blob: ceb94945dc8bed2a6e28321208cd8b09b7acf2f0 [file] [log] [blame]
xf.li86118912025-03-19 20:07:27 -07001"""distutils.spawn
2
3Provides the 'spawn()' function, a front-end to various platform-
4specific functions for launching another program in a sub-process.
5Also provides the 'find_executable()' to search the path for a given
6executable name.
7"""
8
9import sys
10import os
11
12from distutils.errors import DistutilsPlatformError, DistutilsExecError
13from distutils.debug import DEBUG
14from distutils import log
15
16def spawn(cmd, search_path=1, verbose=0, dry_run=0):
17 """Run another program, specified as a command list 'cmd', in a new process.
18
19 'cmd' is just the argument list for the new process, ie.
20 cmd[0] is the program to run and cmd[1:] are the rest of its arguments.
21 There is no way to run a program with a name different from that of its
22 executable.
23
24 If 'search_path' is true (the default), the system's executable
25 search path will be used to find the program; otherwise, cmd[0]
26 must be the exact path to the executable. If 'dry_run' is true,
27 the command will not actually be run.
28
29 Raise DistutilsExecError if running the program fails in any way; just
30 return on success.
31 """
32 # cmd is documented as a list, but just in case some code passes a tuple
33 # in, protect our %-formatting code against horrible death
34 cmd = list(cmd)
35 if os.name == 'posix':
36 _spawn_posix(cmd, search_path, dry_run=dry_run)
37 elif os.name == 'nt':
38 _spawn_nt(cmd, search_path, dry_run=dry_run)
39 else:
40 raise DistutilsPlatformError(
41 "don't know how to spawn programs on platform '%s'" % os.name)
42
43def _nt_quote_args(args):
44 """Quote command-line arguments for DOS/Windows conventions.
45
46 Just wraps every argument which contains blanks in double quotes, and
47 returns a new argument list.
48 """
49 # XXX this doesn't seem very robust to me -- but if the Windows guys
50 # say it'll work, I guess I'll have to accept it. (What if an arg
51 # contains quotes? What other magic characters, other than spaces,
52 # have to be escaped? Is there an escaping mechanism other than
53 # quoting?)
54 for i, arg in enumerate(args):
55 if ' ' in arg:
56 args[i] = '"%s"' % arg
57 return args
58
59def _spawn_nt(cmd, search_path=1, verbose=0, dry_run=0):
60 executable = cmd[0]
61 cmd = _nt_quote_args(cmd)
62 if search_path:
63 # either we find one or it stays the same
64 executable = find_executable(executable) or executable
65 log.info(' '.join([executable] + cmd[1:]))
66 if not dry_run:
67 # spawn for NT requires a full path to the .exe
68 try:
69 rc = os.spawnv(os.P_WAIT, executable, cmd)
70 except OSError as exc:
71 # this seems to happen when the command isn't found
72 if not DEBUG:
73 cmd = executable
74 raise DistutilsExecError(
75 "command %r failed: %s" % (cmd, exc.args[-1]))
76 if rc != 0:
77 # and this reflects the command running but failing
78 if not DEBUG:
79 cmd = executable
80 raise DistutilsExecError(
81 "command %r failed with exit status %d" % (cmd, rc))
82
83if sys.platform == 'darwin':
84 _cfg_target = None
85 _cfg_target_split = None
86
87def _spawn_posix(cmd, search_path=1, verbose=0, dry_run=0):
88 log.info(' '.join(cmd))
89 if dry_run:
90 return
91 executable = cmd[0]
92 exec_fn = search_path and os.execvp or os.execv
93 env = None
94 if sys.platform == 'darwin':
95 global _cfg_target, _cfg_target_split
96 if _cfg_target is None:
97 from distutils import sysconfig
98 _cfg_target = sysconfig.get_config_var(
99 'MACOSX_DEPLOYMENT_TARGET') or ''
100 if _cfg_target:
101 _cfg_target_split = [int(x) for x in _cfg_target.split('.')]
102 if _cfg_target:
103 # ensure that the deployment target of build process is not less
104 # than that used when the interpreter was built. This ensures
105 # extension modules are built with correct compatibility values
106 cur_target = os.environ.get('MACOSX_DEPLOYMENT_TARGET', _cfg_target)
107 if _cfg_target_split > [int(x) for x in cur_target.split('.')]:
108 my_msg = ('$MACOSX_DEPLOYMENT_TARGET mismatch: '
109 'now "%s" but "%s" during configure'
110 % (cur_target, _cfg_target))
111 raise DistutilsPlatformError(my_msg)
112 env = dict(os.environ,
113 MACOSX_DEPLOYMENT_TARGET=cur_target)
114 exec_fn = search_path and os.execvpe or os.execve
115 pid = os.fork()
116 if pid == 0: # in the child
117 try:
118 if env is None:
119 exec_fn(executable, cmd)
120 else:
121 exec_fn(executable, cmd, env)
122 except OSError as e:
123 if not DEBUG:
124 cmd = executable
125 sys.stderr.write("unable to execute %r: %s\n"
126 % (cmd, e.strerror))
127 os._exit(1)
128
129 if not DEBUG:
130 cmd = executable
131 sys.stderr.write("unable to execute %r for unknown reasons" % cmd)
132 os._exit(1)
133 else: # in the parent
134 # Loop until the child either exits or is terminated by a signal
135 # (ie. keep waiting if it's merely stopped)
136 while True:
137 try:
138 pid, status = os.waitpid(pid, 0)
139 except OSError as exc:
140 if not DEBUG:
141 cmd = executable
142 raise DistutilsExecError(
143 "command %r failed: %s" % (cmd, exc.args[-1]))
144 if os.WIFSIGNALED(status):
145 if not DEBUG:
146 cmd = executable
147 raise DistutilsExecError(
148 "command %r terminated by signal %d"
149 % (cmd, os.WTERMSIG(status)))
150 elif os.WIFEXITED(status):
151 exit_status = os.WEXITSTATUS(status)
152 if exit_status == 0:
153 return # hey, it succeeded!
154 else:
155 if not DEBUG:
156 cmd = executable
157 raise DistutilsExecError(
158 "command %r failed with exit status %d"
159 % (cmd, exit_status))
160 elif os.WIFSTOPPED(status):
161 continue
162 else:
163 if not DEBUG:
164 cmd = executable
165 raise DistutilsExecError(
166 "unknown error executing %r: termination status %d"
167 % (cmd, status))
168
169def find_executable(executable, path=None):
170 """Tries to find 'executable' in the directories listed in 'path'.
171
172 A string listing directories separated by 'os.pathsep'; defaults to
173 os.environ['PATH']. Returns the complete filename or None if not found.
174 """
175 _, ext = os.path.splitext(executable)
176 if (sys.platform == 'win32') and (ext != '.exe'):
177 executable = executable + '.exe'
178
179 if os.path.isfile(executable):
180 return executable
181
182 if path is None:
183 path = os.environ.get('PATH', None)
184 if path is None:
185 try:
186 path = os.confstr("CS_PATH")
187 except (AttributeError, ValueError):
188 # os.confstr() or CS_PATH is not available
189 path = os.defpath
190 # bpo-35755: Don't use os.defpath if the PATH environment variable is
191 # set to an empty string
192
193 # PATH='' doesn't match, whereas PATH=':' looks in the current directory
194 if not path:
195 return None
196
197 paths = path.split(os.pathsep)
198 for p in paths:
199 f = os.path.join(p, executable)
200 if os.path.isfile(f):
201 # the file exists, we have a shot at spawn working
202 return f
203 return None