#include "qapi/error.h"
#include "qemu/cutils.h"
#include "trace/control.h"
+#include "qemu/thread.h"
+#include "qemu/lockable.h"
static char *logfilename;
-FILE *qemu_logfile;
+static QemuMutex qemu_logfile_mutex;
+QemuLogFile *qemu_logfile;
int qemu_loglevel;
static int log_append = 0;
static GArray *debug_regions;
int qemu_log(const char *fmt, ...)
{
int ret = 0;
- if (qemu_logfile) {
+ QemuLogFile *logfile;
+
+ rcu_read_lock();
+ logfile = qatomic_rcu_read(&qemu_logfile);
+ if (logfile) {
va_list ap;
va_start(ap, fmt);
- ret = vfprintf(qemu_logfile, fmt, ap);
+ ret = vfprintf(logfile->fd, fmt, ap);
va_end(ap);
/* Don't pass back error results. */
ret = 0;
}
}
+ rcu_read_unlock();
return ret;
}
+static void __attribute__((__constructor__)) qemu_logfile_init(void)
+{
+ qemu_mutex_init(&qemu_logfile_mutex);
+}
+
+static void qemu_logfile_free(QemuLogFile *logfile)
+{
+ g_assert(logfile);
+
+ if (logfile->fd != stderr) {
+ fclose(logfile->fd);
+ }
+ g_free(logfile);
+}
+
static bool log_uses_own_buffers;
/* enable or disable low levels log */
void qemu_set_log(int log_flags)
{
+ bool need_to_open_file = false;
+ QemuLogFile *logfile;
+
qemu_loglevel = log_flags;
#ifdef CONFIG_TRACE_LOG
qemu_loglevel |= LOG_TRACE;
#endif
- if (!qemu_logfile &&
- (is_daemonized() ? logfilename != NULL : qemu_loglevel)) {
+ /*
+ * In all cases we only log if qemu_loglevel is set.
+ * Also:
+ * If not daemonized we will always log either to stderr
+ * or to a file (if there is a logfilename).
+ * If we are daemonized,
+ * we will only log if there is a logfilename.
+ */
+ if (qemu_loglevel && (!is_daemonized() || logfilename)) {
+ need_to_open_file = true;
+ }
+ QEMU_LOCK_GUARD(&qemu_logfile_mutex);
+ if (qemu_logfile && !need_to_open_file) {
+ logfile = qemu_logfile;
+ qatomic_rcu_set(&qemu_logfile, NULL);
+ call_rcu(logfile, qemu_logfile_free, rcu);
+ } else if (!qemu_logfile && need_to_open_file) {
+ logfile = g_new0(QemuLogFile, 1);
if (logfilename) {
- qemu_logfile = fopen(logfilename, log_append ? "a" : "w");
- if (!qemu_logfile) {
+ logfile->fd = fopen(logfilename, log_append ? "a" : "w");
+ if (!logfile->fd) {
+ g_free(logfile);
perror(logfilename);
_exit(1);
}
/* In case we are a daemon redirect stderr to logfile */
if (is_daemonized()) {
- dup2(fileno(qemu_logfile), STDERR_FILENO);
- fclose(qemu_logfile);
+ dup2(fileno(logfile->fd), STDERR_FILENO);
+ fclose(logfile->fd);
/* This will skip closing logfile in qemu_log_close() */
- qemu_logfile = stderr;
+ logfile->fd = stderr;
}
} else {
/* Default to stderr if no log file specified */
assert(!is_daemonized());
- qemu_logfile = stderr;
+ logfile->fd = stderr;
}
/* must avoid mmap() usage of glibc by setting a buffer "by hand" */
if (log_uses_own_buffers) {
static char logfile_buf[4096];
- setvbuf(qemu_logfile, logfile_buf, _IOLBF, sizeof(logfile_buf));
+ setvbuf(logfile->fd, logfile_buf, _IOLBF, sizeof(logfile_buf));
} else {
#if defined(_WIN32)
/* Win32 doesn't support line-buffering, so use unbuffered output. */
- setvbuf(qemu_logfile, NULL, _IONBF, 0);
+ setvbuf(logfile->fd, NULL, _IONBF, 0);
#else
- setvbuf(qemu_logfile, NULL, _IOLBF, 0);
+ setvbuf(logfile->fd, NULL, _IOLBF, 0);
#endif
log_append = 1;
}
- }
- if (qemu_logfile &&
- (is_daemonized() ? logfilename == NULL : !qemu_loglevel)) {
- qemu_log_close();
+ qatomic_rcu_set(&qemu_logfile, logfile);
}
}
* Allow the user to include %d in their logfile which will be
* substituted with the current PID. This is useful for debugging many
* nested linux-user tasks but will result in lots of logs.
+ *
+ * filename may be NULL. In that case, log output is sent to stderr
*/
void qemu_set_log_filename(const char *filename, Error **errp)
{
- char *pidstr;
g_free(logfilename);
logfilename = NULL;
- pidstr = strstr(filename, "%");
- if (pidstr) {
- /* We only accept one %d, no other format strings */
- if (pidstr[1] != 'd' || strchr(pidstr + 2, '%')) {
- error_setg(errp, "Bad logfile format: %s", filename);
- return;
- } else {
- logfilename = g_strdup_printf(filename, getpid());
- }
- } else {
- logfilename = g_strdup(filename);
+ if (filename) {
+ char *pidstr = strstr(filename, "%");
+ if (pidstr) {
+ /* We only accept one %d, no other format strings */
+ if (pidstr[1] != 'd' || strchr(pidstr + 2, '%')) {
+ error_setg(errp, "Bad logfile format: %s", filename);
+ return;
+ } else {
+ logfilename = g_strdup_printf(filename, getpid());
+ }
+ } else {
+ logfilename = g_strdup(filename);
+ }
}
+
qemu_log_close();
qemu_set_log(qemu_loglevel);
}
/* fflush() the log file */
void qemu_log_flush(void)
{
- fflush(qemu_logfile);
+ QemuLogFile *logfile;
+
+ rcu_read_lock();
+ logfile = qatomic_rcu_read(&qemu_logfile);
+ if (logfile) {
+ fflush(logfile->fd);
+ }
+ rcu_read_unlock();
}
/* Close the log file */
void qemu_log_close(void)
{
- if (qemu_logfile) {
- if (qemu_logfile != stderr) {
- fclose(qemu_logfile);
- }
- qemu_logfile = NULL;
+ QemuLogFile *logfile;
+
+ qemu_mutex_lock(&qemu_logfile_mutex);
+ logfile = qemu_logfile;
+
+ if (logfile) {
+ qatomic_rcu_set(&qemu_logfile, NULL);
+ call_rcu(logfile, qemu_logfile_free, rcu);
}
+ qemu_mutex_unlock(&qemu_logfile_mutex);
}
const QEMULogItem qemu_log_items[] = {
#ifdef CONFIG_PLUGIN
{ CPU_LOG_PLUGIN, "plugin", "output from TCG plugins\n"},
#endif
+ { LOG_STRACE, "strace",
+ "log every user-mode syscall, its input, and its result" },
{ 0, NULL, NULL },
};
projects / qemu.git / blobdiff