log: Add locking to large logging blocks

Reuse the existing locking provided by stdio to keep in_asm, cpu,
op, op_opt, op_ind, and out_asm as contiguous blocks.

While it isn't possible to interleave e.g. in_asm or op_opt logs
because of the TB lock protecting all code generation, it is
possible to interleave cpu logs, or to interleave a cpu dump with
an out_asm dump.

For mingw32, we appear to have no viable solution for this.  The locking
functions are not properly exported from the system runtime library.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/qemu/log.h b/include/qemu/log.h
index 00bf37fc0f..a50e994c21 100644
--- a/include/qemu/log.h
+++ b/include/qemu/log.h
@@ -51,6 +51,22 @@ static inline bool qemu_loglevel_mask(int mask)
     return (qemu_loglevel & mask) != 0;
 }
 
+/* Lock output for a series of related logs.  Since this is not needed
+ * for a single qemu_log / qemu_log_mask / qemu_log_mask_and_addr, we
+ * assume that qemu_loglevel_mask has already been tested, and that
+ * qemu_loglevel is never set when qemu_logfile is unset.
+ */
+
+static inline void qemu_log_lock(void)
+{
+    qemu_flockfile(qemu_logfile);
+}
+
+static inline void qemu_log_unlock(void)
+{
+    qemu_funlockfile(qemu_logfile);
+}
+
 /* Logging functions: */
 
 /* main logging function