[tor-bugs] #25399 [Core Tor/Tor]: mmap length doesn't need to be page-aligned

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#25399: mmap length doesn't need to be page-aligned
-----------------------------+------------------------------------
 Reporter:  Hello71          |          Owner:  (none)
     Type:  defect           |         Status:  merge_ready
 Priority:  Low              |      Milestone:  Tor: 0.3.4.x-final
Component:  Core Tor/Tor     |        Version:
 Severity:  Minor            |     Resolution:
 Keywords:  review-group-34  |  Actual Points:
Parent ID:                   |         Points:  0.5
 Reviewer:  ahf              |        Sponsor:
-----------------------------+------------------------------------
Changes (by ahf):

 * status:  needs_review => merge_ready


Comment:

 As far as I can tell this looks good. Even the man pages mentions that
 `getpagesize()` is deprecated and `sysconf(_SC_PAGESIZE)` should be used
 instead.

 The interesting part from POSIX:

 {{{
 The off argument is constrained to be aligned and sized according to the
 value
 returned by sysconf() when passed _SC_PAGESIZE or _SC_PAGE_SIZE. When
 MAP_FIXED
 is specified, the argument addr must also meet these constraints. The
 implementation performs mapping operations over whole pages. Thus, while
 the
 argument len need not meet a size or alignment constraint, the
 implementation
 will include, in any mapping operation, any partial page specified by the
 range
 [pa, pa + len).
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25399#comment:6>
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