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agent/src/os/linux/salibelf.c@8db2b3e46c38 (annotated)

agent/src/os/linux/salibelf.c

Wed, 14 Jan 2009 19:45:01 -0800

author

swamyv

date

Wed, 14 Jan 2009 19:45:01 -0800

changeset 964

8db2b3e46c38

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6786948: SA on core file fails on solaris-amd64 if vm started with -XX:+StartAttachListener
Reviewed-by: jjh, dcubed

duke@435	1	/*
duke@435	2	* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	#include "salibelf.h"
duke@435	26	#include <stdlib.h>
duke@435	27	#include <unistd.h>
duke@435	28
duke@435	29	extern void print_debug(const char*,...);
duke@435	30
duke@435	31	// ELF file parsing helpers. Note that we do *not* use libelf here.
duke@435	32	int read_elf_header(int fd, ELF_EHDR* ehdr) {
duke@435	33	if (pread(fd, ehdr, sizeof (ELF_EHDR), 0) != sizeof (ELF_EHDR) ||
duke@435	34	memcmp(&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG) != 0 ||
duke@435	35	ehdr->e_version != EV_CURRENT) {
duke@435	36	return 0;
duke@435	37	}
duke@435	38	return 1;
duke@435	39	}
duke@435	40
duke@435	41	bool is_elf_file(int fd) {
duke@435	42	ELF_EHDR ehdr;
duke@435	43	return read_elf_header(fd, &ehdr);
duke@435	44	}
duke@435	45
duke@435	46	// read program header table of an ELF file
duke@435	47	ELF_PHDR* read_program_header_table(int fd, ELF_EHDR* hdr) {
duke@435	48	ELF_PHDR* phbuf = 0;
duke@435	49	// allocate memory for program header table
duke@435	50	size_t nbytes = hdr->e_phnum * hdr->e_phentsize;
duke@435	51
duke@435	52	if ((phbuf = (ELF_PHDR*) malloc(nbytes)) == NULL) {
duke@435	53	print_debug("can't allocate memory for reading program header table\n");
duke@435	54	return NULL;
duke@435	55	}
duke@435	56
duke@435	57	if (pread(fd, phbuf, nbytes, hdr->e_phoff) != nbytes) {
duke@435	58	print_debug("ELF file is truncated! can't read program header table\n");
duke@435	59	free(phbuf);
duke@435	60	return NULL;
duke@435	61	}
duke@435	62
duke@435	63	return phbuf;
duke@435	64	}
duke@435	65
duke@435	66	// read section header table of an ELF file
duke@435	67	ELF_SHDR* read_section_header_table(int fd, ELF_EHDR* hdr) {
duke@435	68	ELF_SHDR* shbuf = 0;
duke@435	69	// allocate memory for section header table
duke@435	70	size_t nbytes = hdr->e_shnum * hdr->e_shentsize;
duke@435	71
duke@435	72	if ((shbuf = (ELF_SHDR*) malloc(nbytes)) == NULL) {
duke@435	73	print_debug("can't allocate memory for reading section header table\n");
duke@435	74	return NULL;
duke@435	75	}
duke@435	76
duke@435	77	if (pread(fd, shbuf, nbytes, hdr->e_shoff) != nbytes) {
duke@435	78	print_debug("ELF file is truncated! can't read section header table\n");
duke@435	79	free(shbuf);
duke@435	80	return NULL;
duke@435	81	}
duke@435	82
duke@435	83	return shbuf;
duke@435	84	}
duke@435	85
duke@435	86	// read a particular section's data
duke@435	87	void* read_section_data(int fd, ELF_EHDR* ehdr, ELF_SHDR* shdr) {
duke@435	88	void *buf = NULL;
duke@435	89	if (shdr->sh_type == SHT_NOBITS || shdr->sh_size == 0) {
duke@435	90	return buf;
duke@435	91	}
duke@435	92	if ((buf = calloc(shdr->sh_size, 1)) == NULL) {
duke@435	93	print_debug("can't allocate memory for reading section data\n");
duke@435	94	return NULL;
duke@435	95	}
duke@435	96	if (pread(fd, buf, shdr->sh_size, shdr->sh_offset) != shdr->sh_size) {
duke@435	97	free(buf);
duke@435	98	print_debug("section data read failed\n");
duke@435	99	return NULL;
duke@435	100	}
duke@435	101	return buf;
duke@435	102	}
duke@435	103
duke@435	104	uintptr_t find_base_address(int fd, ELF_EHDR* ehdr) {
duke@435	105	uintptr_t baseaddr = (uintptr_t)-1;
duke@435	106	int cnt;
duke@435	107	ELF_PHDR *phbuf, *phdr;
duke@435	108
duke@435	109	// read program header table
duke@435	110	if ((phbuf = read_program_header_table(fd, ehdr)) == NULL) {
duke@435	111	goto quit;
duke@435	112	}
duke@435	113
duke@435	114	// the base address of a shared object is the lowest vaddr of
duke@435	115	// its loadable segments (PT_LOAD)
duke@435	116	for (phdr = phbuf, cnt = 0; cnt < ehdr->e_phnum; cnt++, phdr++) {
duke@435	117	if (phdr->p_type == PT_LOAD && phdr->p_vaddr < baseaddr) {
duke@435	118	baseaddr = phdr->p_vaddr;
duke@435	119	}
duke@435	120	}
duke@435	121
duke@435	122	quit:
duke@435	123	if (phbuf) free(phbuf);
duke@435	124	return baseaddr;
duke@435	125	}