as libkrb5) which contains common symbols with our own
+        # libraries, then that is not an error
+        if lib in bld.env.library_dict:
+            ret = ret.union(get_libs_recursive(bld, lib, seen))
+    return ret
+
+
+
+def find_syslib_path(bld, libname, deps):
+    '''find the path to the syslib we will link against'''
+    # the strategy is to use the targets that depend on the library, and run ldd
+    # on it to find the real location of the library that is used
+
+    linkpath = deps[0].link_task.outputs[0].abspath(bld.env)
+
+    if libname == "python":
+        libname += bld.env.PYTHON_VERSION
+
+    return find_ldd_path(bld, "lib%s" % libname.lower(), linkpath)
+
+
+def build_symbol_sets(bld, tgt_list):
+    '''build the public_symbols and undefined_symbols attributes for each target'''
+
+    if bld.env.public_symbols:
+        return
+
+    objlist = []  # list of object file
+    objmap = {}   # map from object filename to target (subsystem) name
+
+    for t in tgt_list:
+        t.public_symbols = set()
+        t.undefined_symbols = set()
+        t.used_symbols = set()
+        for tsk in getattr(t, 'compiled_tasks', []):
+            for output in tsk.outputs:
+                objpath = output.abspath(bld.env)
+                objlist.append(objpath)
+                objmap[objpath] = t
+
+    symbols = symbols_extract(bld, objlist)
+    for obj in objlist:
+        t = objmap[obj]
+        t.public_symbols = t.public_symbols.union(symbols[obj]["PUBLIC"])
+        t.undefined_symbols = t.undefined_symbols.union(symbols[obj]["UNDEFINED"])
+        t.used_symbols = t.used_symbols.union(symbols[obj]["UNDEFINED"])
+
+    t.undefined_symbols = t.undefined_symbols.difference(t.public_symbols)
+
+    # and the reverse map of public symbols to subsystem name
+    bld.env.symbol_map = {}
+
+    for t in tgt_list:
+        for s in t.public_symbols:
+            if not s in bld.env.symbol_map:
+                bld.env.symbol_map[s] = []
+            bld.env.symbol_map[s].append(real_name(t.sname))
+
+    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
+
+    bld.env.public_symbols = {}
+    for t in tgt_list:
+        name = real_name(t.sname)
+        if name in bld.env.public_symbols:
+            bld.env.public_symbols[name] = bld.env.public_symbols[name].union(t.public_symbols)
+        else:
+            bld.env.public_symbols[name] = t.public_symbols
+        if t.samba_type in ['LIBRARY', 'PLUGIN']:
+            for dep in t.add_objects:
+                t2 = bld.get_tgen_by_name(dep)
+                bld.ASSERT(t2 is not None, "Library '%s' has unknown dependency '%s'" % (name, dep))
+                bld.env.public_symbols[name] = bld.env.public_symbols[name].union(t2.public_symbols)
+
+    bld.env.used_symbols = {}
+    for t in tgt_list:
+        name = real_name(t.sname)
+        if name in bld.env.used_symbols:
+            bld.env.used_symbols[name] = bld.env.used_symbols[name].union(t.used_symbols)
+        else:
+            bld.env.used_symbols[name] = t.used_symbols
+        if t.samba_type in ['LIBRARY', 'PLUGIN']:
+            for dep in t.add_objects:
+                t2 = bld.get_tgen_by_name(dep)
+                bld.ASSERT(t2 is not None, "Library '%s' has unknown dependency '%s'" % (name, dep))
+                bld.env.used_symbols[name] = bld.env.used_symbols[name].union(t2.used_symbols)
+
+
+def build_library_dict(bld, tgt_list):
+    '''build the library_dict dictionary'''
+
+    if bld.env.library_dict:
+        return
+
+    bld.env.library_dict = {}
+
+    for t in tgt_list:
+        if t.samba_type in [ 'LIBRARY', 'PLUGIN', 'PYTHON' ]:
+            linkpath = os.path.realpath(t.link_task.outputs[0].abspath(bld.env))
+            bld.env.library_dict[linkpath] = t.sname
+
+
+def build_syslib_sets(bld, tgt_list):
+    '''build the public_symbols for all syslibs'''
+
+    if bld.env.syslib_symbols:
+        return
+
+    # work out what syslibs we depend on, and what targets those are used in
+    syslibs = {}
+    objmap = {}
+    for t in tgt_list:
+        if getattr(t, 'uselib', []) and t.samba_type in [ 'LIBRARY', 'PLUGIN', 'BINARY', 'PYTHON' ]:
