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Re: PATH_MAX (Re: [PATCH] system_path: use a static buffer)

From
Lasse Makholm <lasse.makholm@gmail.com>
Date
Mar 21, 2011, 12:37 UTC
Message-ID
<AANLkTinh4K0Crhs39wuZpKhmxcZkSGhKdZNarmHoimoH@mail.gmail.com>
In-Reply-To
<1300700875.2583.8.camel@bee.lab.cmartin.tk>
On 21 March 2011 10:47, Carlos Martín Nieto <cmn@elego.de> wrote:
Show 19 quoted lines
> On vie, 2011-03-18 at 06:38 -0500, Jonathan Nieder wrote:
>> Hi,
>>
>> Nguyen Thai Ngoc Duy wrote:
>>
>> > It was pointed out elsewhere [1] that PATH_MAX only specifies max
>> > length of a path element, not full path. I think we'd need to stay
>> > away from preallocated PATH_MAX-sized arrays.
>>
>> No, PATH_MAX is actually the maximum length of a path, and when you
>> use, say, open(2), it will fail if your path is longer than that.  The
>> maximum length of a path component on most filesytems is 255 or 256;
>> PATH_MAX on Linux is 4096.
>>
>> It is indeed possible to have paths with length longer than that.  The
>> way to support that is to use relative paths wherever possible, which
>
>  So what PATH_MAX describes is the maximum length of a string
> representing a path, but not necessarily the length of the path itself.

According to this at least, PATH_MAX is bogus: http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html

I think the sane thing would be to never rely on a fixed max path length.

-- /Lasse

Previous: Carlos Martín NietoNext: Nguyen Thai Ngoc Duy
Message 36 of 48 in “Fix some errors reported by valgrind”
  1. 0/3 Fix some errors reported by valgrindCarlos Martín Nieto, Mar 14, 2011
  2. 1/3 make_absolute_path: Don't try to copy a string to itselfCarlos Martín Nieto, Mar 14, 2011
  3. Jeff KingMar 14, 2011
  4. Junio C HamanoMar 14, 2011
  5. Carlos Martín NietoMar 14, 2011
  6. Junio C HamanoMar 14, 2011
  7. Carlos Martín NietoMar 15, 2011
  8. Carlos Martín NietoMar 15, 2011
  9. Junio C HamanoMar 15, 2011
  10. Carlos Martín NietoMar 15, 2011
  11. Nguyen Thai Ngoc DuyMar 16, 2011
  12. Carlos Martín NietoMar 16, 2011
  13. Nguyen Thai Ngoc DuyMar 16, 2011
  14. Nguyen Thai Ngoc DuyMar 16, 2011
  15. Carlos Martín NietoMar 16, 2011
  16. 2/3 setup_path(): Free temporary bufferCarlos Martín Nieto, Mar 14, 2011
  17. Jeff KingMar 14, 2011
  18. Carlos Martín NietoMar 14, 2011
  19. system_path: use a static bufferCarlos Martín Nieto, Mar 16, 2011
  20. Erik Faye-LundMar 16, 2011
  21. Carlos Martín NietoMar 16, 2011
  22. system_path: use a static bufferCarlos Martín Nieto, Mar 16, 2011
  23. Junio C HamanoMar 16, 2011
  24. system_path: use a static bufferCarlos Martín Nieto, Mar 17, 2011
  25. system_path: use a static bufferCarlos Martín Nieto, Mar 17, 2011
  26. Junio C HamanoMar 18, 2011
  27. Carlos Martín NietoMar 21, 2011
  28. Jeff KingMar 21, 2011
  29. Carlos Martín NietoMar 21, 2011
  30. Jeff KingMar 21, 2011
  31. Carlos Martín NietoMar 21, 2011
  32. Nguyen Thai Ngoc DuyMar 18, 2011
  33. PATH_MAX (Re: [PATCH] system_path: use a static buffer)Jonathan Nieder, Mar 18, 2011
  34. Nguyen Thai Ngoc DuyMar 18, 2011
  35. Carlos Martín NietoMar 21, 2011
  36. Lasse MakholmMar 21, 2011
  37. Nguyen Thai Ngoc DuyMar 21, 2011
  38. 1/2 wrapper.c: add xgetcwd()Nguyễn Thái Ngọc Duy, Mar 18, 2011
  39. 2/2 setup_gently: use xgetcwd()Nguyễn Thái Ngọc Duy, Mar 18, 2011
  40. Junio C HamanoMar 14, 2011
  41. Carlos Martín NietoMar 14, 2011
  42. Jeff KingMar 15, 2011
  43. t/README: Add a note about running commands under valgrindCarlos Martín Nieto, Mar 15, 2011
  44. Junio C HamanoMar 15, 2011
  45. Carlos Martín NietoMar 15, 2011
  46. 3/3 clone: Free a few pathsCarlos Martín Nieto, Mar 14, 2011
  47. Jonathan NiederMar 14, 2011
  48. Junio C HamanoMar 18, 2011

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