qemu-io: Drop command functions' return values

For qemu-io, a function returns an integer with two possible values: 0
for "qemu-io may continue execution", or 1 for "qemu-io should exit".
However, there is only a single command that returns 1, and that is
"quit".

So let's turn this case into a global variable instead so we can make
better use of the return value in a later patch.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180509194302.21585-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

include/qemu-io.h

@@ -22,7 +22,7 @@
 
 #define CMD_FLAG_GLOBAL ((int)0x80000000) /* don't iterate "args" */
 
-typedef int (*cfunc_t)(BlockBackend *blk, int argc, char **argv);
+typedef void (*cfunc_t)(BlockBackend *blk, int argc, char **argv);
 typedef void (*helpfunc_t)(void);
 
 typedef struct cmdinfo {
@@ -41,10 +41,10 @@ typedef struct cmdinfo {
 
 extern bool qemuio_misalign;
 
-bool qemuio_command(BlockBackend *blk, const char *cmd);
+void qemuio_command(BlockBackend *blk, const char *cmd);
 
 void qemuio_add_command(const cmdinfo_t *ci);
-int qemuio_command_usage(const cmdinfo_t *ci);
+void qemuio_command_usage(const cmdinfo_t *ci);
 void qemuio_complete_command(const char *input,
                              void (*fn)(const char *cmd, void *opaque),
                              void *opaque);

qemu-io.c

@@ -37,6 +37,7 @@
 static char *progname;
 
 static BlockBackend *qemuio_blk;
+static bool quit_qemu_io;
 
 /* qemu-io commands passed using -c */
 static int ncmdline;
@@ -65,11 +66,10 @@ static int get_eof_char(void)
 #endif
 }
 
-static int close_f(BlockBackend *blk, int argc, char **argv)
+static void close_f(BlockBackend *blk, int argc, char **argv)
 {
     blk_unref(qemuio_blk);
     qemuio_blk = NULL;
-    return 0;
 }
 
 static const cmdinfo_t close_cmd = {
@@ -136,7 +136,7 @@ static void open_help(void)
 "\n");
 }
 
-static int open_f(BlockBackend *blk, int argc, char **argv);
+static void open_f(BlockBackend *blk, int argc, char **argv);
 
 static const cmdinfo_t open_cmd = {
     .name       = "open",
@@ -160,7 +160,7 @@ static QemuOptsList empty_opts = {
     },
 };
 
-static int open_f(BlockBackend *blk, int argc, char **argv)
+static void open_f(BlockBackend *blk, int argc, char **argv)
 {
     int flags = BDRV_O_UNMAP;
     int readonly = 0;
@@ -192,25 +192,25 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
             if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) < 0) {
                 error_report("Invalid cache option: %s", optarg);
                 qemu_opts_reset(&empty_opts);
-                return 0;
+                return;
             }
             break;
         case 'd':
             if (bdrv_parse_discard_flags(optarg, &flags) < 0) {
                 error_report("Invalid discard option: %s", optarg);
                 qemu_opts_reset(&empty_opts);
-                return 0;
+                return;
             }
             break;
         case 'o':
             if (imageOpts) {
                 printf("--image-opts and 'open -o' are mutually exclusive\n");
                 qemu_opts_reset(&empty_opts);
-                return 0;
+                return;
             }
             if (!qemu_opts_parse_noisily(&empty_opts, optarg, false)) {
                 qemu_opts_reset(&empty_opts);
-                return 0;
+                return;
             }
             break;
         case 'U':
@@ -218,7 +218,8 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
             break;
         default:
             qemu_opts_reset(&empty_opts);
-            return qemuio_command_usage(&open_cmd);
+            qemuio_command_usage(&open_cmd);
+            return;
         }
     }
 
@@ -229,7 +230,7 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
     if (imageOpts && (optind == argc - 1)) {
         if (!qemu_opts_parse_noisily(&empty_opts, argv[optind], false)) {
             qemu_opts_reset(&empty_opts);
-            return 0;
+            return;
         }
         optind++;
     }
@@ -246,12 +247,11 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
         qobject_unref(opts);
         qemuio_command_usage(&open_cmd);
     }
-    return 0;
 }
 
-static int quit_f(BlockBackend *blk, int argc, char **argv)
+static void quit_f(BlockBackend *blk, int argc, char **argv)
 {
-    return 1;
+    quit_qemu_io = true;
 }
 
 static const cmdinfo_t quit_cmd = {
@@ -392,18 +392,18 @@ static void prep_fetchline(void *opaque)
 
 static void command_loop(void)
 {
-    int i, done = 0, fetchable = 0, prompted = 0;
+    int i, fetchable = 0, prompted = 0;
     char *input;
 
-    for (i = 0; !done && i < ncmdline; i++) {
-        done = qemuio_command(qemuio_blk, cmdline[i]);
+    for (i = 0; !quit_qemu_io && i < ncmdline; i++) {
+        qemuio_command(qemuio_blk, cmdline[i]);
     }
     if (cmdline) {
         g_free(cmdline);
         return;
     }
 
-    while (!done) {
+    while (!quit_qemu_io) {
         if (!prompted) {
             printf("%s", get_prompt());
             fflush(stdout);
@@ -421,7 +421,7 @@ static void command_loop(void)
         if (input == NULL) {
             break;
         }
-        done = qemuio_command(qemuio_blk, input);
+        qemuio_command(qemuio_blk, input);
         g_free(input);
 
         prompted = 0;