348 lines
9.6 KiB
C
348 lines
9.6 KiB
C
/* $NetBSD: search.c,v 1.1 1996/12/16 20:38:05 cgd Exp $ */
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/*
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* Copyright 1996 Matt Thomas <matt@3am-software.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Polstra.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Dynamic linker for ELF.
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*
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* John Polstra <jdp@polstra.com>.
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*/
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <stdio.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/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include "debug.h"
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#include "rtld.h"
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#define CONCAT(x,y) __CONCAT(x,y)
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#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
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#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
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#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE))
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#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
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/*
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* Data declarations.
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*/
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typedef struct {
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const char *si_name;
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const char *si_best_name;
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char *si_best_fullpath;
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const Search_Path *si_best_path;
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size_t si_namelen;
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int si_desired_major;
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int si_desired_minor;
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int si_best_major;
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int si_best_minor;
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unsigned si_exact : 1;
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} Search_Info;
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typedef enum {
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Search_FoundNothing,
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Search_FoundLower,
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Search_FoundHigher,
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Search_FoundExact
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} Search_Result;
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static bool
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_rtld_check_library(
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const Search_Path *sp,
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const char *name,
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size_t namelen,
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char **fullpath_p)
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{
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struct stat mystat;
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char *fullpath;
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Elf_Ehdr ehdr;
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int fd;
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fullpath = xmalloc(sp->sp_pathlen + 1 + namelen + 1);
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strncpy(fullpath, sp->sp_path, sp->sp_pathlen);
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fullpath[sp->sp_pathlen] = '/';
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strcpy(&fullpath[sp->sp_pathlen + 1], name);
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dbg(" Trying \"%s\"", fullpath);
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if (stat(fullpath, &mystat) >= 0 && S_ISREG(mystat.st_mode)) {
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if ((fd = open(fullpath, O_RDONLY)) >= 0) {
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if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
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goto lose;
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/* Elf_e_ident includes class */
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if (memcmp(Elf_e_ident, ehdr.e_ident, Elf_e_siz) != 0)
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goto lose;
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switch (ehdr.e_machine) {
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ELFDEFNNAME(MACHDEP_ID_CASES)
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default:
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goto lose;
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}
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if (ehdr.e_ident[Elf_ei_version] != Elf_ev_current ||
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ehdr.e_version != Elf_ev_current ||
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ehdr.e_ident[Elf_ei_data] != ELFDEFNNAME(MACHDEP_ENDIANNESS) ||
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ehdr.e_type != Elf_et_dyn)
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goto lose;
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if (*fullpath_p != NULL)
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free(*fullpath_p);
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*fullpath_p = fullpath;
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return true;
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lose:
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close(fd);
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}
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}
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free(fullpath);
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return false;
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}
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static Search_Result
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_rtld_search_directory(
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const Search_Path *sp,
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Search_Info *si)
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{
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struct dirent *entry;
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DIR *dirp;
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Search_Result result = Search_FoundNothing;
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dbg("_rtld_search_directory");
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if (sp->sp_path == NULL || sp->sp_path[0] == '\0')
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return result;
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dbg("_rtld_search_directory 2");
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if ((dirp = opendir(sp->sp_path)) == NULL) {
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dbg("_rtld_search_directory 2.1");
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return result;
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}
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dbg("_rtld_search_directory 3");
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while ((entry = readdir(dirp)) != NULL) {
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long major = -1;
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long minor = -1;
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if (strncmp(entry->d_name, si->si_name, si->si_namelen))
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continue;
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/*
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* We are matching libfoo.so only (no more info). Only take
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* it as a last resort.
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*/
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if (si->si_exact) {
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if (strcmp(entry->d_name, si->si_name))
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continue;
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#ifdef notyet
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} else if (entry->d_namlen == si->si_namelen) {
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if (si->si_best_path != NULL || si->si_best_major != -1)
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continue;
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#endif
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} else {
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char *cp;
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/*
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* We expect (demand!) that it be of the form
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* "libfoo.so.<something>"
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*/
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if (entry->d_name[si->si_namelen] != '.')
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continue;
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/*
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* This file has a least a major number (well, maybe not if it
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* has a name of "libfoo.so." but treat that as equivalent to 0.
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* It had better match what we are looking for.
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*/
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major = strtol(&entry->d_name[si->si_namelen+1], &cp, 10);
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if (major < 0 || (cp[0] != '\0' && cp[0] != '.')
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|| &entry->d_name[si->si_namelen+1] == cp)
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continue;
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if (cp[0] == '.') {
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char *cp2;
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minor = strtol(&cp[1], &cp2, 10);
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if (minor < 0 || cp2[0] != '\0' || cp == cp2)
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continue;
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} else {
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minor = 0;
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}
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if (major != si->si_desired_major || minor <= si->si_best_minor)
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continue;
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}
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/*
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* We have a better candidate...
