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- /* Load an ELF sharable library into memory.
- Copyright (C) 1993-1996, Eric Youngdale.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- This program 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 General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
- /* This file contains the helper routines to load an ELF sharable
- library into memory and add the symbol table info to the chain. */
- #include <linux/types.h>
- #include <linux/fcntl.h>
- #include <linux/errno.h>
- #include "string.h"
- /*#include <stdlib.h>*/
- #include <linux/mman.h>
- #include <linux/stat.h>
- #include "hash.h"
- #include "linuxelf.h"
- #include "sysdep.h"
- #include <linux/unistd.h>
- #include "syscall.h"
- #ifdef USE_CACHE
- #include "../config.h"
- #endif
- extern char *_dl_progname;
- #ifdef USE_CACHE
- static caddr_t _dl_cache_addr = NULL;
- static size_t _dl_cache_size = 0;
- int _dl_map_cache(void)
- {
- int fd;
- struct kernel_stat st;
- header_t *header;
- libentry_t *libent;
- int i, strtabsize;
- if (_dl_cache_addr == (caddr_t)-1)
- return -1;
- else if (_dl_cache_addr != NULL)
- return 0;
- if (_dl_stat(LDSO_CACHE, &st) || (fd = _dl_open(LDSO_CACHE, O_RDONLY)) < 0)
- {
- _dl_fdprintf(2, "%s: can't open cache '%s'\n", _dl_progname, LDSO_CACHE);
- _dl_cache_addr = (caddr_t)-1; /* so we won't try again */
- return -1;
- }
- _dl_cache_size = st.st_size;
- _dl_cache_addr = (caddr_t)_dl_mmap(0, _dl_cache_size, PROT_READ,
- MAP_SHARED, fd, 0);
- _dl_close (fd);
- if (_dl_cache_addr == (caddr_t)-1)
- {
- _dl_fdprintf(2, "%s: can't map cache '%s'\n", _dl_progname, LDSO_CACHE);
- return -1;
- }
- header = (header_t *)_dl_cache_addr;
- if (_dl_cache_size < sizeof (header_t) ||
- _dl_memcmp(header->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN) ||
- _dl_memcmp(header->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN) ||
- _dl_cache_size <
- (sizeof (header_t) + header->nlibs * sizeof (libentry_t)) ||
- _dl_cache_addr[_dl_cache_size-1] != '\0')
- {
- _dl_fdprintf(2, "%s: cache '%s' is corrupt\n", _dl_progname, LDSO_CACHE);
- goto fail;
- }
- strtabsize = _dl_cache_size - sizeof (header_t) -
- header->nlibs * sizeof (libentry_t);
- libent = (libentry_t *)&header[1];
- for (i = 0; i < header->nlibs; i++)
- {
- if (libent[i].sooffset >= strtabsize ||
- libent[i].liboffset >= strtabsize)
- {
- _dl_fdprintf(2, "%s: cache '%s' is corrupt\n", _dl_progname, LDSO_CACHE);
- goto fail;
- }
- }
- return 0;
- fail:
- _dl_munmap(_dl_cache_addr, _dl_cache_size);
- _dl_cache_addr = (caddr_t)-1;
- return -1;
- }
- int _dl_unmap_cache(void)
- {
- if (_dl_cache_addr == NULL || _dl_cache_addr == (caddr_t)-1)
- return -1;
- #if 1
- _dl_munmap (_dl_cache_addr, _dl_cache_size);
- _dl_cache_addr = NULL;
- #endif
- return 0;
- }
- #endif
- /*
- * Used to return error codes back to dlopen et. al.
- */
- unsigned int _dl_error_number;
- unsigned int _dl_internal_error_number;
- struct elf_resolve * _dl_load_shared_library(int secure,
- struct elf_resolve * tpnt, char * full_libname) {
- char * pnt, *pnt1, *pnt2;
- struct elf_resolve *tpnt1 = NULL;
- char mylibname[2050];
- char * libname;
- _dl_internal_error_number = 0;
- /* quick hack to ensure mylibname buffer doesn't overflow. don't
- allow full_libname or any directory to be longer than 1024. */
- if (_dl_strlen(full_libname) > 1024)
- goto goof;
- pnt = libname = full_libname;
- while (*pnt) {
- if(*pnt == '/') libname = pnt+1;
- pnt++;
- }
- /* If the filename has any '/', try it straight and leave it at that.
