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Bug 592194 - Fix missing _SC_PAGE_SIZE macro 

Autoconfiscate a simple call to mprotect() even more.
This commit is contained in:
Behdad Esfahbod 2009-08-18 15:49:23 -04:00
parent 3c69bd46e2
commit 4ff2a58952
1 changed files with 63 additions and 37 deletions
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100
src/hb-blob.c
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@ -234,6 +234,59 @@ hb_blob_is_writeable (hb_blob_t *blob)
return mode == HB_MEMORY_MODE_WRITEABLE;
}
static hb_bool_t
_try_make_writeable_inplace_unix_locked (hb_blob_t *blob)
{
#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
unsigned int pagesize = -1, mask, length;
const char *addr;
#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
pagesize = (unsigned int) sysconf (_SC_PAGE_SIZE);
#elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
pagesize = (unsigned int) sysconf (_SC_PAGESIZE);
#elif defined(HAVE_GETPAGESIZE)
pagesize = (unsigned int) getpagesize ();
#endif
if ((unsigned int) -1 == pagesize) {
#if HB_DEBUG
fprintf (stderr, "%p %s: failed to get pagesize: %s\n", blob, __FUNCTION__, strerror (errno));
#endif
return FALSE;
}
#if HB_DEBUG
fprintf (stderr, "%p %s: pagesize is %u\n", blob, __FUNCTION__, pagesize);
#endif
mask = ~(pagesize-1);
addr = (const char *) (((size_t) blob->data) & mask);
length = (const char *) (((size_t) blob->data + blob->length + pagesize-1) & mask) - addr;
#if HB_DEBUG
fprintf (stderr, "%p %s: calling mprotect on [%p..%p] (%d bytes)\n",
blob, __FUNCTION__,
addr, addr+length, length);
#endif
if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
#if HB_DEBUG
fprintf (stderr, "%p %s: %s\n", blob, __FUNCTION__, strerror (errno));
#endif
return FALSE;
}
#if HB_DEBUG
fprintf (stderr, "%p %s: successfully made [%p..%p] (%d bytes) writeable\n",
blob, __FUNCTION__,
addr, addr+length, length);
#endif
return TRUE;
#else
return FALSE;
#endif
}
hb_bool_t
hb_blob_try_writeable_inplace (hb_blob_t *blob)
{
@ -244,53 +297,26 @@ hb_blob_try_writeable_inplace (hb_blob_t *blob)
hb_mutex_lock (blob->lock);
#ifdef HAVE_SYS_MMAN_H
if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITEABLE) {
unsigned int pagesize, mask, length;
const char *addr;
#if HB_DEBUG
fprintf (stderr, "%p %s: making writeable\n", blob, __FUNCTION__);
#endif
pagesize = (unsigned int) sysconf(_SC_PAGE_SIZE);
if ((unsigned int) -1 == pagesize) {
if (_try_make_writeable_inplace_unix_locked (blob)) {
#if HB_DEBUG
fprintf (stderr, "%p %s: %s\n", blob, __FUNCTION__, strerror (errno));
fprintf (stderr, "%p %s: making writeable -> succeeded\n", blob, __FUNCTION__);
#endif
goto done;
blob->mode = HB_MEMORY_MODE_WRITEABLE;
} else {
#if HB_DEBUG
fprintf (stderr, "%p %s: making writeable -> FAILED\n", blob, __FUNCTION__);
#endif
/* Failed to make writeable inplace, mark that */
blob->mode = HB_MEMORY_MODE_READONLY;
}
#if HB_DEBUG
fprintf (stderr, "%p %s: pagesize is %u\n", blob, __FUNCTION__, pagesize);
#endif
mask = ~(pagesize-1);
addr = (const char *) (((size_t) blob->data) & mask);
length = (const char *) (((size_t) blob->data + blob->length + pagesize-1) & mask) - addr;
#if HB_DEBUG
fprintf (stderr, "%p %s: calling mprotect on [%p..%p] (%d bytes)\n",
blob, __FUNCTION__,
addr, addr+length, length);
#endif
if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
#if HB_DEBUG
fprintf (stderr, "%p %s: %s\n", blob, __FUNCTION__, strerror (errno));
#endif
goto done;
}
blob->mode = HB_MEMORY_MODE_WRITEABLE;
#if HB_DEBUG
fprintf (stderr, "%p %s: successfully made [%p..%p] (%d bytes) writeable\n",
blob, __FUNCTION__,
addr, addr+length, length);
#endif
}
#else /* !HAVE_SYS_MMAN_H */
#warning "No way to make readonly memory writeable. This is suboptimal."
#endif
done:
mode = blob->mode;
hb_mutex_unlock (blob->lock);