/*
* Copyright (c) 2011 Jiri Svoboda
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - 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.
*/
/** @addtogroup taskdump
* @{
*/
/** @file Write ELF core files.
*
* Creates ELF core files. Core files do not seem to be specified by some
* standard (the System V ABI explicitely states that it does not specify
* them).
*
* Looking at core files produced by Linux, these don't have section headers,
* only program headers, although objdump shows them as having sections.
* Basically at the beginning there should be a note segment followed
* by one loadable segment per memory area.
*
* The note segment contains a series of records with register state,
* process info etc. We only write one record NT_PRSTATUS which contains
* process/register state (anything which is not register state we fill
* with zeroes).
*/
#include <align.h>
#include <elf/elf.h>
#include <elf/elf_linux.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stddef.h>
#include <errno.h>
#include <str_error.h>
#include <mem.h>
#include <as.h>
#include <udebug.h>
#include <macros.h>
#include <libarch/istate.h>
#include <vfs/vfs.h>
#include <str.h>
#include "elf_core.h"
static off64_t align_foff_up(off64_t, uintptr_t, size_t);
static errno_t write_mem_area(int, aoff64_t *, as_area_info_t *, async_sess_t *);
#define BUFFER_SIZE 0x1000
static uint8_t buffer[BUFFER_SIZE];
/** Save ELF core file.
*
* @param file_name Name of file to save to.
* @param ainfo Array of @a n memory area info structures.
* @param n Number of memory areas.
* @param sess Debugging session.
*
* @return EOK on sucess.
* @return ENOENT if file cannot be created.
* @return ENOMEM on out of memory.
* @return EIO on write error.
*
*/
errno_t elf_core_save(const char *file_name, as_area_info_t *ainfo, unsigned int n,
async_sess_t *sess, istate_t *istate)
{
elf_header_t elf_hdr;
off64_t foff;
size_t n_ph;
elf_word flags;
elf_segment_header_t *p_hdr;
elf_prstatus_t pr_status;
elf_note_t note;
size_t word_size;
aoff64_t pos = 0;
int fd;
errno_t rc;
size_t nwr;
unsigned int i;
#ifdef __32_BITS__
word_size = 4;
#endif
#ifdef __64_BITS__
/*
* This should be 8 per the 64-bit ELF spec, but the Linux kernel
* screws up and uses 4 anyway (and screws up elf_note_t as well)
* and we are trying to be compatible with Linux GDB target. Sigh.
*/
word_size = 4;
#endif
memset(&pr_status, 0, sizeof(pr_status));
istate_to_elf_regs(istate, &pr_status.regs);
n_ph = n + 1;
p_hdr = malloc(sizeof(elf_segment_header_t) * n_ph);
if (p_hdr == NULL) {
printf("Failed allocating memory.\n");
return ENOMEM;
}
rc = vfs_lookup_open(file_name, WALK_REGULAR | WALK_MAY_CREATE,
MODE_WRITE, &fd);
if (rc != EOK) {
printf("Failed opening file '%s': %s.\n", file_name, str_error(rc));
free(p_hdr);
return ENOENT;
}
/*
* File layout:
*
* ELF header
* program headers
* note segment
* repeat:
* (pad for alignment)
* core segment
* end repeat
*/
memset(&elf_hdr, 0, sizeof(elf_hdr));
elf_hdr.e_ident[EI_MAG0] = ELFMAG0;
elf_hdr.e_ident[EI_MAG1] = ELFMAG1;
elf_hdr.e_ident[EI_MAG2] = ELFMAG2;
elf_hdr.e_ident[EI_MAG3] = ELFMAG3;
elf_hdr.e_ident[EI_CLASS] = ELF_CLASS;
elf_hdr.e_ident[EI_DATA] = ELF_DATA_ENCODING;
elf_hdr.e_ident[EI_VERSION] = EV_CURRENT;
elf_hdr.e_type = ET_CORE;
elf_hdr.e_machine = ELF_MACHINE;
elf_hdr.e_version = EV_CURRENT;
elf_hdr.e_entry = 0;
elf_hdr.e_phoff = sizeof(elf_header_t);
elf_hdr.e_shoff = 0;
elf_hdr.e_flags = 0;
elf_hdr.e_ehsize = sizeof(elf_hdr);
elf_hdr.e_phentsize = sizeof(elf_segment_header_t);