- For IBCS2 compatibility under linux, we substitute the string
- /usr/i486-sysv4/lib for /usr/lib in library names. */
- if (libname != full_libname) {
- tpnt1 = _dl_load_elf_shared_library(secure, full_libname, 0);
- if (tpnt1)
- return tpnt1;
- goto goof;
- }
- /*
- * The ABI specifies that RPATH is searched before LD_*_PATH or
- * the default path of /usr/lib.
- * Check in rpath directories
- */
- for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
- if (tpnt->libtype == elf_executable) {
- pnt1 = (char *)tpnt->dynamic_info[DT_RPATH];
- if(pnt1) {
- pnt1 += (unsigned int) tpnt->loadaddr + tpnt->dynamic_info[DT_STRTAB];
- while(*pnt1){
- pnt2 = mylibname;
- while(*pnt1 && *pnt1 != ':') {
- if (pnt2 - mylibname < 1024)
- *pnt2++ = *pnt1++;
- else
- pnt1++;
- }
- if (pnt2 - mylibname >= 1024)
- break;
- if(pnt2[-1] != '/') *pnt2++ = '/';
- pnt = libname;
- while(*pnt) *pnt2++ = *pnt++;
- *pnt2++ = 0;
- tpnt1 = _dl_load_elf_shared_library(secure, mylibname, 0);
- if(tpnt1) return tpnt1;
- if(*pnt1 == ':') pnt1++;
- }
- }
- }
- }
-
- /* Check in LD_{ELF_}LIBRARY_PATH, if specified and allowed */
- pnt1 = _dl_library_path;
- if (pnt1 && *pnt1) {
- while (*pnt1) {
- pnt2 = mylibname;
- while(*pnt1 && *pnt1 != ':' && *pnt1 != ';') {
- if (pnt2 - mylibname < 1024)
- *pnt2++ = *pnt1++;
- else
- pnt1++;
- }
- if (pnt2 - mylibname >= 1024)
- break;
- if(pnt2[-1] != '/') *pnt2++ = '/';
- pnt = libname;
- while(*pnt) *pnt2++ = *pnt++;
- *pnt2++ = 0;
- tpnt1 = _dl_load_elf_shared_library(secure, mylibname, 0);
- if(tpnt1) return tpnt1;
- if(*pnt1 == ':' || *pnt1 == ';') pnt1++;
- }
- }
- /*
- * Where should the cache be searched? There is no such concept in the
- * ABI, so we have some flexibility here. For now, search it before
- * the default path of /usr/lib.
- */
- #ifdef USE_CACHE
- if (_dl_cache_addr != NULL && _dl_cache_addr != (caddr_t)-1)
- {
- int i;
- header_t *header = (header_t *)_dl_cache_addr;
- libentry_t *libent = (libentry_t *)&header[1];
- char *strs = (char *)&libent[header->nlibs];
- for (i = 0; i < header->nlibs; i++)
- {
- if ((libent[i].flags == LIB_ELF ||
- libent[i].flags == LIB_ELF_LIBC5) &&
- _dl_strcmp(libname, strs+libent[i].sooffset) == 0 &&
- (tpnt1 = _dl_load_elf_shared_library(secure, strs+libent[i].liboffset, 0)))
- return tpnt1;
- }
- }
- #endif
- #ifdef UCLIBC_DEVEL
- /* Check in /usr/<arch>-linux-uclibc/lib */
- pnt1 = UCLIBC_INSTALL_DIR"/lib";
- pnt = mylibname;
- while(*pnt1) *pnt++ = *pnt1++;
- pnt1 = libname;
- while(*pnt1) *pnt++ = *pnt1++;
- *pnt++ = 0;
- tpnt1 = _dl_load_elf_shared_library(secure, mylibname, 0);
- if (tpnt1) return tpnt1;
-
- #else /* UCLIBC_DEVEL */
- /* Check in /usr/lib */
- pnt1 = "/usr/lib/";
- pnt = mylibname;
- while(*pnt1) *pnt++ = *pnt1++;
- pnt1 = libname;
- while(*pnt1) *pnt++ = *pnt1++;
- *pnt++ = 0;
- tpnt1 = _dl_load_elf_shared_library(secure, mylibname, 0);
- if (tpnt1) return tpnt1;
-
- /* Check in /lib */
- /* try "/lib/". */
- pnt1 = "/lib/";
- pnt = mylibname;
- while(*pnt1) *pnt++ = *pnt1++;
- pnt1 = libname;
- while(*pnt1) *pnt++ = *pnt1++;
- *pnt++ = 0;
- tpnt1 = _dl_load_elf_shared_library(secure, mylibname, 0);
- if (tpnt1) return tpnt1;
- #endif /* UCLIBC_DEVEL */
- goof:
- /* Well, we shot our wad on that one. All we can do now is punt */
- if (_dl_internal_error_number) _dl_error_number = _dl_internal_error_number;
- else _dl_error_number = DL_ERROR_NOFILE;
- return NULL;
- }
- /*
- * Read one ELF library into memory, mmap it into the correct locations and
- * add the symbol info to the symbol chain. Perform any relocations that
- * are required.