+            for lib in t.uselib:
+                if lib in ['PYEMBED', 'PYEXT']:
+                    lib = "python"
+                if not lib in syslibs:
+                    syslibs[lib] = []
+                syslibs[lib].append(t)
+
+    # work out the paths to each syslib
+    syslib_paths = []
+    for lib in syslibs:
+        path = find_syslib_path(bld, lib, syslibs[lib])
+        if path is None:
+            Logs.warn("Unable to find syslib path for %s" % lib)
+        if path is not None:
+            syslib_paths.append(path)
+            objmap[path] = lib.lower()
+
+    # add in libc
+    syslib_paths.append(bld.env.libc_path)
+    objmap[bld.env.libc_path] = 'c'
+
+    symbols = symbols_extract(bld, syslib_paths, dynamic=True)
+
+    # keep a map of syslib names to public symbols
+    bld.env.syslib_symbols = {}
+    for lib in symbols:
+        bld.env.syslib_symbols[lib] = symbols[lib]["PUBLIC"]
+
+    # add to the map of symbols to dependencies
+    for lib in symbols:
+        for sym in symbols[lib]["PUBLIC"]:
+            if not sym in bld.env.symbol_map:
+                bld.env.symbol_map[sym] = []
+            bld.env.symbol_map[sym].append(objmap[lib])
+
+    # keep the libc symbols as well, as these are useful for some of the
+    # sanity checks
+    bld.env.libc_symbols = symbols[bld.env.libc_path]["PUBLIC"]
+
+    # add to the combined map of dependency name to public_symbols
+    for lib in bld.env.syslib_symbols:
+        bld.env.public_symbols[objmap[lib]] = bld.env.syslib_symbols[lib]
+
+
+def build_autodeps(bld, t):
+    '''build the set of dependencies for a target'''
+    deps = set()
+    name = real_name(t.sname)
+
+    targets    = LOCAL_CACHE(bld, 'TARGET_TYPE')
+
+    for sym in t.undefined_symbols:
+        if sym in t.public_symbols:
+            continue
+        if sym in bld.env.symbol_map:
+            depname = bld.env.symbol_map[sym]
+            if depname == [ name ]:
+                # self dependencies aren't interesting
+                continue
+            if t.in_library == depname:
+                # no need to depend on the library we are part of
+                continue
+            if depname[0] in ['c', 'python']:
+                # these don't go into autodeps
+                continue
+            if targets[depname[0]] in [ 'SYSLIB' ]:
+                deps.add(depname[0])
+                continue
+            t2 = bld.get_tgen_by_name(depname[0])
+            if len(t2.in_library) != 1:
+                deps.add(depname[0])
+                continue
+            if t2.in_library == t.in_library:
+                # if we're part of the same library, we don't need to autodep
+                continue
+            deps.add(t2.in_library[0])
+    t.autodeps = deps
+
+
+def build_library_names(bld, tgt_list):
+    '''add a in_library attribute to all targets that are part of a library'''
+
+    if bld.env.done_build_library_names:
+        return
+
+    for t in tgt_list:
+        t.in_library = []
+
+    for t in tgt_list:
+        if t.samba_type in ['LIBRARY', 'PLUGIN']:
+            for obj in t.samba_deps_extended:
+                t2 = bld.get_tgen_by_name(obj)
+                if t2 and t2.samba_type in [ 'SUBSYSTEM', 'BUILTIN', 'ASN1' ]:
+                    if not t.sname in t2.in_library:
+                        t2.in_library.append(t.sname)
+    bld.env.done_build_library_names = True
+
+
+def check_library_deps(bld, t):
+    '''check that all the autodeps that have mutual dependency of this
+    target are in the same library as the target'''
+
+    name = real_name(t.sname)
+
+    if len(t.in_library) > 1:
+        Logs.warn("WARNING: Target '%s' in multiple libraries: %s" % (t.sname, t.in_library))
+
+    for dep in t.autodeps:
+        t2 = bld.get_tgen_by_name(dep)
+        if t2 is None:
+            continue
+        for dep2 in t2.autodeps:
+            if dep2 == name and t.in_library != t2.in_library:
+                Logs.warn("WARNING: mutual dependency %s <=> %s" % (name, real_name(t2.sname)))
+                Logs.warn("Libraries should match. %s != %s" % (t.in_library, t2.in_library))
+                # raise Errors.WafError("illegal mutual dependency")
