1 """Helper functions and classes for bup."""
2 import sys, os, pwd, subprocess, errno, socket, select, mmap, stat, re
3 from bup import _version
6 # Write (blockingly) to sockets that may or may not be in blocking mode.
7 # We need this because our stderr is sometimes eaten by subprocesses
8 # (probably ssh) that sometimes make it nonblocking, if only temporarily,
9 # leading to race conditions. Ick. We'll do it the hard way.
10 def _hard_write(fd, buf):
12 (r,w,x) = select.select([], [fd], [], None)
14 raise IOError('select(fd) returned without being writable')
16 sz = os.write(fd, buf)
18 if e.errno != errno.EAGAIN:
24 """Print a log message to stderr."""
26 _hard_write(sys.stderr.fileno(), s)
30 """Recursively create directories on path 'd'.
32 Unlike os.makedirs(), it doesn't raise an exception if the last element of
33 the path already exists.
38 if e.errno == errno.EEXIST:
45 """Get the next item from an iterator, None if we reached the end."""
53 """Delete a file at path 'f' if it currently exists.
55 Unlike os.unlink(), does not throw an exception if the file didn't already
61 if e.errno == errno.ENOENT:
62 pass # it doesn't exist, that's what you asked for
66 """Run a subprocess and return its output."""
67 p = subprocess.Popen(argv, stdout=subprocess.PIPE)
74 """Get the absolute path of a file.
76 Behaves like os.path.realpath, but doesn't follow a symlink for the last
77 element. (ie. if 'p' itself is a symlink, this one won't follow it, but it
78 will follow symlinks in p's directory)
84 if st and stat.S_ISLNK(st.st_mode):
85 (dir, name) = os.path.split(p)
86 dir = os.path.realpath(dir)
87 out = os.path.join(dir, name)
89 out = os.path.realpath(p)
90 #log('realpathing:%r,%r\n' % (p, out))
96 """Get the user's login name."""
101 _username = pwd.getpwuid(uid)[0]
103 _username = 'user%d' % uid
109 """Get the user's full name."""
111 if not _userfullname:
114 _userfullname = pwd.getpwuid(uid)[4].split(',')[0]
116 _userfullname = 'user%d' % uid
122 """Get the FQDN of this machine."""
125 _hostname = socket.getfqdn()
129 class NotOk(Exception):
133 """A helper class for bup's client-server protocol."""
134 def __init__(self, inp, outp):
138 def read(self, size):
139 """Read 'size' bytes from input stream."""
141 return self.inp.read(size)
144 """Read from input stream until a newline is found."""
146 return self.inp.readline()
148 def write(self, data):
149 """Write 'data' to output stream."""
150 #log('%d writing: %d bytes\n' % (os.getpid(), len(data)))
151 self.outp.write(data)
154 """Return true if input stream is readable."""
155 [rl, wl, xl] = select.select([self.inp.fileno()], [], [], 0)
157 assert(rl[0] == self.inp.fileno())
163 """Indicate end of output from last sent command."""
167 """Indicate server error to the client."""
168 s = re.sub(r'\s+', ' ', str(s))
169 self.write('\nerror %s\n' % s)
171 def _check_ok(self, onempty):
174 for rl in linereader(self.inp):
175 #log('%d got line: %r\n' % (os.getpid(), rl))
176 if not rl: # empty line
180 elif rl.startswith('error '):
181 #log('client: error: %s\n' % rl[6:])
185 raise Exception('server exited unexpectedly; see errors above')
187 def drain_and_check_ok(self):
188 """Remove all data for the current command from input stream."""
191 return self._check_ok(onempty)
194 """Verify that server action completed successfully."""
196 raise Exception('expected "ok", got %r' % rl)
197 return self._check_ok(onempty)
201 """Generate a list of input lines from 'f' without terminating newlines."""
209 def chunkyreader(f, count = None):
210 """Generate a list of chunks of data read from 'f'.
212 If count is None, read until EOF is reached.
214 If count is a positive integer, read 'count' bytes from 'f'. If EOF is
215 reached while reading, raise IOError.
