NetBSD/dist/file/readelf.c

711 lines
17 KiB
C

/* $NetBSD: readelf.c,v 1.2 2003/02/28 18:25:09 thorpej Exp $ */
#include "file.h"
#ifdef BUILTIN_ELF
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "readelf.h"
#ifndef lint
#if 0
FILE_RCSID("@(#)Id: readelf.c,v 1.23 2003/02/08 18:33:53 christos Exp ")
#else
__RCSID("$NetBSD: readelf.c,v 1.2 2003/02/28 18:25:09 thorpej Exp $");
#endif
#endif
#ifdef ELFCORE
static void dophn_core(int, int, int, off_t, int, size_t);
#endif
static void dophn_exec(int, int, int, off_t, int, size_t);
static void doshn(int, int, int, off_t, int, size_t);
static uint16_t getu16(int, uint16_t);
static uint32_t getu32(int, uint32_t);
static uint64_t getu64(int, uint64_t);
static uint16_t
getu16(int swap, uint16_t value)
{
union {
uint16_t ui;
char c[2];
} retval, tmpval;
if (swap) {
tmpval.ui = value;
retval.c[0] = tmpval.c[1];
retval.c[1] = tmpval.c[0];
return retval.ui;
} else
return value;
}
static uint32_t
getu32(int swap, uint32_t value)
{
union {
uint32_t ui;
char c[4];
} retval, tmpval;
if (swap) {
tmpval.ui = value;
retval.c[0] = tmpval.c[3];
retval.c[1] = tmpval.c[2];
retval.c[2] = tmpval.c[1];
retval.c[3] = tmpval.c[0];
return retval.ui;
} else
return value;
}
static uint64_t
getu64(int swap, uint64_t value)
{
union {
uint64_t ui;
char c[8];
} retval, tmpval;
if (swap) {
tmpval.ui = value;
retval.c[0] = tmpval.c[7];
retval.c[1] = tmpval.c[6];
retval.c[2] = tmpval.c[5];
retval.c[3] = tmpval.c[4];
retval.c[4] = tmpval.c[3];
retval.c[5] = tmpval.c[2];
retval.c[6] = tmpval.c[1];
retval.c[7] = tmpval.c[0];
return retval.ui;
} else
return value;
}
#define sh_addr (class == ELFCLASS32 \
? (void *) &sh32 \
: (void *) &sh64)
#define shs_type (class == ELFCLASS32 \
? getu32(swap, sh32.sh_type) \
: getu32(swap, sh64.sh_type))
#define ph_addr (class == ELFCLASS32 \
? (void *) &ph32 \
: (void *) &ph64)
#define ph_type (class == ELFCLASS32 \
? getu32(swap, ph32.p_type) \
: getu32(swap, ph64.p_type))
#define ph_offset (class == ELFCLASS32 \
? getu32(swap, ph32.p_offset) \
: getu64(swap, ph64.p_offset))
#define ph_align (class == ELFCLASS32 \
? (ph32.p_align ? getu32(swap, ph32.p_align) : 4) \
: (ph64.p_align ? getu64(swap, ph64.p_align) : 4))
#define nh_size (class == ELFCLASS32 \
? sizeof *nh32 \
: sizeof *nh64)
#define nh_type (class == ELFCLASS32 \
? getu32(swap, nh32->n_type) \
: getu32(swap, nh64->n_type))
#define nh_namesz (class == ELFCLASS32 \
? getu32(swap, nh32->n_namesz) \
: getu32(swap, nh64->n_namesz))
#define nh_descsz (class == ELFCLASS32 \
? getu32(swap, nh32->n_descsz) \
: getu32(swap, nh64->n_descsz))
#define prpsoffsets(i) (class == ELFCLASS32 \
? prpsoffsets32[i] \
: prpsoffsets64[i])
static void
doshn(int class, int swap, int fd, off_t off, int num, size_t size)
{
Elf32_Shdr sh32;
Elf64_Shdr sh64;
if (lseek(fd, off, SEEK_SET) == -1)
error("lseek failed (%s).\n", strerror(errno));
for ( ; num; num--) {
if (read(fd, sh_addr, size) == -1)
error("read failed (%s).\n", strerror(errno));
if (shs_type == SHT_SYMTAB /* || shs_type == SHT_DYNSYM */) {
(void) printf (", not stripped");
return;
}
}
(void) printf (", stripped");
}
/*
* Look through the program headers of an executable image, searching
* for a PT_INTERP section; if one is found, it's dynamically linked,
* otherwise it's statically linked.
