1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
# A parallelized "find(1)" using the thread module.
# This demonstrates the use of a work queue and worker threads.
# It really does do more stats/sec when using multiple threads,
# although the improvement is only about 20-30 percent.
# I'm too lazy to write a command line parser for the full find(1)
# command line syntax, so the predicate it searches for is wired-in,
# see function selector() below. (It currently searches for files with
# group or world write permission.)
# Usage: parfind.py [-w nworkers] [directory] ...
# Default nworkers is 4, maximum appears to be 8 (on Irix 4.0.2)
import sys
import getopt
import string
import time
import os
from stat import *
import thread
# Work queue class. Usage:
# wq = WorkQ()
# wq.addwork(func, (arg1, arg2, ...)) # one or more calls
# wq.run(nworkers)
# The work is done when wq.run() completes.
# The function calls executed by the workers may add more work.
# Don't use keyboard interrupts!
class WorkQ:
# Invariants:
# - busy and work are only modified when mutex is locked
# - len(work) is the number of jobs ready to be taken
# - busy is the number of jobs being done
# - todo is locked iff there is no work and somebody is busy
def __init__(self):
self.mutex = thread.allocate()
self.todo = thread.allocate()
self.todo.acquire()
self.work = []
self.busy = 0
def addwork(self, func, args):
job = (func, args)
self.mutex.acquire()
self.work.append(job)
self.mutex.release()
if len(self.work) == 1:
self.todo.release()
def _getwork(self):
self.todo.acquire()
self.mutex.acquire()
if self.busy == 0 and len(self.work) == 0:
self.mutex.release()
self.todo.release()
return None
job = self.work[0]
del self.work[0]
self.busy = self.busy + 1
self.mutex.release()
if len(self.work) > 0:
self.todo.release()
return job
def _donework(self):
self.mutex.acquire()
self.busy = self.busy - 1
if self.busy == 0 and len(self.work) == 0:
self.todo.release()
self.mutex.release()
def _worker(self):
time.sleep(0.00001) # Let other threads run
while 1:
job = self._getwork()
if not job:
break
func, args = job
apply(func, args)
self._donework()
def run(self, nworkers):
if not self.work:
return # Nothing to do
for i in range(nworkers-1):
thread.start_new(self._worker, ())
self._worker()
self.todo.acquire()
# Main program
def main():
sys.argv.append("/tmp")
nworkers = 4
opts, args = getopt.getopt(sys.argv[1:], '-w:')
for opt, arg in opts:
if opt == '-w':
nworkers = string.atoi(arg)
if not args:
args = [os.curdir]
wq = WorkQ()
for dir in args:
wq.addwork(find, (dir, selector, wq))
t1 = time.time()
wq.run(nworkers)
t2 = time.time()
sys.stderr.write('Total time ' + `t2-t1` + ' sec.\n')
# The predicate -- defines what files we look for.
# Feel free to change this to suit your purpose
def selector(dir, name, fullname, stat):
# Look for group or world writable files
return (stat[ST_MODE] & 0022) != 0
# The find procedure -- calls wq.addwork() for subdirectories
def find(dir, pred, wq):
try:
names = os.listdir(dir)
except os.error, msg:
print `dir`, ':', msg
return
for name in names:
if name not in (os.curdir, os.pardir):
fullname = os.path.join(dir, name)
try:
stat = os.lstat(fullname)
except os.error, msg:
print `fullname`, ':', msg
continue
if pred(dir, name, fullname, stat):
print fullname
if S_ISDIR(stat[ST_MODE]):
if not os.path.ismount(fullname):
wq.addwork(find, (fullname, pred, wq))
# Call the main program
main()
|
