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/*
* Copyright (c) 1995 by Sun Microsystems, Inc.
* All rights reserved.
*
* This source code is a product of Sun Microsystems, Inc. and is provided
* for unrestricted use provided that this legend is included on all tape
* media and as a part of the software program in whole or part. Users
* may copy or modify this source code without charge, but are not authorized
* to license or distribute it to anyone else except as part of a product or
* program developed by the user.
*
* THIS PROGRAM CONTAINS SOURCE CODE COPYRIGHTED BY SUN MICROSYSTEMS, INC.
* SUN MICROSYSTEMS, INC., MAKES NO REPRESENTATIONS ABOUT THE SUITABLITY
* OF SUCH SOURCE CODE FOR ANY PURPOSE. IT IS PROVIDED "AS IS" WITHOUT
* EXPRESS OR IMPLIED WARRANTY OF ANY KIND. SUN MICROSYSTEMS, INC. DISCLAIMS
* ALL WARRANTIES WITH REGARD TO SUCH SOURCE CODE, INCLUDING ALL IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN
* NO EVENT SHALL SUN MICROSYSTEMS, INC. BE LIABLE FOR ANY SPECIAL, INDIRECT,
* INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM USE OF SUCH SOURCE CODE, REGARDLESS OF THE THEORY OF LIABILITY.
*
* This source code is provided with no support and without any obligation on
* the part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS
* SOURCE CODE OR ANY PART THEREOF.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
/*
* dynodump(3x) dumps a running executable into a specified ELF file. The new
* file consists of the memory contents of the original file together with any
* heap. This heap is assigned to a new `.heap' section within the new file.
*
* The new file may be re-executed, and will contain any data modifications
* made to the original image up until the time dynodump(3x) was called.
*
* The original image may have undergone relocations (performed by ld.so.1)
* prior to control being transferred to the image. These relocations will
* reside as the data copied from the image. To prevent subsequent executions
* of the new image from undergoing the same relocations, any relocation entries
* (besides copy or jump slot relocations) are nulled out. Note that copy
* relocations such as required for __iob must be reinitialized each time the
* process starts, so it is not sufficient to simply null out the .dynamic
* sections relocation information. The effect of this is that if the new
* image was bound to definitions in any shared object dependencies, then these
* dependencies *must* reside in the same location as when dynodump(3x) was
* called. Any changes to the shared object dependencies of the new image, or
* uses of such things as LD_PRELOAD, may result in the bindings encoded in the
* image becoming invalid.
*
* The following flags modify the data of the image created:
*
* RTLD_SAVREL save the original relocation data. Under this option any
* relocation offset is reset to contain the same data as was
* found in the images original file.
*
* This option allows relocation information to be retained in the
* new image so that it may be re-executed when the new image is
* run. This allows far greater flexibility as the new image can
* now take advantage of new shared objects.
*
* Note. under this mechanism, any data item that undergoes
* relocation and is then further modified during the execution of
* the image before dynodump(3x) is called will lose the
* modification that occured during the applications execution.
*
* N.B. The above commentary is not quite correct in the flags have been hardwired
* to RTLD_SAVREL.
*/
#pragma ident "@(#) $Id: dynodump.c,v 1.5 1995/06/26 20:11:08 georgn Exp $ - SMI"
#include <sys/param.h>
#include <sys/procfs.h>
#include <fcntl.h>
#include <stdio.h>
#include <libelf.h>
#include <link.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <malloc.h>
#include "machdep.h"
#include "_dynodump.h"
/*
* Generic elf error message generator
*/
static int
elferr(const char * str)
{
fprintf(stderr, "%s: %s\n", str, elf_errmsg(elf_errno()));
return (1);
}
int dynodump (const char *file);
int
dynodump (const char *file)
{
Elf *ielf, *oelf;
Ehdr *iehdr, *oehdr;
Phdr *iphdr, *ophdr, *data_phdr = 0;
Cache *icache, *ocache, *_icache, *_ocache;
Cache *data_cache = 0, *shstr_cache = 0;
Elf_Scn *scn;
Shdr *shdr;
Elf_Data *data, rundata;
Half ndx, _ndx;
int fd, _fd;
Addr edata, _addr;
char *istrs, *ostrs, *_ostrs, proc[16];
const char heap[] = ".heap";
prstatus_t pstat;
/*
* Obtain a file descriptor for this process,
* for the executable and get a prstatus_t
* structure.