*/
static void
dophn_exec(int class, int swap, int fd, off_t off, int num, size_t size)
{
Elf32_Phdr ph32;
Elf32_Nhdr *nh32 = NULL;
Elf64_Phdr ph64;
Elf64_Nhdr *nh64 = NULL;
char *linking_style = "statically";
char *shared_libraries = "";
char nbuf[BUFSIZ];
int bufsize;
size_t offset, nameoffset;
off_t savedoffset;
if (lseek(fd, off, SEEK_SET) == -1)
error("lseek failed (%s).\n", strerror(errno));
for ( ; num; num--) {
if (read(fd, ph_addr, size) == -1)
error("read failed (%s).\n", strerror(errno));
if ((savedoffset = lseek(fd, 0, SEEK_CUR)) == -1)
error("lseek failed (%s).\n", strerror(errno));
switch (ph_type) {
case PT_DYNAMIC:
linking_style = "dynamically";
break;
case PT_INTERP:
shared_libraries = " (uses shared libs)";
break;
case PT_NOTE:
/*
* This is a PT_NOTE section; loop through all the notes
* in the section.
*/
if (lseek(fd, (off_t) ph_offset, SEEK_SET) == -1)
error("lseek failed (%s).\n", strerror(errno));
bufsize = read(fd, nbuf, sizeof(nbuf));
if (bufsize == -1)
error(": " "read failed (%s).\n",
strerror(errno));
offset = 0;
for (;;) {
if (offset >= bufsize)
break;
if (class == ELFCLASS32)
nh32 = (Elf32_Nhdr *)&nbuf[offset];
else
nh64 = (Elf64_Nhdr *)&nbuf[offset];
offset += nh_size;
if (offset + nh_namesz >= bufsize) {
/*
* We're past the end of the buffer.
*/
break;
}
nameoffset = offset;
offset += nh_namesz;
offset = ((offset+ph_align-1)/ph_align)*ph_align;
if ((nh_namesz == 0) && (nh_descsz == 0)) {
/*
* We're out of note headers.
*/
break;
}
if (offset + nh_descsz >= bufsize)
break;
if (nh_namesz == 4 &&
strcmp(&nbuf[nameoffset], "GNU") == 0 &&
nh_type == NT_GNU_VERSION &&
nh_descsz == 16) {
uint32_t *desc =
(uint32_t *)&nbuf[offset];
printf(", for GNU/");
switch (getu32(swap, desc[0])) {
case GNU_OS_LINUX:
printf("Linux");
break;
case GNU_OS_HURD:
printf("Hurd");
break;
case GNU_OS_SOLARIS:
printf("Solaris");
break;
default:
printf("<unknown>");
}
printf(" %d.%d.%d",
getu32(swap, desc[1]),
getu32(swap, desc[2]),
getu32(swap, desc[3]));
}
if (nh_namesz == 7 &&
strcmp(&nbuf[nameoffset], "NetBSD") == 0 &&
nh_type == NT_NETBSD_VERSION &&
nh_descsz == 4) {
uint32_t desc = getu32(swap,
*(uint32_t *)&nbuf[offset]);
printf(", for NetBSD");
/*
* The version number used to be
* stuck as 199906, and was thus
* basically content-free. Newer
* versions of NetBSD have fixed
* this, however, and now use the
* encoding of __NetBSD_Version__:
*
* MMmmrrpp00
*
* M = major version
* m = minor version
* r = release ["",A-Z,Z[A-Z] but
* numeric]
* p = patchlevel
*/
if (desc > 100000000U) {
u_int ver_patch =
(desc / 100) % 100;
u_int ver_rel =
(desc / 10000) % 100;
u_int ver_min =
(desc / 1000000) % 100;
u_int ver_maj =
desc / 100000000;
printf(" %u.%u", ver_maj,
ver_min);
if (ver_rel == 0 &&
ver_patch != 0) {
printf(".%u",
ver_patch);
} else if (ver_rel != 0 &&
ver_rel <= 26) {
printf("%c",
'A' + ver_rel - 1);
} else if (ver_rel != 0 &&
ver_rel <= 52) {
printf("Z%c",
'A' + ver_rel - 1);
