Daniel Berger wrote:
Ruby 1.8.4 (one click)
Windows XP
Check this out segfault:
# strtest.rb
require 'Win32API'
GetFullPathNameW = Win32API.new('kernel32','GetFullPathNameW','PLPP', 'L')
path = "C:\\test"
buf = 0.chr * 260
if GetFullPathNameW.call(path, buf.size, buf, 0) == 0
puts "Failed"
end
#p buf
p buf.split("\0\0").first # boom!
# Result
strtest.rb:13: [BUG] Segmentation fault
ruby 1.8.4 (2005-12-24) [i386-mswin32]
This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.
I noticed that if I dropped the 'buf' to 245 or fewer characters, it works ok. Also, it segfaults on just about any op that modifies buf, not just String#split.
Any ideas?
Thanks,
Dan
The solution was found by Heesob, which I have pasted below (taken from the win32utils-devel mailing list):
I have found out what is the problem.
It's not bug of Ruby or Windows, it is only bug of code.
First try this:
require 'Win32API'
GetFullPathNameW = Win32API.new('kernel32','GetFullPathNameW','PLPP', 'L')
for i in 1..100
path = "c:\\test"
buf = 0.chr * 260
if GetFullPathNameW.call(path, buf.size, buf, 0) == 0
puts "Failed"
end
p buf.split("\0\0").first
end
It will cause various errors like
uninitialized constant GetFullPathNameW (NameError)
or
segfault.
Next, try this:
require 'Win32API'
GetFullPathNameW = Win32API.new('kernel32','GetFullPathNameW','PLPP', 'L')
for i in 1..100
path = "c:\\test"
buf = 0.chr * 260
# buf.size/2 -> actual length of buf
if GetFullPathNameW.call(path, buf.size/2, buf, 0) == 0
puts "Failed"
end
p buf.split("\0\0").first
end
It runs Ok. but the result is not correct.
Next , try this:
require 'Win32API'
GetFullPathNameW = Win32API.new('kernel32','GetFullPathNameW','PLPP', 'L')
for i in 1..100
# append \0 to path
path = "c:\\test\0"
buf = 0.chr * 260
# buf.size/2 -> actual length of buf in unicode string
if GetFullPathNameW.call(path, buf.size/2, buf, 0) == 0
puts "Failed"
end
p buf.split("\0\0").first
end
It runs ok. The result is correct.
Finally, the complete and correct code is like this:
require 'Win32API'
GetFullPathNameW = Win32API.new('kernel32','GetFullPathNameW','PLPP', 'L')
for i in 1..100
path = "c\0:\0\\\0t\0e\0s\0t\0\0"
buf = 0.chr * 260
# buf.size/2 -> actual length of buf in unicode string
if GetFullPathNameW.call(path, buf.size/2, buf, 0) == 0
puts "Failed"
end
buf = buf.split("\0\0").first
buf = (buf.size % 2).zero? ? buf : buf+"\0"
p buf
end
Remeber, Ruby's string is terminated with "\0" implicitly, but UTF16
string requires double "\0".
For ascii chars, it happens trailing three "\0" : one for ascii char
and two for string termination.
Regards,
Park Heesob