1168 lines
32 KiB
C
1168 lines
32 KiB
C
/* Map in a shared object's segments from the file.
|
||
Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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||
The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
|
||
published by the Free Software Foundation; either version 2 of the
|
||
License, or (at your option) any later version.
|
||
|
||
The GNU C Library is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Library General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Library General Public
|
||
License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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||
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||
#include <elf.h>
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||
#include <errno.h>
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||
#include <fcntl.h>
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||
#include <link.h>
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||
#include <stdlib.h>
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||
#include <string.h>
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||
#include <unistd.h>
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#include <sys/mman.h>
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||
#include <sys/stat.h>
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#include <sys/types.h>
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#include "dynamic-link.h"
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||
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||
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/* On some systems, no flag bits are given to specify file mapping. */
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#ifndef MAP_FILE
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#define MAP_FILE 0
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#endif
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/* The right way to map in the shared library files is MAP_COPY, which
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makes a virtual copy of the data at the time of the mmap call; this
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guarantees the mapped pages will be consistent even if the file is
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overwritten. Some losing VM systems like Linux's lack MAP_COPY. All we
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get is MAP_PRIVATE, which copies each page when it is modified; this
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means if the file is overwritten, we may at some point get some pages
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from the new version after starting with pages from the old version. */
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#ifndef MAP_COPY
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#define MAP_COPY MAP_PRIVATE
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#endif
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/* Some systems link their relocatable objects for another base address
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than 0. We want to know the base address for these such that we can
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subtract this address from the segment addresses during mapping.
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This results in a more efficient address space usage. Defaults to
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zero for almost all systems. */
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#ifndef MAP_BASE_ADDR
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#define MAP_BASE_ADDR(l) 0
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#endif
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#include <endian.h>
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#if BYTE_ORDER == BIG_ENDIAN
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#define byteorder ELFDATA2MSB
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#define byteorder_name "big-endian"
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#elif BYTE_ORDER == LITTLE_ENDIAN
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#define byteorder ELFDATA2LSB
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#define byteorder_name "little-endian"
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#else
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#error "Unknown BYTE_ORDER " BYTE_ORDER
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#define byteorder ELFDATANONE
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#endif
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#define STRING(x) __STRING (x)
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#ifdef MAP_ANON
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/* The fd is not examined when using MAP_ANON. */
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#define ANONFD -1
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#else
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int _dl_zerofd = -1;
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#define ANONFD _dl_zerofd
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#endif
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/* Handle situations where we have a preferred location in memory for
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the shared objects. */
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#ifdef ELF_PREFERRED_ADDRESS_DATA
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ELF_PREFERRED_ADDRESS_DATA;
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#endif
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#ifndef ELF_PREFERRED_ADDRESS
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#define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
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#endif
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#ifndef ELF_FIXED_ADDRESS
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#define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
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#endif
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size_t _dl_pagesize;
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extern const char *_dl_platform;
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extern size_t _dl_platformlen;
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/* This is a fake list to store the RPATH information for static
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binaries. */
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static struct r_search_path_elem **fake_path_list;
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||
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/* Local version of `strdup' function. */
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static inline char *
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local_strdup (const char *s)
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{
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size_t len = strlen (s) + 1;
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void *new = malloc (len);
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if (new == NULL)
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return NULL;
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return (char *) memcpy (new, s, len);
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}
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/* Add `name' to the list of names for a particular shared object.
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`name' is expected to have been allocated with malloc and will
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be freed if the shared object already has this name.
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Returns false if the object already had this name. */
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static int
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add_name_to_object (struct link_map *l, char *name)
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{
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struct libname_list *lnp, *lastp;
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struct libname_list *newname;
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||
|
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if (name == NULL)
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{
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/* No more memory. */
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_dl_signal_error (ENOMEM, NULL, "could not allocate name string");
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return 0;
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}
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lastp = NULL;
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for (lnp = l->l_libname; lnp != NULL; lastp = lnp, lnp = lnp->next)
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if (strcmp (name, lnp->name) == 0)
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{
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free (name);
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return 0;
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}
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newname = malloc (sizeof *newname);
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if (newname == NULL)
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{
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/* No more memory. */
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_dl_signal_error (ENOMEM, name, "cannot allocate name record");
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free (name);
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return 0;
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}
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/* The object should have a libname set from _dl_new_object. */
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assert (lastp != NULL);
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newname->name = name;
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newname->next = NULL;
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lastp->next = newname;
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return 1;
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}
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/* Implement cache for search path lookup. */
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#include "rtldtbl.h"
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static size_t max_dirnamelen;
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static inline struct r_search_path_elem **
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fillin_rpath (char *rpath, struct r_search_path_elem **result, const char *sep,
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const char **trusted, const char *what, const char *where)
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{
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char *cp;
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size_t nelems = 0;
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while ((cp = __strsep (&rpath, sep)) != NULL)
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{
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struct r_search_path_elem *dirp;
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size_t len = strlen (cp);
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/* Remove trailing slashes. */