- */
- //extern _elf_rtbndr(void);
- struct elf_resolve * _dl_load_elf_shared_library(int secure,
- char * libname, int flag) {
- struct elfhdr * epnt;
- unsigned int dynamic_addr = 0;
- unsigned int dynamic_size = 0;
- struct dynamic * dpnt;
- struct elf_resolve * tpnt;
- struct elf_phdr * ppnt;
- int piclib;
- char * status;
- int flags;
- char header[4096];
- int dynamic_info[24];
- int * lpnt;
- unsigned int libaddr;
- unsigned int minvma=0xffffffff, maxvma=0;
-
- int i;
- int infile;
- /* If this file is already loaded, skip this step */
- tpnt = _dl_check_hashed_files(libname);
- if(tpnt) return tpnt;
- /* If we are in secure mode (i.e. a setu/gid binary using LD_PRELOAD),
- we don't load the library if it isn't setuid. */
- if (secure) {
- struct kernel_stat st;
- if (_dl_stat(libname, &st) || !(st.st_mode & S_ISUID))
- return NULL;
- }
- libaddr = 0;
- infile = _dl_open(libname, O_RDONLY);
- if(infile < 0)
- {
- #if 0
- /*
- * NO! When we open shared libraries we may search several paths.
- * it is inappropriate to generate an error here.
- */
- _dl_fdprintf(2, "%s: can't open '%s'\n", _dl_progname, libname);
- #endif
- _dl_internal_error_number = DL_ERROR_NOFILE;
- return NULL;
- }
-
- _dl_read(infile, header, sizeof(header));
- epnt = (struct elfhdr *) header;
- if (epnt->e_ident[0] != 0x7f ||
- epnt->e_ident[1] != 'E' ||
- epnt->e_ident[2] != 'L' ||
- epnt->e_ident[3] != 'F') {
- _dl_fdprintf(2, "%s: '%s' is not an ELF file\n", _dl_progname, libname);
- _dl_internal_error_number = DL_ERROR_NOTELF;
- _dl_close(infile);
- return NULL;
- };
-
- if((epnt->e_type != ET_DYN) ||
- (epnt->e_machine != MAGIC1
- #ifdef MAGIC2
- && epnt->e_machine != MAGIC2
- #endif
- )){
- _dl_internal_error_number = (epnt->e_type != ET_DYN ? DL_ERROR_NOTDYN : DL_ERROR_NOTMAGIC);
- _dl_fdprintf(2, "%s: '%s' is not an ELF executable for " ELF_TARGET "\n",
- _dl_progname, libname);
- _dl_close(infile);
- return NULL;
- };
- ppnt = (struct elf_phdr *) &header[epnt->e_phoff];
- piclib = 1;
- for(i=0;i < epnt->e_phnum; i++){
- if(ppnt->p_type == PT_DYNAMIC) {
- if (dynamic_addr)
- _dl_fdprintf(2, "%s: '%s' has more than one dynamic section\n",
- _dl_progname, libname);
- dynamic_addr = ppnt->p_vaddr;
- dynamic_size = ppnt->p_filesz;
- };
- if(ppnt->p_type == PT_LOAD) {
- /* See if this is a PIC library. */
- if(i == 0 && ppnt->p_vaddr > 0x1000000) {
- piclib = 0;
- minvma=ppnt->p_vaddr;
- }
- if(piclib && ppnt->p_vaddr < minvma) {
- minvma = ppnt->p_vaddr;
- }
- if(((unsigned int)ppnt->p_vaddr + ppnt->p_memsz) > maxvma) {
- maxvma = ppnt->p_vaddr + ppnt->p_memsz;
- }
- }
- ppnt++;
- };
- maxvma=(maxvma+0xfffU)&~0xfffU;
- minvma=minvma&~0xffffU;
-
- flags = MAP_PRIVATE /*| MAP_DENYWRITE*/;
- if(!piclib) flags |= MAP_FIXED;
