[Qemu-devel] [PATCH, RFC] Use help sub-sections to create sub-help options

[Laurent Vivier <lvivier@redhat.com>]

As '-help' output is 400 lines long it is not easy
to find information, but generally we know from
which area we want the information.

As subsections already exist in the help description,
add some command options to only display the wanted
subsection.

As more is better, this patch adds 13 lines to the -help output:

    -help-standard  display standard options
    -help-block     display block options
    -help-usb       display usb options
    -help-display   display display options
    -help-machine   display machine options
    -help-network   display network options
    -help-character display character options
    -help-url       display url options
    -help-bt        display bt options
    -help-tpm       display tpm options
    -help-kernel    display kernel options
    -help-expert    display expert options
    -help-object    display object options

Example:

    $ qemu-system-x86_64 -help-kernel
    Linux/Multiboot boot specific:
    -kernel bzImage use 'bzImage' as kernel image
    -append cmdline use 'cmdline' as kernel command line
    -initrd file    use 'file' as initial ram disk
    -dtb    file    use 'file' as device tree image

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 qemu-options.hx | 137 +++++++++++++++++++++++++++++++++++++++++++--
 vl.c            | 169 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 302 insertions(+), 4 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 77f5853..091cc21 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -6,17 +6,122 @@ HXCOMM construct option structures, enums and help message for specified
 HXCOMM architectures.
 HXCOMM HXCOMM can be used for comments, discarded from both texi and C
 
+#if !(defined(QEMU_HELP_DISABLE_STANDARD) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Standard options:)
 STEXI
 @table @option
 ETEXI
 
 DEF("help", 0, QEMU_OPTION_h,
-    "-h or -help     display this help and exit\n", QEMU_ARCH_ALL)
+    "-h or -help     display all help options and exit\n", QEMU_ARCH_ALL)
 STEXI
 @item -h
 @findex -h
-Display help and exit
+Display all help options and exit
+ETEXI
+
+DEF("help-standard", 0, QEMU_OPTION_h_standard,
+    "-help-standard  display standard options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-standard
+@findex -help-standard
+Display standard options
+ETEXI
+
+DEF("help-block", 0, QEMU_OPTION_h_block,
+    "-help-block     display block options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-block
+@findex -help-block
+Display block options
+ETEXI
+
+DEF("help-usb", 0, QEMU_OPTION_h_usb,
+    "-help-usb       display usb options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-usb
+@findex -help-usb
+Display usb options
+ETEXI
+
+DEF("help-display", 0, QEMU_OPTION_h_display,
+    "-help-display   display display options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-display
+@findex -help-display
+Display display options
+ETEXI
+
+DEF("help-machine", 0, QEMU_OPTION_h_machine,
+    "-help-machine   display machine options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-machine
+@findex -help-machine
+Display machine options
+ETEXI
+
+DEF("help-network", 0, QEMU_OPTION_h_network,
+    "-help-network   display network options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-network
+@findex -help-network
+Display network options
+ETEXI
+
+DEF("help-character", 0, QEMU_OPTION_h_character,
+    "-help-character display character options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-character
+@findex -help-character
+Display character options
+ETEXI
+
+DEF("help-url", 0, QEMU_OPTION_h_url,
+    "-help-url       display url options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-url
+@findex -help-url
+Display url options
+ETEXI
+
+DEF("help-bt", 0, QEMU_OPTION_h_bt,
+    "-help-bt        display bt options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-bt
+@findex -help-bt
+Display bt options
+ETEXI
+
+DEF("help-tpm", 0, QEMU_OPTION_h_tpm,
+    "-help-tpm       display tpm options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-tpm
+@findex -help-tpm
+Display tpm options
+ETEXI
+
+DEF("help-kernel", 0, QEMU_OPTION_h_kernel,
+    "-help-kernel    display kernel options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-kernel
+@findex -help-kernel
+Display kernel options
+ETEXI
+
+DEF("help-expert", 0, QEMU_OPTION_h_expert,
+    "-help-expert    display expert options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-expert
+@findex -help-expert
+Display expert options
+ETEXI
+
+DEF("help-object", 0, QEMU_OPTION_h_object,
+    "-help-object    display object options\n", QEMU_ARCH_ALL)
+STEXI
+@item -help-object
+@findex -help-object
+Display object options
 ETEXI
 