*/
sprintf(proc, "/proc/%ld", getpid());
if (((_fd = open(proc, O_RDONLY, 0)) == -1) ||
((fd = ioctl(_fd, PIOCOPENM, (void *)0)) == -1) ||
(ioctl(_fd, PIOCSTATUS, &pstat) == -1)) {
fprintf(stderr, "/proc: initialization error: %s\n",
strerror(errno));
close(_fd);
return (1);
}
close(_fd);
/*
* Initialize with the ELF library and make sure this is an executable
* ELF file we're dealing with.
*/
elf_version(EV_CURRENT);
if ((ielf = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
close(fd);
return (elferr("elf_begin"));
}
close(fd);
if ((elf_kind(ielf) != ELF_K_ELF) ||
((iehdr = elf_getehdr(ielf)) == NULL) ||
(iehdr->e_type != ET_EXEC)) {
fprintf(stderr, "image is not an ELF executable\n");
elf_end(ielf);
return (1);
}
/*
* Elf_elf_header(iehdr);
*/
/*
* Create the new output file.
*/
if ((fd = open(file, O_RDWR | O_CREAT | O_TRUNC, 0777)) == -1) {
fprintf(stderr, "%s: open failed: %s\n", file,
strerror(errno));
elf_end(ielf);
return (1);
}
if ((oelf = elf_begin(fd, ELF_C_WRITE, NULL)) == NULL) {
elf_end(ielf);
close(fd);
return (elferr("elf_begin"));
}
/*
* Obtain the input program headers. Remember the data segments
* program header entry as this will be updated later to reflect the
* new .heap sections size.
*/
if ((iphdr = elf_getphdr(ielf)) == NULL)
return (elferr("elf_getphdr"));
for (ndx = 0, ophdr = iphdr; ndx != iehdr->e_phnum; ndx++, ophdr++) {
/*
* Save the program header that contains the NOBITS section, or
* the last loadable program header if no NOBITS exists.
* A NOBITS section translates to a memory size requirement that
* is greater than the file data it is mapped from.
*/
if (ophdr->p_type == PT_LOAD) {
if (ophdr->p_filesz != ophdr->p_memsz)
data_phdr = ophdr;
else if (data_phdr) {
if (data_phdr->p_vaddr < ophdr->p_vaddr)
data_phdr = ophdr;
} else
data_phdr = ophdr;
}
}
if (data_phdr == 0) {
fprintf(stderr, "no data segment found!\n");
return (0);
}
/*
* Obtain the input files section header string table.
*/
if ((scn = elf_getscn(ielf, iehdr->e_shstrndx)) == NULL)
return (elferr("elf_getscn"));
if ((data = elf_getdata(scn, NULL)) == NULL)
return (elferr("elf_getdata"));
istrs = data->d_buf;
/*
* Construct a cache to maintain the input files section information.
*/
if ((icache = (Cache *) malloc(iehdr->e_shnum * sizeof (Cache))) == 0) {
fprintf(stderr, "malloc failed: %s\n", strerror(errno));
return (1);
}
_icache = icache;
_icache++;
/*
* Traverse each section from the input file.
*/
for (ndx = 1, scn = 0;
(_icache->c_scn = elf_nextscn(ielf, scn));
ndx++, scn = _icache->c_scn, _icache++) {
if ((_icache->c_shdr = shdr = elf_getshdr(_icache->c_scn)) == NULL)
return (elferr("elf_getshdr"));
if ((_icache->c_data = elf_getdata(_icache->c_scn, NULL)) == NULL)
return (elferr("elf_getdata"));
_icache->c_name = istrs + (size_t)(shdr->sh_name);
/*
* For each section that has a virtual address reestablish the
* data buffer to point to the memory image.