} else if (ver_rel != 0) {
printf("<unknown>");
}
}
}
if (nh_namesz == 8 &&
strcmp(&nbuf[nameoffset], "FreeBSD") == 0 &&
nh_type == NT_FREEBSD_VERSION &&
nh_descsz == 4) {
uint32_t desc = getu32(swap,
*(uint32_t *)&nbuf[offset]);
printf(", for FreeBSD");
/*
* Contents is __FreeBSD_version,
* whose relation to OS versions is
* defined by a huge table in the
* Porters' Handbook. Happily, the
* first three digits are the version
* number, at least in versions of
* FreeBSD that use this note.
*/
printf(" %d.%d", desc / 100000,
desc / 10000 % 10);
if (desc / 1000 % 10 > 0)
printf(".%d",
desc / 1000 % 10);
}
if (nh_namesz == 8 &&
strcmp(&nbuf[nameoffset], "OpenBSD") == 0 &&
nh_type == NT_OPENBSD_VERSION &&
nh_descsz == 4) {
printf(", for OpenBSD");
/* Content of note is always 0 */
}
}
if ((lseek(fd, savedoffset + offset, SEEK_SET)) == -1)
error("lseek failed (%s).\n", strerror(errno));
break;
}
}
printf(", %s linked%s", linking_style, shared_libraries);
}
#ifdef ELFCORE
size_t prpsoffsets32[] = {
8, /* FreeBSD */
28, /* Linux 2.0.36 */
32, /* Linux (I forget which kernel version) */
84, /* SunOS 5.x */
};
size_t prpsoffsets64[] = {
120, /* SunOS 5.x, 64-bit */
};
#define NOFFSETS32 (sizeof prpsoffsets32 / sizeof prpsoffsets32[0])
#define NOFFSETS64 (sizeof prpsoffsets64 / sizeof prpsoffsets64[0])
#define NOFFSETS (class == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
/*
* Look through the program headers of an executable image, searching
* for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE" or
* "FreeBSD"; if one is found, try looking in various places in its
* contents for a 16-character string containing only printable
* characters - if found, that string should be the name of the program
* that dropped core. Note: right after that 16-character string is,
* at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
* Linux, a longer string (80 characters, in 5.x, probably other
* SVR4-flavored systems, and Linux) containing the start of the
* command line for that program.
*
* The signal number probably appears in a section of type NT_PRSTATUS,
* but that's also rather OS-dependent, in ways that are harder to
* dissect with heuristics, so I'm not bothering with the signal number.
* (I suppose the signal number could be of interest in situations where
* you don't have the binary of the program that dropped core; if you
* *do* have that binary, the debugger will probably tell you what
* signal it was.)
*/
#define OS_STYLE_SVR4 0
#define OS_STYLE_FREEBSD 1
#define OS_STYLE_NETBSD 2
static const char *os_style_names[] = {
"SVR4",
"FreeBSD",
"NetBSD",
};
static void
dophn_core(int class, int swap, int fd, off_t off, int num, size_t size)
{
Elf32_Phdr ph32;
Elf32_Nhdr *nh32 = NULL;
Elf64_Phdr ph64;
Elf64_Nhdr *nh64 = NULL;
size_t offset, nameoffset, noffset, reloffset;
unsigned char c;
int i, j;
char nbuf[BUFSIZ];
int bufsize;
int os_style = -1;
/*
* Loop through all the program headers.
