Loader/tools/ldd.c

283 lines
6.6 KiB
C

/* $Id$ */
/* Copyright (c) 2010 Pierre Pronchery <khorben@defora.org> */
/* This file is part of DeforaOS System Loader */
/* 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, version 3 of the License.
*
* 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, see <http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <elf.h>
/* private */
/* prototypes */
static int _ldd(char const * filename);
static int _error(char const * error1, char const * error2, int ret);
static int _usage(void);
/* public */
/* functions */
/* main */
int main(int argc, char * argv[])
{
int ret = 0;
int o;
int i;
while((o = getopt(argc, argv, "")) != -1)
switch(o)
{
default:
return _usage();
}
if(optind == argc)
return _usage();
for(i = optind; i < argc; i++)
ret |= _ldd(argv[i]);
return (ret == 0) ? 0 : 2;
}
/* private */
/* functions */
/* ldd */
static int _ldd_do32(char const * filename, FILE * fp, Elf32_Ehdr * ehdr);
static int _ldd_do64(char const * filename, FILE * fp, Elf64_Ehdr * ehdr);
static int _do64_phdr(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Phdr * phdr);
static int _do64_phdr_dyn(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Phdr * phdr, Elf64_Dyn * dyn);
static char * _do64_string(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Addr addr, Elf64_Xword index);
static int _ldd(char const * filename)
{
int ret = 1;
FILE * fp;
union
{
unsigned char e_ident[EI_NIDENT];
Elf32_Ehdr ehdr32;
Elf64_Ehdr ehdr64;
} elf;
if((fp = fopen(filename, "r")) == NULL)
return _error(filename, strerror(errno), 1);
if(fread(&elf, sizeof(elf), 1, fp) == 1)
{
if(memcmp(elf.e_ident, ELFMAG, SELFMAG) != 0)
ret = -_error(filename, "Not an ELF file", 1);
else if(elf.e_ident[EI_CLASS] == ELFCLASS32)
ret = _ldd_do32(filename, fp, &elf.ehdr32);
else if(elf.e_ident[EI_CLASS] == ELFCLASS64)
ret = _ldd_do64(filename, fp, &elf.ehdr64);
else
ret = -_error(filename, "Could not determine ELF class",
1);
}
else
{
if(ferror(fp) != 0)
return -_error(filename, strerror(errno), 1);
ret = -_error(filename, "Not an ELF file", 1);
}
fclose(fp);
return ret;
}
static int _ldd_do32(char const * filename, FILE * fp, Elf32_Ehdr * ehdr)
{
/* FIXME implement */
return 0;
}
static int _ldd_do64(char const * filename, FILE * fp, Elf64_Ehdr * ehdr)
{
int ret;
Elf64_Phdr * phdr;
if(ehdr->e_phnum == 0)
return -_error(filename, "No program header found", 1);
if(ehdr->e_phentsize != sizeof(*phdr))
return -_error(filename, "Unexpected program header size", 1);
if(fseek(fp, ehdr->e_phoff, SEEK_SET) != 0)
return -_error(filename, strerror(errno), 1);
if((phdr = malloc(sizeof(*phdr) * ehdr->e_phnum)) == NULL)
return -_error(filename, strerror(errno), 1);
ret = _do64_phdr(filename, fp, ehdr, phdr);
free(phdr);
return ret;
}
static int _do64_phdr(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Phdr * phdr)
{
int ret = 0;
size_t i;
Elf64_Dyn * dyn;
if(fread(phdr, sizeof(*phdr), ehdr->e_phnum, fp) != ehdr->e_phnum)
{
if(ferror(fp) != 0)
ret = -_error(filename, strerror(errno), 1);
else
ret = -_error(filename, "Corrupted ELF file", 1);
return ret;
}
printf("%s:\n", filename);
for(i = 0; i < ehdr->e_phnum; i++)
{
if(phdr[i].p_type != PT_DYNAMIC)
continue;
if(fseek(fp, phdr[i].p_offset, SEEK_SET) != 0)
{
ret |= -_error(filename, strerror(errno), 1);
continue;
}
if((dyn = malloc(phdr[i].p_filesz)) == NULL)
{
ret |= -_error(filename, strerror(errno), 1);
continue;
}
if(fread(dyn, phdr[i].p_filesz, 1, fp) == 1)
ret = _do64_phdr_dyn(filename, fp, ehdr, &phdr[i], dyn);
else
{
if(ferror(fp) != 0)
ret |= -_error(filename, strerror(errno), 1);
else
ret |= -_error(filename, "Corrupted ELF file",
1);
}
free(dyn);
}
return ret;
}
static int _do64_phdr_dyn(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Phdr * phdr, Elf64_Dyn * dyn)
{
ssize_t s = -1;
ssize_t r = -1;
size_t i;
char * p;
for(i = 0; (i + 1) * sizeof(*dyn) < phdr->p_filesz; i++)
{
if(dyn[i].d_tag == DT_NULL)
break;
if(dyn[i].d_tag == DT_STRTAB)
s = i;
else if(dyn[i].d_tag == DT_RPATH)
r = i;
}
if(s < 0)
return -_error(filename, "Missing string section", 1);
#ifdef DEBUG
fprintf(stderr, "DEBUG: %s() strtab=%ld\n", __func__, s);
#endif
for(i = 0; (i + 1) * sizeof(*dyn) < phdr->p_filesz; i++)
{
if(dyn[i].d_tag == DT_NULL)
break;
if(dyn[i].d_tag != DT_NEEDED)
continue;
if((p = _do64_string(filename, fp, ehdr, dyn[s].d_un.d_ptr,
dyn[i].d_un.d_val)) == NULL)
continue;
printf("\t%s\n", p);
/* FIXME display the full filename and address */
free(p);
}
return 0;
}
static char * _do64_string(char const * filename, FILE * fp, Elf64_Ehdr * ehdr,
Elf64_Addr addr, Elf64_Xword index)
{
char * ret;
size_t i;
Elf64_Shdr shdr;
char * p = NULL;
if(fseek(fp, ehdr->e_shoff, SEEK_SET) != 0)
{
_error(filename, strerror(errno), 1);
return NULL;
}
for(i = 0; i < ehdr->e_shnum; i++)
{
if(fread(&shdr, sizeof(shdr), 1, fp) != 1)
{
if(ferror(fp) != 0)
_error(filename, strerror(errno), 1);
else
_error(filename, "Corrupted ELF file", 1);
break;
}
if(shdr.sh_type != SHT_STRTAB)
continue;
if(shdr.sh_addr != addr)
continue;
if(fseek(fp, shdr.sh_offset, SEEK_SET) != 0
|| (p = malloc(shdr.sh_size)) == NULL)
{
_error(filename, strerror(errno), 1);
break;
}
if(fread(p, sizeof(*p), shdr.sh_size, fp) != shdr.sh_size)
{
if(ferror(fp) != 0)
_error(filename, strerror(errno), 1);
else
_error(filename, "Corrupted ELF file", 1);
break;
}
for(i = index; i < shdr.sh_size; i++)
{
if(p[i] != '\0')
continue;
if((ret = strdup(&p[index])) == NULL)
_error(filename, strerror(errno), 1);
free(p);
return ret;
}
break;
}
free(p);
return NULL;
}
/* error */
static int _error(char const * error1, char const * error2, int ret)
{
fprintf(stderr, "%s: %s%s%s\n", "ldd", error1, (error2 != NULL) ? ": "
: "", (error2 != NULL) ? error2 : "");
return ret;
}
/* usage */
static int _usage(void)
{
fputs("Usage: ldd filename...\n", stderr);
return 1;
}