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bbafa43d0d
freebsd-skq/sys/kern/imgact_elf.c
jdp bbafa43d0d Change the load address of the ELF dynamic linker from "2L*MAXDSIZ" 
to an architecture-specific value defined in <machine/elf.h>.  This
solves problems on large-memory systems that have a high value for
MAXDSIZ.

The load address is controlled by a new macro ELF_RTLD_ADDR(vmspace).
On the i386 it is hard-wired to 0x08000000, which is the standard
SVR4 location for the dynamic linker.

On the Alpha, the dynamic linker is loaded MAXDSIZ bytes beyond
the start of the program's data segment.  This is the same place
a userland mmap(0, ...) call would put it, so it ends up just below
all the shared libraries.  The rationale behind the calculation is
that it allows room for the data segment to grow to its maximum
possible size.

These changes have been tested on the i386 for several months
without problems.  They have been tested on the Alpha as well,
though not for nearly as long.  I would like to merge the changes
into 3.1 within a week if no problems have surfaced as a result of
them.
1999-02-07 23:49:56 +00:00

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/*-
* Copyright (c) 1995-1996 Søren Schmidt
* Copyright (c) 1996 Peter Wemm
* 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
* in this position and unchanged.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software withough 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.
*
* $Id: imgact_elf.c,v 1.52 1999/02/07 21:48:21 dillon Exp $
*/
#include "opt_rlimit.h"
#include <sys/param.h>
#include <sys/acct.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/namei.h>
#include <sys/pioctl.h>
#include <sys/proc.h>
#include <sys/procfs.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <sys/lock.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_prot.h>
#include <vm/vm_extern.h>
#include <machine/elf.h>
#include <machine/md_var.h>
__ElfType(Brandinfo);
__ElfType(Auxargs);
static int elf_check_header __P((const Elf_Ehdr *hdr, int type));
static int elf_freebsd_fixup __P((long **stack_base,
struct image_params *imgp));
static int elf_load_file __P((struct proc *p, char *file, u_long *addr,
u_long *entry));
static int elf_load_section __P((struct proc *p,
struct vmspace *vmspace, struct vnode *vp,
vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz,
vm_prot_t prot));
static int exec_elf_imgact __P((struct image_params *imgp));
static int elf_trace = 0;
SYSCTL_INT(_debug, OID_AUTO, elf_trace, CTLFLAG_RW, &elf_trace, 0, "");
/*
* XXX Maximum length of an ELF brand (sysctl wants a statically-allocated
* buffer).
*/
#define MAXBRANDLEN 16
static struct sysentvec elf_freebsd_sysvec = {
SYS_MAXSYSCALL,
sysent,
0,
0,
0,
0,
0,
0,
elf_freebsd_fixup,
sendsig,
sigcode,
&szsigcode,
0,
"FreeBSD ELF",
elf_coredump
};
static Elf_Brandinfo freebsd_brand_info = {
"FreeBSD",
"",
"/usr/libexec/ld-elf.so.1",
&elf_freebsd_sysvec
};
static Elf_Brandinfo *elf_brand_list[MAX_BRANDS] = {
&freebsd_brand_info,
NULL, NULL, NULL,
NULL, NULL, NULL, NULL
};
int
elf_insert_brand_entry(Elf_Brandinfo *entry)
{
int i;
for (i=1; i<MAX_BRANDS; i++) {
if (elf_brand_list[i] == NULL) {
elf_brand_list[i] = entry;
break;
}
}
if (i == MAX_BRANDS)
return -1;
return 0;
}
int
elf_remove_brand_entry(Elf_Brandinfo *entry)
{
int i;
for (i=1; i<MAX_BRANDS; i++) {
if (elf_brand_list[i] == entry) {
elf_brand_list[i] = NULL;
break;
}
}
if (i == MAX_BRANDS)
return -1;
return 0;
}
int
elf_brand_inuse(Elf_Brandinfo *entry)
{
struct proc *p;
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (p->p_sysent == entry->sysvec)
return TRUE;
}
return FALSE;
}
static int
elf_check_header(const Elf_Ehdr *hdr, int type)
{
if (!IS_ELF(*hdr) ||
hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT)
return ENOEXEC;
if (!ELF_MACHINE_OK(hdr->e_machine))
return ENOEXEC;
if (hdr->e_type != type || hdr->e_version != ELF_TARG_VER)
return ENOEXEC;
return 0;
}
static int
elf_load_section(struct proc *p, struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot)
{
size_t map_len;
vm_offset_t map_addr;
int error, rv;
size_t copy_len;
vm_object_t object;
vm_offset_t file_addr;
vm_offset_t data_buf = 0;
object = vp->v_object;
error = 0;
map_addr = trunc_page((vm_offset_t)vmaddr);
file_addr = trunc_page(offset);
/*
* We have two choices. We can either clear the data in the last page
* of an oversized mapping, or we can start the anon mapping a page
* early and copy the initialized data into that first page. We
* choose the second..
