Support 'help' as a synonym for '?' in command line options

For command line options which permit '?' meaning 'please list the
permitted values', add support for 'help' as a synonym, by abstracting
the check out into a helper function.

This change means that in some cases where we were being lazy in
our string parsing, "?junk" will now be rejected as an invalid option
rather than being (undocumentedly) treated the same way as "?".

Update the documentation to use 'help' rather than '?', since '?'
is a shell metacharacter and thus prone to fail confusingly if there
is a single character filename in the current working directory and
the '?' has not been escaped. It's therefore better to steer users
towards 'help', though '?' is retained for backwards compatibility.

We do not, however, update the output of the system emulator's -help
(or any documentation autogenerated from the qemu-options.hx which
is the source of the -help text) because libvirt parses our -help
output and will break. At a later date when QEMU provides a better
interface so libvirt can avoid having to do this, we can update the
-help text too.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
17 files changed
tree: a923a40f0857c4de2e8feddbdadc4a2cc6d6bb59
  1. audio/
  2. block/
  3. bsd-user/
  4. default-configs/
  5. docs/
  6. fpu/
  7. fsdev/
  8. gdb-xml/
  9. hw/
  10. include/
  11. libcacard/
  12. linux-headers/
  13. linux-user/
  14. net/
  15. pc-bios/
  16. qapi/
  17. qga/
  18. QMP/
  19. qom/
  20. roms/
  21. scripts/
  22. slirp/
  23. sysconfigs/
  24. target-alpha/
  25. target-arm/
  26. target-cris/
  27. target-i386/
  28. target-lm32/
  29. target-m68k/
  30. target-microblaze/
  31. target-mips/
  32. target-openrisc/
  33. target-ppc/
  34. target-s390x/
  35. target-sh4/
  36. target-sparc/
  37. target-unicore32/
  38. target-xtensa/
  39. tcg/
  40. tests/
  41. trace/
  42. ui/
  43. .gitignore
  44. .gitmodules
  45. .mailmap
  46. a.out.h
  47. acl.c
  48. acl.h
  49. aes.c
  50. aes.h
  51. aio.c
  52. alpha-dis.c
  53. alpha.ld
  54. arch_init.c
  55. arch_init.h
  56. arm-dis.c
  57. arm.ld
  58. async.c
  59. balloon.c
  60. balloon.h
  61. bitmap.c
  62. bitmap.h
  63. bitops.c
  64. bitops.h
  65. block-migration.c
  66. block-migration.h
  67. block.c
  68. block.h
  69. block_int.h
  70. blockdev.c
  71. blockdev.h
  72. bswap.h
  73. bt-host.c
  74. bt-host.h
  75. bt-vhci.c
  76. buffered_file.c
  77. buffered_file.h
  78. cache-utils.c
  79. cache-utils.h
  80. Changelog
  81. cmd.c
  82. cmd.h
  83. CODING_STYLE
  84. compatfd.c
  85. compatfd.h
  86. compiler.h
  87. config.h
  88. configure
  89. console.c
  90. console.h
  91. COPYING
  92. COPYING.LIB
  93. coroutine-gthread.c
  94. coroutine-sigaltstack.c
  95. coroutine-ucontext.c
  96. coroutine-win32.c
  97. cpu-all.h
  98. cpu-common.h
  99. cpu-defs.h
  100. cpu-exec.c
  101. cpus.c
  102. cpus.h
  103. cputlb.c
  104. cputlb.h
  105. cris-dis.c
  106. cursor.c
  107. cursor_hidden.xpm
  108. cursor_left_ptr.xpm
  109. cutils.c
  110. def-helper.h
  111. device_tree.c
  112. device_tree.h
  113. dis-asm.h
  114. disas.c
  115. disas.h
  116. dma-helpers.c
  117. dma.h
  118. dump-stub.c
  119. dump.c
  120. dump.h
  121. dyngen-exec.h
  122. elf.h
  123. envlist.c
  124. envlist.h
  125. error.c
  126. error.h
  127. error_int.h
  128. event_notifier.c
  129. event_notifier.h
  130. exec-all.h
  131. exec-memory.h
  132. exec-obsolete.h
  133. exec.c
  134. gdbstub.c
  135. gdbstub.h
  136. gen-icount.h
  137. HACKING
  138. hmp-commands.hx
  139. hmp.c
  140. hmp.h
  141. host-utils.c
  142. host-utils.h
  143. hppa-dis.c
  144. hppa.ld
  145. i386-dis.c
  146. i386.ld
