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prevent race conditions with uvwasi_fd_close() #91

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Merged
merged 1 commit into from
Jan 22, 2020
Merged

prevent race conditions with uvwasi_fd_close() #91

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6 changes: 3 additions & 3 deletions include/fd_table.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,9 +56,9 @@ uvwasi_errno_t uvwasi_fd_table_get_nolock(struct uvwasi_fd_table_t* table,
struct uvwasi_fd_wrap_t** wrap,
uvwasi_rights_t rights_base,
uvwasi_rights_t rights_inheriting);
uvwasi_errno_t uvwasi_fd_table_remove(struct uvwasi_s* uvwasi,
struct uvwasi_fd_table_t* table,
const uvwasi_fd_t id);
uvwasi_errno_t uvwasi_fd_table_remove_nolock(struct uvwasi_s* uvwasi,
struct uvwasi_fd_table_t* table,
const uvwasi_fd_t id);
uvwasi_errno_t uvwasi_fd_table_renumber(struct uvwasi_s* uvwasi,
struct uvwasi_fd_table_t* table,
const uvwasi_fd_t dst,
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26 changes: 8 additions & 18 deletions src/fd_table.c
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Expand Up @@ -306,37 +306,27 @@ uvwasi_errno_t uvwasi_fd_table_get_nolock(struct uvwasi_fd_table_t* table,
}


uvwasi_errno_t uvwasi_fd_table_remove(uvwasi_t* uvwasi,
struct uvwasi_fd_table_t* table,
const uvwasi_fd_t id) {
uvwasi_errno_t uvwasi_fd_table_remove_nolock(uvwasi_t* uvwasi,
struct uvwasi_fd_table_t* table,
const uvwasi_fd_t id) {
struct uvwasi_fd_wrap_t* entry;
uvwasi_errno_t err;

if (table == NULL)
return UVWASI_EINVAL;

uv_rwlock_wrlock(&table->rwlock);

if (id >= table->size) {
err = UVWASI_EBADF;
goto exit;
}
if (id >= table->size)
return UVWASI_EBADF;

entry = table->fds[id];

if (entry == NULL || entry->id != id) {
err = UVWASI_EBADF;
goto exit;
}
if (entry == NULL || entry->id != id)
return UVWASI_EBADF;

uv_mutex_destroy(&entry->mutex);
uvwasi__free(uvwasi, entry);
table->fds[id] = NULL;
table->used--;
err = UVWASI_ESUCCESS;
exit:
uv_rwlock_wrunlock(&table->rwlock);
return err;
return UVWASI_ESUCCESS;
}


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18 changes: 13 additions & 5 deletions src/uvwasi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -878,18 +878,26 @@ uvwasi_errno_t uvwasi_fd_close(uvwasi_t* uvwasi, uvwasi_fd_t fd) {
if (uvwasi == NULL)
return UVWASI_EINVAL;

err = uvwasi_fd_table_get(&uvwasi->fds, fd, &wrap, 0, 0);
uvwasi_fd_table_lock(&uvwasi->fds);

err = uvwasi_fd_table_get_nolock(&uvwasi->fds, fd, &wrap, 0, 0);
if (err != UVWASI_ESUCCESS)
return err;
goto exit;

r = uv_fs_close(NULL, &req, wrap->fd, NULL);
uv_mutex_unlock(&wrap->mutex);
uv_fs_req_cleanup(&req);

if (r != 0)
return uvwasi__translate_uv_error(r);
if (r != 0) {
err = uvwasi__translate_uv_error(r);
goto exit;
}

err = uvwasi_fd_table_remove_nolock(uvwasi, &uvwasi->fds, fd);

return uvwasi_fd_table_remove(uvwasi, &uvwasi->fds, fd);
exit:
uvwasi_fd_table_unlock(&uvwasi->fds);
return err;
}


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