*/
if (memsz > filsz)
map_len = trunc_page(offset+filsz) - file_addr;
else
map_len = round_page(offset+filsz) - file_addr;
if (map_len != 0) {
vm_object_reference(object);
vm_map_lock(&vmspace->vm_map);
rv = vm_map_insert(&vmspace->vm_map,
object,
file_addr, /* file offset */
map_addr, /* virtual start */
map_addr + map_len,/* virtual end */
prot,
VM_PROT_ALL,
MAP_COPY_NEEDED | MAP_COPY_ON_WRITE);
vm_map_unlock(&vmspace->vm_map);
if (rv != KERN_SUCCESS)
return EINVAL;
/* prefault the page tables */
pmap_object_init_pt(&vmspace->vm_pmap,
map_addr,
object,
(vm_pindex_t) OFF_TO_IDX(file_addr),
map_len,
0);
/* we can stop now if we've covered it all */
if (memsz == filsz)
return 0;
}
/*
* We have to get the remaining bit of the file into the first part
* of the oversized map segment. This is normally because the .data
* segment in the file is extended to provide bss. It's a neat idea
* to try and save a page, but it's a pain in the behind to implement.
*/
copy_len = (offset + filsz) - trunc_page(offset + filsz);
map_addr = trunc_page((vm_offset_t)vmaddr + filsz);
map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr;
/* This had damn well better be true! */
if (map_len != 0) {
vm_map_lock(&vmspace->vm_map);
rv = vm_map_insert(&vmspace->vm_map, NULL, 0,
map_addr, map_addr + map_len,
VM_PROT_ALL, VM_PROT_ALL, 0);
vm_map_unlock(&vmspace->vm_map);
if (rv != KERN_SUCCESS)
return EINVAL;
}
if (copy_len != 0) {
vm_object_reference(object);
rv = vm_map_find(exec_map,
object,
trunc_page(offset + filsz),
&data_buf,
PAGE_SIZE,
TRUE,
VM_PROT_READ,
VM_PROT_ALL,
MAP_COPY_ON_WRITE | MAP_COPY_NEEDED);
if (rv != KERN_SUCCESS) {
vm_object_deallocate(object);
return EINVAL;
}
pmap_object_init_pt(exec_map->pmap, data_buf, object,
(vm_pindex_t) OFF_TO_IDX(trunc_page(offset + filsz)),
PAGE_SIZE, 1);
/* send the page fragment to user space */
error = copyout((caddr_t)data_buf, (caddr_t)map_addr, copy_len);
vm_map_remove(exec_map, data_buf, data_buf + PAGE_SIZE);
if (error)
return (error);
}
/*
* set it to the specified protection
*/
vm_map_protect(&vmspace->vm_map, map_addr, map_addr + map_len, prot,
FALSE);
return error;
}
static int
elf_load_file(struct proc *p, char *file, u_long *addr, u_long *entry)
{
const Elf_Ehdr *hdr = NULL;
const Elf_Phdr *phdr = NULL;
struct nameidata nd;
struct vmspace *vmspace = p->p_vmspace;
struct vattr attr;
struct image_params image_params, *imgp;
vm_prot_t prot;
unsigned long text_size = 0, data_size = 0;
unsigned long text_addr = 0, data_addr = 0;
int error, i;
imgp = &image_params;
/*
* Initialize part of the common data
*/
imgp->proc = p;
imgp->uap = NULL;
imgp->attr = &attr;
imgp->firstpage = NULL;
imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
if (imgp->image_header == NULL) {
nd.ni_vp = NULL;
error = ENOMEM;
goto fail;
}
NDINIT(&nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, p);
if ((error = namei(&nd)) != 0) {
nd.ni_vp = NULL;
goto fail;
}
imgp->vp = nd.ni_vp;
/*
* Check permissions, modes, uid, etc on the file, and "open" it.
