| 1 | """
|
| 2 | pyos.py -- Wrappers for the operating system.
|
| 3 |
|
| 4 | Like py{error,util}.py, it won't be translated to C++.
|
| 5 | """
|
| 6 | from __future__ import print_function
|
| 7 |
|
| 8 | from errno import EINTR
|
| 9 | import pwd
|
| 10 | import resource
|
| 11 | import select
|
| 12 | import sys
|
| 13 | import termios # for read -n
|
| 14 | import time
|
| 15 |
|
| 16 | from mycpp.iolib import gSignalSafe
|
| 17 | from mycpp import mops
|
| 18 | from mycpp.mylib import log
|
| 19 |
|
| 20 | import posix_ as posix
|
| 21 | from posix_ import WUNTRACED
|
| 22 |
|
| 23 | from typing import Optional, Tuple, List, Dict, cast, Any, TYPE_CHECKING
|
| 24 | if TYPE_CHECKING:
|
| 25 | from core import error
|
| 26 |
|
| 27 | _ = log
|
| 28 |
|
| 29 | EOF_SENTINEL = 256 # bigger than any byte
|
| 30 | NEWLINE_CH = 10 # ord('\n')
|
| 31 |
|
| 32 |
|
| 33 | def FlushStdout():
|
| 34 | # type: () -> Optional[error.IOError_OSError]
|
| 35 | """Flush CPython buffers.
|
| 36 |
|
| 37 | Return error because we call this in a C++ destructor, and those can't
|
| 38 | throw exceptions.
|
| 39 | """
|
| 40 | err = None # type: Optional[error.IOError_OSError]
|
| 41 | try:
|
| 42 | sys.stdout.flush()
|
| 43 | except (IOError, OSError) as e:
|
| 44 | err = e
|
| 45 | return err
|
| 46 |
|
| 47 |
|
| 48 | def WaitPid(waitpid_options):
|
| 49 | # type: (int) -> Tuple[int, int]
|
| 50 | """
|
| 51 | Return value:
|
| 52 | pid is 0 if WNOHANG passed, and nothing has changed state
|
| 53 | status: value that can be parsed with WIFEXITED() etc.
|
| 54 | """
|
| 55 | try:
|
| 56 | # Notes:
|
| 57 | # - The arg -1 makes it like wait(), which waits for any process.
|
| 58 | # - WUNTRACED is necessary to get stopped jobs. What about WCONTINUED?
|
| 59 | # - We don't retry on EINTR, because the 'wait' builtin should be
|
| 60 | # interruptible.
|
| 61 | # - waitpid_options can be WNOHANG
|
| 62 | pid, status = posix.waitpid(-1, WUNTRACED | waitpid_options)
|
| 63 | except OSError as e:
|
| 64 | if e.errno == EINTR and gSignalSafe.PollUntrappedSigInt():
|
| 65 | raise KeyboardInterrupt()
|
| 66 | return -1, e.errno
|
| 67 |
|
| 68 | return pid, status
|
| 69 |
|
| 70 |
|
| 71 | class ReadError(Exception):
|
| 72 | """Wraps errno returned by read().
|
| 73 |
|
| 74 | Used by 'read' and 'mapfile' builtins.
|
| 75 | """
|
| 76 |
|
| 77 | def __init__(self, err_num):
|
| 78 | # type: (int) -> None
|
| 79 | self.err_num = err_num
|
| 80 |
|
| 81 |
|
| 82 | def Read(fd, n, chunks):
|
| 83 | # type: (int, int, List[str]) -> Tuple[int, int]
|
| 84 | """C-style wrapper around Python's posix.read() that uses return values
|
| 85 | instead of exceptions for errors.
|
| 86 |
|
| 87 | We will implement this directly in C++ and not use exceptions at all.
|
| 88 |
|
| 89 | It reads n bytes from the given file descriptor and appends it to chunks.
|
| 90 |
|
| 91 | Returns:
|
| 92 | (-1, errno) on failure
|
| 93 | (number of bytes read, 0) on success. Where 0 bytes read indicates EOF.
