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-rw-r--r--file/readelf.c515
1 files changed, 515 insertions, 0 deletions
diff --git a/file/readelf.c b/file/readelf.c
new file mode 100644
index 000000000..b455675ae
--- /dev/null
+++ b/file/readelf.c
@@ -0,0 +1,515 @@
+#include "file.h"
+
+#ifdef BUILTIN_ELF
+#include <sys/types.h>
+#include <string.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <errno.h>
+
+#include "readelf.h"
+
+#ifndef lint
+FILE_RCSID("@(#)Id: readelf.c,v 1.17 2000/08/05 19:00:12 christos Exp ")
+#endif
+
+#ifdef ELFCORE
+static void dophn_core __P((int, int, int, off_t, int, size_t));
+#endif
+static void dophn_exec __P((int, int, int, off_t, int, size_t));
+static void doshn __P((int, int, int, off_t, int, size_t));
+
+static uint16_t getu16 __P((int, int));
+static uint32_t getu32 __P((int, uint32_t));
+static uint64_t getu64 __P((int, uint64_t));
+
+static uint16_t
+getu16(swap, value)
+ 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(swap, value)
+ 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(swap, value)
+ 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 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(class, swap, fd, off, num, size)
+ 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(class, swap, fd, off, num, size)
+ int class;
+ int swap;
+ int fd;
+ off_t off;
+ int num;
+ size_t size;
+{
+ Elf32_Phdr ph32;
+ Elf64_Phdr ph64;
+ char *linking_style = "statically";
+ char *shared_libraries = "";
+
+ 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));
+
+ switch (ph_type) {
+ case PT_DYNAMIC:
+ linking_style = "dynamically";
+ break;
+ case PT_INTERP:
+ shared_libraries = " (uses shared libs)";
+ 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.)
+ */
+static void
+dophn_core(class, swap, fd, off, num, size)
+ int class;
+ int swap;
+ int fd;
+ off_t off;
+ int num;
+ size_t size;
+{
+ Elf32_Phdr ph32;
+ Elf32_Nhdr *nh32;
+ Elf64_Phdr ph64;
+ Elf64_Nhdr *nh64;
+ size_t offset, nameoffset, noffset, reloffset;
+ unsigned char c;
+ int i, j;
+ char nbuf[BUFSIZ];
+ int bufsize;
+ int is_freebsd;
+
+ /*
+ * 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".
+ */
+ 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 ((nh_namesz == 4 &&
+ strncmp(&nbuf[nameoffset], "CORE", 4) == 0) ||
+ (nh_namesz == 5 &&
+ strcmp(&nbuf[nameoffset], "CORE") == 0))
+ is_freebsd = 0;
+ else if ((nh_namesz == 8 &&
+ strcmp(&nbuf[nameoffset], "FreeBSD") == 0))
+ is_freebsd = 1;
+ else
+ continue;
+ if (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(fd, buf, nbytes)
+ int fd;
+ unsigned char *buf;
+ int nbytes;
+{
+ union {
+ int32 l;
+ char c[sizeof (int32)];
+ } u;
+ int class;
+ int swap;
+
+ /*
+ * 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) - 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) - 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
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