*/
error = exec_check_permissions(imgp);
if (error) {
VOP_UNLOCK(nd.ni_vp, 0, p);
goto fail;
}
error = exec_map_first_page(imgp);
VOP_UNLOCK(nd.ni_vp, 0, p);
if (error)
goto fail;
hdr = (const Elf_Ehdr *)imgp->image_header;
if ((error = elf_check_header(hdr, ET_DYN)) != 0)
goto fail;
/* Only support headers that fit within first page for now */
if ((hdr->e_phoff > PAGE_SIZE) ||
(hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
error = ENOEXEC;
goto fail;
}
phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
for (i = 0; i < hdr->e_phnum; i++) {
if (phdr[i].p_type == PT_LOAD) { /* Loadable segment */
prot = 0;
if (phdr[i].p_flags & PF_X)
prot |= VM_PROT_EXECUTE;
if (phdr[i].p_flags & PF_W)
prot |= VM_PROT_WRITE;
if (phdr[i].p_flags & PF_R)
prot |= VM_PROT_READ;
if ((error = elf_load_section(p, vmspace, nd.ni_vp,
phdr[i].p_offset,
(caddr_t)phdr[i].p_vaddr +
(*addr),
phdr[i].p_memsz,
phdr[i].p_filesz, prot)) != 0)
goto fail;
/*
* Is this .text or .data ??
*
* We only handle one each of those yet XXX
*/
if (hdr->e_entry >= phdr[i].p_vaddr &&
hdr->e_entry <(phdr[i].p_vaddr+phdr[i].p_memsz)) {
text_addr = trunc_page(phdr[i].p_vaddr+(*addr));
text_size = round_page(phdr[i].p_memsz +
phdr[i].p_vaddr -
trunc_page(phdr[i].p_vaddr));
*entry=(unsigned long)hdr->e_entry+(*addr);
} else {
data_addr = trunc_page(phdr[i].p_vaddr+(*addr));
data_size = round_page(phdr[i].p_memsz +
phdr[i].p_vaddr -
trunc_page(phdr[i].p_vaddr));
}
}
}
fail:
if (imgp->firstpage)
exec_unmap_first_page(imgp);
if (imgp->image_header)
kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
PAGE_SIZE);
if (nd.ni_vp)
vrele(nd.ni_vp);
return error;
}
static char fallback_elf_brand[MAXBRANDLEN+1] = { "none" };
SYSCTL_STRING(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
fallback_elf_brand, sizeof(fallback_elf_brand),
"ELF brand of last resort");
static int
exec_elf_imgact(struct image_params *imgp)
{
const Elf_Ehdr *hdr = (const Elf_Ehdr *) imgp->image_header;
const Elf_Phdr *phdr;
Elf_Auxargs *elf_auxargs = NULL;
struct vmspace *vmspace;
vm_prot_t prot;
u_long text_size = 0, data_size = 0;
u_long text_addr = 0, data_addr = 0;
u_long addr, entry = 0, proghdr = 0;
int error, i;
const char *interp = NULL;
Elf_Brandinfo *brand_info;
const char *brand;
char path[MAXPATHLEN];
/*
* Do we have a valid ELF header ?
*/
if (elf_check_header(hdr, ET_EXEC))
return -1;
/*
* From here on down, we return an errno, not -1, as we've
* detected an ELF file.
*/
if ((hdr->e_phoff > PAGE_SIZE) ||
(hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
/* Only support headers in first page for now */
return ENOEXEC;
}
phdr = (const Elf_Phdr*)(imgp->image_header + hdr->e_phoff);
/*
* From this point on, we may have resources that need to be freed.
