Mercurial > hg
view mercurial/hook.py @ 50336:cf4d2f31660d stable
chg: populate CHGHG if not set
Normally, chg determines which `hg` executable to use by first consulting the
`$CHGHG` and `$HG` environment variables, and if neither are present defaults
to the `hg` found in the user's `$PATH`. If built with the `HGPATHREL` compiler
flag, chg will instead assume that there exists an `hg` executable in the same
directory as the `chg` binary and attempt to use that.
This can cause problems in situations where there are multiple actively-used
Mercurial installations on the same system. When a `chg` client connects to a
running command server, the server process performs some basic validation to
determine whether a new command server needs to be spawned. These checks include
things like checking certain "sensitive" environment variables and config
sections, as well as checking whether the mtime of the extensions, hg's
`__version__.py` module, and the Python interpreter have changed.
Crucially, the command server doesn't explicitly check whether the executable it
is running from matches the executable that the `chg` client would have
otherwise invoked had there been no existing command server process. Without
`HGPATHREL`, this still gets implicitly checked during the validation step,
because the only way to specify an alternate hg executable (apart from `$PATH`)
is via the `$CHGHG` and `$HG` environment variables, both of which are checked.
With `HGPATHREL`, however, the command server has no way of knowing which hg
executable the client would have run. This means that a client located at
`/version_B/bin/chg` will happily connect to a command server running
`/version_A/bin/hg` instead of `/version_B/bin/hg` as expected. A simple
solution is to have the client set `$CHGHG` itself, which then allows the
command server's environment validation to work as intended.
I have tested this manually using two locally built hg installations and it
seems to work with no ill effects. That said, I'm not sure how to write an
automated test for this since the `chg` available to the tests isn't even built
with the `HGPATHREL` compiler flag to begin with.
author | Arun Kulshreshtha <akulshreshtha@janestreet.com> |
---|---|
date | Mon, 27 Mar 2023 17:30:14 -0400 |
parents | 2761ce777fc4 |
children | c642c03969ff |
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# hook.py - hook support for mercurial # # Copyright 2007 Olivia Mackall <olivia@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import contextlib import errno import os import sys from .i18n import _ from .pycompat import getattr from . import ( demandimport, encoding, error, extensions, pycompat, util, ) from .utils import ( procutil, resourceutil, stringutil, ) def pythonhook(ui, repo, htype, hname, funcname, args, throw): """call python hook. hook is callable object, looked up as name in python module. if callable returns "true", hook fails, else passes. if hook raises exception, treated as hook failure. exception propagates if throw is "true". reason for "true" meaning "hook failed" is so that unmodified commands (e.g. mercurial.commands.update) can be run as hooks without wrappers to convert return values.""" if callable(funcname): obj = funcname funcname = pycompat.sysbytes(obj.__module__ + "." + obj.__name__) else: d = funcname.rfind(b'.') if d == -1: raise error.HookLoadError( _(b'%s hook is invalid: "%s" not in a module') % (hname, funcname) ) modname = funcname[:d] oldpaths = sys.path if resourceutil.mainfrozen(): # binary installs require sys.path manipulation modpath, modfile = os.path.split(modname) if modpath and modfile: sys.path = sys.path[:] + [modpath] modname = modfile with demandimport.deactivated(): try: obj = __import__(pycompat.sysstr(modname)) except (ImportError, SyntaxError): e1 = sys.exc_info() try: # extensions are loaded with hgext_ prefix obj = __import__("hgext_%s" % pycompat.sysstr(modname)) except (ImportError, SyntaxError): e2 = sys.exc_info() if ui.tracebackflag: ui.warn( _( b'exception from first failed import ' b'attempt:\n' ) ) ui.traceback(e1) if ui.tracebackflag: ui.warn( _( b'exception from second failed import ' b'attempt:\n' ) ) ui.traceback(e2) if not ui.tracebackflag: tracebackhint = _( b'run with --traceback for stack trace' ) else: tracebackhint = None raise error.HookLoadError( _(b'%s hook is invalid: import of "%s" failed') % (hname, modname), hint=tracebackhint, ) sys.path = oldpaths try: for p in funcname.split(b'.')[1:]: obj = getattr(obj, p) except AttributeError: raise error.HookLoadError( _(b'%s hook is invalid: "%s" is not defined') % (hname, funcname) ) if not callable(obj): raise error.HookLoadError( _(b'%s hook is invalid: "%s" is not callable') % (hname, funcname) ) ui.note(_(b"calling hook %s: %s\n") % (hname, funcname)) starttime = util.timer() try: r = obj(ui=ui, repo=repo, hooktype=htype, **pycompat.strkwargs(args)) except Exception as exc: if isinstance(exc, error.Abort): ui.warn(_(b'error: %s hook failed: %s\n') % (hname, exc.args[0])) else: ui.warn( _(b'error: %s hook raised an exception: %s\n') % (hname, stringutil.forcebytestr(exc)) ) if throw: raise if not ui.tracebackflag: ui.warn(_(b'(run with --traceback for stack trace)\n')) ui.traceback() return True, True finally: duration = util.timer() - starttime ui.log( b'pythonhook', b'pythonhook-%s: %s finished in %0.2f seconds\n', htype, funcname, duration, ) if r: if throw: raise error.HookAbort(_(b'%s hook