*/
for ( ; num; num--) {
if (lseek(fd, off, SEEK_SET) == -1)
error("lseek failed (%s).\n", strerror(errno));
if (read(fd, ph_addr, size) == -1)
error("read failed (%s).\n", strerror(errno));
off += size;
if (ph_type != PT_NOTE)
continue;
/*
* This is a PT_NOTE section; loop through all the notes
* in the section.
*/
if (lseek(fd, (off_t) ph_offset, SEEK_SET) == -1)
error("lseek failed (%s).\n", strerror(errno));
bufsize = read(fd, nbuf, BUFSIZ);
if (bufsize == -1)
error(": " "read failed (%s).\n", strerror(errno));
offset = 0;
for (;;) {
if (offset >= bufsize)
break;
if (class == ELFCLASS32)
nh32 = (Elf32_Nhdr *)&nbuf[offset];
else
nh64 = (Elf64_Nhdr *)&nbuf[offset];
offset += nh_size;
/*
* Check whether this note has the name "CORE" or
* "FreeBSD", or "NetBSD-CORE".
*/
if (offset + nh_namesz >= bufsize) {
/*
* We're past the end of the buffer.
*/
break;
}
nameoffset = offset;
offset += nh_namesz;
offset = ((offset + 3)/4)*4;
/*
* Sigh. The 2.0.36 kernel in Debian 2.1, at
* least, doesn't correctly implement name
* sections, in core dumps, as specified by
* the "Program Linking" section of "UNIX(R) System
* V Release 4 Programmer's Guide: ANSI C and
* Programming Support Tools", because my copy
* clearly says "The first 'namesz' bytes in 'name'
* contain a *null-terminated* [emphasis mine]
* character representation of the entry's owner
* or originator", but the 2.0.36 kernel code
* doesn't include the terminating null in the
* name....
*/
if (os_style == -1) {
if ((nh_namesz == 4 &&
strncmp(&nbuf[nameoffset],
"CORE", 4) == 0) ||
(nh_namesz == 5 &&
strcmp(&nbuf[nameoffset],
"CORE") == 0)) {
os_style = OS_STYLE_SVR4;
} else
if ((nh_namesz == 8 &&
strcmp(&nbuf[nameoffset],
"FreeBSD") == 0)) {
os_style = OS_STYLE_FREEBSD;
} else
if ((nh_namesz >= 11 &&
strncmp(&nbuf[nameoffset],
"NetBSD-CORE", 11) == 0)) {
os_style = OS_STYLE_NETBSD;
} else
continue;
printf(", %s-style", os_style_names[os_style]);
}
if (os_style == OS_STYLE_NETBSD &&
nh_type == NT_NETBSD_CORE_PROCINFO) {
uint32_t signo;
/*
* Extract the program name. It is at
* offset 0x7c, and is up to 32-bytes,
* including the terminating NUL.
*/
printf(", from '%.31s'", &nbuf[offset + 0x7c]);
/*
* Extract the signal number. It is at
* offset 0x08.
*/
memcpy(&signo, &nbuf[offset + 0x08],
sizeof(signo));
printf(" (signal %u)", getu32(swap, signo));
} else
if (os_style != OS_STYLE_NETBSD &&
nh_type == NT_PRPSINFO) {
/*
* Extract the program name. We assume
* it to be 16 characters (that's what it
* is in SunOS 5.x and Linux).
*
* Unfortunately, it's at a different offset
* in varous OSes, so try multiple offsets.
* If the characters aren't all printable,
* reject it.
*/
for (i = 0; i < NOFFSETS; i++) {
reloffset = prpsoffsets(i);
noffset = offset + reloffset;
for (j = 0; j < 16;
j++, noffset++, reloffset++) {
/*
* Make sure we're not past
* the end of the buffer; if
* we are, just give up.