*/
if ((error = exec_extract_strings(imgp)) != 0)
goto fail;
exec_new_vmspace(imgp);
vmspace = imgp->proc->p_vmspace;
for (i = 0; i < hdr->e_phnum; i++) {
switch(phdr[i].p_type) {
case PT_LOAD: /* Loadable segment */
prot = 0;
if (phdr[i].p_flags & PF_X)
prot |= VM_PROT_EXECUTE;
if (phdr[i].p_flags & PF_W)
prot |= VM_PROT_WRITE;
if (phdr[i].p_flags & PF_R)
prot |= VM_PROT_READ;
if ((error = elf_load_section(imgp->proc,
vmspace, imgp->vp,
phdr[i].p_offset,
(caddr_t)phdr[i].p_vaddr,
phdr[i].p_memsz,
phdr[i].p_filesz, prot)) != 0)
goto fail;
/*
* Is this .text or .data ??
*
* We only handle one each of those yet XXX
*/
if (hdr->e_entry >= phdr[i].p_vaddr &&
hdr->e_entry <(phdr[i].p_vaddr+phdr[i].p_memsz)) {
text_addr = trunc_page(phdr[i].p_vaddr);
text_size = round_page(phdr[i].p_memsz +
phdr[i].p_vaddr -
text_addr);
entry = (u_long)hdr->e_entry;
} else {
data_addr = trunc_page(phdr[i].p_vaddr);
data_size = round_page(phdr[i].p_memsz +
phdr[i].p_vaddr -
data_addr);
}
break;
case PT_INTERP: /* Path to interpreter */
if (phdr[i].p_filesz > MAXPATHLEN ||
phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) {
error = ENOEXEC;
goto fail;
}
interp = imgp->image_header + phdr[i].p_offset;
break;
case PT_PHDR: /* Program header table info */
proghdr = phdr[i].p_vaddr;
break;
default:
break;
}
}
vmspace->vm_tsize = text_size >> PAGE_SHIFT;
vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr;
vmspace->vm_dsize = data_size >> PAGE_SHIFT;
vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
addr = ELF_RTLD_ADDR(vmspace);
imgp->entry_addr = entry;
/* If the executable has a brand, search for it in the brand list. */
brand_info = NULL;
brand = (const char *)&hdr->e_ident[EI_BRAND];
if (brand[0] != '\0') {
for (i = 0; i < MAX_BRANDS; i++) {
Elf_Brandinfo *bi = elf_brand_list[i];
if (bi != NULL && strcmp(brand, bi->brand) == 0) {
brand_info = bi;
break;
}
}
}
/* Lacking a known brand, search for a recognized interpreter. */
if (brand_info == NULL && interp != NULL) {
for (i = 0; i < MAX_BRANDS; i++) {
Elf_Brandinfo *bi = elf_brand_list[i];
if (bi != NULL &&
strcmp(interp, bi->interp_path) == 0) {
brand_info = bi;
break;
}
}
}
/* Lacking a recognized interpreter, try the default brand */
if (brand_info == NULL && fallback_elf_brand[0] != '\0') {
for (i = 0; i < MAX_BRANDS; i++) {
Elf_Brandinfo *bi = elf_brand_list[i];
if (bi != NULL
&& strcmp(fallback_elf_brand, bi->brand) == 0) {
brand_info = bi;
break;
}
}
}
#ifdef __alpha__
/* XXX - Assume FreeBSD on the alpha. */
if (brand_info == NULL)
brand_info = &freebsd_brand_info;
#endif
if (brand_info == NULL) {
if (brand[0] == 0)
uprintf("ELF binary type not known."