  147. ia64-dis.c
  148. ia64.ld
  149. input.c
  150. int128.h
  151. iohandler.c
  152. ioport.c
  153. ioport.h
  154. iorange.h
  155. iov.c
  156. iov.h
  157. json-lexer.c
  158. json-lexer.h
  159. json-parser.c
  160. json-parser.h
  161. json-streamer.c
  162. json-streamer.h
  163. kvm-all.c
  164. kvm-stub.c
  165. kvm.h
  166. libfdt_env.h
  167. LICENSE
  168. linux-aio.c
  169. lm32-dis.c
  170. m68k-dis.c
  171. m68k.ld
  172. main-loop.c
  173. main-loop.h
  174. MAINTAINERS
  175. Makefile
  176. Makefile.dis
  177. Makefile.hw
  178. Makefile.objs
  179. Makefile.target
  180. Makefile.user
  181. memory.c
  182. memory.h
  183. memory_mapping-stub.c
  184. memory_mapping.c
  185. memory_mapping.h
  186. microblaze-dis.c
  187. migration-exec.c
  188. migration-fd.c
  189. migration-tcp.c
  190. migration-unix.c
  191. migration.c
  192. migration.h
  193. mips-dis.c
  194. mips.ld
  195. module.c
  196. module.h
  197. monitor.c
  198. monitor.h
  199. nbd.c
  200. nbd.h
  201. net.c
  202. net.h
  203. notify.c
  204. notify.h
  205. os-posix.c
  206. os-win32.c
  207. osdep.c
  208. osdep.h
  209. oslib-posix.c
  210. oslib-win32.c
  211. path.c
  212. pci-ids.txt
  213. pflib.c
  214. pflib.h
  215. poison.h
  216. posix-aio-compat.c
  217. ppc-dis.c
  218. ppc.ld
  219. ppc64.ld
  220. qapi-schema-guest.json
  221. qapi-schema-test.json
  222. qapi-schema.json
  223. qbool.c
  224. qbool.h
  225. qdict-test-data.txt
  226. qdict.c
  227. qdict.h
  228. qemu-aio.h
  229. qemu-barrier.h
  230. qemu-bridge-helper.c
  231. qemu-char.c
  232. qemu-char.h
  233. qemu-common.h
  234. qemu-config.c
  235. qemu-config.h
  236. qemu-coroutine-int.h
  237. qemu-coroutine-io.c
  238. qemu-coroutine-lock.c
  239. qemu-coroutine-sleep.c
  240. qemu-coroutine.c
  241. qemu-coroutine.h
  242. qemu-doc.texi
  243. qemu-error.c
  244. qemu-error.h
  245. qemu-file.h
  246. qemu-ga.c
  247. qemu-img-cmds.hx
  248. qemu-img.c
  249. qemu-img.texi
  250. qemu-io.c
  251. qemu-lock.h
  252. qemu-log.c
  253. qemu-log.h
  254. qemu-nbd.c
  255. qemu-nbd.texi
  256. qemu-objects.h
  257. qemu-option-internal.h
  258. qemu-option.c
  259. qemu-option.h
  260. qemu-options-wrapper.h
  261. qemu-options.h
  262. qemu-options.hx
  263. qemu-os-posix.h
  264. qemu-os-win32.h
  265. qemu-progress.c
  266. qemu-queue.h
  267. qemu-sockets.c
  268. qemu-tech.texi
  269. qemu-thread-posix.c
  270. qemu-thread-posix.h
  271. qemu-thread-win32.c
  272. qemu-thread-win32.h
  273. qemu-thread.h
  274. qemu-timer-common.c
  275. qemu-timer.c
  276. qemu-timer.h
  277. qemu-tls.h
  278. qemu-tool.c
  279. qemu-user.c
  280. qemu-x509.h
  281. qemu-xattr.h
  282. qemu.sasl
  283. qemu_socket.h
  284. qerror.c
  285. qerror.h
  286. qfloat.c
  287. qfloat.h
  288. qint.c
  289. qint.h
  290. qjson.c
  291. qjson.h
  292. qlist.c
  293. qlist.h
  294. qmp-commands.hx
  295. qmp.c
  296. qobject.h
  297. qstring.c
  298. qstring.h
  299. qtest.c
  300. qtest.h
  301. range.h
  302. readline.c
  303. readline.h
  304. README
  305. rules.mak
  306. s390-dis.c
  307. s390.ld
  308. savevm.c
  309. sh4-dis.c
  310. softmmu-semi.h
  311. softmmu_defs.h
  312. softmmu_exec.h
  313. softmmu_header.h
  314. softmmu_template.h
  315. sparc-dis.c
  316. sparc.ld
  317. sparc64.ld
  318. spice-qemu-char.c
  319. sysemu.h
  320. targphys.h
  321. tcg-runtime.c
  322. tci-dis.c
  323. tci.c
  324. thunk.c
  325. thunk.h
  326. TODO
  327. trace-events
  328. translate-all.c
  329. uboot_image.h
  330. user-exec.c
  331. VERSION
  332. version.rc
  333. vgafont.h
  334. vl.c
  335. vmstate.h
  336. x86_64.ld
  337. xen-all.c
  338. xen-mapcache.c
  339. xen-mapcache.h
  340. xen-stub.c