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2001-11-12  Ulrich Drepper  <drepper@redhat.com>

	* elf/dl-reloc.c (_dl_relocate_object): Avoid iterating over
	program header twice.  Construct list with the needed information.
This commit is contained in:
Ulrich Drepper 2001-11-12 21:04:45 +00:00
parent e5b27fe5d1
commit f133c09767
2 changed files with 56 additions and 48 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2001-11-12 Ulrich Drepper <drepper@redhat.com>
* elf/dl-reloc.c (_dl_relocate_object): Avoid iterating over
program header twice. Construct list with the needed information.
2001-11-10 Ulrich Drepper <drepper@redhat.com>
* po/ca.po: Update from translation team.

99
elf/dl-reloc.c
View File

@ -35,6 +35,16 @@ void
_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
int lazy, int consider_profiling)
{
struct textrels
{
caddr_t start;
size_t len;
int prot;
struct textrels *next;
} *textrels = NULL;
/* Initialize it to make the compiler happy. */
const char *errstring = NULL;
if (l->l_relocated)
return;
@ -48,6 +58,9 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
_dl_printf ("\nrelocation processing: %s%s\n",
l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : "");
/* DT_TEXTREL is now in level 2 and might phase out at some time.
But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make
testing easier and therefore it will be available at all time. */
if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
{
/* Bletch. We must make read-only segments writable
@ -56,15 +69,36 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
{
caddr_t mapstart = ((caddr_t) l->l_addr +
(ph->p_vaddr & ~(_dl_pagesize - 1)));
caddr_t mapend = ((caddr_t) l->l_addr +
((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
& ~(_dl_pagesize - 1)));
if (__builtin_expect (__mprotect (mapstart, mapend - mapstart,
PROT_READ|PROT_WRITE), 0) < 0)
_dl_signal_error (errno, l->l_name, NULL, N_("\
cannot make segment writable for relocation"));
struct textrels *newp;
newp = (struct textrels *) alloca (sizeof (*newp));
newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
& ~(_dl_pagesize - 1))
- (ph->p_vaddr & ~(_dl_pagesize - 1)));
newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1))
+ (caddr_t) l->l_addr);
if (__mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0)
{
errstring = N_("cannot make segment writable for relocation");
call_error:
_dl_signal_error (errno, l->l_name, NULL, errstring);
}
#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
newp->prot = (PF_TO_PROT
>> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
#else
newp->prot = 0;
if (ph->p_flags & PF_R)
newp->prot |= PROT_READ;
if (ph->p_flags & PF_W)
newp->prot |= PROT_WRITE;
if (ph->p_flags & PF_X)
newp->prot |= PROT_EXEC;
#endif
newp->next = textrels;
textrels = newp;
}
}
@ -122,8 +156,6 @@ cannot make segment writable for relocation"));
if (__builtin_expect (consider_profiling, 0))
{
const char *errstring = NULL;
/* Allocate the array which will contain the already found
relocations. If the shared object lacks a PLT (for example
if it only contains lead function) the l_info[DT_PLTRELSZ]
@ -152,45 +184,16 @@ cannot make segment writable for relocation"));
/* Mark the object so we know this work has been done. */
l->l_relocated = 1;
/* DT_TEXTREL is now in level 2 and might phase out at some time.
But we rewrite the DT_FLAGS entry to make testing easier and
therefore it will be available at all time. */
if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
/* Undo the segment protection changes. */
while (__builtin_expect (textrels != NULL, 0))
{
/* Undo the protection change we made before relocating. */
const ElfW(Phdr) *ph;
for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
{
caddr_t mapstart = ((caddr_t) l->l_addr +
(ph->p_vaddr & ~(_dl_pagesize - 1)));
caddr_t mapend = ((caddr_t) l->l_addr +
((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
& ~(_dl_pagesize - 1)));
int prot;
if (__mprotect (textrels->start, textrels->len, textrels->prot) < 0)
{
errstring = N_("cannot restore segment prot after reloc");
goto call_error;
}
#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
prot = (PF_TO_PROT
>> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
#else
prot = 0;
if (ph->p_flags & PF_R)
prot |= PROT_READ;
if (ph->p_flags & PF_W)
prot |= PROT_WRITE;
if (ph->p_flags & PF_X)
prot |= PROT_EXEC;
#endif
if (__builtin_expect (__mprotect (mapstart, mapend - mapstart,
prot), 0) < 0)
_dl_signal_error (errno, l->l_name, NULL,
N_("can't restore segment prot after reloc"));
#ifdef CLEAR_CACHE
CLEAR_CACHE (mapstart, mapend);
#endif
}
textrels = textrels->next;
}
}