" Use \"brandelf\" to brand it.\n");
else
uprintf("ELF binary type \"%.*s\" not known.\n",
EI_NIDENT - EI_BRAND, brand);
error = ENOEXEC;
goto fail;
}
imgp->proc->p_sysent = brand_info->sysvec;
if (interp != NULL) {
snprintf(path, sizeof(path), "%s%s",
brand_info->emul_path, interp);
if ((error = elf_load_file(imgp->proc, path, &addr,
&imgp->entry_addr)) != 0) {
uprintf("ELF interpreter %s not found\n", path);
goto fail;
}
}
/*
* Construct auxargs table (used by the fixup routine)
*/
elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK);
elf_auxargs->execfd = -1;
elf_auxargs->phdr = proghdr;
elf_auxargs->phent = hdr->e_phentsize;
elf_auxargs->phnum = hdr->e_phnum;
elf_auxargs->pagesz = PAGE_SIZE;
elf_auxargs->base = addr;
elf_auxargs->flags = 0;
elf_auxargs->entry = entry;
elf_auxargs->trace = elf_trace;
imgp->auxargs = elf_auxargs;
imgp->interpreted = 0;
/* don't allow modifying the file while we run it */
imgp->vp->v_flag |= VTEXT;
fail:
return error;
}
static int
elf_freebsd_fixup(long **stack_base, struct image_params *imgp)
{
Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
long *pos;
pos = *stack_base + (imgp->argc + imgp->envc + 2);
if (args->trace) {
AUXARGS_ENTRY(pos, AT_DEBUG, 1);
}
if (args->execfd != -1) {
AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
}
AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
AUXARGS_ENTRY(pos, AT_BASE, args->base);
AUXARGS_ENTRY(pos, AT_NULL, 0);
free(imgp->auxargs, M_TEMP);
imgp->auxargs = NULL;
(*stack_base)--;
suword(*stack_base, (long) imgp->argc);
return 0;
}
/*
* Code for generating ELF core dumps.
*/
typedef void (*segment_callback) __P((vm_map_entry_t, void *));
/* Closure for cb_put_phdr(). */
struct phdr_closure {
Elf_Phdr *phdr; /* Program header to fill in */
Elf_Off offset; /* Offset of segment in core file */
};
/* Closure for cb_size_segment(). */
struct sseg_closure {
int count; /* Count of writable segments. */
size_t size; /* Total size of all writable segments. */
};
static void cb_put_phdr __P((vm_map_entry_t, void *));
static void cb_size_segment __P((vm_map_entry_t, void *));
static void each_writable_segment __P((struct proc *, segment_callback,
void *));
static int elf_corehdr __P((struct proc *, struct vnode *, struct ucred *,
int, void *, size_t));
static void elf_puthdr __P((struct proc *, void *, size_t *,
const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int));
static void elf_putnote __P((void *, size_t *, const char *, int,
const void *, size_t));
extern int osreldate;
int
elf_coredump(p)
register struct proc *p;
{
register struct vnode *vp;
register struct ucred *cred = p->p_cred->pc_ucred;
struct nameidata nd;
struct vattr vattr;
int error, error1;
char *name; /* name of corefile */
struct sseg_closure seginfo;
void *hdr;
size_t hdrsize;
STOPEVENT(p, S_CORE, 0);
if (sugid_coredump == 0 && p->p_flag & P_SUGID)
return (EFAULT);
/* Size the program segments. */
seginfo.count = 0;
seginfo.size = 0;
each_writable_segment(p, cb_size_segment, &seginfo);
/*
* Calculate the size of the core file header area by making
* a dry run of generating it. Nothing is written, but the
* size is calculated.
*/
hdrsize = 0;
elf_puthdr((struct proc *)NULL, (void *)NULL, &hdrsize,
(const prstatus_t *)NULL, (const prfpregset_t *)NULL,
(const prpsinfo_t *)NULL, seginfo.count);
if (hdrsize + seginfo.size >= p->p_rlimit[RLIMIT_CORE].rlim_cur)
return (EFAULT);
name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
if (name == NULL)
return (EFAULT); /* XXX -- not the best error */
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE, S_IRUSR | S_IWUSR);
free(name, M_TEMP);
if (error)
return (error);
vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) {
error = EFAULT;
goto out;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
VOP_LEASE(vp, p, cred, LEASE_WRITE);
VOP_SETATTR(vp, &vattr, cred, p);
p->p_acflag |= ACORE;
/*
* Allocate memory for building the header, fill it up,
* and write it out.
