hw/9pfs: use g_strdup_printf() instead of PATH_MAX limitation

When path is truncated by PATH_MAX limitation, it causes QEMU to access
incorrect file. So use original full path instead of PATH_MAX within
9pfs (need check/process ENOMEM for related memory allocation).

The related test:

 - Environments (for qemu-devel):

   - Host is under fedora17 desktop with ext4fs:

     qemu-system-x86_64 -hda test.img -m 1024 \
       -net nic,vlan=4,model=virtio,macaddr=00:16:35:AF:94:04 \
       -net tap,vlan=4,ifname=tap4,script=no,downscript=no \
       -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=hostshare \
       -fsdev local,security_model=passthrough,id=fsdev0,\
         path=/upstream/vm/data/share/1234567890abcdefghijklmnopqrstuvwxyz\
           ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890acdefghijklmnopqrstuvwxyz\
           ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890/111111111111111111111111111\
           1111111111111111111111111111111111111111111111111111222222222222\
           2222222222222222222222222222222222222222222222222222222222222222\
           2222222222222222222222222222222222233333333333333333333333333333\
           3333333333333333333333333333333333

    - Guest is ubuntu12 server with 9pfs.

      mount -t 9p -o trans=virtio,version=9p2000.L hostshare /share

    - Limitations:

      full path limitation is PATH_MAX (4096B include nul) under Linux.
      file/dir node name maximized length is 256 (include nul) under ext4.

 - Special test:

    Under host, modify the file: "/upstream/vm/data/share/1234567890abcdefg\
      hijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890acdefghijklmno\
      pqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890/111111111111111111111\
      111111111111111111111111111111111111111111111111111111111122222222222\
      222222222222222222222222222222222222222222222222222222222222222222222\
      222222222222222222222222222222233333333333333333333333333333333333333\
      3333333333333333333333333/4444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444444444444444444444444444444444\
      444444444444444444444444444444444444444/55555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      555555555555555555555555555555555555555555555555555555555555555555555\
      55555555/666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666666666666666666666666666666666666666666666666666\
      666666666666666666666/77777777777777777777777777777777777777777777777\
      777777777777777777777777777777777777777777777777777777777777777777777\
      777777777777777777777777777777777777777777777777777777777777777777777\
      77777777777777777777777777777777777777777777777777777777777/888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888888888888888888888888888888888888888888888888888888888888888\
      888888888/99999999999999999999999999999999999999999999999999999999999\
      999999999999999999999999999999999999999999999999999999999999999999999\
      999999999999999999999999999999999999999999999999999999999999999999999\
      99999999999999999999999999999999999999999/000000000000000000000000000\
      000000000000000000000000000000000000000000000000000000000000000000000\
      000000000000000000000000000000000000000000000000000000000000000000000\
      000000000000000000000000000000000000000000000000/aaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\
      bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/ccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc\
      cccccccccc/dddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd\
      dddddddddddddddddddddd/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee\
      eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee/fffffffffffffff\
      fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff\
      fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff\
      ffffffffffffffffffffffffffffffffffffffffffffffffffffffffff/gggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg\
      ggggggggggggggggggggggg/iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii\
      iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii/jjjjjjjjjjjjj\
      jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj\
      jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj/ppppppppppppppppppppp\
      ppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp\
      ppppppppppppppppppppppppppppppppppppppp/test1234567890file.log"
        (need enter dir firstly, then modify file, or can not open it).

   Under guest, still allow modify "test1234567890file.log" (will generate
   "test123456" file with contents).

   After apply this patch, can not open "test1234567890file.log" under guest
   (permission denied).

 - Common test:

   All are still OK after apply this path.