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while (len > 1 && cp[len - 1] == '/')
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--len;
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/* Make sure we don't use untrusted directories if we run SUID. */
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if (trusted != NULL)
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{
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const char **trun = trusted;
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/* All trusted directory must be complete name. */
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if (cp[0] != '/')
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continue;
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while (*trun != NULL
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&& (memcmp (*trun, cp, len) != 0 || (*trun)[len] != '\0'))
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++trun;
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if (*trun == NULL)
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/* It's no trusted directory, skip it. */
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continue;
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}
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/* Now add one. */
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if (len > 0)
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cp[len++] = '/';
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/* See if this directory is already known. */
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for (dirp = all_dirs; dirp != NULL; dirp = dirp->next)
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if (dirp->dirnamelen == len && strcmp (cp, dirp->dirname) == 0)
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break;
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if (dirp != NULL)
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{
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/* It is available, see whether it's in our own list. */
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size_t cnt;
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for (cnt = 0; cnt < nelems; ++cnt)
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if (result[cnt] == dirp)
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break;
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||
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if (cnt == nelems)
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result[nelems++] = dirp;
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||
}
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else
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{
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/* It's a new directory. Create an entry and add it. */
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dirp = (struct r_search_path_elem *) malloc (sizeof (*dirp));
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if (dirp == NULL)
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_dl_signal_error (ENOMEM, NULL,
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"cannot create cache for search path");
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dirp->dirnamelen = len;
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/* We have to make sure all the relative directories are never
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ignored. The current directory might change and all our
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saved information would be void. */
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dirp->dirstatus = cp[0] != '/' ? existing : unknown;
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||
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/* Add the name of the machine dependent directory if a machine
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||
is defined. */
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if (_dl_platform != NULL)
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||
{
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char *tmp;
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||
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dirp->machdirnamelen = len + _dl_platformlen + 1;
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tmp = (char *) malloc (len + _dl_platformlen + 2);
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if (tmp == NULL)
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_dl_signal_error (ENOMEM, NULL,
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"cannot create cache for search path");
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dirp->dirname = tmp;
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tmp = __mempcpy (tmp, cp, len);
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tmp = __mempcpy (tmp, _dl_platform, _dl_platformlen);
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*tmp++ = '/';
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*tmp = '\0';
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dirp->machdirstatus = dirp->dirstatus;
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if (max_dirnamelen < dirp->machdirnamelen)
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max_dirnamelen = dirp->machdirnamelen;
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}
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else
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{
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char *tmp;
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dirp->machdirnamelen = len;
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dirp->machdirstatus = nonexisting;
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||
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||
tmp = (char *) malloc (len + 1);
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if (tmp == NULL)
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_dl_signal_error (ENOMEM, NULL,
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"cannot create cache for search path");
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dirp->dirname = tmp;
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*((char *) __mempcpy (tmp, cp, len)) = '\0';
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if (max_dirnamelen < dirp->dirnamelen)
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max_dirnamelen = dirp->dirnamelen;
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||
}
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dirp->what = what;
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dirp->where = where;
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dirp->next = all_dirs;
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all_dirs = dirp;
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/* Put it in the result array. */
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result[nelems++] = dirp;
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}
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}
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/* Terminate the array. */
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||
result[nelems] = NULL;
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||
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||
return result;
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||
}
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||
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||
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||
static struct r_search_path_elem **
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||
decompose_rpath (const char *rpath, size_t additional_room,
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const char *what, const char *where)
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||
{
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/* Make a copy we can work with. */
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char *copy = strdupa (rpath);
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char *cp;
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struct r_search_path_elem **result;
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/* First count the number of necessary elements in the result array. */
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size_t nelems = 0;
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||
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for (cp = copy; *cp != '\0'; ++cp)
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if (*cp == ':')
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++nelems;
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||
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||
/* Allocate room for the result. NELEMS + 1 + ADDITIONAL_ROOM is an upper
|
||
limit for the number of necessary entries. */
|
||
result = (struct r_search_path_elem **) malloc ((nelems + 1
|
||
+ additional_room + 1)
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||
* sizeof (*result));
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||
if (result == NULL)
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_dl_signal_error (ENOMEM, NULL, "cannot create cache for search path");
|
||
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return fillin_rpath (copy, result, ":", NULL, what, where);
|
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}
|
||
|
||
|
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void
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_dl_init_paths (const char *llp)
|
||
{
|
||
static const char *trusted_dirs[] =
|
||
{
|
||
#include "trusted-dirs.h"
|
||
NULL
|
||
};
|
||
|
||
struct r_search_path_elem **pelem;
|
||
|
||
/* We have in `search_path' the information about the RPATH of the
|
||
dynamic loader. Now fill in the information about the applications
|
||
RPATH and the directories addressed by the LD_LIBRARY_PATH environment
|
||
variable. */
|
||
struct link_map *l;
|
||
|
||
/* Number of elements in the library path. */
|
||
size_t nllp;
|
||
|
||
/* First determine how many elements the LD_LIBRARY_PATH contents has. */
|
||
if (llp != NULL && *llp != '\0')
|
||
{
|
||
/* Simply count the number of colons. */
|
||
const char *cp = llp;
|
||
nllp = 1;
|
||
while (*cp)
|
||
if (*cp++ == ':')
|
||
++nllp;
|
||
}
|
||
else
|
||
nllp = 0;
|
||
|
||
l = _dl_loaded;
|
||
if (l != NULL)
|
||
{
|
||
if (l->l_type != lt_loaded && l->l_info[DT_RPATH])
|
||
{
|
||
/* Allocate room for the search path and fill in information
|
||
from RPATH. */
|
||
l->l_rpath_dirs =
|
||
decompose_rpath ((const char *)
|
||
(l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr
|
||
+ l->l_info[DT_RPATH]->d_un.d_val),
|
||
nllp, "RPATH", l->l_name);
|
||
}
|
||
else
|
||
{
|
||
/* If we have no LD_LIBRARY_PATH and no RPATH we must tell
|
||
this somehow to prevent we look this up again and again. */
|
||
if (nllp == 0)
|
||
l->l_rpath_dirs = (struct r_search_path_elem **) -1l;
|
||
else
|
||
{
|
||
l->l_rpath_dirs = (struct r_search_path_elem **)
|
||
malloc ((nllp + 1) * sizeof (*l->l_rpath_dirs));
|
||
if (l->l_rpath_dirs == NULL)
|
||
_dl_signal_error (ENOMEM, NULL,
|
||
"cannot create cache for search path");
|
||
l->l_rpath_dirs[0] = NULL;
|
||
}
|
||
}
|
||
|
||
/* We don't need to search the list of fake entries which is searched
|
||
when no dynamic objects were loaded at this time. */
|
||
fake_path_list = NULL;
|
||
|
||
if (nllp > 0)
|
||
{
|
||
char *copy = strdupa (llp);
|
||
|
||
/* Decompose the LD_LIBRARY_PATH and fill in the result.