*
* if (shdr->sh_addr)
* _icache->c_data->d_buf = (void *)shdr->sh_addr;
*/
/*
* Remember the last section of the data segment, the new .heap
* section will be added after this section.
*/
if ((shdr->sh_addr + shdr->sh_size)
== (data_phdr->p_vaddr + data_phdr->p_memsz))
data_cache = _icache;
/*
* Remember the section header string table as this will be
* rewritten with the new .heap name.
*/
if ((shdr->sh_type == SHT_STRTAB) &&
((strcmp(_icache->c_name, ".shstrtab")) == 0))
shstr_cache = _icache;
}
if (data_cache == 0) {
fprintf(stderr, "final data section not found!\n");
return (0);
}
/*
* Determine the new .heap section to create.
*/
#ifdef notdef
rundata.d_buf = (void *)(data_cache->c_shdr->sh_addr +
data_cache->c_shdr->sh_size);
rundata.d_size = (int)sbrk(0) - (int)rundata.d_buf;
#else
rundata.d_buf = pstat.pr_brkbase;
rundata.d_size = pstat.pr_brksize;
#endif
rundata.d_type = ELF_T_BYTE;
rundata.d_off = 0;
rundata.d_align = 1;
rundata.d_version = EV_CURRENT;
/*
* From the new data buffer determine the new value for _end and _edata.
* This will also be used to update the data segment program header.
*/
edata = S_ROUND((data_phdr->p_vaddr + data_phdr->p_memsz),
rundata.d_align) + rundata.d_size;
/*
* We're now ready to construct the new elf image.
*
* Obtain a new elf header and initialize it with any basic information
* that isn't calculated as part of elf_update(). Bump the section
* header string table index to account for the .heap section we'll be
* adding.
*/
if ((oehdr = elf_newehdr(oelf)) == NULL)
return (elferr("elf_newehdr"));
oehdr->e_entry = iehdr->e_entry;
oehdr->e_machine = iehdr->e_machine;
oehdr->e_type = iehdr->e_type;
oehdr->e_shstrndx = iehdr->e_shstrndx + 1;
/*
* Obtain a new set of program headers. Initialize these with the same
* information as the input program headers and update the data segment
* to reflect the new .heap section.
*/
if ((ophdr = elf_newphdr(oelf, iehdr->e_phnum)) == NULL)
return (elferr("elf_newphdr"));
for (ndx = 0; ndx != iehdr->e_phnum; ndx++, iphdr++, ophdr++) {
*ophdr = *iphdr;
if (data_phdr == iphdr)
ophdr->p_filesz = ophdr->p_memsz = edata - ophdr->p_vaddr;
}
/*
* Obtain a new set of sections.
*/
_icache = icache;
_icache++;
for (ndx = 1; ndx != iehdr->e_shnum; ndx++, _icache++) {
/*
* Create a matching section header in the output file.
*/
if ((scn = elf_newscn(oelf)) == NULL)
return (elferr("elf_newscn"));
if ((shdr = elf_getshdr(scn)) == NULL)
return (elferr("elf_getshdr"));
*shdr = *_icache->c_shdr;
/*
* Create a matching data buffer for this section.
*/
if ((data = elf_newdata(scn)) == NULL)
return (elferr("elf_newdata"));
*data = *_icache->c_data;
/*
* For each section that has a virtual address reestablish the
* data buffer to point to the memory image. Note, we skip
* the plt section.
*/
if ((shdr->sh_addr) && (!((shdr->sh_type == SHT_PROGBITS)
&& (strcmp(_icache->c_name, ".plt") == 0))))
data->d_buf = (void *)shdr->sh_addr;
/*
* Update any NOBITS section to indicate that it now contains
* data.
*/
if (shdr->sh_type == SHT_NOBITS)
shdr->sh_type = SHT_PROGBITS;
/*
* Add the new .heap section after the last section of the
* present data segment.
