The seek() method is broken for any 'whence' value (seek from
start, current, orend) other than the default. I have a patch
that fixes that as well as gets mmap'd files working on
Linux64 and Win64.
For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.
(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode. I'm also holding back on his
change to main.c, which seems unnecessary to me.)
The bug is in mmap_read_line_method(), and its loop that searches for
newlines. After the loop reaches EOF, eol is incremented and points
after the end of the memory. This results in readline() method
sometimes picking up and returning a byte after the end of the string.
This is usually a bogus \0, but it could cause SIGSEGV if it's after
the end of the page).
The patch fixes the problem. Also, it uses memchr() for finding a
character, which is in fact the "strnchr" the comment is asking for.
memchr() is already used in Python sources, so there should be no
portability problems.
Reformatted for 8-space tabs and fitted into 80-char lines by GvR.
Mark writes:
* the Win32 version now accepts the same args as the Unix version.
The win32 specific "tag" param is now optional. The end result is
that the exact same test suite runs on Windows (definately a worthy
goal!).
* I changed the error object. All occurences of the error, except
for 1, corresponds to an underlying OS error. This one was changed
to a ValueError (a better error for that condition), and the module
error object is now simply EnvironmentError. All win32 error
routines now call the new Windows specific error handler.
Andrew M. Kuchling
Guido van Rossum
Fred Drake