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source: trunk/kernel/libk/elf.c @ 333

Last change on this file since 333 was 333, checked in by max@…, 7 years ago
vfs_user_move() returns an error_t, so don't return a count.
File size: 10.7 KB

Rev	Line
[1]	1	/*
	2	* elf.c - elf parser: find and map process CODE and DATA segments
	3	*
	4	* Authors Alain Greiner (2016)
	5	*
	6	* Copyright (c) UPMC Sorbonne Universites
	7	*
	8	* This file is part of ALMOS-MKH.
	9	*
	10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
	11	* under the terms of the GNU General Public License as published by
	12	* the Free Software Foundation; version 2.0 of the License.
	13	*
	14	* ALMOS-MKH is distributed in the hope that it will be useful, but
	15	* WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
	21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	22	*/
	23
[14]	24	#include <kernel_config.h>
[1]	25	#include <hal_types.h>
	26	#include <hal_uspace.h>
	27	#include <printk.h>
	28	#include <process.h>
	29	#include <vseg.h>
	30	#include <kmem.h>
	31	#include <vfs.h>
	32	#include <elf.h>
[23]	33	#include <syscalls.h>
[1]	34
	35	///////////////////////////////////////////////////////////////////
	36	// This static function checks the .elf header.
	37	// - return true if legal header.
	38	// - return false with an error message if illegal header.
	39	///////////////////////////////////////////////////////////////////
[227]	40	static bool_t elf_isValidHeader(Elf_Ehdr *header)
[1]	41	{
[270]	42	if((header->e_ident[EI_CLASS] == ELFCLASS)
[156]	43	&& (header->e_ident[EI_DATA] == ELFDATA2LSB)
[1]	44	&& (header->e_ident[EI_VERSION] == EV_CURRENT)
[270]	45	/*
[1]	46	&& (header->e_ident[EI_OSABI] == ELFOSABI_NONE)
[270]	47	*/
[156]	48	&& ((header->e_machine == EM_MIPS) \|\|
[1]	49	(header->e_machine == EM_MIPS_RS3_LE) \|\|
[157]	50	(header->e_machine == EM_X86_64))
[156]	51	&& (header->e_type == ET_EXEC))
	52	return true;
	53
[270]	54	if( header->e_ident[EI_CLASS] != ELFCLASS )
	55	printk("\n[ERROR] in %s : Elf is not 32/64-Binary\n", __FUNCTION__ );
[1]	56
	57	if( header->e_ident[EI_DATA] != ELFDATA2LSB )
[156]	58	printk("\n[ERROR] in %s : Elf is not 2's complement, little endian\n", __FUNCTION__ );
[1]	59
[156]	60	if( header->e_ident[EI_VERSION] != EV_CURRENT )
	61	printk("\n[ERROR] in %s : Elf is not in Current Version\n", __FUNCTION__);
[270]	62	/*
[1]	63	if( header->e_ident[EI_OSABI] != ELFOSABI_NONE )
[156]	64	printk("\n[ERROR] in %s : Unexpected Elf ABI, need UNIX System V ABI\n", __FUNCTION__ );
[270]	65	*/
	66	if( (header->e_machine != EM_MIPS) &&
	67	(header->e_machine != EM_MIPS_RS3_LE) &&
	68	(header->e_machine != EM_X86_64) )
[157]	69	printk("\n[ERROR] in %s : unexpected core / accept only MIPS or x86_64\n", __FUNCTION__ );
[1]	70
[270]	71	if( header->e_type != ET_EXEC )
[156]	72	printk("\n[ERROR] in %s : Elf is not executable binary\n", __FUNCTION__ );
[1]	73
	74	return false;
	75	}
	76
	77	///////////////////////////////////////////////////////////////////////////////////////
[156]	78	// This function loads the .elf header in the buffer allocated by the caller.
[204]	79	///////////////////////////////////////////////////////////////////////////////////////
[1]	80	// @ file : extended pointer on the remote file descriptor.
	81	// @ buffer : pointer on buffer allocated by the caller.
	82	// @ size : number of bytes to read.
