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authorRoland McGrath <roland@gnu.org>1996-06-04 23:06:02 +0000
committerRoland McGrath <roland@gnu.org>1996-06-04 23:06:02 +0000
commitf68b86cc7bdcee246296d49f3a3318c1b97693f0 (patch)
tree34a9e7bde9fd4f15d76192869b800ff7ff461874 /elf
parent14d898aef6373abaf64a7b17f32e8ce3f655cdf3 (diff)
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Tue Jun 4 18:57:57 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>
* elf/dladdr.c: Remove #include <setjmp.h>, we don't use it. * shlib-versions: Set libdl=2. * elf/dl-deps.c (_dl_map_object_deps): Use a linked list of alloca'd elements and then scan it to fill the single malloc'd array, instead of using realloc to grow the array in the first pass. _dl_map_object may do some mallocs that break our stream of reallocs, and the minimal realloc can't handle that. * elf/dl-init.c (_dl_init_next): Take argument, link_map whose searchlist describes the piece of the DT_NEEDED graph to be initialized. * elf/link.h: Update prototype. * sysdeps/i386/dl-machine.h (RTLD_START): Pass _dl_loaded as argument to _dl_init_next. * sysdeps/m68k/dl-machine.h: Likewise. * elf/dl-deps.c (_dl_open): Pass new object as arg to _dl_init_next. * elf/link.h (struct link_map): Add `l_reserved' member, soaking up extra bits in last byte. * elf/dl-deps.c (_dl_map_object_deps): Use that for mark bit to avoid putting dup elts in search list. * elf/dlclose.c: Use MAP->l_searchlist to find deps to close. * elf/dlsym.c: Don't tweak linked list. Scope array given to _dl_lookup_symbol does the right thing. Tue Jun 4 02:25:44 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-deps.c65
-rw-r--r--elf/dl-init.c58
-rw-r--r--elf/dladdr.c2
-rw-r--r--elf/dlclose.c100
-rw-r--r--elf/dlsym.c10
-rw-r--r--elf/link.h10
6 files changed, 126 insertions, 119 deletions
diff --git a/elf/dl-deps.c b/elf/dl-deps.c
index f87475a..92403d4 100644
--- a/elf/dl-deps.c
+++ b/elf/dl-deps.c
@@ -25,20 +25,33 @@ Cambridge, MA 02139, USA. */
void
_dl_map_object_deps (struct link_map *map)
{
- unsigned int nlist = 1;
- struct link_map **list = malloc (sizeof *list);
- unsigned int done;
+ struct list
+ {
+ struct link_map *map;
+ struct list *next;
+ };
+ struct list head, *tailp, *scanp;
+ unsigned int nlist;
/* Start the search list with one element: MAP itself. */
- list[0] = map;
+ head.map = map;
+ head.next = NULL;
+ nlist = 1;
+
/* Process each element of the search list, loading each of its immediate
dependencies and appending them to the list as we step through it.
This produces a flat, ordered list that represents a breadth-first
search of the dependency tree. */
- for (done = 0; done < nlist; ++done)
+ for (scanp = tailp = &head; scanp; scanp = scanp->next)
{
- struct link_map *l = list[done];
+ struct link_map *l = scanp->map;
+
+ /* We use `l_reserved' as a mark bit to detect objects we have
+ already put in the search list and avoid adding duplicate elements
+ later in the list. */
+ l->l_reserved = 1;
+
if (l->l_info[DT_NEEDED])
{
const char *strtab
@@ -47,24 +60,42 @@ _dl_map_object_deps (struct link_map *map)
for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
if (d->d_tag == DT_NEEDED)
{
- /* Extend the list and put this object on the end. */
- struct link_map **n
- = realloc (list, (nlist + 1) * sizeof *list);
- if (n)
- list = n;
+ /* Map in the needed object. */
+ struct link_map *dep
+ = _dl_map_object (l, strtab + d->d_un.d_val);
+
+ if (dep->l_reserved)
+ /* This object is already in the search list we are
+ building. Don't add a duplicate pointer. Release the
+ reference just added by _dl_map_object. */
+ --dep->l_opencount;
else
{
- free (list);
- _dl_signal_error (ENOMEM, map->l_name,
- "finding dependencies");
+ /* Append DEP to the search list. */
+ tailp->next = alloca (sizeof *tailp);
+ tailp = tailp->next;
+ tailp->map = dep;
+ tailp->next = NULL;
+ ++nlist;
}
- list[nlist++] = _dl_map_object (l, strtab + d->d_un.d_val);
}
}
}
- map->l_searchlist = list;
+ /* Store the search list we built in the object. It will be used for
+ searches in the scope of this object. */
+ map->l_searchlist = malloc (nlist * sizeof (struct link_map *));
map->l_nsearchlist = nlist;
+
+ nlist = 0;
+ for (scanp = &head; scanp; scanp = scanp->next)
+ {
+ map->l_searchlist[nlist++] = scanp->map;
+
+ /* Now clear all the mark bits we set in the objects on the search list
+ to avoid duplicates, so the next call starts fresh. */
+ scanp->map->l_reserved = 0;
+ }
}
@@ -86,7 +117,7 @@ _dl_open (struct link_map *parent, const char *file, int mode)
_dl_relocate_object (l, (mode & RTLD_BINDING_MASK) == RTLD_LAZY);
/* Run the initializer functions of new objects. */
- while (init = _dl_init_next ())
+ while (init = _dl_init_next (new))
(*(void (*) (void)) init) ();
return new;
diff --git a/elf/dl-init.c b/elf/dl-init.c
index 7375c5f..ee99ce3 100644
--- a/elf/dl-init.c
+++ b/elf/dl-init.c
@@ -1,5 +1,5 @@
/* Return the next shared object initializer function not yet run.