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*/
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if (!_rtld_check_library(sp, entry->d_name, entry->d_namlen,
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&si->si_best_fullpath))
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continue;
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si->si_best_name = &si->si_best_fullpath[sp->sp_pathlen + 1];
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si->si_best_major = major;
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si->si_best_minor = minor;
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si->si_best_path = sp;
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if (si->si_exact || si->si_best_minor == si->si_desired_minor)
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result = Search_FoundExact;
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else if (si->si_best_minor > si->si_desired_minor)
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result = Search_FoundHigher;
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else
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result = Search_FoundLower;
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/*
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* We were looking for, and found, an exact match. We're done.
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*/
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if (si->si_exact)
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break;
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}
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dbg("found %s (%d.%d) match for %s (%d.%d) -> %s",
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result == Search_FoundNothing ? "no"
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: result == Search_FoundLower ? "lower"
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: result == Search_FoundExact ? "exact" : "higher",
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si->si_best_major, si->si_best_minor,
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si->si_name,
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si->si_desired_major, si->si_desired_minor,
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si->si_best_fullpath ? si->si_best_fullpath : sp->sp_path);
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closedir(dirp);
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return result;
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}
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static char *
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_rtld_search_library_paths(
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const char *name,
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Search_Path *paths,
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const Search_Path *rpaths)
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{
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Search_Info info;
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Search_Path *path;
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const char *cp;
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Search_Result result = Search_FoundNothing;
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memset(&info, 0, sizeof(info));
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info.si_name = name;
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info.si_desired_major = -1;
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info.si_desired_minor = -1;
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info.si_best_major = -1;
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info.si_best_minor = -1;
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cp = strstr(name, ".so");
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if (cp == NULL) {
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info.si_exact = true;
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} else {
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cp += sizeof(".so") - 1;
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info.si_namelen = cp - name;
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if (cp[0] != '.') {
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info.si_exact = true;
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} else {
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info.si_desired_major = atoi(&cp[1]);
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if ((cp = strchr(&cp[1], '.')) != NULL) {
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info.si_desired_minor = atoi(&cp[1]);
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} else {
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info.si_desired_minor = 0;
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}
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}
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}
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if (rpaths != NULL && result < Search_FoundHigher) { /* Exact? */
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dbg(" checking rpaths..");
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for (; rpaths != NULL; rpaths = rpaths->sp_next) {
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dbg(" in \"%s\"", rpaths->sp_path);
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result = _rtld_search_directory(rpaths, &info);
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if (result >= Search_FoundHigher) /* Exact? */
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break;
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}
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}
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if (result < Search_FoundHigher) { /* Exact? */
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dbg(" checking default paths..");
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for (path = paths; path != NULL; path = path->sp_next) {
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dbg(" in \"%s\"", path->sp_path);
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result = _rtld_search_directory(path, &info);
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if (result >= Search_FoundHigher) /* Exact? */
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break;
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}
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}
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if (result >= Search_FoundHigher)
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return info.si_best_fullpath;
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if (info.si_best_fullpath != NULL)
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free(info.si_best_fullpath);
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return NULL;
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}
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/*
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* Find the library with the given name, and return its full pathname.
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* The returned string is dynamically allocated. Generates an error
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* message and returns NULL if the library cannot be found.
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*
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* If the second argument is non-NULL, then it refers to an already-
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* loaded shared object, whose library search path will be searched.
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*/
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char *
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_rtld_find_library(
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const char *name,
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const Obj_Entry *refobj)
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{
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char *pathname;
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if (strchr(name, '/') != NULL) { /* Hard coded pathname */
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if (name[0] != '/' && !_rtld_trust) {
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_rtld_error("Absolute pathname required for shared object \"%s\"",
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name);
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return NULL;
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}
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#ifdef SVR4_LIBDIR
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if (strncmp(name, SVR4_LIBDIR, SVR4_LIBDIRLEN) == 0
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&& name[SVR4_LIBDIRLEN] == '/') { /* In "/usr/lib" */
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/* Map hard-coded "/usr/lib" onto our ELF library directory. */
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pathname = xmalloc(strlen(name) + LIBDIRLEN - SVR4_LIBDIRLEN + 1);
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strcpy(pathname, LIBDIR);
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strcpy(pathname + LIBDIRLEN, name + SVR4_LIBDIRLEN);
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return pathname;
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}
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#endif /* SVR4_LIBDIR */
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return xstrdup(name);
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}
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dbg(" Searching for \"%s\" (%p)", name, refobj);
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pathname = _rtld_search_library_paths(name, _rtld_paths,
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refobj ? refobj->rpaths : NULL);
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if (pathname == NULL)
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_rtld_error("Shared object \"%s\" not found", name);
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return pathname;
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}
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