|
| 94 | """
|
| 95 | try:
|
| 96 | chunk = posix.read(fd, n)
|
| 97 | except OSError as e:
|
| 98 | if e.errno == EINTR and gSignalSafe.PollUntrappedSigInt():
|
| 99 | raise KeyboardInterrupt()
|
| 100 | return -1, e.errno
|
| 101 | else:
|
| 102 | length = len(chunk)
|
| 103 | if length:
|
| 104 | chunks.append(chunk)
|
| 105 | return length, 0
|
| 106 |
|
| 107 |
|
| 108 | def ReadByte(fd):
|
| 109 | # type: (int) -> Tuple[int, int]
|
| 110 | """Low-level interface that returns values rather than raising exceptions.
|
| 111 |
|
| 112 | Used by _ReadUntilDelim() and _ReadLineSlowly().
|
| 113 |
|
| 114 | Returns:
|
| 115 | failure: (-1, errno) on failure
|
| 116 | success: (ch integer value or EOF_SENTINEL, 0)
|
| 117 | """
|
| 118 | try:
|
| 119 | b = posix.read(fd, 1)
|
| 120 | except OSError as e:
|
| 121 | if e.errno == EINTR and gSignalSafe.PollUntrappedSigInt():
|
| 122 | raise KeyboardInterrupt()
|
| 123 | return -1, e.errno
|
| 124 | else:
|
| 125 | if len(b):
|
| 126 | return ord(b), 0
|
| 127 | else:
|
| 128 | return EOF_SENTINEL, 0
|
| 129 |
|
| 130 |
|
| 131 | def Environ():
|
| 132 | # type: () -> Dict[str, str]
|
| 133 | return posix.environ
|
| 134 |
|
| 135 |
|
| 136 | def Chdir(dest_dir):
|
| 137 | # type: (str) -> int
|
| 138 | """Returns 0 for success and nonzero errno for error."""
|
| 139 | try:
|
| 140 | posix.chdir(dest_dir)
|
| 141 | except OSError as e:
|
| 142 | return e.errno
|
| 143 | return 0
|
| 144 |
|
| 145 |
|
| 146 | def GetMyHomeDir():
|
| 147 | # type: () -> Optional[str]
|
| 148 | """Get the user's home directory from the /etc/pyos.
|
| 149 |
|
| 150 | Used by $HOME initialization in osh/state.py. Tilde expansion and
|
| 151 | readline initialization use mem.GetValue('HOME').
|
| 152 | """
|
| 153 | uid = posix.getuid()
|
| 154 | try:
|
| 155 | e = pwd.getpwuid(uid)
|
| 156 | except KeyError:
|
| 157 | return None
|
| 158 |
|
| 159 | return e.pw_dir
|
| 160 |
|
| 161 |
|
| 162 | def GetHomeDir(user_name):
|
| 163 | # type: (str) -> Optional[str]
|
| 164 | """For ~otheruser/src.
|
| 165 |
|
| 166 | TODO: Should this be cached?
|
| 167 | """
|
| 168 | # http://linux.die.net/man/3/getpwnam
|
| 169 | try:
|
| 170 | e = pwd.getpwnam(user_name)
|
| 171 | except KeyError:
|
| 172 | return None
|
| 173 |
|
| 174 | return e.pw_dir
|
| 175 |
|
| 176 |
|
| 177 | class PasswdEntry(object):
|
| 178 |
|
| 179 | def __init__(self, pw_name, uid, gid):
|
| 180 | # type: (str, int, int) -> None
|
| 181 | self.pw_name = pw_name
|
| 182 | self.pw_uid = uid
|
| 183 | self.pw_gid = gid
|
| 184 |
|
| 185 |
|
| 186 | def GetAllUsers():
|
| 187 | # type: () -> List[PasswdEntry]
|
| 188 | users = [
|
| 189 | PasswdEntry(u.pw_name, u.pw_uid, u.pw_gid) for u in pwd.getpwall()
|
| 190 | ]
|
| 191 | return users
|
| 192 |
|
| 193 |
|
| 194 | def GetUserName(uid):
|
| 195 | # type: (int) -> str
|
| 196 | try:
|
| 197 | e = pwd.getpwuid(uid)
|
| 198 | except KeyError:
|
| 199 | return "<ERROR: Couldn't determine user name for uid %d>" % uid
|
| 200 | else:
|
| 201 | return e.pw_name
|
| 202 |
|
| 203 |
|
