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-rw-r--r--include/exec/log.h33
-rw-r--r--include/qemu/log.h41
-rw-r--r--tcg/tcg.c12
-rw-r--r--util/log.c72
4 files changed, 125 insertions, 33 deletions
diff --git a/include/exec/log.h b/include/exec/log.h
index e2cfd436e6..9bd1e4aa20 100644
--- a/include/exec/log.h
+++ b/include/exec/log.h
@@ -15,8 +15,15 @@
  */
 static inline void log_cpu_state(CPUState *cpu, int flags)
 {
+    QemuLogFile *logfile;
+
     if (qemu_log_enabled()) {
-        cpu_dump_state(cpu, qemu_logfile, flags);
+        rcu_read_lock();
+        logfile = atomic_rcu_read(&qemu_logfile);
+        if (logfile) {
+            cpu_dump_state(cpu, logfile->fd, flags);
+        }
+        rcu_read_unlock();
     }
 }
 
@@ -40,19 +47,37 @@ static inline void log_cpu_state_mask(int mask, CPUState *cpu, int flags)
 static inline void log_target_disas(CPUState *cpu, target_ulong start,
                                     target_ulong len)
 {
-    target_disas(qemu_logfile, cpu, start, len);
+    QemuLogFile *logfile;
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        target_disas(logfile->fd, cpu, start, len);
+    }
+    rcu_read_unlock();
 }
 
 static inline void log_disas(void *code, unsigned long size)
 {
-    disas(qemu_logfile, code, size);
+    QemuLogFile *logfile;
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        disas(logfile->fd, code, size);
+    }
+    rcu_read_unlock();
 }
 
 #if defined(CONFIG_USER_ONLY)
 /* page_dump() output to the log file: */
 static inline void log_page_dump(void)
 {
-    page_dump(qemu_logfile);
+    QemuLogFile *logfile;
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        page_dump(logfile->fd);
+    }
+    rcu_read_unlock();
 }
 #endif
 #endif
diff --git a/include/qemu/log.h b/include/qemu/log.h
index a7c5b01571..e0f4e40628 100644
--- a/include/qemu/log.h
+++ b/include/qemu/log.h
@@ -3,9 +3,16 @@
 
 /* A small part of this API is split into its own header */
 #include "qemu/log-for-trace.h"
+#include "qemu/rcu.h"
+
+typedef struct QemuLogFile {
+    struct rcu_head rcu;
+    FILE *fd;
+} QemuLogFile;
 
 /* Private global variable, don't use */
-extern FILE *qemu_logfile;
+extern QemuLogFile *qemu_logfile;
+
 
 /* 
  * The new API:
@@ -25,7 +32,16 @@ static inline bool qemu_log_enabled(void)
  */
 static inline bool qemu_log_separate(void)
 {
-    return qemu_logfile != NULL && qemu_logfile != stderr;
+    QemuLogFile *logfile;
+    bool res = false;
+
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile && logfile->fd != stderr) {
+        res = true;
+    }
+    rcu_read_unlock();
+    return res;
 }
 
 #define CPU_LOG_TB_OUT_ASM (1 << 0)
@@ -55,8 +71,15 @@ static inline bool qemu_log_separate(void)
 
 static inline FILE *qemu_log_lock(void)
 {
-    qemu_flockfile(qemu_logfile);
-    return logfile->fd;
+    QemuLogFile *logfile;
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        qemu_flockfile(logfile->fd);
+        return logfile->fd;
+    } else {
+        return NULL;
+    }
 }
 
 static inline void qemu_log_unlock(FILE *fd)
@@ -64,6 +87,7 @@ static inline void qemu_log_unlock(FILE *fd)
     if (fd) {
         qemu_funlockfile(fd);
     }
+    rcu_read_unlock();
 }
 
 /* Logging functions: */
@@ -73,9 +97,14 @@ static inline void qemu_log_unlock(FILE *fd)
 static inline void GCC_FMT_ATTR(1, 0)
 qemu_log_vprintf(const char *fmt, va_list va)
 {
-    if (qemu_logfile) {
-        vfprintf(qemu_logfile, fmt, va);
+    QemuLogFile *logfile;
+
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        vfprintf(logfile->fd, fmt, va);
     }
+    rcu_read_unlock();
 }
 
 /* log only if a bit is set on the current loglevel mask:
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 0511266d85..4f616ba38b 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -2114,9 +2114,17 @@ static void tcg_dump_ops(TCGContext *s, bool have_prefs)
         }
 
         if (have_prefs || op->life) {
-            for (; col < 40; ++col) {
-                putc(' ', qemu_logfile);
+
+            QemuLogFile *logfile;
+
+            rcu_read_lock();
+            logfile = atomic_rcu_read(&qemu_logfile);
+            if (logfile) {
+                for (; col < 40; ++col) {
+                    putc(' ', logfile->fd);
+                }
             }
+            rcu_read_unlock();
         }
 
         if (op->life) {
diff --git a/util/log.c b/util/log.c
index 953a66b5a8..867264da8d 100644
--- a/util/log.c
+++ b/util/log.c
@@ -28,7 +28,7 @@
 
 static char *logfilename;
 static QemuMutex qemu_logfile_mutex;
-FILE *qemu_logfile;
+QemuLogFile *qemu_logfile;
 int qemu_loglevel;
 static int log_append = 0;
 static GArray *debug_regions;
@@ -37,10 +37,14 @@ static GArray *debug_regions;
 int qemu_log(const char *fmt, ...)
 {
     int ret = 0;
-    if (qemu_logfile) {
+    QemuLogFile *logfile;
+
+    rcu_read_lock();
+    logfile = atomic_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.  */
@@ -48,6 +52,7 @@ int qemu_log(const char *fmt, ...)
             ret = 0;
         }
     }
+    rcu_read_unlock();
     return ret;
 }
 
@@ -56,12 +61,24 @@ 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;
@@ -79,43 +96,47 @@ void qemu_set_log(int log_flags)
     }
     qemu_mutex_lock(&qemu_logfile_mutex);
     if (qemu_logfile && !need_to_open_file) {
-        qemu_mutex_unlock(&qemu_logfile_mutex);
-        qemu_log_close();
+        logfile = qemu_logfile;
+        atomic_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;
         }
-        qemu_mutex_unlock(&qemu_logfile_mutex);
+        atomic_rcu_set(&qemu_logfile, logfile);
     }
+    qemu_mutex_unlock(&qemu_logfile_mutex);
 }
 
 void qemu_log_needs_buffers(void)
@@ -244,18 +265,27 @@ out:
 /* fflush() the log file */
 void qemu_log_flush(void)
 {
-    fflush(qemu_logfile);
+    QemuLogFile *logfile;
+
+    rcu_read_lock();
+    logfile = atomic_rcu_read(&qemu_logfile);
+    if (logfile) {
+        fflush(logfile->fd);
+    }
+    rcu_read_unlock();
 }
 
 /* Close the log file */
 void qemu_log_close(void)
 {
+    QemuLogFile *logfile;
+
     qemu_mutex_lock(&qemu_logfile_mutex);
-    if (qemu_logfile) {
-        if (qemu_logfile != stderr) {
-            fclose(qemu_logfile);
-        }
-        qemu_logfile = NULL;
+    logfile = qemu_logfile;
+
+    if (logfile) {
+        atomic_rcu_set(&qemu_logfile, NULL);
+        call_rcu(logfile, qemu_logfile_free, rcu);
     }
     qemu_mutex_unlock(&qemu_logfile_mutex);
 }