NetBSD/libexec/ld.elf_so/search.c

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/* $NetBSD: search.c,v 1.10 2000/07/27 10:44:39 kleink Exp $ */
/*
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <dirent.h>
#include "debug.h"
#include "rtld.h"
/*
* Data declarations.
*/
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static bool _rtld_check_library __P((const char *));
static char *_rtld_search_library_path __P((const char *, size_t, const char *,
size_t));
static bool
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_rtld_check_library(pathname)
const char *pathname;
{
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struct stat mystat;
Elf_Ehdr ehdr;
int fd;
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if (stat(pathname, &mystat) == -1 || !S_ISREG(mystat.st_mode))
return false;
if ((fd = open(pathname, O_RDONLY)) == -1)
return false;
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if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
goto lose;
/* ELF_Ehdr.e_ident includes class */
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
ehdr.e_ident[EI_CLASS] != ELFCLASS)
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goto lose;
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switch (ehdr.e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
goto lose;
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}
if (ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
ehdr.e_version != EV_CURRENT ||
ehdr.e_ident[EI_DATA] != ELFDEFNNAME(MACHDEP_ENDIANNESS) ||
ehdr.e_type != ET_DYN)
goto lose;
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close(fd);
return true;
lose:
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close(fd);
return false;
}
static char *
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_rtld_search_library_path(name, namelen, dir, dirlen)
const char *name;
size_t namelen;
const char *dir;
size_t dirlen;
{
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char *pathname;
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pathname = xmalloc(dirlen + 1 + namelen + 1);
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(void)strncpy(pathname, dir, dirlen);
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pathname[dirlen] = '/';
strcpy(pathname + dirlen + 1, name);
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dbg((" Trying \"%s\"", pathname));
if (_rtld_check_library(pathname)) /* We found it */
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return pathname;
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free(pathname);
return NULL;
}
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/*
* Find the library with the given name, and return its full pathname.
* The returned string is dynamically allocated. Generates an error
* message and returns NULL if the library cannot be found.
*
* If the second argument is non-NULL, then it refers to an already-
* loaded shared object, whose library search path will be searched.
*/
char *
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_rtld_find_library(name, refobj)
const char *name;
const Obj_Entry *refobj;
{
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Search_Path *sp;
char *pathname;
int namelen;
if (strchr(name, '/') != NULL) { /* Hard coded pathname */
if (name[0] != '/' && !_rtld_trust) {
_rtld_error(
"Absolute pathname required for shared object \"%s\"",
name);
return NULL;
}
#ifdef SVR4_LIBDIR
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if (strncmp(name, SVR4_LIBDIR, SVR4_LIBDIRLEN) == 0
&& name[SVR4_LIBDIRLEN] == '/') { /* In "/usr/lib" */
/*
* Map hard-coded "/usr/lib" onto our ELF library
* directory.
*/
pathname = xmalloc(strlen(name) + LIBDIRLEN -
SVR4_LIBDIRLEN + 1);
(void)strcpy(pathname, LIBDIR);
(void)strcpy(pathname + LIBDIRLEN, name +
SVR4_LIBDIRLEN);
return pathname;
}
#endif /* SVR4_LIBDIR */
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return xstrdup(name);
}
dbg((" Searching for \"%s\" (%p)", name, refobj));
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namelen = strlen(name);
for (sp = _rtld_paths; sp != NULL; sp = sp->sp_next)
if ((pathname = _rtld_search_library_path(name, namelen,
sp->sp_path, sp->sp_pathlen)) != NULL)
return (pathname);
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if (refobj != NULL)
for (sp = refobj->rpaths; sp != NULL; sp = sp->sp_next)
if ((pathname = _rtld_search_library_path(name,
namelen, sp->sp_path, sp->sp_pathlen)) != NULL)
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return (pathname);
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for (sp = _rtld_default_paths; sp != NULL; sp = sp->sp_next)
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if ((pathname = _rtld_search_library_path(name, namelen,
sp->sp_path, sp->sp_pathlen)) != NULL)
return (pathname);
#if 0
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if ((refobj != NULL &&
(pathname = _rtld_search_library_path(name,
refobj->rpath)) != NULL) ||
(pathname = _rtld_search_library_path(name,
ld_library_path)) != NULL
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#ifdef SVR4_LIBDIR
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LOSE !
||(pathname = _rtld_search_library_path(name, SVR4_LIBDIR)) != NULL
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#endif
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)
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return pathname;
#endif
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_rtld_error("Shared object \"%s\" not found", name);
return NULL;
}