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From d1b3bbb46402af77089906a97c413c14ed1740d2 Mon Sep 17 00:00:00 2001
From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 4 Jul 2024 14:13:10 +0200
Subject: [PATCH 47/56] tools/libxs: Fix CLOEXEC handling in get_dev()
Move the O_CLOEXEC compatibility outside of an #ifdef USE_PTHREAD block.
Introduce set_cloexec() to wrap fcntl() setting FD_CLOEXEC. It will be reused
for other CLOEXEC fixes too.
Use set_cloexec() when O_CLOEXEC isn't available as a best-effort fallback.
Fixes: f4f2f3402b2f ("tools/libxs: Open /dev/xen/xenbus fds as O_CLOEXEC")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>
master commit: bf7c1464706adfa903f1e7d59383d042c3a88e39
master date: 2024-07-02 10:51:06 +0100
---
tools/libs/store/xs.c | 38 ++++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
index 1498515073..037e79d98b 100644
--- a/tools/libs/store/xs.c
+++ b/tools/libs/store/xs.c
@@ -40,6 +40,10 @@
#include <xentoolcore_internal.h>
#include <xen_list.h>
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
struct xs_stored_msg {
XEN_TAILQ_ENTRY(struct xs_stored_msg) list;
struct xsd_sockmsg hdr;
@@ -54,10 +58,6 @@ struct xs_stored_msg {
#include <dlfcn.h>
#endif
-#ifndef O_CLOEXEC
-#define O_CLOEXEC 0
-#endif
-
struct xs_handle {
/* Communications channel to xenstore daemon. */
int fd;
@@ -176,6 +176,16 @@ static bool setnonblock(int fd, int nonblock) {
return true;
}
+static bool set_cloexec(int fd)
+{
+ int flags = fcntl(fd, F_GETFL);
+
+ if (flags < 0)
+ return false;
+
+ return fcntl(fd, flags | FD_CLOEXEC) >= 0;
+}
+
int xs_fileno(struct xs_handle *h)
{
char c = 0;
@@ -230,8 +240,24 @@ error:
static int get_dev(const char *connect_to)
{
- /* We cannot open read-only because requests are writes */
- return open(connect_to, O_RDWR | O_CLOEXEC);
+ int fd, saved_errno;
+
+ fd = open(connect_to, O_RDWR | O_CLOEXEC);
+ if (fd < 0)
+ return -1;
+
+ /* Compat for non-O_CLOEXEC environments. Racy. */
+ if (!O_CLOEXEC && !set_cloexec(fd))
+ goto error;
+
+ return fd;
+
+error:
+ saved_errno = errno;
+ close(fd);
+ errno = saved_errno;
+
+ return -1;
}
static int all_restrict_cb(Xentoolcore__Active_Handle *ah, domid_t domid) {
--
2.45.2
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