WebSVN – HelenOS-historic – Blame – /kernel/trunk/generic/src/lib/elf.c

Rev	Author	Line No.	Line
854	bondari	1	/*
		2	* Copyright (C) 2006 Sergey Bondari
1424	jermar	3	* Copyright (C) 2006 Jakub Jermar
854	bondari	4	* All rights reserved.
		5	*
		6	* Redistribution and use in source and binary forms, with or without
		7	* modification, are permitted provided that the following conditions
		8	* are met:
		9	*
		10	* - Redistributions of source code must retain the above copyright
		11	* notice, this list of conditions and the following disclaimer.
		12	* - Redistributions in binary form must reproduce the above copyright
		13	* notice, this list of conditions and the following disclaimer in the
		14	* documentation and/or other materials provided with the distribution.
		15	* - The name of the author may not be used to endorse or promote products
		16	* derived from this software without specific prior written permission.
		17	*
		18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		19	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		20	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		23	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		24	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		25	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		26	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		27	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		28	*/
		29
1264	jermar	30	/**
		31	* @file elf.c
		32	* @brief Kernel ELF loader.
		33	*/
		34
910	bondari	35	#include <elf.h>
938	jermar	36	#include <debug.h>
		37	#include <arch/types.h>
		38	#include <typedefs.h>
		39	#include <mm/as.h>
		40	#include <mm/frame.h>
952	jermar	41	#include <mm/slab.h>
938	jermar	42	#include <align.h>
952	jermar	43	#include <memstr.h>
		44	#include <macros.h>
1409	jermar	45	#include <arch.h>
854	bondari	46
938	jermar	47	static char *error_codes[] = {
		48	"no error",
		49	"invalid image",
		50	"address space error",
		51	"incompatible image",
		52	"unsupported image type",
		53	"irrecoverable error"
		54	};
		55
952	jermar	56	static int segment_header(elf_segment_header_t entry, elf_header_t elf, as_t *as);
		57	static int section_header(elf_section_header_t entry, elf_header_t elf, as_t *as);
		58	static int load_segment(elf_segment_header_t entry, elf_header_t elf, as_t *as);
938	jermar	59
		60	/** ELF loader
854	bondari	61	*
		62	* @param header Pointer to ELF header in memory
		63	* @param as Created and properly mapped address space
		64	* @return EE_OK on success
		65	*/
938	jermar	66	int elf_load(elf_header_t header, as_t as)
		67	{
		68	int i, rc;
910	bondari	69
		70	/* Identify ELF */
938	jermar	71	if (header->e_ident[EI_MAG0] != ELFMAG0 \|\| header->e_ident[EI_MAG1] != ELFMAG1 \|\|
		72	header->e_ident[EI_MAG2] != ELFMAG2 \|\| header->e_ident[EI_MAG3] != ELFMAG3) {
910	bondari	73	return EE_INVALID;
		74	}
		75
		76	/* Identify ELF compatibility */
938	jermar	77	if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING \|\| header->e_machine != ELF_MACHINE \|\|
		78	header->e_ident[EI_VERSION] != EV_CURRENT \|\| header->e_version != EV_CURRENT \|\|
		79	header->e_ident[EI_CLASS] != ELF_CLASS) {
		80	return EE_INCOMPATIBLE;
		81	}
		82
952	jermar	83	if (header->e_phentsize != sizeof(elf_segment_header_t))
938	jermar	84	return EE_INCOMPATIBLE;
		85
952	jermar	86	if (header->e_shentsize != sizeof(elf_section_header_t))
		87	return EE_INCOMPATIBLE;
		88
938	jermar	89	/* Check if the object type is supported. */
		90	if (header->e_type != ET_EXEC)
910	bondari	91	return EE_UNSUPPORTED;
938	jermar	92
952	jermar	93	/* Walk through all segment headers and process them. */
938	jermar	94	for (i = 0; i < header->e_phnum; i++) {
952	jermar	95	rc = segment_header(&((elf_segment_header_t )(((__u8 ) header) + header->e_phoff))[i], header, as);
938	jermar	96	if (rc != EE_OK)
		97	return rc;
910	bondari	98	}
938	jermar	99
952	jermar	100	/* Inspect all section headers and proccess them. */
		101	for (i = 0; i < header->e_shnum; i++) {
		102	rc = section_header(&((elf_section_header_t )(((__u8 ) header) + header->e_shoff))[i], header, as);
		103	if (rc != EE_OK)
		104	return rc;
		105	}
		106
938	jermar	107	return EE_OK;
		108	}
		109
		110	/** Print error message according to error code.