+
+
+def check_syslib_collisions(bld, tgt_list):
+    '''check if a target has any symbol collisions with a syslib
+
+    We do not want any code in Samba to use a symbol name from a
+    system library. The chance of that causing problems is just too
+    high. Note that libreplace uses a rep_XX approach of renaming
+    symbols via macros
+    '''
+
+    has_error = False
+    for t in tgt_list:
+        for lib in bld.env.syslib_symbols:
+            common = t.public_symbols.intersection(bld.env.syslib_symbols[lib])
+            if common:
+                Logs.error("ERROR: Target '%s' has symbols '%s' which is also in syslib '%s'" % (t.sname, common, lib))
+                has_error = True
+    if has_error:
+        raise Errors.WafError("symbols in common with system libraries")
+
+
+def check_dependencies(bld, t):
+    '''check for depenencies that should be changed'''
+
+    if bld.get_tgen_by_name(t.sname + ".objlist"):
+        return
+
+    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
+
+    remaining = t.undefined_symbols.copy()
+    remaining = remaining.difference(t.public_symbols)
+
+    sname = real_name(t.sname)
+
+    deps = set(t.samba_deps)
+    for d in t.samba_deps:
+        if targets[d] in [ 'EMPTY', 'DISABLED', 'SYSLIB', 'GENERATOR' ]:
+            continue
+        bld.ASSERT(d in bld.env.public_symbols, "Failed to find symbol list for dependency '%s'" % d)
+        diff = remaining.intersection(bld.env.public_symbols[d])
+        if not diff and targets[sname] != 'LIBRARY':
+            Logs.info("Target '%s' has no dependency on %s" % (sname, d))
+        else:
+            remaining = remaining.difference(diff)
+
+    t.unsatisfied_symbols = set()
+    needed = {}
+    for sym in remaining:
+        if sym in bld.env.symbol_map:
+            dep = bld.env.symbol_map[sym]
+            if not dep[0] in needed:
+                needed[dep[0]] = set()
+            needed[dep[0]].add(sym)
+        else:
+            t.unsatisfied_symbols.add(sym)
+
+    for dep in needed:
+        Logs.info("Target '%s' should add dep '%s' for symbols %s" % (sname, dep, " ".join(needed[dep])))
+
+
+
+def check_syslib_dependencies(bld, t):
+    '''check for syslib depenencies'''
+
+    if bld.get_tgen_by_name(t.sname + ".objlist"):
+        return
+
+    sname = real_name(t.sname)
+
+    remaining = set()
+
+    features = TO_LIST(t.features)
+    if 'pyembed' in features or 'pyext' in features:
+        if 'python' in bld.env.public_symbols:
+            t.unsatisfied_symbols = t.unsatisfied_symbols.difference(bld.env.public_symbols['python'])
+
+    needed = {}
+    for sym in t.unsatisfied_symbols:
+        if sym in bld.env.symbol_map:
+            dep = bld.env.symbol_map[sym][0]
+            if dep == 'c':
+                continue
+            if not dep in needed:
+                needed[dep] = set()
+            needed[dep].add(sym)
+        else:
+            remaining.add(sym)
+
+    for dep in needed:
+        Logs.info("Target '%s' should add syslib dep '%s' for symbols %s" % (sname, dep, " ".join(needed[dep])))
+
+    if remaining:
+        debug("deps: Target '%s' has unsatisfied symbols: %s" % (sname, " ".join(remaining)))
+
+
+
+def symbols_symbolcheck(task):
+    '''check the internal dependency lists'''
+    bld = task.env.bld
+    tgt_list = get_tgt_list(bld)
+
+    build_symbol_sets(bld, tgt_list)
+    build_library_names(bld, tgt_list)
+
+    for t in tgt_list:
+        t.autodeps = set()
+        if getattr(t, 'source', ''):
+            build_autodeps(bld, t)
+
+    for t in tgt_list:
+        check_dependencies(bld, t)
+
+    for t in tgt_list:
+        check_library_deps(bld, t)
+
+def symbols_syslibcheck(task):
+    '''check the syslib dependencies'''
+    bld = task.env.bld
+    tgt_list = get_tgt_list(bld)
+
+    build_syslib_sets(bld, tgt_list)
+    check_syslib_collisions(bld, tgt_list)
+
+    for t in tgt_list:
+        check_syslib_dependencies(bld, t)
+
+
+def symbols_whyneeded(task):
+    """check why 'target' needs to link to 'subsystem'"""
+    bld = task.env.bld
+    tgt_list = get_tgt_list(bld)
+
+    why = Options.options.WHYNEEDED.split(":")