-
- status = (char *) _dl_mmap((char *) (piclib?0:minvma),
- maxvma-minvma,
- PROT_NONE,
- flags | MAP_ANONYMOUS, -1,
- 0);
- if(_dl_mmap_check_error(status)) {
- _dl_fdprintf(2, "%s: can't map '/dev/zero'\n", _dl_progname);
- _dl_internal_error_number = DL_ERROR_MMAP_FAILED;
- _dl_close(infile);
- return NULL;
- };
- libaddr=(unsigned int)status;
- flags|=MAP_FIXED;
- /* Get the memory to store the library */
- ppnt = (struct elf_phdr *) &header[epnt->e_phoff];
-
- for(i=0;i < epnt->e_phnum; i++){
- if(ppnt->p_type == PT_LOAD) {
- /* See if this is a PIC library. */
- if(i == 0 && ppnt->p_vaddr > 0x1000000) {
- piclib = 0;
- /* flags |= MAP_FIXED; */
- }
-
- if(ppnt->p_flags & PF_W) {
- unsigned int map_size;
- char * cpnt;
-
- status = (char *) _dl_mmap((char *) ((piclib?libaddr:0) +
- (ppnt->p_vaddr & 0xfffff000)),
- (ppnt->p_vaddr & 0xfff) + ppnt->p_filesz,
- LXFLAGS(ppnt->p_flags),
- flags, infile,
- ppnt->p_offset & 0x7ffff000);
-
- if(_dl_mmap_check_error(status)) {
- _dl_fdprintf(2, "%s: can't map '%s'\n", _dl_progname, libname);
- _dl_internal_error_number = DL_ERROR_MMAP_FAILED;
- _dl_munmap((char *)libaddr, maxvma-minvma);
- _dl_close(infile);
- return NULL;
- };
-
- /* Pad the last page with zeroes. */
- cpnt =(char *) (status + (ppnt->p_vaddr & 0xfff) + ppnt->p_filesz);
- while(((unsigned int) cpnt) & 0xfff) *cpnt++ = 0;
- /* I am not quite sure if this is completely correct to do or not, but
- the basic way that we handle bss segments is that we mmap /dev/zero if
- there are any pages left over that are not mapped as part of the file */
- map_size = (ppnt->p_vaddr + ppnt->p_filesz + 0xfff) & 0xfffff000;
- if(map_size < ppnt->p_vaddr + ppnt->p_memsz)
- status = (char *) _dl_mmap((char *) map_size + (piclib?libaddr:0),
- ppnt->p_vaddr + ppnt->p_memsz - map_size,
- LXFLAGS(ppnt->p_flags),
- flags | MAP_ANONYMOUS, -1, 0);
- } else
- status = (char *) _dl_mmap((char *) (ppnt->p_vaddr & 0xfffff000) +
- (piclib?libaddr:0),
- (ppnt->p_vaddr & 0xfff) + ppnt->p_filesz,
- LXFLAGS(ppnt->p_flags),
- flags, infile,
- ppnt->p_offset & 0x7ffff000);
- if(_dl_mmap_check_error(status)) {
- _dl_fdprintf(2, "%s: can't map '%s'\n", _dl_progname, libname);
- _dl_internal_error_number = DL_ERROR_MMAP_FAILED;
- _dl_munmap((char *)libaddr, maxvma-minvma);
- _dl_close(infile);
- return NULL;
- };
- /* if(libaddr == 0 && piclib) {
- libaddr = (unsigned int) status;
- flags |= MAP_FIXED;
- }; */
- };
- ppnt++;
- };
- _dl_close(infile);
-
- /* For a non-PIC library, the addresses are all absolute */
- if(piclib) {
- dynamic_addr += (unsigned int) libaddr;
- }
- /*
- * OK, the ELF library is now loaded into VM in the correct locations
- * The next step is to go through and do the dynamic linking (if needed).
