From: Jason Andryuk Date: Mon, 19 May 2014 18:36:37 +0000 (-0400) Subject: libxl: Reset toolstack_save file position in libxl X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~4954 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b327a3f421bb57d262b7d1fb3c43b710852b103b;p=xen.git libxl: Reset toolstack_save file position in libxl toolstack_save data is written to a temporary file in libxl and read back in libxl-save-helper. The file position must be reset prior to reading the file, which is done in libxl-save-helper with lseek. lseek is unsupported for pipes and sockets, so a wrapper passing such an fd to libxl-save-helper fails the lseek. Moving the lseek to libxl avoids the error, allowing the save to continue. Signed-off-by: Jason Andryuk Reviewed-by: Andrew Cooper Acked-by: Ian Jackson --- diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c index e3bda8f812..c35da4dfed 100644 --- a/tools/libxl/libxl_save_callout.c +++ b/tools/libxl/libxl_save_callout.c @@ -105,6 +105,10 @@ void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss, toolstack_data_buf, toolstack_data_len, "toolstack data tmpfile", 0); if (r) { rc = ERROR_FAIL; goto out; } + + /* file position must be reset before passing to libxl-save-helper. */ + r = lseek(toolstack_data_fd, 0, SEEK_SET); + if (r) { rc = ERROR_FAIL; goto out; } } const unsigned long argnums[] = { diff --git a/tools/libxl/libxl_save_helper.c b/tools/libxl/libxl_save_helper.c index c36314ca0a..b259bd0215 100644 --- a/tools/libxl/libxl_save_helper.c +++ b/tools/libxl/libxl_save_helper.c @@ -163,10 +163,9 @@ static uint32_t toolstack_save_len; static int toolstack_save_cb(uint32_t domid, uint8_t **buf, uint32_t *len, void *data) { - assert(toolstack_save_fd > 0); + int r; - int r = lseek(toolstack_save_fd, 0, SEEK_SET); - if (r) fail(errno,"rewind toolstack data tmpfile"); + assert(toolstack_save_fd > 0); *buf = xmalloc(toolstack_save_len); r = read_exactly(toolstack_save_fd, *buf, toolstack_save_len);