failed') % hname) ui.warn(_(b'warning: %s hook failed\n') % hname) return r, False def _exthook(ui, repo, htype, name, cmd, args, throw): starttime = util.timer() env = {} # make in-memory changes visible to external process if repo is not None: tr = repo.currenttransaction() repo.dirstate.write(tr) if tr and tr.writepending(): env[b'HG_PENDING'] = repo.root env[b'HG_HOOKTYPE'] = htype env[b'HG_HOOKNAME'] = name if ui.config(b'hooks', b'%s:run-with-plain' % name) == b'auto': plain = ui.plain() else: plain = ui.configbool(b'hooks', b'%s:run-with-plain' % name) if plain: env[b'HGPLAIN'] = b'1' else: env[b'HGPLAIN'] = b'' for k, v in args.items(): # transaction changes can accumulate MBs of data, so skip it # for external hooks if k == b'changes': continue if callable(v): v = v() if isinstance(v, (dict, list)): v = stringutil.pprint(v) env[b'HG_' + k.upper()] = v if ui.configbool(b'hooks', b'tonative.%s' % name, False): oldcmd = cmd cmd = procutil.shelltonative(cmd, env) if cmd != oldcmd: ui.note(_(b'converting hook "%s" to native\n') % name) ui.note(_(b"running hook %s: %s\n") % (name, cmd)) if repo: cwd = repo.root else: cwd = encoding.getcwd() r = ui.system(cmd, environ=env, cwd=cwd, blockedtag=b'exthook-%s' % (name,)) if repo is not None and repo.currentwlock() is None: repo.invalidatedirstate() if repo is not None and repo.currentlock() is None: repo.invalidate() duration = util.timer() - starttime ui.log( b'exthook', b'exthook-%s: %s finished in %0.2f seconds\n', name, cmd, duration, ) if r: desc = procutil.explainexit(r) if throw: raise error.HookAbort(_(b'%s hook %s') % (name, desc)) ui.warn(_(b'warning: %s hook %s\n') % (name, desc)) return r # represent an untrusted hook command _fromuntrusted = object() def _allhooks(ui): """return a list of (hook-id, cmd) pairs sorted by priority""" hooks = _hookitems(ui) # Be careful in this section, propagating the real commands from untrusted # sources would create a security vulnerability, make sure anything altered # in that section uses "_fromuntrusted" as its command. untrustedhooks = _hookitems(ui, _untrusted=True) for name, value in untrustedhooks.items(): trustedvalue = hooks.get(name, ((), (), name, _fromuntrusted)) if value != trustedvalue: (lp, lo, lk, lv) = trustedvalue hooks[name] = (lp, lo, lk, _fromuntrusted) # (end of the security sensitive section) return [(k, v) for p, o, k, v in sorted(hooks.values())] def _hookitems(ui, _untrusted=False): """return all hooks items ready to be sorted""" hooks = {} for name, cmd in ui.configitems(b'hooks', untrusted=_untrusted): if ( name.startswith(b'priority.') or name.startswith(b'tonative.') or b':' in name ): continue priority = ui.configint(b'hooks', b'priority.%s' % name, 0) hooks[name] = ((-priority,), (len(hooks),), name, cmd) return hooks _redirect = False def redirect(state): global _redirect _redirect = state def hashook(ui, htype): """return True if a hook is configured for 'htype'""" if not ui.callhooks: return False for hname, cmd in _allhooks(ui): if hname.split(b'.')[0] == htype and cmd: return True return False def hook(ui, repo, htype, throw=False, **args): if not ui.callhooks: return False hooks = [] for hname, cmd in _allhooks(ui): if hname.split(b'.')[0] == htype and cmd: hooks.append((hname, cmd)) res = runhooks(ui, repo, htype, hooks, throw=throw, **args) r = False for hname, cmd in hooks: r = res[hname][0] or r return r @contextlib.contextmanager def redirect_stdio(): """Redirects stdout to stderr, if possible.""" oldstdout = -1 try: if _redirect: try: stdoutno = procutil.stdout.fileno() stderrno = procutil.stderr.fileno() # temporarily redirect stdout to stderr, if possible if stdoutno >= 0 and stderrno >= 0: procutil.stdout.flush() oldstdout = os.dup(stdoutno) os.dup2(stderrno, stdoutno) except (OSError, AttributeError): # files seem to be bogus, give up on redirecting (WSGI, etc) pass yield finally: # The stderr is fully buffered on Windows when connected to a pipe. # A forcible flush is required to make small stderr data in the # remote side available to the client immediately. try: procutil.stderr.flush() except IOError as err: if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF): raise error.StdioError(err) if _redirect and oldstdout >= 0: try: procutil.stdout.flush() # write hook output to stderr fd except IOError as err: if err.errno not in (errno.EPIPE, errno.EIO, errno.EBADF): raise error.StdioError(err) os.dup2(oldstdout, stdoutno) os.close(oldstdout) def runhooks(ui, repo, htype, hooks, throw=False, **args): args = pycompat.byteskwargs(args) res = {} with redirect_stdio(): for hname, cmd in hooks: if cmd is _fromuntrusted: if throw: raise error.HookAbort( _(b'untrusted hook %s not executed') % hname, hint=_(b"see 'hg help config.trusted'"), ) ui.warn(_(b'warning: untrusted hook %s not executed\n') % hname) r = 1 raised = False elif callable(cmd): r, raised = pythonhook(ui, repo, htype, hname, cmd, args, throw) elif cmd.startswith(b'python:'): if cmd.count(b':') >= 2: path, cmd = cmd[7:].rsplit(b':', 1) path = util.expandpath(path) if repo: path = os.path.join(repo.root, path) try: mod = extensions.loadpath(path, b'hghook.%s' % hname) except Exception: ui.write(_(b"loading %s hook failed:\n") % hname) raise hookfn = getattr(mod, cmd) else: hookfn = cmd[7:].strip() r, raised = pythonhook( ui, repo, htype, hname, hookfn, args, throw ) else: r = _exthook(ui, repo, htype, hname, cmd, args, throw) raised = False res[hname] = r, raised return res