Command line support for altering the log file location

Add command line support for logging to a location other than /tmp/qemu.log.

With logging enabled (command line option -d), the log is written to
the hard-coded path /tmp/qemu.log. This patch adds support for writing
the log to a different location by passing the -D option.

Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/vl.c b/vl.c
index c1cc614666..7b83c43e73 100644
--- a/vl.c
+++ b/vl.c
@@ -2067,6 +2067,8 @@ int main(int argc, char **argv, char **envp)
 #endif
     int defconfig = 1;
     const char *trace_file = NULL;
+    const char *log_mask = NULL;
+    const char *log_file = NULL;
 
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
@@ -2441,7 +2443,10 @@ int main(int argc, char **argv, char **envp)
                 break;
 #endif
             case QEMU_OPTION_d:
-                set_cpu_log(optarg);
+                log_mask = optarg;
+                break;
+            case QEMU_OPTION_D:
+                log_file = optarg;
                 break;
             case QEMU_OPTION_s:
                 gdbstub_dev = "tcp::" DEFAULT_GDBSTUB_PORT;
@@ -2907,6 +2912,18 @@ int main(int argc, char **argv, char **envp)
     }
     loc_set_none();
 
+    /* Open the logfile at this point, if necessary. We can't open the logfile
+     * when encountering either of the logging options (-d or -D) because the
+     * other one may be encountered later on the command line, changing the
+     * location or level of logging.
+     */
+    if (log_mask) {
+        if (log_file) {
+            set_cpu_log_filename(log_file);
+        }
+        set_cpu_log(log_mask);
+    }
+
     if (!st_init(trace_file)) {
         fprintf(stderr, "warning: unable to initialize simple trace backend\n");
     }