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unix: fix a possible memory leak in uv_fs_readdir

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Some scandir implementations allocate the dirent struct even if the
directory is empty, so if `scandir` returns 0 there may still be memory
that needs to get deallocated. I have altered uv__fs_readdir to go to
the "deallocation exit area" when 0 files are found in the directory
and continue to return early on a return value of -1.

I went to add a test for this functionality, but it appears that one
already exists (reading an empty directory), so I imagine that the
valgrind builds must only be happening on linux instead of OSX as well?
I have confirmed manually that a program without this fix will
infinitely leak memory, and with this fix the memory usage stays
constant.
This commit is contained in:
Alex Crichton 2013-12-17 13:03:52 -08:00 committed by Fedor Indutny
parent f3d311edc4
commit 7c6bddbe2a
1 changed files with 5 additions and 2 deletions
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7
src/unix/fs.c
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@ -202,9 +202,12 @@ static ssize_t uv__fs_readdir(uv_fs_t* req) {
int i;
int n;
dents = NULL;
n = scandir(req->path, &dents, uv__fs_readdir_filter, alphasort);
if (n == -1 || n == 0)
if (n == 0)
goto out; /* osx still needs to deallocate some memory */
else if (n == -1)
return n;
len = 0;
@ -232,7 +235,7 @@ static ssize_t uv__fs_readdir(uv_fs_t* req) {
out:
saved_errno = errno;
{
if (dents != NULL) {
for (i = 0; i < n; i++)
free(dents[i]);
free(dents);