 DEF("version", 0, QEMU_OPTION_version,
@@ -410,7 +515,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_BLOCK) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Block device options:)
 STEXI
 @table @option
@@ -798,7 +905,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_USB) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(USB options:)
 STEXI
 @table @option
@@ -862,7 +971,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_DISPLAY) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Display options:)
 STEXI
 @table @option
@@ -1329,7 +1440,9 @@ STEXI
 @end table
 ETEXI
 ARCHHEADING(, QEMU_ARCH_I386)
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_MACHINE) && defined(QEMU_OPTIONS_GENERATE_HELP))
 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
 STEXI
 @table @option
@@ -1441,7 +1554,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_NETWORK) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Network options:)
 STEXI
 @table @option
@@ -1995,7 +2110,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_CHARACTER) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Character device options:)
 STEXI
 
@@ -2273,7 +2390,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_URL) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Device URL Syntax:)
 STEXI
 
@@ -2482,7 +2601,9 @@ ETEXI
 STEXI
 @end table
 ETEXI
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_BT) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Bluetooth(R) options:)
 STEXI
 @table @option
@@ -2557,7 +2678,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_TPM) && defined(QEMU_OPTIONS_GENERATE_HELP))
 #ifdef CONFIG_TPM
 DEFHEADING(TPM device options:)
 
@@ -2632,7 +2755,9 @@ ETEXI
 DEFHEADING()
 
 #endif
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_KERNEL) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Linux/Multiboot boot specific:)
 STEXI
 
@@ -2688,7 +2813,9 @@ STEXI
 @end table
 ETEXI
 DEFHEADING()
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_EXPERT) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Debug/Expert options:)
 STEXI
 @table @option
@@ -3510,7 +3637,7 @@ DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
     "                Output vmstate information in JSON format to file.\n"
     "                Use the scripts/vmstate-static-checker.py file to\n"
     "                check for possible regressions in migration code\n"
-    "                by comparing two such vmstate dumps.",
+    "                by comparing two such vmstate dumps.\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -dump-vmstate @var{file}
@@ -3518,7 +3645,9 @@ STEXI
 Dump json-encoded vmstate information for current machine type to file
 in @var{file}
 ETEXI
+#endif
 
+#if !(defined(QEMU_HELP_DISABLE_OBJECT) && defined(QEMU_OPTIONS_GENERATE_HELP))
 DEFHEADING(Generic object creation)
 
 DEF("object", HAS_ARG, QEMU_OPTION_object,
@@ -3571,7 +3700,7 @@ to the RNG daemon.
 @end table
 
 ETEXI
-
+#endif
 
 HXCOMM This is the last statement. Insert new options before this line!
 STEXI
diff --git a/vl.c b/vl.c
index 584ca88..65a815f 100644
--- a/vl.c
+++ b/vl.c
@@ -1931,6 +1931,136 @@ static void help(int exitcode)
     exit(exitcode);
 }
 
