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Add a mutex to guarantee single writer to qemu_logfile handle.

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Also added qemu_logfile_init() for initializing the logfile mutex.

Note that inside qemu_set_log() we needed to add a pair of
qemu_mutex_unlock() calls in order to avoid a double lock in
qemu_log_close().  This unavoidable temporary ugliness will be
cleaned up in a later patch in this series.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20191118211528.3221-4-robert.foley@linaro.org>
This commit is contained in:
Robert Foley 2019-11-18 16:15:25 -05:00 committed by Alex Bennée
parent 045e8861df
commit b8121fe7c0
1 changed files with 12 additions and 0 deletions
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12
util/log.c
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@ -24,8 +24,10 @@
#include "qapi/error.h" #include "qapi/error.h"
#include "qemu/cutils.h" #include "qemu/cutils.h"
#include "trace/control.h" #include "trace/control.h"
#include "qemu/thread.h"
static char *logfilename; static char *logfilename;
static QemuMutex qemu_logfile_mutex;
FILE *qemu_logfile; FILE *qemu_logfile;
int qemu_loglevel; int qemu_loglevel;
static int log_append = 0; static int log_append = 0;
@ -49,6 +51,11 @@ int qemu_log(const char *fmt, ...)
return ret; return ret;
} }
static void __attribute__((__constructor__)) qemu_logfile_init(void)
{
qemu_mutex_init(&qemu_logfile_mutex);
}
static bool log_uses_own_buffers; static bool log_uses_own_buffers;
/* enable or disable low levels log */ /* enable or disable low levels log */
@ -70,7 +77,9 @@ void qemu_set_log(int log_flags)
if (qemu_loglevel && (!is_daemonized() || logfilename)) { if (qemu_loglevel && (!is_daemonized() || logfilename)) {
need_to_open_file = true; need_to_open_file = true;
} }
qemu_mutex_lock(&qemu_logfile_mutex);
if (qemu_logfile && !need_to_open_file) { if (qemu_logfile && !need_to_open_file) {
qemu_mutex_unlock(&qemu_logfile_mutex);
qemu_log_close(); qemu_log_close();
} else if (!qemu_logfile && need_to_open_file) { } else if (!qemu_logfile && need_to_open_file) {
if (logfilename) { if (logfilename) {
@ -105,6 +114,7 @@ void qemu_set_log(int log_flags)
#endif #endif
log_append = 1; log_append = 1;
} }
qemu_mutex_unlock(&qemu_logfile_mutex);
} }
} }
@ -240,12 +250,14 @@ void qemu_log_flush(void)
/* Close the log file */ /* Close the log file */
void qemu_log_close(void) void qemu_log_close(void)
{ {
qemu_mutex_lock(&qemu_logfile_mutex);
if (qemu_logfile) { if (qemu_logfile) {
if (qemu_logfile != stderr) { if (qemu_logfile != stderr) {
fclose(qemu_logfile); fclose(qemu_logfile);
} }
qemu_logfile = NULL; qemu_logfile = NULL;
} }
qemu_mutex_unlock(&qemu_logfile_mutex);
} }
const QEMULogItem qemu_log_items[] = { const QEMULogItem qemu_log_items[] = {