*/
hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
if (hdr == NULL) {
error = EINVAL;
goto out;
}
error = elf_corehdr(p, vp, cred, seginfo.count, hdr, hdrsize);
/* Write the contents of all of the writable segments. */
if (error == 0) {
Elf_Phdr *php;
off_t offset;
int i;
php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
offset = hdrsize;
for (i = 0; i < seginfo.count; i++) {
error = vn_rdwr(UIO_WRITE, vp, (caddr_t)php->p_vaddr,
php->p_filesz, offset, UIO_USERSPACE,
IO_NODELOCKED|IO_UNIT, cred, (int *)NULL, p);
if (error != 0)
break;
offset += php->p_filesz;
php++;
}
}
free(hdr, M_TEMP);
out:
VOP_UNLOCK(vp, 0, p);
error1 = vn_close(vp, FWRITE, cred, p);
if (error == 0)
error = error1;
return (error);
}
/*
* A callback for each_writable_segment() to write out the segment's
* program header entry.
*/
static void
cb_put_phdr(entry, closure)
vm_map_entry_t entry;
void *closure;
{
struct phdr_closure *phc = (struct phdr_closure *)closure;
Elf_Phdr *phdr = phc->phdr;
phc->offset = round_page(phc->offset);
phdr->p_type = PT_LOAD;
phdr->p_offset = phc->offset;
phdr->p_vaddr = entry->start;
phdr->p_paddr = 0;
phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
phdr->p_align = PAGE_SIZE;
phdr->p_flags = 0;
if (entry->protection & VM_PROT_READ)
phdr->p_flags |= PF_R;
if (entry->protection & VM_PROT_WRITE)
phdr->p_flags |= PF_W;
if (entry->protection & VM_PROT_EXECUTE)
phdr->p_flags |= PF_X;
phc->offset += phdr->p_filesz;
phc->phdr++;
}
/*
* A callback for each_writable_segment() to gather information about
* the number of segments and their total size.
*/
static void
cb_size_segment(entry, closure)
vm_map_entry_t entry;
void *closure;
{
struct sseg_closure *ssc = (struct sseg_closure *)closure;
ssc->count++;
ssc->size += entry->end - entry->start;
}
/*
* For each writable segment in the process's memory map, call the given
* function with a pointer to the map entry and some arbitrary
* caller-supplied data.
*/
static void
each_writable_segment(p, func, closure)
struct proc *p;
segment_callback func;
void *closure;
{
vm_map_t map = &p->p_vmspace->vm_map;
vm_map_entry_t entry;
for (entry = map->header.next; entry != &map->header;
entry = entry->next) {
vm_object_t obj;
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) ||
(entry->protection & (VM_PROT_READ|VM_PROT_WRITE)) !=
(VM_PROT_READ|VM_PROT_WRITE))
continue;
if ((obj = entry->object.vm_object) == NULL)
continue;
/* Find the deepest backing object. */
while (obj->backing_object != NULL)
obj = obj->backing_object;
/* Ignore memory-mapped devices and such things. */
if (obj->type != OBJT_DEFAULT &&
obj->type != OBJT_SWAP &&
obj->type != OBJT_VNODE)
continue;
(*func)(entry, closure);
}
}
/*
* Write the core file header to the file, including padding up to
* the page boundary.