|
||
First search for the next place to enter elements. */
|
||
struct r_search_path_elem **result = l->l_rpath_dirs;
|
||
while (*result != NULL)
|
||
++result;
|
||
|
||
/* We need to take care that the LD_LIBRARY_PATH environment
|
||
variable can contain a semicolon. */
|
||
(void) fillin_rpath (copy, result, ":;",
|
||
__libc_enable_secure ? trusted_dirs : NULL,
|
||
"LD_LIBRARY_PATH", NULL);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* This is a statically linked program but we still have to
|
||
take care for the LD_LIBRARY_PATH environment variable. We
|
||
use a fake link_map entry. This will only contain the
|
||
l_rpath_dirs information. */
|
||
|
||
if (nllp == 0)
|
||
fake_path_list = NULL;
|
||
else
|
||
{
|
||
fake_path_list = (struct r_search_path_elem **)
|
||
malloc ((nllp + 1) * sizeof (struct r_search_path_elem *));
|
||
if (fake_path_list == NULL)
|
||
_dl_signal_error (ENOMEM, NULL,
|
||
"cannot create cache for search path");
|
||
|
||
(void) fillin_rpath (local_strdup (llp), fake_path_list, ":;",
|
||
__libc_enable_secure ? trusted_dirs : NULL,
|
||
"LD_LIBRARY_PATH", NULL);
|
||
}
|
||
}
|
||
|
||
/* Now set up the rest of the rtld_search_dirs. */
|
||
for (pelem = rtld_search_dirs; *pelem != NULL; ++pelem)
|
||
{
|
||
struct r_search_path_elem *relem = *pelem;
|
||
|
||
if (_dl_platform != NULL)
|
||
{
|
||
char *tmp, *orig;
|
||
|
||
relem->machdirnamelen = relem->dirnamelen + _dl_platformlen + 1;
|
||
tmp = (char *) malloc (relem->machdirnamelen + 1);
|
||
if (tmp == NULL)
|
||
_dl_signal_error (ENOMEM, NULL,
|
||
"cannot create cache for search path");
|
||
|
||
orig = tmp;
|
||
tmp = __mempcpy (tmp, relem->dirname, relem->dirnamelen);
|
||
tmp = __mempcpy (tmp, _dl_platform, _dl_platformlen);
|
||
*tmp++ = '/';
|
||
*tmp = '\0';
|
||
relem->dirname = orig;
|
||
|
||
relem->machdirstatus = unknown;
|
||
|
||
if (max_dirnamelen < relem->machdirnamelen)
|
||
max_dirnamelen = relem->machdirnamelen;
|
||
}
|
||
else
|
||
{
|
||
relem->machdirnamelen = relem->dirnamelen;
|
||
relem->machdirstatus = nonexisting;
|
||
|
||
if (max_dirnamelen < relem->dirnamelen)
|
||
max_dirnamelen = relem->dirnamelen;
|
||
}
|
||
|
||
relem->what = "system search path";
|
||
relem->where = NULL;
|
||
}
|
||
}
|
||
|
||
|
||
/* Map in the shared object NAME, actually located in REALNAME, and already
|
||
opened on FD. */
|
||
|
||
struct link_map *
|
||
_dl_map_object_from_fd (char *name, int fd, char *realname,
|
||
struct link_map *loader, int l_type)
|
||
{
|
||
struct link_map *l = NULL;
|
||
void *file_mapping = NULL;
|
||
size_t mapping_size = 0;
|
||
|
||
#define LOSE(s) lose (0, (s))
|
||
void lose (int code, const char *msg)
|
||
{
|
||
(void) __close (fd);
|
||
if (file_mapping)
|
||
__munmap (file_mapping, mapping_size);
|
||
if (l)
|
||
{
|
||
/* Remove the stillborn object from the list and free it. */
|
||
if (l->l_prev)
|
||
l->l_prev->l_next = l->l_next;
|
||
if (l->l_next)
|
||
l->l_next->l_prev = l->l_prev;
|
||
free (l);
|
||
}
|
||
free (realname);
|
||
_dl_signal_error (code, name, msg);
|
||
free (name); /* Hmmm. Can this leak memory? Better
|
||
than a segfault, anyway. */
|
||
}
|
||
|
||
inline caddr_t map_segment (ElfW(Addr) mapstart, size_t len,
|
||
int prot, int fixed, off_t offset)
|
||
{
|
||
caddr_t mapat = __mmap ((caddr_t) mapstart, len, prot,
|
||
fixed|MAP_COPY|MAP_FILE,
|
||
fd, offset);
|
||
if (mapat == MAP_FAILED)
|
||
lose (errno, "failed to map segment from shared object");
|
||
return mapat;
|
||
}
|
||
|
||
/* Make sure LOCATION is mapped in. */
|
||
void *map (off_t location, size_t size)
|
||
{
|
||
if ((off_t) mapping_size <= location + (off_t) size)
|
||
{
|
||
void *result;
|
||
if (file_mapping)
|
||
__munmap (file_mapping, mapping_size);
|
||
mapping_size = (location + size + 1 + _dl_pagesize - 1);
|
||