- */
-
- /* Start by scanning the dynamic section to get all of the pointers */
-
- if(!dynamic_addr) {
- _dl_internal_error_number = DL_ERROR_NODYNAMIC;
- _dl_fdprintf(2, "%s: '%s' is missing a dynamic section\n", _dl_progname, libname);
- return NULL;
- }
- dpnt = (struct dynamic *) dynamic_addr;
- dynamic_size = dynamic_size / sizeof(struct dynamic);
- _dl_memset(dynamic_info, 0, sizeof(dynamic_info));
- for(i=0; i< dynamic_size; i++){
- if( dpnt->d_tag > DT_JMPREL ) {dpnt++; continue; }
- dynamic_info[dpnt->d_tag] = dpnt->d_un.d_val;
- if(dpnt->d_tag == DT_TEXTREL ||
- SVR4_BUGCOMPAT) dynamic_info[DT_TEXTREL] = 1;
- dpnt++;
- };
- /* If the TEXTREL is set, this means that we need to make the pages
- writable before we perform relocations. Do this now. They get set back
- again later. */
- if (dynamic_info[DT_TEXTREL]) {
- ppnt = (struct elf_phdr *) &header[epnt->e_phoff];
- for(i=0;i < epnt->e_phnum; i++, ppnt++){
- if(ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
- _dl_mprotect((void *) ((piclib?libaddr:0) + (ppnt->p_vaddr & 0xfffff000)),
- (ppnt->p_vaddr & 0xfff) + (unsigned int) ppnt->p_filesz,
- PROT_READ | PROT_WRITE | PROT_EXEC);
- }
- }
- tpnt = _dl_add_elf_hash_table(libname, (char *) libaddr, dynamic_info, dynamic_addr,
- dynamic_size);
- tpnt->ppnt = (struct elf_phdr *) (tpnt->loadaddr + epnt->e_phoff);
- tpnt->n_phent = epnt->e_phnum;
- /*
- * OK, the next thing we need to do is to insert the dynamic linker into
- * the proper entry in the GOT so that the PLT symbols can be properly
- * resolved.
- */
-
- lpnt = (int *) dynamic_info[DT_PLTGOT];
-
- if(lpnt) {
- lpnt = (int *) (dynamic_info[DT_PLTGOT] + ((int) libaddr));
- INIT_GOT(lpnt, tpnt);
- };
-
- return tpnt;
- }
- /* Ugly, ugly. Some versions of the SVr4 linker fail to generate COPY
- relocations for global variables that are present both in the image and
- the shared library. Go through and do it manually. If the images
- are guaranteed to be generated by a trustworthy linker, then this
- step can be skipped. */
- int _dl_copy_fixups(struct dyn_elf * rpnt)
- {
- int goof = 0;
- struct elf_resolve * tpnt;
- if(rpnt->next) goof += _dl_copy_fixups(rpnt->next);
- else return 0;
- tpnt = rpnt->dyn;
-
- if (tpnt->init_flag & COPY_RELOCS_DONE) return goof;
- tpnt->init_flag |= COPY_RELOCS_DONE;
-
- #ifdef ELF_USES_RELOCA
- goof += _dl_parse_copy_information(rpnt, tpnt->dynamic_info[DT_RELA],
- tpnt->dynamic_info[DT_RELASZ], 0);
- #else
- goof += _dl_parse_copy_information(rpnt, tpnt->dynamic_info[DT_REL],
- tpnt->dynamic_info[DT_RELSZ], 0);
- #endif
- return goof;
- }
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