remove -writeconfig

Like -set and -readconfig, it would not really be too hard to
extend -writeconfig to parsing mechanisms other than QemuOpts.
However, the uses of -writeconfig are substantially more
limited, as it is generally easier to write the configuration
by hand in the first place.  In addition, -writeconfig does
not even try to detect cases where it prints incorrect
syntax (for example if values have a quote in them, since
qemu_config_parse does not support any kind of escaping.
Just remove it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220414145721.326866-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/about/deprecated.rst

@@ -67,13 +67,6 @@ and will cause a warning.
 The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on``
 rather than ``delay=off``.
 
-``-writeconfig`` (since 6.0)
-'''''''''''''''''''''''''''''
-
-The ``-writeconfig`` option is not able to serialize the entire contents
-of the QEMU command line.  It is thus considered a failed experiment
-and deprecated, with no current replacement.
-
 Userspace local APIC with KVM (x86, since 6.0)
 ''''''''''''''''''''''''''''''''''''''''''''''
 

docs/about/removed-features.rst

@@ -348,6 +348,13 @@ or ``gnutls`` library enabled as a cryptography provider.
 Neither the ``nettle`` library, or the built-in cryptography provider are
 supported on FIPS enabled hosts.
 
+``-writeconfig`` (removed in 7.1)
+'''''''''''''''''''''''''''''''''
+
+The ``-writeconfig`` option was not able to serialize the entire contents
+of the QEMU command line.  It is thus considered a failed experiment
+and removed without a replacement.
+
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
 

include/qemu/config-file.h

@@ -12,7 +12,6 @@ void qemu_add_opts(QemuOptsList *list);
 void qemu_add_drive_opts(QemuOptsList *list);
 int qemu_global_option(const char *str);
 
-void qemu_config_write(FILE *fp);
 int qemu_config_parse(FILE *fp, QemuOptsList **lists, const char *fname,
                       Error **errp);
 

qemu-options.hx

@@ -4622,18 +4622,14 @@ SRST
 ERST
 
 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
-    "-readconfig <file>\n", QEMU_ARCH_ALL)
+    "-readconfig <file>\n"
+    "                read config file\n", QEMU_ARCH_ALL)
 SRST
 ``-readconfig file``
     Read device configuration from file. This approach is useful when
     you want to spawn QEMU process with many command line options but
     you don't want to exceed the command line character limit.
 ERST
-DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
-    "-writeconfig <file>\n"
-    "                read/write config file (deprecated)\n", QEMU_ARCH_ALL)
-SRST
-ERST
 
 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
     "-no-user-config\n"

softmmu/vl.c

@@ -3551,26 +3551,6 @@ void qemu_init(int argc, char **argv, char **envp)
                 display_remote++;
                 break;
 #endif
-            case QEMU_OPTION_writeconfig:
-                {
-                    FILE *fp;
-                    warn_report("-writeconfig is deprecated and will go away without a replacement");
-                    if (strcmp(optarg, "-") == 0) {
-                        fp = stdout;
-                    } else {
-                        fp = fopen(optarg, "w");
-                        if (fp == NULL) {
-                            error_report("open %s: %s", optarg,
-                                         strerror(errno));
-                            exit(1);
-                        }
-                    }
-                    qemu_config_write(fp);
-                    if (fp != stdout) {
-                        fclose(fp);
-                    }
-                    break;
-                }
             case QEMU_OPTION_qtest:
                 qtest_chrdev = optarg;
                 break;

util/qemu-config.c

@@ -314,48 +314,6 @@ void qemu_add_opts(QemuOptsList *list)
     abort();
 }
 
-struct ConfigWriteData {
-    QemuOptsList *list;
-    FILE *fp;
-};
-
-static int config_write_opt(void *opaque, const char *name, const char *value,
-                            Error **errp)
-{
-    struct ConfigWriteData *data = opaque;
-
-    fprintf(data->fp, "  %s = \"%s\"\n", name, value);
-    return 0;
-}
-
-static int config_write_opts(void *opaque, QemuOpts *opts, Error **errp)
-{
-    struct ConfigWriteData *data = opaque;
-    const char *id = qemu_opts_id(opts);
-
-    if (id) {
-        fprintf(data->fp, "[%s \"%s\"]\n", data->list->name, id);
-    } else {
-        fprintf(data->fp, "[%s]\n", data->list->name);
-    }
-    qemu_opt_foreach(opts, config_write_opt, data, NULL);
-    fprintf(data->fp, "\n");
-    return 0;
-}
-
-void qemu_config_write(FILE *fp)
-{
-    struct ConfigWriteData data = { .fp = fp };
-    QemuOptsList **lists = vm_config_groups;
-    int i;
-
-    fprintf(fp, "# qemu config file\n\n");
-    for (i = 0; lists[i] != NULL; i++) {
-        data.list = lists[i];
-        qemu_opts_foreach(data.list, config_write_opts, &data, NULL);
-    }
-}
-
 /* Returns number of config groups on success, -errno on error */
 static int qemu_config_foreach(FILE *fp, QEMUConfigCB *cb, void *opaque,
                                const char *fname, Error **errp)