mapping_size &= ~(_dl_pagesize - 1);
|
||
result = __mmap (file_mapping, mapping_size, PROT_READ,
|
||
MAP_COPY|MAP_FILE, fd, 0);
|
||
if (result == MAP_FAILED)
|
||
lose (errno, "cannot map file data");
|
||
file_mapping = result;
|
||
}
|
||
return file_mapping + location;
|
||
}
|
||
|
||
const ElfW(Ehdr) *header;
|
||
const ElfW(Phdr) *phdr;
|
||
const ElfW(Phdr) *ph;
|
||
int type;
|
||
|
||
/* Look again to see if the real name matched another already loaded. */
|
||
for (l = _dl_loaded; l; l = l->l_next)
|
||
if (! strcmp (realname, l->l_name))
|
||
{
|
||
/* The object is already loaded.
|
||
Just bump its reference count and return it. */
|
||
__close (fd);
|
||
|
||
/* If the name is not in the list of names for this object add
|
||
it. */
|
||
free (realname);
|
||
add_name_to_object (l, name);
|
||
++l->l_opencount;
|
||
return l;
|
||
}
|
||
|
||
/* Map in the first page to read the header. */
|
||
header = map (0, sizeof *header);
|
||
|
||
/* Check the header for basic validity. */
|
||
if (*(Elf32_Word *) &header->e_ident !=
|
||
#if BYTE_ORDER == LITTLE_ENDIAN
|
||
((ELFMAG0 << (EI_MAG0 * 8)) |
|
||
(ELFMAG1 << (EI_MAG1 * 8)) |
|
||
(ELFMAG2 << (EI_MAG2 * 8)) |
|
||
(ELFMAG3 << (EI_MAG3 * 8)))
|
||
#else
|
||
((ELFMAG0 << (EI_MAG3 * 8)) |
|
||
(ELFMAG1 << (EI_MAG2 * 8)) |
|
||
(ELFMAG2 << (EI_MAG1 * 8)) |
|
||
(ELFMAG3 << (EI_MAG0 * 8)))
|
||
#endif
|
||
)
|
||
LOSE ("invalid ELF header");
|
||
#define ELF32_CLASS ELFCLASS32
|
||
#define ELF64_CLASS ELFCLASS64
|
||
if (header->e_ident[EI_CLASS] != ELFW(CLASS))
|
||
LOSE ("ELF file class not " STRING(__ELF_NATIVE_CLASS) "-bit");
|
||
if (header->e_ident[EI_DATA] != byteorder)
|
||
LOSE ("ELF file data encoding not " byteorder_name);
|
||
if (header->e_ident[EI_VERSION] != EV_CURRENT)
|
||
LOSE ("ELF file version ident not " STRING(EV_CURRENT));
|
||
if (header->e_version != EV_CURRENT)
|
||
LOSE ("ELF file version not " STRING(EV_CURRENT));
|
||
if (! elf_machine_matches_host (header->e_machine))
|
||
LOSE ("ELF file machine architecture not " ELF_MACHINE_NAME);
|
||
if (header->e_phentsize != sizeof (ElfW(Phdr)))
|
||
LOSE ("ELF file's phentsize not the expected size");
|
||
|
||
#ifndef MAP_ANON
|
||
#define MAP_ANON 0
|
||
if (_dl_zerofd == -1)
|
||
{
|
||
_dl_zerofd = _dl_sysdep_open_zero_fill ();
|
||
if (_dl_zerofd == -1)
|
||
{
|
||
__close (fd);
|
||
_dl_signal_error (errno, NULL, "cannot open zero fill device");
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* Enter the new object in the list of loaded objects. */
|
||
l = _dl_new_object (realname, name, l_type);
|
||
if (! l)
|
||
lose (ENOMEM, "cannot create shared object descriptor");
|
||
l->l_opencount = 1;
|
||
l->l_loader = loader;
|
||
|
||
/* Extract the remaining details we need from the ELF header
|
||
and then map in the program header table. */
|
||
l->l_entry = header->e_entry;
|
||
type = header->e_type;
|
||
l->l_phnum = header->e_phnum;
|
||
phdr = map (header->e_phoff, l->l_phnum * sizeof (ElfW(Phdr)));
|
||
|
||
{
|
||
/* Scan the program header table, collecting its load commands. */
|
||
struct loadcmd
|
||
{
|
||
ElfW(Addr) mapstart, mapend, dataend, allocend;
|
||
off_t mapoff;
|
||
int prot;
|
||
} loadcmds[l->l_phnum], *c;
|
||
size_t nloadcmds = 0;
|
||
|
||
l->l_ld = 0;
|
||
l->l_phdr = 0;
|
||
l->l_addr = 0;
|
||
for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
|
||
switch (ph->p_type)
|
||
{
|
||
/* These entries tell us where to find things once the file's
|
||
segments are mapped in. We record the addresses it says
|
||
verbatim, and later correct for the run-time load address. */
|
||
case PT_DYNAMIC:
|
||
l->l_ld = (void *) ph->p_vaddr;
|
||
break;
|
||
case PT_PHDR:
|
||
l->l_phdr = (void *) ph->p_vaddr;
|
||
break;
|
||
|
||
case PT_LOAD:
|
||
/* A load command tells us to map in part of the file.