-Copyright (C) 1995 Free Software Foundation, Inc.
+Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -21,45 +21,35 @@ Cambridge, MA 02139, USA. */
#include <link.h>
+/* Run initializers for MAP and its dependencies, in inverse dependency
+ order (that is, leaf nodes first). */
+
Elf32_Addr
-_dl_init_next (void)
+_dl_init_next (struct link_map *map)
{
- struct link_map *l;
- Elf32_Addr init;
+ unsigned int i;
+
+ /* The search list for symbol lookup is a flat list in top-down
+ dependency order, so processing that list from back to front gets us
+ breadth-first leaf-to-root order. */
- Elf32_Addr next_init (struct link_map *l)
+ i = map->l_nsearchlist;
+ while (i-- > 0)
{
+ struct link_map *l = map->l_searchlist[i];
+
if (l->l_init_called)
/* This object is all done. */
- return 0;
+ continue;
+
if (l->l_init_running)
{
/* This object's initializer was just running.
Now mark it as having run, so this object
will be skipped in the future. */
- l->l_init_called = 1;
l->l_init_running = 0;
- return 0;
- }
-
- if (l->l_info[DT_NEEDED])
- {
- /* Find each dependency in order, and see if it
- needs to run an initializer. */
- const char *strtab
- = ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
- const Elf32_Dyn *d;
- for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
- if (d->d_tag == DT_NEEDED)
- {
- struct link_map *needed
- = _dl_map_object (l, strtab + d->d_un.d_val);
- Elf32_Addr init;
- --needed->l_opencount;
- init = next_init (needed); /* Recurse on this dependency. */
- if (init != 0)
- return init;
- }
+ l->l_init_called = 1;
+ continue;
}
if (l->l_info[DT_INIT] &&
@@ -73,17 +63,7 @@ _dl_init_next (void)
/* No initializer for this object.
Mark it so we will skip it in the future. */
l->l_init_called = 1;
- return 0;
- }
-
- /* Look for the first initializer not yet called. */
- l = _dl_loaded;
- do
- {
- init = next_init (l);
- l = l->l_next;
}
- while (init == 0 && l);
- return init;
+ return 0;
}
diff --git a/elf/dladdr.c b/elf/dladdr.c
index 166952a..87283e2 100644
--- a/elf/dladdr.c
+++ b/elf/dladdr.c
@@ -20,7 +20,6 @@ Cambridge, MA 02139, USA. */
#include <stddef.h>
#include <link.h>
#include <dlfcn.h>
-#include <setjmp.h>
int
@@ -30,7 +29,6 @@ dladdr (void *address, Dl_info *info)
struct link_map *l, *match;
const Elf32_Sym *symtab, *matchsym;
const char *strtab;
- Elf32_Word symidx;
/* Find the highest-addressed object that ADDRESS is not below. */
match = NULL;
diff --git a/elf/dlclose.c b/elf/dlclose.c
index 06b2d1b..fbb3ca6 100644
--- a/elf/dlclose.c
+++ b/elf/dlclose.c
@@ -1,5 +1,5 @@
/* dlclose -- Close a handle opened by `dlopen'.
-Copyright (C) 1995 Free Software Foundation, Inc.
+Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -32,64 +32,68 @@ dlclose (void *handle)
void doit (void)
{
struct link_map *map = handle;
+ struct link_map **list;
+ unsigned int i;
if (map->l_opencount == 0)
LOSE ("shared object not open");
/* Decrement the reference count. */
- --map->l_opencount;
-
- if (map->l_opencount == 0 && map->l_type == lt_loaded)
+ if (--map->l_opencount > 0 || map->l_type != lt_loaded)
+ /* There are still references to this object. Do nothing more. */
+ return;
+
+ list = map->l_searchlist;
+
+ /* The search list contains a counted reference to each object it
+ points to, the 0th elt being MAP itself. Decrement the reference
+ counts on all the objects MAP depends on. */
+ for (i = 1; i < map->l_nsearchlist; ++i)
+ --list[i]->l_opencount;
+
+ /* Clear the search list so it doesn't get freed while we are still
+ using it. We have cached it in LIST and will free it when
+ finished. */
+ map->l_searchlist = NULL;
+
+ /* Check each element of the search list to see if all references to
+ it are gone. */
+ for (i = 0; i < map->l_nsearchlist; ++i)
{
- /* That was the last reference, and this was a dlopen-loaded
- object. We can unmap it. */
- const Elf32_Phdr *ph;
-
- if (map->l_info[DT_FINI])
- /* Call its termination function. */
- (*(void (*) (void)) ((void *) map->l_addr +
- map->l_info[DT_FINI]->d_un.d_ptr)) ();
-
- if (map->l_info[DT_NEEDED])
+ struct link_map *map = list[i];
+ if (map->l_opencount == 0 && map->l_type == lt_loaded)
{
- /* Also close all the dependencies. */
- const char *strtab
- = (void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr;
- const Elf32_Dyn *d;
- for (d = map->l_ld; d->d_tag != DT_NULL; ++d)
- if (d->d_tag == DT_NEEDED)
+ /* That was the last reference, and this was a dlopen-loaded
+ object. We can unmap it. */
+ const Elf32_Phdr *ph;
+
+ if (map->l_info[DT_FINI])
+ /* Call its termination function. */
+ (*(void (*) (void)) ((void *) map->l_addr +
+ map->l_info[DT_FINI]->d_un.d_ptr)) ();
+
+ /* Unmap the segments. */
+ for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)
+ if (ph->p_type == PT_LOAD)
{
- /* It must already be open, since this one needed it;
- so dlopen will just find us its `struct link_map'
- and bump its reference count. */
- struct link_map *o, *dep
- = dlopen (strtab + d->d_un.d_val, RTLD_LAZY);
- --dep->l_opencount; /* Lose the ref from that dlopen. */
- /* Now we have the handle; we can close it for real. */
- o = map;
- map = dep;
- doit ();
- map = o;
+ Elf32_Addr mapstart = ph->p_vaddr & ~(ph->p_align - 1);
+ Elf32_Addr mapend = ((ph->p_vaddr + ph->p_memsz
+ + ph->p_align - 1)
+ & ~(ph->p_align - 1));
+ munmap ((caddr_t) mapstart, mapend - mapstart);
}
- }
- /* Unmap the segments. */
- for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)
- if (ph->p_type == PT_LOAD)
- {
- Elf32_Addr mapstart = ph->p_vaddr & ~(ph->p_align - 1);
- Elf32_Addr mapend = ((ph->p_vaddr + ph->p_memsz
- + ph->p_align - 1)
- & ~(ph->p_align - 1));
- munmap ((caddr_t) mapstart, mapend - mapstart);
- }
-
- /* Finally, unlink the data structure and free it. */
- map->l_prev->l_next = map->l_next;
- if (map->l_next)
- map->l_next->l_prev = map->l_prev;
- free (map);
+ /* Finally, unlink the data structure and free it. */
+ map->l_prev->l_next = map->l_next;
+ if (map->l_next)
+ map->l_next->l_prev = map->l_prev;
+ if (map->l_searchlist)
+ free (map->l_searchlist);
+ free (map);
+ }
}
+
+ free (list);
}
return _dlerror_run (doit) ? -1 : 0;
diff --git a/elf/dlsym.c b/elf/dlsym.c
index 804d404..f874af7 100644
--- a/elf/dlsym.c
+++ b/elf/dlsym.c
@@ -27,21 +27,13 @@ void *
dlsym (void *handle, const char *name)
{
struct link_map *map = handle;
- struct link_map *real_next;
Elf32_Addr loadbase;
const Elf32_Sym *ref = NULL;
- int lose;
void doit (void)
{
struct link_map *scope[2] = { map, NULL };
loadbase = _dl_lookup_symbol (name, &ref, scope, map->l_name, 0, 0);
}
- /* Confine the symbol scope to just this map. */
- real_next = map->l_next;
- map->l_next = NULL;
- lose = _dlerror_run (doit);
- map->l_next = real_next;
-
- return lose ? NULL : (void *) (loadbase + ref->st_value);
+ return _dlerror_run (doit) ? NULL : (void *) (loadbase + ref->st_value);
}
diff --git a/elf/link.h b/elf/link.h
index 73782d8..51740ee 100644
--- a/elf/link.h
+++ b/elf/link.h
@@ -111,6 +111,7 @@ struct link_map
unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
unsigned int l_init_running:1; /* Nonzero while DT_INIT function runs. */
+ unsigned int l_reserved:3; /* Reserved for internal use. */
};
/* Internal functions of the run-time dynamic linker.
@@ -231,10 +232,11 @@ extern struct link_map *_dl_new_object (char *realname, const char *libname,
If LAZY is nonzero, don't relocate its PLT. */
extern void _dl_relocate_object (struct link_map *map, int lazy);
-/* Return the address of the next initializer function not yet run.
- When there are no more initializers to be run, this returns zero.
- The functions are returned in the order they should be called. */
-extern Elf32_Addr _dl_init_next (void);
+/* Return the address of the next initializer function for MAP or one of
+ its dependencies that has not yet been run. When there are no more
+ initializers to be run, this returns zero. The functions are returned
+ in the order they should be called. */
+extern Elf32_Addr _dl_init_next (struct link_map *map);
/* Call the finalizer functions of all shared objects whose
initializer functions have completed. */