[libvirt] [PATCH] qemu driver: use lseek64 for setting position in logfile
While doing some testing with Qemu and creating huge logfiles I
encountered the case where the VM could not start anymore due to the
lseek() to the end of the Qemu VM's log file failing. The patch below
replaces the two occurrences of lseek() in the relevant path with
lseek64() and solves this problem. It may be a good idea to look at
other occurrences of lseek() as well whether they should be replaced.
off_t is 8 bytes long (64 bit), so it doesn't need to be replaced with
the explicit off64_t.
To reproduce this error, you could do the following:
dd if=/dev/zero of=/var/log/libvirt/qemu/<name of VM>.log bs=1024
count=$((1024*2048))
and you should get an error like this:
error: Failed to start domain <name of VM>
error: Unable to seek to -2147482651 in /var/log/libvirt/qemu/<name of
VM>.log: Success
Signed-off-by: Stefan Berger <stefanb(a)us.ibm.com>
---
src/qemu/qemu_driver.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Index: libvirt-acl/src/qemu/qemu_driver.c
===================================================================
--- libvirt-acl.orig/src/qemu/qemu_driver.c
+++ libvirt-acl/src/qemu/qemu_driver.c
@@ -238,7 +238,7 @@ qemudLogReadFD(const char* logDir, const
VIR_FREE(logfile);
return -1;
}
- if (pos < 0 || lseek(fd, pos, SEEK_SET) < 0) {
+ if (pos < 0 || lseek64(fd, pos, SEEK_SET) < 0) {
virReportSystemError(pos < 0 ? 0 : errno,
_("Unable to seek to %lld in %s"),
(long long) pos, logfile);
@@ -2624,7 +2624,7 @@ static int qemudStartVMDaemon(virConnect
enum virVMOperationType vmop) {
int ret;
unsigned long long qemuCmdFlags;
- int pos = -1;
+ off_t pos = -1;
char ebuf[1024];
char *pidfile = NULL;
int logfile = -1;
@@ -2839,7 +2839,7 @@ static int qemudStartVMDaemon(virConnect
virCommandWriteArgLog(cmd, logfile);
- if ((pos = lseek(logfile, 0, SEEK_END)) < 0)
+ if ((pos = lseek64(logfile, 0, SEEK_END)) < 0)
VIR_WARN("Unable to seek to end of logfile: %s",
virStrerror(errno, ebuf, sizeof ebuf));