|
||
We record the load commands and process them all later. */
|
||
if (ph->p_align % _dl_pagesize != 0)
|
||
LOSE ("ELF load command alignment not page-aligned");
|
||
if ((ph->p_vaddr - ph->p_offset) % ph->p_align)
|
||
LOSE ("ELF load command address/offset not properly aligned");
|
||
{
|
||
struct loadcmd *c = &loadcmds[nloadcmds++];
|
||
c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
|
||
c->mapend = ((ph->p_vaddr + ph->p_filesz + _dl_pagesize - 1)
|
||
& ~(_dl_pagesize - 1));
|
||
c->dataend = ph->p_vaddr + ph->p_filesz;
|
||
c->allocend = ph->p_vaddr + ph->p_memsz;
|
||
c->mapoff = ph->p_offset & ~(ph->p_align - 1);
|
||
c->prot = 0;
|
||
if (ph->p_flags & PF_R)
|
||
c->prot |= PROT_READ;
|
||
if (ph->p_flags & PF_W)
|
||
c->prot |= PROT_WRITE;
|
||
if (ph->p_flags & PF_X)
|
||
c->prot |= PROT_EXEC;
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* We are done reading the file's headers now. Unmap them. */
|
||
__munmap (file_mapping, mapping_size);
|
||
|
||
/* Now process the load commands and map segments into memory. */
|
||
c = loadcmds;
|
||
|
||
if (type == ET_DYN || type == ET_REL)
|
||
{
|
||
/* This is a position-independent shared object. We can let the
|
||
kernel map it anywhere it likes, but we must have space for all
|
||
the segments in their specified positions relative to the first.
|
||
So we map the first segment without MAP_FIXED, but with its
|
||
extent increased to cover all the segments. Then we remove
|
||
access from excess portion, and there is known sufficient space
|
||
there to remap from the later segments.
|
||
|
||
As a refinement, sometimes we have an address that we would
|
||
prefer to map such objects at; but this is only a preference,
|
||
the OS can do whatever it likes. */
|
||
caddr_t mapat;
|
||
ElfW(Addr) mappref;
|
||
size_t maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
|
||
mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
|
||
- MAP_BASE_ADDR (l));
|
||
mapat = map_segment (mappref, maplength, c->prot, 0, c->mapoff);
|
||
l->l_addr = (ElfW(Addr)) mapat - c->mapstart;
|
||
|
||
/* Change protection on the excess portion to disallow all access;
|
||
the portions we do not remap later will be inaccessible as if
|
||
unallocated. Then jump into the normal segment-mapping loop to
|
||
handle the portion of the segment past the end of the file
|
||
mapping. */
|
||
__mprotect ((caddr_t) (l->l_addr + c->mapend),
|
||
loadcmds[nloadcmds - 1].allocend - c->mapend,
|
||
0);
|
||
goto postmap;
|
||
}
|
||
else
|
||
{
|
||
/* Notify ELF_PREFERRED_ADDRESS that we have to load this one
|
||
fixed. */
|
||
ELF_FIXED_ADDRESS (loader, c->mapstart);
|
||
}
|
||
|
||
while (c < &loadcmds[nloadcmds])
|
||
{
|
||
if (c->mapend > c->mapstart)
|
||
/* Map the segment contents from the file. */
|
||
map_segment (l->l_addr + c->mapstart, c->mapend - c->mapstart,
|
||
c->prot, MAP_FIXED, c->mapoff);
|
||
|
||
postmap:
|
||
if (c->allocend > c->dataend)
|
||
{
|
||
/* Extra zero pages should appear at the end of this segment,
|
||
after the data mapped from the file. */
|
||
ElfW(Addr) zero, zeroend, zeropage;
|
||
|
||
zero = l->l_addr + c->dataend;
|
||
zeroend = l->l_addr + c->allocend;
|
||
zeropage = (zero + _dl_pagesize - 1) & ~(_dl_pagesize - 1);
|
||
|
||
if (zeroend < zeropage)
|
||
/* All the extra data is in the last page of the segment.
