qemu-log: Abstract out "print usage message about valid log categories"

Abstract out the "print a human readable list of all the
valid log categories" functionality which is currently duplicated
in three separate places. (We leave the monitor.c help_cmd()
implementation as-is since it wants to send the message to
the monitor and add its own information.)
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

bsd-user/main.c

@@ -864,14 +864,10 @@ int main(int argc, char **argv)
     qemu_set_log_filename(log_file);
     if (log_mask) {
         int mask;
-        const CPULogItem *item;
 
         mask = cpu_str_to_log_mask(log_mask);
         if (!mask) {
-            printf("Log items (comma separated):\n");
-            for (item = cpu_log_items; item->mask != 0; item++) {
-                printf("%-10s %s\n", item->name, item->help);
-            }
+            qemu_print_log_usage(stdout);
             exit(1);
         }
         cpu_set_log(mask);

cpus.c

@@ -1178,14 +1178,10 @@ void set_numa_modes(void)
 void set_cpu_log(const char *optarg)
 {
     int mask;
-    const CPULogItem *item;
 
     mask = cpu_str_to_log_mask(optarg);
     if (!mask) {
-        printf("Log items (comma separated):\n");
-        for (item = cpu_log_items; item->mask != 0; item++) {
-            printf("%-10s %s\n", item->name, item->help);
-        }
+        qemu_print_log_usage(stdout);
         exit(1);
     }
     cpu_set_log(mask);

include/qemu/log.h

@@ -157,4 +157,9 @@ static inline void cpu_set_log(int log_flags)
 void qemu_set_log_filename(const char *filename);
 int cpu_str_to_log_mask(const char *str);
 
+/* Print a usage message listing all the valid logging categories
+ * to the specified FILE*.
+ */
+void qemu_print_log_usage(FILE *f);
+
 #endif

linux-user/main.c

@@ -3098,14 +3098,10 @@ static void handle_arg_help(const char *arg)
 static void handle_arg_log(const char *arg)
 {
     int mask;
-    const CPULogItem *item;
 
     mask = cpu_str_to_log_mask(arg);
     if (!mask) {
-        printf("Log items (comma separated):\n");
-        for (item = cpu_log_items; item->mask != 0; item++) {
-            printf("%-10s %s\n", item->name, item->help);
-        }
+        qemu_print_log_usage(stdout);
         exit(1);
     }
     cpu_set_log(mask);

qemu-log.c

@@ -170,3 +170,12 @@ int cpu_str_to_log_mask(const char *str)
     }
     return mask;
 }
+
+void qemu_print_log_usage(FILE *f)
+{
+    const CPULogItem *item;
+    fprintf(f, "Log items (comma separated):\n");
+    for (item = cpu_log_items; item->mask != 0; item++) {
+        fprintf(f, "%-10s %s\n", item->name, item->help);
+    }
+}