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Consolidate link map sorting

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Combine the four places where link maps are sorted into a single function.
This also moves the logic to skip the first map (representing the main
binary) to the callers.
This commit is contained in:
Andreas Schwab
2017-11-07 15:24:19 +01:00
parent de61465c04
commit c2c299fd24
8 changed files with 153 additions and 215 deletions
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105
elf/dl-fini.c
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@@ -25,104 +25,6 @@
typedef void (*fini_t) (void);
void
_dl_sort_fini (struct link_map **maps, size_t nmaps, char *used, Lmid_t ns)
{
/* A list of one element need not be sorted. */
if (nmaps == 1)
return;
/* We can skip looking for the binary itself which is at the front
of the search list for the main namespace. */
unsigned int i = ns == LM_ID_BASE;
uint16_t seen[nmaps];
memset (seen, 0, nmaps * sizeof (seen[0]));
while (1)
{
/* Keep track of which object we looked at this round. */
++seen[i];
struct link_map *thisp = maps[i];
/* Do not handle ld.so in secondary namespaces and object which
are not removed. */
if (thisp != thisp->l_real || thisp->l_idx == -1)
goto skip;
/* Find the last object in the list for which the current one is
a dependency and move the current object behind the object
with the dependency. */
unsigned int k = nmaps - 1;
while (k > i)
{
struct link_map **runp = maps[k]->l_initfini;
if (runp != NULL)
/* Look through the dependencies of the object. */
while (*runp != NULL)
if (__glibc_unlikely (*runp++ == thisp))
{
move:
/* Move the current object to the back past the last
object with it as the dependency. */
memmove (&maps[i], &maps[i + 1],
(k - i) * sizeof (maps[0]));
maps[k] = thisp;
if (used != NULL)
{
char here_used = used[i];
memmove (&used[i], &used[i + 1],
(k - i) * sizeof (used[0]));
used[k] = here_used;
}
if (seen[i + 1] > nmaps - i)
{
++i;
goto next_clear;
}
uint16_t this_seen = seen[i];
memmove (&seen[i], &seen[i + 1], (k - i) * sizeof (seen[0]));
seen[k] = this_seen;
goto next;
}
if (__glibc_unlikely (maps[k]->l_reldeps != NULL))
{
unsigned int m = maps[k]->l_reldeps->act;
struct link_map **relmaps = &maps[k]->l_reldeps->list[0];
/* Look through the relocation dependencies of the object. */
while (m-- > 0)
if (__glibc_unlikely (relmaps[m] == thisp))
{
/* If a cycle exists with a link time dependency,
preserve the latter. */
struct link_map **runp = thisp->l_initfini;
if (runp != NULL)
while (*runp != NULL)
if (__glibc_unlikely (*runp++ == maps[k]))
goto ignore;
goto move;
}
ignore:;
}
--k;
}
skip:
if (++i == nmaps)
break;
next_clear:
memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0]));
next:;
}
}
void
_dl_fini (void)
{
@@ -186,8 +88,11 @@ _dl_fini (void)
assert (ns == LM_ID_BASE || i == nloaded || i == nloaded - 1);
unsigned int nmaps = i;
/* Now we have to do the sorting. */
_dl_sort_fini (maps, nmaps, NULL, ns);
/* Now we have to do the sorting. We can skip looking for the
binary itself which is at the front of the search list for
the main namespace. */
_dl_sort_maps (maps + (ns == LM_ID_BASE), nmaps - (ns == LM_ID_BASE),
NULL, true);
/* We do not rely on the linked list of loaded object anymore
from this point on. We have our own list here (maps). The