From 56a87a090558ea69a9857d05c3dcf286801bbd7a Mon Sep 17 00:00:00 2001 From: Fred Drake Date: Tue, 4 Apr 2000 18:17:35 +0000 Subject: [PATCH] Patch from Hrvoje Niksic : 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. --- Modules/mmapmodule.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c index bf40274e82..a17f55e223 100644 --- a/Modules/mmapmodule.c +++ b/Modules/mmapmodule.c @@ -132,20 +132,20 @@ static PyObject * mmap_read_line_method (mmap_object * self, PyObject * args) { - char * start; + char * start = self->data+self->pos; char * eof = self->data+self->size; char * eol; PyObject * result; CHECK_VALID(NULL); - start = self->data+self->pos; - /* strchr was a bad idea here - there's no way to range - check it. there is no 'strnchr' */ - for (eol = start; (eol < eof) && (*eol != '\n') ; eol++) - { /* do nothing */ } - - result = Py_BuildValue("s#", start, (long) (++eol - start)); + eol = memchr(start, '\n', self->size - self->pos); + if (!eol) + eol = eof; + else + ++eol; /* we're interested in the position after the + newline. */ + result = PyString_FromStringAndSize(start, (long) (eol - start)); self->pos += (eol - start); return (result); } -- 2.50.1