	83	///////////////////////////////////////////////////////////////////////////////////////
[204]	84	static error_t elf_header_load( xptr_t file_xp,
[1]	85	void * buffer,
	86	uint32_t size )
[156]	87	{
[332]	88	error_t error;
[328]	89	xptr_t buf_xp;
	90	void * buf_ptr;
[1]	91
[328]	92	buf_ptr = GET_PTR( buffer );
	93	buf_xp = XPTR( local_cxy , buf_ptr );
	94
[156]	95	// load .elf header
[332]	96	error = vfs_kernel_move( true, // to_buffer
[328]	97	file_xp,
	98	buf_xp,
	99	size );
[1]	100
[332]	101	if( error )
[1]	102	{
[332]	103	printk("\n[ERROR] in %s : cannot read ELF header size : %d\n",
	104	__FUNCTION__ , size );
[1]	105	return -1;
	106	}
	107
[227]	108	Elf_Ehdr * header = (Elf_Ehdr *)buffer;
[156]	109
[1]	110	if( (header->e_ident[EI_MAG0] != ELFMAG0) \|\|
	111	(header->e_ident[EI_MAG1] != ELFMAG1) \|\|
	112	(header->e_ident[EI_MAG2] != ELFMAG2) \|\|
	113	(header->e_ident[EI_MAG3] != ELFMAG3) )
	114	{
[332]	115	printk("\n[ERROR] in %s : file not in ELF format\n", __FUNCTION__ );
[1]	116	return -1;
	117	}
	118
	119	if( !(elf_isValidHeader( header ) ) )
	120	{
	121	printk("\n[ERROR] in %s : not supported Elf\n", __FUNCTION__ );
	122	return -1;
	123	}
	124	return 0;
	125
[204]	126	} // end elf_header_load()
	127
[1]	128	///////////////////////////////////////////////////////////////////////////////////////
	129	// This function registers in the process VMM the CODE and DATA segments.
[204]	130	///////////////////////////////////////////////////////////////////////////////////////
[1]	131	// @ file : extended pointer on the remote file descriptor.
	132	// @ segs_base : local pointer on buffer containing the segments descriptors array
	133	// @ segs_nr : number of segments in segment descriptors array.
	134	// @ process : local pointer on process descriptor.
	135	///////////////////////////////////////////////////////////////////////////////////////
[313]	136	static error_t elf_segments_register( xptr_t file_xp,
	137	void * segs_base,
	138	uint32_t nb_segs,
	139	process_t * process )
[1]	140	{
	141	uint32_t index;
[313]	142	intptr_t file_size;
	143	intptr_t mem_size;
	144	intptr_t file_offset;
	145	intptr_t vbase;
[1]	146	uint32_t type;
	147	uint32_t flags;
[156]	148	vseg_t * vseg;
[1]	149
[227]	150	Elf_Phdr * seg_ptr = (Elf_Phdr *)segs_base;
[1]	151
[156]	152	// loop on segments
	153	for( index = 0 ; index < nb_segs ; index++ , seg_ptr++ )
	154	{
	155	if( seg_ptr->p_type != PT_LOAD)
	156	continue;
	157
	158	// get segment attributes
[313]	159	vbase = seg_ptr->p_vaddr; // vseg base vaddr
	160	mem_size = seg_ptr->p_memsz; // actual vseg size
	161	file_offset = seg_ptr->p_offset; // vseg offset in .elf file
	162	file_size = seg_ptr->p_filesz; // vseg size in .elf file
	163	flags = seg_ptr->p_flags;
[1]	164
	165	if( flags & PF_X ) // found CODE segment
	166	{
[156]	167	type = VSEG_TYPE_CODE;
[315]	168	process->vmm.code_vpn_base = vbase >> CONFIG_PPM_PAGE_SHIFT;
[1]	169
[279]	170	elf_dmsg("\n[INFO] %s : found CODE vseg / base = %x / size = %x\n",
[315]	171	__FUNCTION__ , vbase , mem_size );
[1]	172	}
[156]	173	else // found DATA segment
[1]	174	{
[156]	175	type = VSEG_TYPE_DATA;
[315]	176	process->vmm.data_vpn_base = vbase >> CONFIG_PPM_PAGE_SHIFT;
[1]	177
[279]	178	elf_dmsg("\n[INFO] %s : found DATA vseg / base = %x / size = %x\n",
[315]	179	__FUNCTION__, vbase , mem_size );
[1]	180	}
	181
[156]	182	// register vseg in VMM
	183	vseg = (vseg_t *)vmm_create_vseg( process,
[313]	184	vbase,
[156]	185	mem_size,
	186	type );
[1]	187	if( vseg == NULL )
	188	{
	189	printk("\n[ERROR] in %s : cannot map segment / base = %x / size = %x\n",
[313]	190	__FUNCTION__ , vbase , mem_size );