|
||
We can just zero it. */
|
||
zeropage = zeroend;
|
||
|
||
if (zeropage > zero)
|
||
{
|
||
/* Zero the final part of the last page of the segment. */
|
||
if ((c->prot & PROT_WRITE) == 0)
|
||
{
|
||
/* Dag nab it. */
|
||
if (__mprotect ((caddr_t) (zero & ~(_dl_pagesize - 1)),
|
||
_dl_pagesize, c->prot|PROT_WRITE) < 0)
|
||
lose (errno, "cannot change memory protections");
|
||
}
|
||
memset ((void *) zero, 0, zeropage - zero);
|
||
if ((c->prot & PROT_WRITE) == 0)
|
||
__mprotect ((caddr_t) (zero & ~(_dl_pagesize - 1)),
|
||
_dl_pagesize, c->prot);
|
||
}
|
||
|
||
if (zeroend > zeropage)
|
||
{
|
||
/* Map the remaining zero pages in from the zero fill FD. */
|
||
caddr_t mapat;
|
||
mapat = __mmap ((caddr_t) zeropage, zeroend - zeropage,
|
||
c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
|
||
ANONFD, 0);
|
||
if (mapat == MAP_FAILED)
|
||
lose (errno, "cannot map zero-fill pages");
|
||
}
|
||
}
|
||
|
||
++c;
|
||
}
|
||
|
||
if (l->l_phdr == 0)
|
||
{
|
||
/* There was no PT_PHDR specified. We need to find the phdr in the
|
||
load image ourselves. We assume it is in fact in the load image
|
||
somewhere, and that the first load command starts at the
|
||
beginning of the file and thus contains the ELF file header. */
|
||
ElfW(Addr) bof = l->l_addr + loadcmds[0].mapstart;
|
||
assert (loadcmds[0].mapoff == 0);
|
||
l->l_phdr = (void *) (bof + ((const ElfW(Ehdr) *) bof)->e_phoff);
|
||
}
|
||
else
|
||
/* Adjust the PT_PHDR value by the runtime load address. */
|
||
(ElfW(Addr)) l->l_phdr += l->l_addr;
|
||
}
|
||
|
||
/* We are done mapping in the file. We no longer need the descriptor. */
|
||
__close (fd);
|
||
|
||
if (l->l_type == lt_library && type == ET_EXEC)
|
||
l->l_type = lt_executable;
|
||
|
||
if (l->l_ld == 0)
|
||
{
|
||
if (type == ET_DYN)
|
||
LOSE ("object file has no dynamic section");
|
||
}
|
||
else
|
||
(ElfW(Addr)) l->l_ld += l->l_addr;
|
||
|
||
l->l_entry += l->l_addr;
|
||
|
||
elf_get_dynamic_info (l->l_ld, l->l_info);
|
||
if (l->l_info[DT_HASH])
|
||
_dl_setup_hash (l);
|
||
|
||
return l;
|
||
}
|
||
|
||
/* Print search path. */
|
||
static void
|
||
print_search_path (struct r_search_path_elem **list,
|
||
const char *what, const char *name)
|
||
{
|
||
int first = 1;
|
||
|
||
_dl_debug_message ("\t search path=", NULL);
|
||
|
||
while (*list != NULL && (*list)->what == what) /* Yes, ==. */
|
||
{
|
||
char *buf = strdupa ((*list)->dirname);
|
||
|
||
if ((*list)->machdirstatus != nonexisting)
|
||
{
|
||
buf[(*list)->machdirnamelen - 1] = '\0';
|
||
_dl_debug_message (first ? "" : ":", buf, NULL);
|
||
first = 0;
|
||
}
|
||
if ((*list)->dirstatus != nonexisting)
|
||
{
|
||
buf[(*list)->dirnamelen - 1] = '\0';
|
||
_dl_debug_message (first ? "" : ":", buf, NULL);
|
||
first = 0;
|
||
}
|
||
++list;
|
||
}
|
||
|
||
if (name != NULL)
|
||
_dl_debug_message ("\t\t(", what, " from file ",
|
||
name[0] ? name : _dl_argv[0], ")\n", NULL);
|
||
else
|
||
_dl_debug_message ("\t\t(", what, ")\n", NULL);
|
||
}
|
||
|
||
/* Try to open NAME in one of the directories in DIRS.