+    if len(why) != 2:
+        raise Errors.WafError("usage: WHYNEEDED=TARGET:DEPENDENCY")
+    target = why[0]
+    subsystem = why[1]
+
+    build_symbol_sets(bld, tgt_list)
+    build_library_names(bld, tgt_list)
+    build_syslib_sets(bld, tgt_list)
+
+    Logs.info("Checking why %s needs to link to %s" % (target, subsystem))
+    if not target in bld.env.used_symbols:
+        Logs.warn("unable to find target '%s' in used_symbols dict" % target)
+        return
+    if not subsystem in bld.env.public_symbols:
+        Logs.warn("unable to find subsystem '%s' in public_symbols dict" % subsystem)
+        return
+    overlap = bld.env.used_symbols[target].intersection(bld.env.public_symbols[subsystem])
+    if not overlap:
+        Logs.info("target '%s' doesn't use any public symbols from '%s'" % (target, subsystem))
+    else:
+        Logs.info("target '%s' uses symbols %s from '%s'" % (target, overlap, subsystem))
+
+
+def report_duplicate(bld, binname, sym, libs, fail_on_error):
+    '''report duplicated symbols'''
+    if sym in ['_init', '_fini', '_edata', '_end', '__bss_start']:
+        return
+    libnames = []
+    for lib in libs:
+        if lib in bld.env.library_dict:
+            libnames.append(bld.env.library_dict[lib])
+        else:
+            libnames.append(lib)
+    if fail_on_error:
+        raise Errors.WafError("%s: Symbol %s linked in multiple libraries %s" % (binname, sym, libnames))
+    else:
+        print("%s: Symbol %s linked in multiple libraries %s" % (binname, sym, libnames))
+
+
+def symbols_dupcheck_binary(bld, binname, fail_on_error):
+    '''check for duplicated symbols in one binary'''
+
+    libs = get_libs_recursive(bld, binname, set())
+    symlist = symbols_extract(bld, libs, dynamic=True)
+
+    symmap = {}
+    for libpath in symlist:
+        for sym in symlist[libpath]['PUBLIC']:
+            if sym == '_GLOBAL_OFFSET_TABLE_':
+                continue
+            if not sym in symmap:
+                symmap[sym] = set()
+            symmap[sym].add(libpath)
+    for sym in symmap:
+        if len(symmap[sym]) > 1:
+            for libpath in symmap[sym]:
+                if libpath in bld.env.library_dict:
+                    report_duplicate(bld, binname, sym, symmap[sym], fail_on_error)
+                    break
+
+def symbols_dupcheck(task, fail_on_error=False):
+    '''check for symbols defined in two different subsystems'''
+    bld = task.env.bld
+    tgt_list = get_tgt_list(bld)
+
+    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
+
+    build_library_dict(bld, tgt_list)
+    for t in tgt_list:
+        if t.samba_type == 'BINARY':
+            binname = os.path.relpath(t.link_task.outputs[0].abspath(bld.env), os.getcwd())
+            symbols_dupcheck_binary(bld, binname, fail_on_error)
+
+
+def symbols_dupcheck_fatal(task):
+    '''check for symbols defined in two different subsystems (and fail if duplicates are found)'''
+    symbols_dupcheck(task, fail_on_error=True)
+
+
+def SYMBOL_CHECK(bld):
+    '''check our dependency lists'''
+    if Options.options.SYMBOLCHECK:
+        bld.SET_BUILD_GROUP('symbolcheck')
+        task = bld(rule=symbols_symbolcheck, always=True, name='symbol checking')
+        task.env.bld = bld
+
+        bld.SET_BUILD_GROUP('syslibcheck')
+        task = bld(rule=symbols_syslibcheck, always=True, name='syslib checking')
+        task.env.bld = bld
+
+        bld.SET_BUILD_GROUP('syslibcheck')
+        task = bld(rule=symbols_dupcheck, always=True, name='symbol duplicate checking')
+        task.env.bld = bld
+
+    if Options.options.WHYNEEDED:
+        bld.SET_BUILD_GROUP('syslibcheck')
+        task = bld(rule=symbols_whyneeded, always=True, name='check why a dependency is needed')
+        task.env.bld = bld
+
+
+Build.BuildContext.SYMBOL_CHECK = SYMBOL_CHECK
+
+def DUP_SYMBOL_CHECK(bld):
+    if Options.options.DUP_SYMBOLCHECK and bld.env.DEVELOPER:
+        '''check for duplicate symbols'''
+        bld.SET_BUILD_GROUP('syslibcheck')
+        task = bld(rule=symbols_dupcheck_fatal, always=True, name='symbol duplicate checking')
+        task.env.bld = bld
+
+Build.BuildContext.DUP_SYMBOL_CHECK = DUP_SYMBOL_CHECK