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From ca749954b09b89e22cd69c4949fb7e689b057963 Mon Sep 17 00:00:00 2001
From: Fam Zheng <famz@redhat.com>
Date: Fri, 11 Aug 2017 19:44:46 +0800
Subject: [PATCH 1/2] osdep: Add runtime OFD lock detection
Build time check of OFD lock is not sufficient and can cause image open
errors when the runtime environment doesn't support it.
Add a helper function to probe it at runtime, additionally. Also provide
a qemu_has_ofd_lock() for callers to check the status.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Upstream-Status: Backport
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
include/qemu/osdep.h | 1 +
util/osdep.c | 66 ++++++++++++++++++++++++++++++++++++++++++++--------
2 files changed, 57 insertions(+), 10 deletions(-)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 3b74f6fcb2..6855b94bbf 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -357,6 +357,7 @@ int qemu_dup(int fd);
int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
int qemu_unlock_fd(int fd, int64_t start, int64_t len);
int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
+bool qemu_has_ofd_lock(void);
#if defined(__HAIKU__) && defined(__i386__)
#define FMT_pid "%ld"
diff --git a/util/osdep.c b/util/osdep.c
index a2863c8e53..a479fedc4a 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -38,14 +38,6 @@ extern int madvise(caddr_t, size_t, int);
#include "qemu/error-report.h"
#include "monitor/monitor.h"
-#ifdef F_OFD_SETLK
-#define QEMU_SETLK F_OFD_SETLK
-#define QEMU_GETLK F_OFD_GETLK
-#else
-#define QEMU_SETLK F_SETLK
-#define QEMU_GETLK F_GETLK
-#endif
-
static bool fips_enabled = false;
static const char *hw_version = QEMU_HW_VERSION;
@@ -82,6 +74,10 @@ int qemu_madvise(void *addr, size_t len, int advice)
}
#ifndef _WIN32
+
+static int fcntl_op_setlk = -1;
+static int fcntl_op_getlk = -1;
+
/*
* Dups an fd and sets the flags
*/
@@ -149,6 +145,54 @@ static int qemu_parse_fdset(const char *param)
return qemu_parse_fd(param);
}
+static void qemu_probe_lock_ops(void)
+{
+ if (fcntl_op_setlk == -1) {
+#ifdef F_OFD_SETLK
+ int fd;
+ int ret;
+ struct flock fl = {
+ .l_whence = SEEK_SET,
+ .l_start = 0,
+ .l_len = 0,
+ .l_type = F_WRLCK,
+ };
+
+ fd = open("/dev/null", O_RDWR);
+ if (fd < 0) {
+ fprintf(stderr,
+ "Failed to open /dev/null for OFD lock probing: %s\n",
+ strerror(errno));
+ fcntl_op_setlk = F_SETLK;
+ fcntl_op_getlk = F_GETLK;
+ return;
+ }
+ ret = fcntl(fd, F_OFD_GETLK, &fl);
+ close(fd);
+ if (!ret) {
+ fcntl_op_setlk = F_OFD_SETLK;
+ fcntl_op_getlk = F_OFD_GETLK;
+ } else {
+ fcntl_op_setlk = F_SETLK;
+ fcntl_op_getlk = F_GETLK;
+ }
+#else
+ fcntl_op_setlk = F_SETLK;
+ fcntl_op_getlk = F_GETLK;
+#endif
+ }
+}
+
+bool qemu_has_ofd_lock(void)
+{
+ qemu_probe_lock_ops();
+#ifdef F_OFD_SETLK
+ return fcntl_op_setlk == F_OFD_SETLK;
+#else
+ return false;
+#endif
+}
+
static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
{
int ret;
@@ -158,7 +202,8 @@ static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
.l_len = len,
.l_type = fl_type,
};
- ret = fcntl(fd, QEMU_SETLK, &fl);
+ qemu_probe_lock_ops();
+ ret = fcntl(fd, fcntl_op_setlk, &fl);
return ret == -1 ? -errno : 0;
}
@@ -181,7 +226,8 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
.l_len = len,
.l_type = exclusive ? F_WRLCK : F_RDLCK,
};
- ret = fcntl(fd, QEMU_GETLK, &fl);
+ qemu_probe_lock_ops();
+ ret = fcntl(fd, fcntl_op_getlk, &fl);
if (ret == -1) {
return -errno;
} else {
--
2.11.0
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