219 b = f.read(min(count, 65536))
221 raise IOError('EOF with %d bytes remaining' % count)
232 """Append "/" to 's' if it doesn't aleady end in "/"."""
233 if s and not s.endswith('/'):
239 def _mmap_do(f, sz, flags, prot):
241 st = os.fstat(f.fileno())
243 map = mmap.mmap(f.fileno(), sz, flags, prot)
244 f.close() # map will persist beyond file close
248 def mmap_read(f, sz = 0):
249 """Create a read-only memory mapped region on file 'f'.
251 If sz is 0, the region will cover the entire file.
253 return _mmap_do(f, sz, mmap.MAP_PRIVATE, mmap.PROT_READ)
256 def mmap_readwrite(f, sz = 0):
257 """Create a read-write memory mapped region on file 'f'.
259 If sz is 0, the region will cover the entire file.
261 return _mmap_do(f, sz, mmap.MAP_SHARED, mmap.PROT_READ|mmap.PROT_WRITE)
265 """Parse data size information into a float number.
267 Here are some examples of conversions:
268 199.2k means 203981 bytes
269 1GB means 1073741824 bytes
270 2.1 tb means 2199023255552 bytes
272 g = re.match(r'([-+\d.e]+)\s*(\w*)', str(s))
274 raise ValueError("can't parse %r as a number" % s)
275 (val, unit) = g.groups()
278 if unit in ['t', 'tb']:
279 mult = 1024*1024*1024*1024
280 elif unit in ['g', 'gb']:
281 mult = 1024*1024*1024
282 elif unit in ['m', 'mb']:
284 elif unit in ['k', 'kb']:
286 elif unit in ['', 'b']:
289 raise ValueError("invalid unit %r in number %r" % (unit, s))
294 """Count the number of elements in an iterator. (consumes the iterator)"""
295 return reduce(lambda x,y: x+1, l)
299 """Convert the string 's' to an integer. Return 0 if s is not a number."""
308 """Append an error message to the list of saved errors.
310 Once processing is able to stop and output the errors, the saved errors are
311 accessible in the module variable helpers.saved_errors.
313 saved_errors.append(e)
316 istty = os.isatty(2) or atoi(os.environ.get('BUP_FORCE_TTY'))
318 """Calls log(s) if stderr is a TTY. Does nothing otherwise."""
324 """Replace the default exception handler for KeyboardInterrupt (Ctrl-C).
326 The new exception handler will make sure that bup will exit without an ugly
327 stacktrace when Ctrl-C is hit.
329 oldhook = sys.excepthook
330 def newhook(exctype, value, traceback):
331 if exctype == KeyboardInterrupt:
332 log('Interrupted.\n')
334 return oldhook(exctype, value, traceback)
335 sys.excepthook = newhook
338 def columnate(l, prefix):
339 """Format elements of 'l' in columns with 'prefix' leading each line.
341 The number of columns is determined automatically based on the string
345 clen = max(len(s) for s in l)
346 ncols = (78 - len(prefix)) / (clen + 2)
351 while len(l) % ncols:
354 for s in range(0, len(l), rows):
355 cols.append(l[s:s+rows])
357 for row in zip(*cols):
358 out += prefix + ''.join(('%-*s' % (clen+2, s)) for s in row) + '\n'
362 # hashlib is only available in python 2.5 or higher, but the 'sha' module
363 # produces a DeprecationWarning in python 2.6 or higher. We want to support
364 # python 2.4 and above without any stupid warnings, so let's try using hashlib
365 # first, and downgrade if it fails.
376 """Format bup's version date string for output."""
377 return _version.DATE.split(' ')[0]
379 def version_commit():
380 """Get the commit hash of bup's current version."""
381 return _version.COMMIT
384 """Format bup's version tag (the official version number).
386 When generated from a commit other than one pointed to with a tag, the
387 returned string will be "unknown-" followed by the first seven positions of
390 names = _version.NAMES.strip()
391 assert(names[0] == '(')
392 assert(names[-1] == ')')
394 l = [n.strip() for n in names.split(',')]
396 if n.startswith('tag: bup-'):
398 return 'unknown-%s' % _version.COMMIT[:7]