*/
static int
elf_corehdr(p, vp, cred, numsegs, hdr, hdrsize)
struct proc *p;
struct vnode *vp;
struct ucred *cred;
int numsegs;
size_t hdrsize;
void *hdr;
{
size_t off;
prstatus_t status;
prfpregset_t fpregset;
prpsinfo_t psinfo;
/* Gather the information for the header. */
bzero(&status, sizeof status);
status.pr_version = PRSTATUS_VERSION;
status.pr_statussz = sizeof(prstatus_t);
status.pr_gregsetsz = sizeof(gregset_t);
status.pr_fpregsetsz = sizeof(fpregset_t);
status.pr_osreldate = osreldate;
status.pr_cursig = p->p_sig;
status.pr_pid = p->p_pid;
fill_regs(p, &status.pr_reg);
fill_fpregs(p, &fpregset);
bzero(&psinfo, sizeof psinfo);
psinfo.pr_version = PRPSINFO_VERSION;
psinfo.pr_psinfosz = sizeof(prpsinfo_t);
strncpy(psinfo.pr_fname, p->p_comm, MAXCOMLEN);
/* XXX - We don't fill in the command line arguments properly yet. */
strncpy(psinfo.pr_psargs, p->p_comm, PRARGSZ);
/* Fill in the header. */
bzero(hdr, hdrsize);
off = 0;
elf_puthdr(p, hdr, &off, &status, &fpregset, &psinfo, numsegs);
/* Write it to the core file. */
return vn_rdwr(UIO_WRITE, vp, hdr, hdrsize, (off_t)0,
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p);
}
static void
elf_puthdr(struct proc *p, void *dst, size_t *off, const prstatus_t *status,
const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
{
size_t ehoff;
size_t phoff;
size_t noteoff;
size_t notesz;
ehoff = *off;
*off += sizeof(Elf_Ehdr);
phoff = *off;
*off += (numsegs + 1) * sizeof(Elf_Phdr);
noteoff = *off;
elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
sizeof *status);
elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
sizeof *fpregset);
elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
sizeof *psinfo);
notesz = *off - noteoff;
/* Align up to a page boundary for the program segments. */
*off = round_page(*off);
if (dst != NULL) {
Elf_Ehdr *ehdr;
Elf_Phdr *phdr;
struct phdr_closure phc;
/*
* Fill in the ELF header.
*/
ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
ehdr->e_ident[EI_MAG0] = ELFMAG0;
ehdr->e_ident[EI_MAG1] = ELFMAG1;
ehdr->e_ident[EI_MAG2] = ELFMAG2;
ehdr->e_ident[EI_MAG3] = ELFMAG3;
ehdr->e_ident[EI_CLASS] = ELF_CLASS;
ehdr->e_ident[EI_DATA] = ELF_DATA;
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
ehdr->e_ident[EI_PAD] = 0;
strncpy(ehdr->e_ident + EI_BRAND, "FreeBSD",
EI_NIDENT - EI_BRAND);
ehdr->e_type = ET_CORE;
ehdr->e_machine = ELF_ARCH;
ehdr->e_version = EV_CURRENT;
ehdr->e_entry = 0;
ehdr->e_phoff = phoff;
ehdr->e_flags = 0;
ehdr->e_ehsize = sizeof(Elf_Ehdr);
ehdr->e_phentsize = sizeof(Elf_Phdr);
ehdr->e_phnum = numsegs + 1;
ehdr->e_shentsize = sizeof(Elf_Shdr);
ehdr->e_shnum = 0;
ehdr->e_shstrndx = SHN_UNDEF;
/*
* Fill in the program header entries.
*/
phdr = (Elf_Phdr *)((char *)dst + phoff);
/* The note segement. */
phdr->p_type = PT_NOTE;
phdr->p_offset = noteoff;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = notesz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 0;
phdr++;
/* All the writable segments from the program. */
phc.phdr = phdr;
phc.offset = *off;
each_writable_segment(p, cb_put_phdr, &phc);
}
}
static void
elf_putnote(void *dst, size_t *off, const char *name, int type,
const void *desc, size_t descsz)
{
Elf_Note note;
note.n_namesz = strlen(name) + 1;
note.n_descsz = descsz;
note.n_type = type;
if (dst != NULL)
bcopy(&note, (char *)dst + *off, sizeof note);
*off += sizeof note;
if (dst != NULL)
bcopy(name, (char *)dst + *off, note.n_namesz);
*off += roundup2(note.n_namesz, sizeof(Elf_Size));
if (dst != NULL)
bcopy(desc, (char *)dst + *off, note.n_descsz);
*off += roundup2(note.n_descsz, sizeof(Elf_Size));
}
/*
* Tell kern_execve.c about it, with a little help from the linker.
* Since `const' objects end up in the text segment, TEXT_SET is the
* correct directive to use.
*/
static struct execsw elf_execsw = {exec_elf_imgact, "ELF"};
EXEC_SET(elf, elf_execsw);
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