Add helper functions to do synchronous I/O to a file from inside the
chrooted environment. This ensures that calls to kern_path() in the
kernel resolves to paths that are relative to the nfsd root directory.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
support/include/workqueue.h | 4 ++
support/misc/workqueue.c | 78 +++++++++++++++++++++++++++++++++++++
2 files changed, 82 insertions(+)
diff --git a/support/include/workqueue.h b/support/include/workqueue.h
index 518be82f1b34..21b1ee6bc873 100644
--- a/support/include/workqueue.h
+++ b/support/include/workqueue.h
@@ -15,4 +15,8 @@ void xthread_work_run_sync(struct xthread_workqueue *wq,
void xthread_workqueue_chroot(struct xthread_workqueue *wq,
const char *path);
+ssize_t xthread_read(struct xthread_workqueue *wq,
+ int fd, char *buf, size_t len);
+ssize_t xthread_write(struct xthread_workqueue *wq,
+ int fd, const char *buf, size_t len);
#endif
diff --git a/support/misc/workqueue.c b/support/misc/workqueue.c
index b8d03446f2c7..9d967cef6547 100644
--- a/support/misc/workqueue.c
+++ b/support/misc/workqueue.c
@@ -1,3 +1,4 @@
+#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
@@ -197,6 +198,72 @@ void xthread_workqueue_chroot(struct xthread_workqueue *wq,
xthread_work_run_sync(wq, xthread_workqueue_do_chroot, (void *)path);
}
+struct xthread_read_data {
+ int fd;
+ char *buf;
+ size_t len;
+ ssize_t ret;
+ int err;
+};
+
+static void xthread_readfunc(void *data)
+{
+ struct xthread_read_data *d = data;
+
+ d->ret = read(d->fd, d->buf, d->len);
+ if (d->ret < 0)
+ d->err = errno;
+}
+
+ssize_t xthread_read(struct xthread_workqueue *wq,
+ int fd, char *buf, size_t len)
+{
+ struct xthread_read_data data = {
+ fd,
+ buf,
+ len,
+ 0,
+ 0
+ };
+ xthread_work_run_sync(wq, xthread_readfunc, &data);
+ if (data.ret < 0)
+ errno = data.err;
+ return data.ret;
+}
+
+struct xthread_write_data {
+ int fd;
+ const char *buf;
+ size_t len;
+ ssize_t ret;
+ int err;
+};
+
+static void xthread_writefunc(void *data)
+{
+ struct xthread_write_data *d = data;
+
+ d->ret = write(d->fd, d->buf, d->len);
+ if (d->ret < 0)
+ d->err = errno;
+}
+
+ssize_t xthread_write(struct xthread_workqueue *wq,
+ int fd, const char *buf, size_t len)
+{
+ struct xthread_write_data data = {
+ fd,
+ buf,
+ len,
+ 0,
+ 0
+ };
+ xthread_work_run_sync(wq, xthread_writefunc, &data);
+ if (data.ret < 0)
+ errno = data.err;
+ return data.ret;
+}
+
#else
struct xthread_workqueue {
@@ -225,4 +292,15 @@ void xthread_workqueue_chroot(struct xthread_workqueue *wq,
xlog_err("Unable to run as chroot");
}
+ssize_t xthread_read(struct xthread_workqueue *wq,
+ int fd, char *buf, size_t len)
+{
+ return read(fd, buf, len);
+}
+
+ssize_t xthread_write(struct xthread_workqueue *wq,
+ int fd, const char *buf, size_t len)
+{
+ return write(fd, buf, len);
+}
#endif /* defined(HAVE_SCHED_H) && defined(HAVE_LIBPTHREAD) && defined(HAVE_UNSHARE) */
--
2.21.0
