host-hpux.c revision 1.1 
1/* HP-UX host-specific hook definitions.
2   Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
3
4   This file is part of GCC.
5
6   GCC is free software; you can redistribute it and/or modify it
7   under the terms of the GNU General Public License as published
8   by the Free Software Foundation; either version 3, or (at your
9   option) any later version.
10
11   GCC is distributed in the hope that it will be useful, but WITHOUT
12   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
14   License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GCC; see the file COPYING3.  If not see
18   <http://www.gnu.org/licenses/>.  */
19
20#include "config.h"
21#include "system.h"
22#include "coretypes.h"
23#include <sys/mman.h>
24#include <unistd.h>
25#include "hosthooks.h"
26#include "hosthooks-def.h"
27
28#ifndef MAP_FAILED
29#define MAP_FAILED (void *)-1L
30#endif
31
32static void *hpux_gt_pch_get_address (size_t, int);
33static int hpux_gt_pch_use_address (void *, size_t, int, size_t);
34
35#undef HOST_HOOKS_GT_PCH_GET_ADDRESS
36#define HOST_HOOKS_GT_PCH_GET_ADDRESS hpux_gt_pch_get_address
37#undef HOST_HOOKS_GT_PCH_USE_ADDRESS
38#define HOST_HOOKS_GT_PCH_USE_ADDRESS hpux_gt_pch_use_address
39
40/* For various ports, try to guess a fixed spot in the vm space
41   that's probably free.  */
42#if (defined(__hppa__) || defined(__ia64__)) && defined(__LP64__)
43# define TRY_EMPTY_VM_SPACE	0x8000000000000000
44#elif defined(__hppa__) || defined(__ia64__)
45# define TRY_EMPTY_VM_SPACE	0x60000000
46#else
47# define TRY_EMPTY_VM_SPACE	0
48#endif
49
50/* Determine a location where we might be able to reliably allocate
51   SIZE bytes.  FD is the PCH file, though we should return with the
52   file unmapped.  */
53
54static void *
55hpux_gt_pch_get_address (size_t size, int fd)
56{
57  void *addr;
58
59  addr = mmap ((void *)TRY_EMPTY_VM_SPACE, size, PROT_READ | PROT_WRITE,
60	       MAP_PRIVATE, fd, 0);
61
62  /* If we failed the map, that means there's *no* free space.  */
63  if (addr == (void *) MAP_FAILED)
64    return NULL;
65  /* Unmap the area before returning.  */
66  munmap (addr, size);
67
68  return addr;
69}
70
71/* Map SIZE bytes of FD+OFFSET at BASE.  Return 1 if we succeeded at
72   mapping the data at BASE, -1 if we couldn't.
73
74   It's not possibly to reliably mmap a file using MAP_PRIVATE to
75   a specific START address on either hpux or linux.  First we see
76   if mmap with MAP_PRIVATE works.  If it does, we are off to the
77   races.  If it doesn't, we try an anonymous private mmap since the
78   kernel is more likely to honor the BASE address in anonymous maps.
79   We then copy the data to the anonymous private map.  This assumes
80   of course that we don't need to change the data in the PCH file
81   after it is created.
82
83   This approach obviously causes a performance penalty but there is
84   little else we can do given the current PCH implementation.  */
85
86static int
87hpux_gt_pch_use_address (void *base, size_t size, int fd, size_t offset)
88{
89  void *addr;
90
91  /* We're called with size == 0 if we're not planning to load a PCH
92     file at all.  This allows the hook to free any static space that
93     we might have allocated at link time.  */
94  if (size == 0)
95    return -1;
96
97  /* Try to map the file with MAP_PRIVATE.  */
98  addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, offset);
99
100  if (addr == base)
101    return 1;
102
103  if (addr != (void *) MAP_FAILED)
104    munmap (addr, size);
105
106  /* Try to make an anonymous private mmap at the desired location.  */
107  addr = mmap (base, size, PROT_READ | PROT_WRITE,
108	       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
109
110  if (addr != base)
111    {
112      if (addr != (void *) MAP_FAILED)
113        munmap (addr, size);
114      return -1;
115    }
116
117  if (lseek (fd, offset, SEEK_SET) == (off_t)-1)
118    return -1;
119
120  while (size)
121    {
122      ssize_t nbytes;
123
124      nbytes = read (fd, base, MIN (size, SSIZE_MAX));
125      if (nbytes <= 0)
126        return -1;
127      base = (char *) base + nbytes;
128      size -= nbytes;
129    }
130
131  return 1;
132}
133
134
135const struct host_hooks host_hooks = HOST_HOOKS_INITIALIZER;
136