| 204 | def GetRLimit(res):
|
| 205 | # type: (int) -> Tuple[mops.BigInt, mops.BigInt]
|
| 206 | """
|
| 207 | Raises IOError
|
| 208 | """
|
| 209 | soft, hard = resource.getrlimit(res)
|
| 210 | return (mops.IntWiden(soft), mops.IntWiden(hard))
|
| 211 |
|
| 212 |
|
| 213 | def SetRLimit(res, soft, hard):
|
| 214 | # type: (int, mops.BigInt, mops.BigInt) -> None
|
| 215 | """
|
| 216 | Raises IOError
|
| 217 | """
|
| 218 | resource.setrlimit(res, (soft.i, hard.i))
|
| 219 |
|
| 220 |
|
| 221 | def Time():
|
| 222 | # type: () -> Tuple[float, float, float]
|
| 223 | t = time.time() # calls gettimeofday() under the hood
|
| 224 | u = resource.getrusage(resource.RUSAGE_SELF)
|
| 225 | return t, u.ru_utime, u.ru_stime
|
| 226 |
|
| 227 |
|
| 228 | def PrintTimes():
|
| 229 | # type: () -> None
|
| 230 | utime, stime, cutime, cstime, elapsed = posix.times()
|
| 231 | print("%dm%.3fs %dm%.3fs" %
|
| 232 | (utime / 60, utime % 60, stime / 60, stime % 60))
|
| 233 | print("%dm%.3fs %dm%.3fs" %
|
| 234 | (cutime / 60, cutime % 60, cstime / 60, cstime % 60))
|
| 235 |
|
| 236 |
|
| 237 | # So builtin_misc.py doesn't depend on termios, which makes C++ translation
|
| 238 | # easier
|
| 239 | TERM_ICANON = termios.ICANON
|
| 240 | TERM_ECHO = termios.ECHO
|
| 241 |
|
| 242 |
|
| 243 | def PushTermAttrs(fd, mask):
|
| 244 | # type: (int, int) -> Tuple[int, Any]
|
| 245 | """Returns opaque type (void* in C++) to be reused in the PopTermAttrs()"""
|
| 246 | # https://docs.python.org/2/library/termios.html
|
| 247 | term_attrs = termios.tcgetattr(fd)
|
| 248 |
|
| 249 | # Flip the bits in one field, e.g. ICANON to disable canonical (buffered)
|
| 250 | # mode.
|
| 251 | orig_local_modes = cast(int, term_attrs[3])
|
| 252 | term_attrs[3] = orig_local_modes & mask
|
| 253 |
|
| 254 | termios.tcsetattr(fd, termios.TCSANOW, term_attrs)
|
| 255 | return orig_local_modes, term_attrs
|
| 256 |
|
| 257 |
|
| 258 | def PopTermAttrs(fd, orig_local_modes, term_attrs):
|
| 259 | # type: (int, int, Any) -> None
|
| 260 |
|
| 261 | term_attrs[3] = orig_local_modes
|
| 262 | try:
|
| 263 | termios.tcsetattr(fd, termios.TCSANOW, term_attrs)
|
| 264 | except termios.error as e:
|
| 265 | # Superficial fix for issue #1001. I'm not sure why we get errno.EIO,
|
| 266 | # but we can't really handle it here. In C++ I guess we ignore the
|
| 267 | # error.
|
| 268 | pass
|
| 269 |
|
| 270 |
|
| 271 | def OsType():
|
| 272 | # type: () -> str
|
| 273 | """Compute $OSTYPE variable."""
|
| 274 | return posix.uname()[0].lower()
|
| 275 |
|
| 276 |
|
| 277 | def InputAvailable(fd):
|
| 278 | # type: (int) -> bool
|
| 279 | # similar to lib/sh/input_avail.c in bash
|
| 280 | # read, write, except
|
| 281 | r, w, exc = select.select([fd], [], [fd], 0)
|
| 282 | return len(r) != 0
|
| 283 |
|
| 284 |
|
| 285 | def MakeDirCacheKey(path):
|
| 286 | # type: (str) -> Tuple[str, int]
|
| 287 | """Returns a pair (path with last modified time) that can be used to cache
|
| 288 | directory accesses."""
|
| 289 | st = posix.stat(path)
|
| 290 | return (path, int(st.st_mtime))
|