		111	*
		112	* @param rc Return code returned by elf_load().
		113	*
		114	* @return NULL terminated description of error.
		115	*/
		116	char *elf_error(int rc)
		117	{
		118	ASSERT(rc < sizeof(error_codes)/sizeof(char *));
		119
		120	return error_codes[rc];
		121	}
		122
952	jermar	123	/** Process segment header.
938	jermar	124	*
952	jermar	125	* @param entry Segment header.
		126	* @param elf ELF header.
938	jermar	127	* @param as Address space into wich the ELF is being loaded.
		128	*
		129	* @return EE_OK on success, error code otherwise.
		130	*/
952	jermar	131	static int segment_header(elf_segment_header_t entry, elf_header_t elf, as_t *as)
938	jermar	132	{
		133	switch (entry->p_type) {
		134	case PT_NULL:
		135	case PT_PHDR:
		136	break;
		137	case PT_LOAD:
952	jermar	138	return load_segment(entry, elf, as);
938	jermar	139	break;
		140	case PT_DYNAMIC:
		141	case PT_INTERP:
		142	case PT_SHLIB:
		143	case PT_NOTE:
		144	case PT_LOPROC:
		145	case PT_HIPROC:
		146	default:
		147	return EE_UNSUPPORTED;
		148	break;
		149	}
		150	return EE_OK;
		151	}
		152
		153	/** Load segment described by program header entry.
		154	*
		155	* @param entry Program header entry describing segment to be loaded.
952	jermar	156	* @param elf ELF header.
1248	jermar	157	* @param as Address space into wich the ELF is being loaded.
938	jermar	158	*
		159	* @return EE_OK on success, error code otherwise.
		160	*/
952	jermar	161	int load_segment(elf_segment_header_t entry, elf_header_t elf, as_t *as)
938	jermar	162	{
		163	as_area_t *a;
1409	jermar	164	int flags = 0;
1425	jermar	165	mem_backend_data_t backend_data;
		166
		167	backend_data.elf = elf;
		168	backend_data.segment = entry;
938	jermar	169
		170	if (entry->p_align > 1) {
		171	if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) {
		172	return EE_INVALID;
		173	}
		174	}
		175
1026	jermar	176	if (entry->p_flags & PF_X)
		177	flags \|= AS_AREA_EXEC;
		178	if (entry->p_flags & PF_W)
		179	flags \|= AS_AREA_WRITE;
		180	if (entry->p_flags & PF_R)
		181	flags \|= AS_AREA_READ;
1424	jermar	182	flags \|= AS_AREA_CACHEABLE;
910	bondari	183
952	jermar	184	/*
		185	* Check if the virtual address starts on page boundary.
		186	*/
		187	if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr)
		188	return EE_UNSUPPORTED;
		189
1424	jermar	190	a = as_area_create(as, flags, entry->p_memsz, entry->p_vaddr, AS_AREA_ATTR_NONE,
		191	&elf_backend, &backend_data);
938	jermar	192	if (!a)
1070	jermar	193	return EE_MEMORY;
938	jermar	194
1409	jermar	195	/*
		196	* The segment will be mapped on demand by elf_page_fault().
		197	*/
		198
938	jermar	199	return EE_OK;
854	bondari	200	}
952	jermar	201
		202	/** Process section header.
		203	*
		204	* @param entry Segment header.
		205	* @param elf ELF header.
		206	* @param as Address space into wich the ELF is being loaded.
		207	*
		208	* @return EE_OK on success, error code otherwise.
		209	*/
		210	static int section_header(elf_section_header_t entry, elf_header_t elf, as_t *as)
		211	{
		212	switch (entry->sh_type) {
		213	default:
		214	break;
		215	}
		216
		217	return EE_OK;
		218	}

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(root)/kernel/trunk/generic/src/lib/elf.c – Rev 1425