* [PATCH] io.c (rb_io_syswrite): avoid leaving garbage after write
@ 2017-01-30 22:03 Eric Wong
0 siblings, 0 replies; only message in thread
From: Eric Wong @ 2017-01-30 22:03 UTC (permalink / raw)
To: spew
As with IO#write, IO#syswrite also generates garbage which can
be harmful in hand-coded read-write loops.
* io.c (swrite_arg, swrite_do, swrite_end): new
(rb_io_syswrite): use new functions to cleanup garbage
[ruby-core:78898] [Bug #13085]
---
io.c | 45 ++++++++++++++++++++++++++++++++++++---------
test/ruby/test_io.rb | 4 +++-
2 files changed, 39 insertions(+), 10 deletions(-)
diff --git a/io.c b/io.c
index d03519be92..57ad592daf 100644
--- a/io.c
+++ b/io.c
@@ -4745,6 +4745,34 @@ rb_io_sysseek(int argc, VALUE *argv, VALUE io)
return OFFT2NUM(pos);
}
+struct swrite_arg {
+ VALUE orig;
+ VALUE tmp;
+ rb_io_t *fptr;
+};
+
+static VALUE
+swrite_do(VALUE arg)
+{
+ struct swrite_arg *sa = (struct swrite_arg *)arg;
+ const char *ptr;
+ long len;
+
+ RSTRING_GETMEM(sa->tmp, ptr, len);
+
+ return (VALUE)rb_write_internal(sa->fptr->fd, ptr, len);
+}
+
+static VALUE
+swrite_end(VALUE arg)
+{
+ struct swrite_arg *sa = (struct swrite_arg *)arg;
+
+ rb_str_tmp_frozen_release(sa->orig, sa->tmp);
+
+ return Qfalse;
+}
+
/*
* call-seq:
* ios.syswrite(string) -> integer
@@ -4761,26 +4789,25 @@ rb_io_sysseek(int argc, VALUE *argv, VALUE io)
static VALUE
rb_io_syswrite(VALUE io, VALUE str)
{
- rb_io_t *fptr;
+ struct swrite_arg sa;
long n;
if (!RB_TYPE_P(str, T_STRING))
str = rb_obj_as_string(str);
io = GetWriteIO(io);
- GetOpenFile(io, fptr);
- rb_io_check_writable(fptr);
-
- str = rb_str_new_frozen(str);
+ GetOpenFile(io, sa.fptr);
+ rb_io_check_writable(sa.fptr);
- if (fptr->wbuf.len) {
+ if (sa.fptr->wbuf.len) {
rb_warn("syswrite for buffered IO");
}
- n = rb_write_internal(fptr->fd, RSTRING_PTR(str), RSTRING_LEN(str));
- RB_GC_GUARD(str);
+ sa.orig = str;
+ sa.tmp = rb_str_tmp_frozen_acquire(str);
+ n = (long)rb_ensure(swrite_do, (VALUE)&sa, swrite_end, (VALUE)&sa);
- if (n == -1) rb_sys_fail_path(fptr->pathv);
+ if (n == -1) rb_sys_fail_path(sa.fptr->pathv);
return LONG2FIX(n);
}
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index c501edd0ab..3cc410881c 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -3512,11 +3512,13 @@ def test_write_no_garbage
with_pipe do |r, w|
before = ObjectSpace.count_objects(res)[:T_STRING]
n = w.write(buf)
+ s = w.syswrite(buf)
after = ObjectSpace.count_objects(res)[:T_STRING]
assert_equal before, after,
'no strings left over after write [ruby-core:78898] [Bug #13085]'
assert_not_predicate buf, :frozen?, 'no inadvertant freeze'
- assert_equal buf.bytesize, n, 'wrote expected size'
+ assert_equal buf.bytesize, n, 'write wrote expected size'
+ assert_equal s, n, 'syswrite wrote expected size'
end
end
end
--
EW
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