+#define QEMU_HELP_DISABLE_BLOCK
+#define QEMU_HELP_DISABLE_USB
+#define QEMU_HELP_DISABLE_DISPLAY
+#define QEMU_HELP_DISABLE_MACHINE
+#define QEMU_HELP_DISABLE_NETWORK
+#define QEMU_HELP_DISABLE_CHARACTER
+#define QEMU_HELP_DISABLE_URL
+#define QEMU_HELP_DISABLE_BT
+#define QEMU_HELP_DISABLE_TPM
+#define QEMU_HELP_DISABLE_KERNEL
+#define QEMU_HELP_DISABLE_EXPERT
+#define QEMU_HELP_DISABLE_OBJECT
+
+static void help_standard(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+
+#define QEMU_HELP_DISABLE_STANDARD
+#undef QEMU_HELP_DISABLE_BLOCK
+static void help_block(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_BLOCK
+#undef QEMU_HELP_DISABLE_USB
+static void help_usb(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_USB
+#undef QEMU_HELP_DISABLE_DISPLAY
+static void help_display(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_DISPLAY
+#undef QEMU_HELP_DISABLE_MACHINE
+static void help_machine(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_MACHINE
+#undef QEMU_HELP_DISABLE_NETWORK
+static void help_network(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_NETWORK
+#undef QEMU_HELP_DISABLE_CHARACTER
+static void help_character(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_CHARACTER
+#undef QEMU_HELP_DISABLE_URL
+static void help_url(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_URL
+#undef QEMU_HELP_DISABLE_BT
+static void help_bt(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_BT
+#undef QEMU_HELP_DISABLE_TPM
+static void help_tpm(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_TPM
+#undef QEMU_HELP_DISABLE_KERNEL
+static void help_kernel(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_KERNEL
+#undef QEMU_HELP_DISABLE_EXPERT
+static void help_expert(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#define QEMU_HELP_DISABLE_EXPERT
+#undef QEMU_HELP_DISABLE_OBJECT
+static void help_object(int exitcode)
+{
+#define QEMU_OPTIONS_GENERATE_HELP
+#include "qemu-options-wrapper.h"
+    exit(exitcode);
+}
+#undef QEMU_HELP_DISABLE_STANDARD
+#undef QEMU_HELP_DISABLE_BLOCK
+#undef QEMU_HELP_DISABLE_USB
+#undef QEMU_HELP_DISABLE_DISPLAY
+#undef QEMU_HELP_DISABLE_NETWORK
+#undef QEMU_HELP_DISABLE_CHARACTER
+#undef QEMU_HELP_DISABLE_URL
+#undef QEMU_HELP_DISABLE_BT
+#undef QEMU_HELP_DISABLE_TPM
+#undef QEMU_HELP_DISABLE_KERNEL
+#undef QEMU_HELP_DISABLE_EXPERT
+#undef QEMU_HELP_DISABLE_OBJECT
+
+
 #define HAS_ARG 0x0001
 
 typedef struct QEMUOption {
@@ -3318,6 +3448,42 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_h:
                 help(0);
                 break;
+            case QEMU_OPTION_h_standard:
+                help_standard(0);
+                break;
+            case QEMU_OPTION_h_block:
+                help_block(0);
+                break;
+            case QEMU_OPTION_h_usb:
+                help_usb(0);
+                break;
+            case QEMU_OPTION_h_display:
+                help_display(0);
+                break;
+            case QEMU_OPTION_h_machine:
+                help_machine(0);
+                break;
+            case QEMU_OPTION_h_network:
+                help_network(0);
+                break;
+            case QEMU_OPTION_h_character:
+                help_character(0);
+                break;
+            case QEMU_OPTION_h_url:
+                help_url(0);
+                break;
+            case QEMU_OPTION_h_bt:
+                help_bt(0);
+                break;
+            case QEMU_OPTION_h_kernel:
+                help_kernel(0);
+                break;
+            case QEMU_OPTION_h_expert:
+                help_expert(0);
+                break;
+            case QEMU_OPTION_h_object:
+                help_object(0);
+                break;
             case QEMU_OPTION_version:
                 version();
                 exit(0);
@@ -3330,6 +3496,9 @@ int main(int argc, char **argv, char **envp)
                 }
                 break;
 #ifdef CONFIG_TPM
+            case QEMU_OPTION_h_tpm:
+                help_tpm(0);
+                break;
             case QEMU_OPTION_tpmdev:
                 if (tpm_config_parse(qemu_find_opts("tpmdev"), optarg) < 0) {
                     exit(1);
-- 
2.1.0