*/
if (data_cache == _icache) {
if ((scn = elf_newscn(oelf)) == NULL)
return (elferr("elf_newscn"));
if ((shdr = elf_getshdr(scn)) == NULL)
return (elferr("elf_getshdr"));
shdr->sh_type = SHT_PROGBITS;
shdr->sh_flags = SHF_ALLOC | SHF_WRITE;
if ((data = elf_newdata(scn)) == NULL)
return (elferr("elf_newdata"));
*data = rundata;
}
/*
* Update the section header string table size to reflect the
* new section name.
*/
if (shstr_cache && (shstr_cache == _icache))
data->d_size += sizeof (heap);
}
/*
* Write out the new image, and obtain a new elf descriptor that will
* allow us to write to the new image.
*/
if (elf_update(oelf, ELF_C_WRITE) == -1)
return (elferr("elf_update"));
elf_end(oelf);
if ((oelf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL)
return (elferr("elf_begin"));
if ((oehdr = elf_getehdr(oelf)) == NULL)
return (elferr("elf_getehdr"));
/*
* Obtain the output files section header string table.
*/
if ((scn = elf_getscn(oelf, oehdr->e_shstrndx)) == NULL)
return (elferr("elf_getscn"));
if ((data = elf_getdata(scn, NULL)) == NULL)
return (elferr("elf_getdata"));
ostrs = _ostrs = data->d_buf;
*_ostrs++ = '\0';
/*
* Construct a cache to maintain the output files section information.
*/
if ((ocache = (Cache *)malloc(oehdr->e_shnum * sizeof (Cache))) == 0) {
fprintf(stderr, "malloc failed: %s\n", strerror(errno));
return (1);
}
_ocache = ocache;
_ocache++;
_icache = icache;
_icache++;
/*
* Traverse each section from the input file rebuilding the section
* header string table as we go.
*/
_ndx = _addr = 0;
for (ndx = 1, scn = 0;
(_ocache->c_scn = elf_nextscn(oelf, scn));
ndx++, scn = _ocache->c_scn, _ocache++, _icache++) {
const char *strs;
if ((_ocache->c_shdr = shdr =
elf_getshdr(_ocache->c_scn)) == NULL)
return (elferr("elf_getshdr"));
if ((_ocache->c_data =
elf_getdata(_ocache->c_scn, NULL)) == NULL)
return (elferr("elf_getdata"));
/*
* If were inserting the new .heap section, insert the new
* section name and initialize it's virtual address.
*/
if (_addr) {
strs = heap;
shdr->sh_addr = S_ROUND(_addr, shdr->sh_addralign);
_addr = 0;
} else
strs = istrs + (size_t)(_icache->c_shdr->sh_name);
strcpy(_ostrs, strs);
shdr->sh_name = _ostrs - ostrs;
_ocache->c_name = _ostrs;
_ostrs += strlen(strs) + 1;
/*
* If we've inserted a new section any later section may need
* their sh_link fields updated.
*/
if (_ndx) {
if (_ocache->c_shdr->sh_link >= _ndx)
_ocache->c_shdr->sh_link++;
}
/*
* If this is the last section of the original data segment
* determine sufficient information to initialize the new .heap
* section which will be obtained next.
*/
if (data_cache == _icache) {
_ndx = ndx + 1;
_addr = shdr->sh_addr + shdr->sh_size;
_icache--;
data_cache = 0;
}
}
/*
* Now that we have a complete description of the new image update any
* sections that are required.
*
* o update the value of _edata and _end.
*
* o reset any relocation entries if necessary.
*/
_ocache = &ocache[1];
_icache = &icache[1];
for (ndx = 1; ndx < oehdr->e_shnum; ndx++, _ocache++, _icache++) {
if ((_ocache->c_shdr->sh_type == SHT_SYMTAB) ||
(_ocache->c_shdr->sh_type == SHT_DYNSYM))
update_sym(ocache, _ocache, edata);
if (_ocache->c_shdr->sh_type == M_REL_SHT_TYPE)
update_reloc(ocache, _ocache, icache, _icache, oehdr->e_shnum);
}
if (elf_update(oelf, ELF_C_WRITE) == -1)
return (elferr("elf_update"));
elf_end(oelf);
elf_end(ielf);
return (0);
}
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