|
||
Return the fd, or -1. If successful, fill in *REALNAME
|
||
with the malloc'd full directory name. */
|
||
|
||
static int
|
||
open_path (const char *name, size_t namelen, int preloaded,
|
||
struct r_search_path_elem **dirs,
|
||
char **realname)
|
||
{
|
||
char *buf;
|
||
int fd = -1;
|
||
const char *current_what = NULL;
|
||
|
||
if (dirs == NULL || *dirs == NULL)
|
||
{
|
||
__set_errno (ENOENT);
|
||
return -1;
|
||
}
|
||
|
||
buf = __alloca (max_dirnamelen + namelen);
|
||
do
|
||
{
|
||
struct r_search_path_elem *this_dir = *dirs;
|
||
size_t buflen = 0;
|
||
|
||
/* If we are debugging the search for libraries print the path
|
||
now if it hasn't happened now. */
|
||
if (_dl_debug_libs && current_what != this_dir->what)
|
||
{
|
||
current_what = this_dir->what;
|
||
print_search_path (dirs, current_what, this_dir->where);
|
||
}
|
||
|
||
if (this_dir->machdirstatus != nonexisting)
|
||
{
|
||
/* Construct the pathname to try. */
|
||
buflen = ((char *) __mempcpy (__mempcpy (buf, this_dir->dirname,
|
||
this_dir->machdirnamelen),
|
||
name, namelen)
|
||
- buf);
|
||
|
||
/* Print name we try if this is wanted. */
|
||
if (_dl_debug_libs)
|
||
_dl_debug_message ("\t trying file=", buf, "\n", NULL);
|
||
|
||
fd = __open (buf, O_RDONLY);
|
||
if (this_dir->machdirstatus == unknown)
|
||
if (fd != -1)
|
||
this_dir->machdirstatus = existing;
|
||
else
|
||
{
|
||
/* We failed to open machine dependent library. Let's
|
||
test whether there is any directory at all. */
|
||
struct stat st;
|
||
|
||
buf[this_dir->machdirnamelen - 1] = '\0';
|
||
|
||
if (__xstat (_STAT_VER, buf, &st) != 0
|
||
|| ! S_ISDIR (st.st_mode))
|
||
/* The directory does not exist ot it is no directory. */
|
||
this_dir->machdirstatus = nonexisting;
|
||
else
|
||
this_dir->machdirstatus = existing;
|
||
}
|
||
if (fd != -1 && preloaded && __libc_enable_secure)
|
||
{
|
||
/* This is an extra security effort to make sure nobody can
|
||
preload broken shared objects which are in the trusted
|
||
directories and so exploit the bugs. */
|
||
struct stat st;
|
||
|
||
if (__fxstat (_STAT_VER, fd, &st) != 0
|
||
|| (st.st_mode & S_ISUID) == 0)
|
||
{
|
||
/* The shared object cannot be tested for being SUID
|
||
or this bit is not set. In this case we must not
|
||
use this object. */
|
||
__close (fd);
|
||
fd = -1;
|
||
/* We simply ignore the file, signal this by setting
|
||
the error value which would have been set by `open'. */
|
||
errno = ENOENT;
|
||
}
|
||
}
|
||
}
|
||
else
|
||
errno = ENOENT;
|
||
|
||
if (fd == -1 && errno == ENOENT && this_dir->dirstatus != nonexisting)
|
||
{
|
||
/* Construct the pathname to try. */
|
||
buflen = ((char *) __mempcpy (__mempcpy (buf, this_dir->dirname,
|
||
this_dir->dirnamelen),
|
||
name, namelen)
|
||
- buf);
|
||
|
||
/* Print name we try if this is wanted. */
|
||
if (_dl_debug_libs)
|
||
_dl_debug_message ("\t trying file=", buf, "\n", NULL);
|
||
|
||
fd = __open (buf, O_RDONLY);
|
||
if (this_dir->dirstatus == unknown)
|
||
if (fd != -1)
|
||
this_dir->dirstatus = existing;
|
||
else
|
||
/* We failed to open library. Let's test whether there
|
||
is any directory at all. */
|
||
if (this_dir->dirnamelen <= 1)
|
||
this_dir->dirstatus = existing;
|
||
else
|
||
{
|
||
struct stat st;
|
||
|
||
buf[this_dir->dirnamelen - 1] = '\0';
|
||
|
||
if (__xstat (_STAT_VER, buf, &st) != 0
|
||
|| ! S_ISDIR (st.st_mode))
|
||
/* The directory does not exist ot it is no directory. */
|
||
this_dir->dirstatus = nonexisting;
|
||
else
|
||
this_dir->dirstatus = existing;
|
||
}
|
||
if (fd != -1 && preloaded && __libc_enable_secure)
|
||
{
|
||
/* This is an extra security effort to make sure nobody can
|
||
preload broken shared objects which are in the trusted
|
||
directories and so exploit the bugs. */
|
||
struct stat st;
|
||
|
||
if (__fxstat (_STAT_VER, fd, &st) != 0
|
||
|| (st.st_mode & S_ISUID) == 0)
|
||
{
|
||
/* The shared object cannot be tested for being SUID
|
||
or this bit is not set. In this case we must not
|
||
use this object. */
|
||
__close (fd);
|
||
fd = -1;
|
||
/* We simply ignore the file, signal this by setting
|
||
the error value which would have been set by `open'. */
|
||
errno = ENOENT;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (fd != -1)
|
||
{
|
||
*realname = malloc (buflen);
|
||
if (*realname != NULL)
|
||
{
|
||
memcpy (*realname, buf, buflen);
|
||
return fd;
|
||
}
|
||
else
|
||
{
|
||
/* No memory for the name, we certainly won't be able
|
||
to load and link it. */
|
||
__close (fd);
|
||
return -1;
|
||
}
|
||
}
|
||
if (errno != ENOENT && errno != EACCES)
|
||
/* The file exists and is readable, but something went wrong. */
|
||
return -1;
|
||
}
|
||
while (*++dirs != NULL);
|
||
|
||
return -1;
|
||
}
|
||
|
||