     "mkdir -p", "create/open file/dir", "modify file/dir", "rm file/dir".
     change various mount point paths under host and/or guest.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
8 files changed
tree: 0fb2161b9f48eeab937b25a14f8911003754bf8c
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. default-configs/
  6. disas/
  7. docs/
  8. fpu/
  9. fsdev/
  10. gdb-xml/
  11. hw/
  12. include/
  13. libcacard/
  14. linux-headers/
  15. linux-user/
  16. net/
  17. pc-bios/
  18. po/
  19. qapi/
  20. qga/
  21. qobject/
  22. qom/
  23. roms/
  24. scripts/
  25. slirp/
  26. stubs/
  27. sysconfigs/
  28. target-alpha/
  29. target-arm/
  30. target-cris/
  31. target-i386/
  32. target-lm32/
  33. target-m68k/
  34. target-microblaze/
  35. target-mips/
  36. target-moxie/
  37. target-openrisc/
  38. target-ppc/
  39. target-s390x/
  40. target-sh4/
  41. target-sparc/
  42. target-unicore32/
  43. target-xtensa/
  44. tcg/
  45. tests/
  46. trace/
  47. ui/
  48. util/
  49. .exrc
  50. .gitignore
  51. .gitmodules
  52. .mailmap
  53. .travis.yml
  54. aio-posix.c
  55. aio-win32.c
  56. arch_init.c
  57. async.c
  58. balloon.c
  59. block-migration.c
  60. block.c
  61. blockdev-nbd.c
  62. blockdev.c
  63. blockjob.c
  64. bt-host.c
  65. bt-vhci.c
  66. Changelog
  67. CODING_STYLE
  68. configure
  69. COPYING
  70. COPYING.LIB
  71. coroutine-gthread.c
  72. coroutine-sigaltstack.c
  73. coroutine-ucontext.c
  74. coroutine-win32.c
  75. cpu-exec.c
  76. cpus.c
  77. cputlb.c
  78. device-hotplug.c
  79. device_tree.c
  80. disas.c
  81. dma-helpers.c
  82. dump.c
  83. exec.c
  84. gdbstub.c
  85. HACKING
  86. hmp-commands.hx
  87. hmp.c
  88. hmp.h
  89. iohandler.c
  90. ioport.c
  91. kvm-all.c
  92. kvm-stub.c
  93. LICENSE
  94. main-loop.c
  95. MAINTAINERS
  96. Makefile
  97. Makefile.objs
  98. Makefile.target
  99. memory.c
  100. memory_mapping.c
  101. migration-exec.c
  102. migration-fd.c
  103. migration-rdma.c
  104. migration-tcp.c
  105. migration-unix.c
  106. migration.c
  107. module-common.c
  108. monitor.c
  109. nbd.c
  110. os-posix.c
  111. os-win32.c
  112. page_cache.c
  113. qapi-schema.json
  114. qdev-monitor.c
  115. qdict-test-data.txt
  116. qemu-bridge-helper.c
  117. qemu-char.c
  118. qemu-coroutine-io.c
  119. qemu-coroutine-lock.c
  120. qemu-coroutine-sleep.c
  121. qemu-coroutine.c
  122. qemu-doc.texi
  123. qemu-file.c
  124. qemu-img-cmds.hx
  125. qemu-img.c
  126. qemu-img.texi
  127. qemu-io-cmds.c
  128. qemu-io.c
  129. qemu-log.c
  130. qemu-nbd.c
  131. qemu-nbd.texi
  132. qemu-options-wrapper.h
  133. qemu-options.h
  134. qemu-options.hx
  135. qemu-seccomp.c
  136. qemu-tech.texi
  137. qemu-timer.c
  138. qemu.nsi
  139. qemu.sasl
  140. qmp-commands.hx
  141. qmp.c
  142. qtest.c
  143. README
  144. rules.mak
  145. savevm.c
  146. spice-qemu-char.c
  147. tcg-runtime.c
  148. tci.c
  149. thread-pool.c
  150. thunk.c
  151. tpm.c
  152. trace-events
  153. translate-all.c
  154. translate-all.h
  155. user-exec.c
  156. VERSION
  157. version.rc
  158. vl.c
  159. vmstate.c
  160. xbzrle.c
  161. xen-all.c
  162. xen-mapcache.c
  163. xen-stub.c