*/
if (noffset >= bufsize)
goto tryanother;
/*
* Make sure we're not past
* the end of the contents;
* if we are, this obviously
* isn't the right offset.
*/
if (reloffset >= nh_descsz)
goto tryanother;
c = nbuf[noffset];
if (c == '\0') {
/*
* A '\0' at the
* beginning is
* obviously wrong.
* Any other '\0'
* means we're done.
*/
if (j == 0)
goto tryanother;
else
break;
} else {
/*
* A nonprintable
* character is also
* wrong.
*/
#define isquote(c) (strchr("'\"`", (c)) != NULL)
if (!isprint(c) ||
isquote(c))
goto tryanother;
}
}
/*
* Well, that worked.
*/
printf(", from '%.16s'",
&nbuf[offset + prpsoffsets(i)]);
break;
tryanother:
;
}
break;
}
offset += nh_descsz;
offset = ((offset + 3)/4)*4;
}
}
}
#endif
void
tryelf(int fd, unsigned char *buf, int nbytes)
{
union {
int32_t l;
char c[sizeof (int32_t)];
} u;
int class;
int swap;
/*
* If we can't seek, it must be a pipe, socket or fifo.
*/
if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
fd = pipe2file(fd, buf, nbytes);
/*
* ELF executables have multiple section headers in arbitrary
* file locations and thus file(1) cannot determine it from easily.
* Instead we traverse thru all section headers until a symbol table
* one is found or else the binary is stripped.
*/
if (buf[EI_MAG0] != ELFMAG0
|| (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
|| buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
return;
class = buf[4];
if (class == ELFCLASS32) {
Elf32_Ehdr elfhdr;
if (nbytes <= sizeof (Elf32_Ehdr))
return;
u.l = 1;
(void) memcpy(&elfhdr, buf, sizeof elfhdr);
swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
if (getu16(swap, elfhdr.e_type) == ET_CORE)
#ifdef ELFCORE
dophn_core(class, swap,
fd,
getu32(swap, elfhdr.e_phoff),
getu16(swap, elfhdr.e_phnum),
getu16(swap, elfhdr.e_phentsize));
#else
;
#endif
else {
if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
dophn_exec(class, swap,
fd,
getu32(swap, elfhdr.e_phoff),
getu16(swap, elfhdr.e_phnum),
getu16(swap, elfhdr.e_phentsize));
}
doshn(class, swap,
fd,
getu32(swap, elfhdr.e_shoff),
getu16(swap, elfhdr.e_shnum),
getu16(swap, elfhdr.e_shentsize));
}
return;
}
if (class == ELFCLASS64) {
Elf64_Ehdr elfhdr;
if (nbytes <= sizeof (Elf64_Ehdr))
return;
u.l = 1;
(void) memcpy(&elfhdr, buf, sizeof elfhdr);
swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
if (getu16(swap, elfhdr.e_type) == ET_CORE)
#ifdef ELFCORE
dophn_core(class, swap,
fd,
#ifdef USE_ARRAY_FOR_64BIT_TYPES
getu32(swap, elfhdr.e_phoff[1]),
#else
getu64(swap, elfhdr.e_phoff),
#endif
getu16(swap, elfhdr.e_phnum),
getu16(swap, elfhdr.e_phentsize));
#else
;
#endif
else
{
if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
dophn_exec(class, swap,
fd,
#ifdef USE_ARRAY_FOR_64BIT_TYPES
getu32(swap, elfhdr.e_phoff[1]),
#else
getu64(swap, elfhdr.e_phoff),
#endif
getu16(swap, elfhdr.e_phnum),
getu16(swap, elfhdr.e_phentsize));
}
doshn(class, swap,
fd,
#ifdef USE_ARRAY_FOR_64BIT_TYPES
getu32(swap, elfhdr.e_shoff[1]),
#else
getu64(swap, elfhdr.e_shoff),
#endif
getu16(swap, elfhdr.e_shnum),
getu16(swap, elfhdr.e_shentsize));
}
return;
}
}
#endif