/* Map in the shared object file NAME. */
|
||
|
||
struct link_map *
|
||
_dl_map_object (struct link_map *loader, const char *name, int preloaded,
|
||
int type, int trace_mode)
|
||
{
|
||
int fd;
|
||
char *realname;
|
||
char *name_copy;
|
||
struct link_map *l;
|
||
|
||
/* Look for this name among those already loaded. */
|
||
for (l = _dl_loaded; l; l = l->l_next)
|
||
{
|
||
/* If the requested name matches the soname of a loaded object,
|
||
use that object. Elide this check for names that have not
|
||
yet been opened. */
|
||
if (l->l_opencount <= 0)
|
||
continue;
|
||
if (!_dl_name_match_p (name, l))
|
||
{
|
||
const char *soname;
|
||
|
||
if (l->l_info[DT_SONAME] == NULL)
|
||
continue;
|
||
|
||
soname = (const char *) (l->l_addr
|
||
+ l->l_info[DT_STRTAB]->d_un.d_ptr
|
||
+ l->l_info[DT_SONAME]->d_un.d_val);
|
||
if (strcmp (name, soname) != 0)
|
||
continue;
|
||
|
||
/* We have a match on a new name -- cache it. */
|
||
add_name_to_object (l, local_strdup (soname));
|
||
}
|
||
|
||
/* We have a match -- bump the reference count and return it. */
|
||
++l->l_opencount;
|
||
return l;
|
||
}
|
||
|
||
if (strchr (name, '/') == NULL)
|
||
{
|
||
/* Search for NAME in several places. */
|
||
|
||
size_t namelen = strlen (name) + 1;
|
||
|
||
if (_dl_debug_libs)
|
||
_dl_debug_message ("\tfind library=", name, "; searching\n", NULL);
|
||
|
||
fd = -1;
|
||
|
||
/* First try the DT_RPATH of the dependent object that caused NAME
|
||
to be loaded. Then that object's dependent, and on up. */
|
||
for (l = loader; fd == -1 && l; l = l->l_loader)
|
||
if (l && l->l_info[DT_RPATH])
|
||
{
|
||
/* Make sure the cache information is available. */
|
||
if (l->l_rpath_dirs == NULL)
|
||
{
|
||
size_t ptrval = (l->l_addr
|
||
+ l->l_info[DT_STRTAB]->d_un.d_ptr
|
||
+ l->l_info[DT_RPATH]->d_un.d_val);
|
||
l->l_rpath_dirs =
|
||
decompose_rpath ((const char *) ptrval, 0,
|
||
"RPATH", l->l_name);
|
||
}
|
||
|
||
if (l->l_rpath_dirs != (struct r_search_path_elem **) -1l)
|
||
fd = open_path (name, namelen, preloaded, l->l_rpath_dirs,
|
||
&realname);
|
||
}
|
||
|
||
/* If dynamically linked, try the DT_RPATH of the executable itself
|
||
and the LD_LIBRARY_PATH environment variable. */
|
||
l = _dl_loaded;
|
||
if (fd == -1 && l && l->l_type != lt_loaded
|
||
&& l->l_rpath_dirs != (struct r_search_path_elem **) -1l)
|
||
fd = open_path (name, namelen, preloaded, l->l_rpath_dirs, &realname);
|
||
|
||
/* This is used if a static binary uses dynamic loading and there
|
||
is a LD_LIBRARY_PATH given. */
|
||
if (fd == -1 && fake_path_list != NULL)
|
||
fd = open_path (name, namelen, preloaded, fake_path_list, &realname);
|
||
|
||
if (fd == -1)
|
||
{
|
||
/* Check the list of libraries in the file /etc/ld.so.cache,
|
||
for compatibility with Linux's ldconfig program. */
|
||
extern const char *_dl_load_cache_lookup (const char *name);
|
||
const char *cached = _dl_load_cache_lookup (name);
|
||
if (cached)
|
||
{
|
||
fd = __open (cached, O_RDONLY);
|
||
if (fd != -1)
|
||
{
|
||
realname = local_strdup (cached);
|
||
if (realname == NULL)
|
||
{
|
||
__close (fd);
|
||
fd = -1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Finally, try the default path. */
|
||
if (fd == -1)
|
||
fd = open_path (name, namelen, preloaded, rtld_search_dirs, &realname);
|
||
|
||
/* Add another newline when we a tracing the library loading. */
|
||
if (_dl_debug_libs)
|
||
_dl_debug_message ("\n", NULL);
|
||
}
|
||
else
|
||
{
|
||
fd = __open (name, O_RDONLY);
|
||
if (fd != -1)
|
||
{
|
||
realname = local_strdup (name);
|
||
if (realname == NULL)
|
||
{
|
||
__close (fd);
|
||
fd = -1;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (fd != -1)
|
||
{
|
||
name_copy = local_strdup (name);
|
||
if (name_copy == NULL)
|
||
{
|
||
__close (fd);
|
||
fd = -1;
|
||
}
|
||
}
|
||
|
||
if (fd == -1)
|
||
{
|
||
if (trace_mode)
|
||
{
|
||
/* We haven't found an appropriate library. But since we
|
||
are only interested in the list of libraries this isn't
|
||
so severe. Fake an entry with all the information we
|
||
have. */
|
||
static const ElfW(Symndx) dummy_bucket = STN_UNDEF;
|
||
|
||
/* Enter the new object in the list of loaded objects. */
|
||
if ((name_copy = local_strdup (name)) == NULL
|
||
|| (l = _dl_new_object (name_copy, name, type)) == NULL)
|
||
_dl_signal_error (ENOMEM, name,
|
||
"cannot create shared object descriptor");
|
||
/* We use an opencount of 0 as a sign for the faked entry. */
|
||
l->l_opencount = 0;
|
||
l->l_reserved = 0;
|
||
l->l_buckets = &dummy_bucket;
|
||
l->l_nbuckets = 1;
|
||
l->l_relocated = 1;
|
||
|
||
return l;
|
||
}
|
||
else
|
||
_dl_signal_error (errno, name, "cannot open shared object file");
|
||
}
|
||
|
||
return _dl_map_object_from_fd (name_copy, fd, realname, loader, type);
|
||
}
|