elf_hdr.e_phnum = n_ph;
elf_hdr.e_shentsize = 0;
elf_hdr.e_shnum = 0;
elf_hdr.e_shstrndx = 0;
/* foff is used for allocation of file space for segment data. */
foff = elf_hdr.e_phoff + n_ph * sizeof(elf_segment_header_t);
memset(&p_hdr[0], 0, sizeof(p_hdr[0]));
p_hdr[0].p_type = PT_NOTE;
p_hdr[0].p_offset = foff;
p_hdr[0].p_vaddr = 0;
p_hdr[0].p_paddr = 0;
p_hdr[0].p_filesz = sizeof(elf_note_t) +
ALIGN_UP((str_size("CORE") + 1), word_size) +
ALIGN_UP(sizeof(elf_prstatus_t), word_size);
p_hdr[0].p_memsz = 0;
p_hdr[0].p_flags = 0;
p_hdr[0].p_align = 1;
foff += p_hdr[0].p_filesz;
for (i = 0; i < n; ++i) {
foff = align_foff_up(foff, ainfo[i].start_addr, PAGE_SIZE);
flags = 0;
if (ainfo[i].flags & AS_AREA_READ)
flags |= PF_R;
if (ainfo[i].flags & AS_AREA_WRITE)
flags |= PF_W;
if (ainfo[i].flags & AS_AREA_EXEC)
flags |= PF_X;
memset(&p_hdr[i + 1], 0, sizeof(p_hdr[i + 1]));
p_hdr[i + 1].p_type = PT_LOAD;
p_hdr[i + 1].p_offset = foff;
p_hdr[i + 1].p_vaddr = ainfo[i].start_addr;
p_hdr[i + 1].p_paddr = 0;
p_hdr[i + 1].p_filesz = ainfo[i].size;
p_hdr[i + 1].p_memsz = ainfo[i].size;
p_hdr[i + 1].p_flags = flags;
p_hdr[i + 1].p_align = PAGE_SIZE;
foff += ainfo[i].size;
}
rc = vfs_write(fd, &pos, &elf_hdr, sizeof(elf_hdr), &nwr);
if (rc != EOK) {
printf("Failed writing ELF header.\n");
free(p_hdr);
return EIO;
}
for (i = 0; i < n_ph; ++i) {
rc = vfs_write(fd, &pos, &p_hdr[i], sizeof(p_hdr[i]), &nwr);
if (rc != EOK) {
printf("Failed writing program header.\n");
free(p_hdr);
return EIO;
}
}
pos = p_hdr[0].p_offset;
/*
* Write note header
*/
note.namesz = str_size("CORE") + 1;
note.descsz = sizeof(elf_prstatus_t);
note.type = NT_PRSTATUS;
rc = vfs_write(fd, &pos, ¬e, sizeof(elf_note_t), &nwr);
if (rc != EOK) {
printf("Failed writing note header.\n");
free(p_hdr);
return EIO;
}
rc = vfs_write(fd, &pos, "CORE", note.namesz, &nwr);
if (rc != EOK) {
printf("Failed writing note header.\n");
free(p_hdr);
return EIO;
}
pos = ALIGN_UP(pos, word_size);
rc = vfs_write(fd, &pos, &pr_status, sizeof(elf_prstatus_t), &nwr);
if (rc != EOK) {
printf("Failed writing register data.\n");
free(p_hdr);
return EIO;
}
for (i = 1; i < n_ph; ++i) {
pos = p_hdr[i].p_offset;
if (write_mem_area(fd, &pos, &ainfo[i - 1], sess) != EOK) {
printf("Failed writing memory data.\n");
free(p_hdr);
return EIO;
}
}
free(p_hdr);
return EOK;
}
/** Align file offset up to be congruent with vaddr modulo page size. */
static off64_t align_foff_up(off64_t foff, uintptr_t vaddr, size_t page_size)
{
off64_t rva = vaddr % page_size;
off64_t rfo = foff % page_size;
if (rva >= rfo)
return (foff + (rva - rfo));
return (foff + (page_size + (rva - rfo)));
}
/** Write memory area from application to core file.
*
* @param fd File to write to.
* @param pos Pointer to the position to write to.
* @param area Memory area info structure.
* @param sess Debugging session.
*
* @return EOK on success, EIO on failure.
*
*/
static errno_t write_mem_area(int fd, aoff64_t *pos, as_area_info_t *area,
async_sess_t *sess)
{
size_t to_copy;
size_t total;
uintptr_t addr;
errno_t rc;
size_t nwr;
addr = area->start_addr;
total = 0;
while (total < area->size) {
to_copy = min(area->size - total, BUFFER_SIZE);
rc = udebug_mem_read(sess, buffer, addr, to_copy);
if (rc != EOK) {
printf("Failed reading task memory.\n");
return EIO;
}
rc = vfs_write(fd, pos, buffer, to_copy, &nwr);
if (rc != EOK) {
printf("Failed writing memory contents.\n");
return EIO;
}
addr += to_copy;
total += to_copy;
}
return EOK;
}
/** @}
*/