[1]	191	return -1;
	192	}
	193
[313]	194	// get .elf file descriptor cluster and local pointer
	195	cxy_t file_cxy = GET_CXY( file_xp );
	196	vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
	197
	198	// initialize "file_mapper", "file_offset", "file_size" fields in vseg
[315]	199	vseg->mapper_xp = (xptr_t)hal_remote_lwd( XPTR( file_cxy , &file_ptr->mapper ) );
[313]	200	vseg->file_offset = file_offset;
	201	vseg->file_size = file_size;
	202
	203	// update reference counter in file descriptor
[1]	204	vfs_file_count_up( file_xp );
	205	}
	206
	207	return 0;
	208
[313]	209	} // end elf_segments_register()
[204]	210
[1]	211	///////////////////////////////////////////////
	212	error_t elf_load_process( char * pathname,
	213	process_t * process)
	214	{
	215	kmem_req_t req; // kmem request for program header
[227]	216	Elf_Ehdr header; // local buffer for .elf header
[1]	217	void * segs_base; // pointer on buffer for segment descriptors array
[156]	218	uint32_t segs_size; // size of buffer for segment descriptors array
[1]	219	xptr_t file_xp; // extended pointer on created file descriptor
[156]	220	uint32_t file_id; // file descriptor index (unused)
[1]	221	error_t error;
	222
[265]	223	elf_dmsg("\n[INFO] %s : enters for <%s>\n", __FUNCTION__ , pathname );
[1]	224
[204]	225	// avoid GCC warning
	226	file_xp = XPTR_NULL;
	227	file_id = -1;
[1]	228
[156]	229	// open file
	230	error = vfs_open( process->vfs_cwd_xp,
[204]	231	pathname,
[156]	232	O_RDONLY,
	233	0,
	234	&file_xp,
	235	&file_id );
[1]	236	if( error )
	237	{
[204]	238	printk("\n[ERROR] in %s : failed to open file %s\n", __FUNCTION__ , pathname );
[1]	239	return -1;
	240	}
	241
[265]	242	elf_dmsg("\n[INFO] %s : file <%s> open\n", __FUNCTION__ , pathname );
[204]	243
[156]	244	// load header in local buffer
[204]	245	error = elf_header_load( file_xp ,
[156]	246	&header,
[227]	247	sizeof(Elf_Ehdr) );
[156]	248	if( error )
	249	{
[204]	250	printk("\n[ERROR] in %s : cannot get header file %s\n", __FUNCTION__ , pathname );
[156]	251	vfs_close( file_xp , file_id );
	252	return -1;
	253	}
[1]	254
[204]	255	elf_dmsg("\n[INFO] %s : loaded elf header for %s\n", __FUNCTION__ , pathname );
[1]	256
	257	if( header.e_phnum == 0 )
	258	{
	259	printk("\n[ERROR] in %s : no segments found\n", __FUNCTION__ );
[156]	260	vfs_close( file_xp , file_id );
[1]	261	return -1;
	262	}
	263
[156]	264	// compute buffer size for segment descriptors array
[227]	265	segs_size = sizeof(Elf_Phdr) * header.e_phnum;
[156]	266
	267	// allocate memory for segment descriptors array
[1]	268	req.type = KMEM_GENERIC;
	269	req.size = segs_size;
	270	req.flags = AF_KERNEL;
	271	segs_base = kmem_alloc( &req );
	272
	273	if( segs_base == NULL )
[156]	274	{
[1]	275	printk("\n[ERROR] in %s : no memory for segment descriptors\n", __FUNCTION__ );
[156]	276	vfs_close( file_xp , file_id );
	277	return -1;
	278	}
[1]	279
[156]	280	// set seek pointer in file descriptor to access segment descriptors array
[23]	281	error = vfs_lseek( file_xp , header.e_phoff, SEEK_SET , NULL );
[1]	282
	283	if( error )
	284	{
	285	printk("\n[ERROR] in %s : cannot seek for descriptors array\n", __FUNCTION__ );
[156]	286	vfs_close( file_xp , file_id );
	287	req.ptr = segs_base;
	288	kmem_free( &req );
[1]	289	return -1;
	290	}
	291
[156]	292	// load seg descriptors array to local buffer
[333]	293	error = vfs_user_move( true, // to_buffer
[315]	294	file_xp,
	295	segs_base,
	296	segs_size );
[1]	297
[333]	298	if( error )
[1]	299	{
	300	printk("\n[ERROR] in %s : cannot read segments descriptors\n", __FUNCTION__ );
[156]	301	vfs_close( file_xp , file_id );
	302	req.ptr = segs_base;
	303	kmem_free( &req );
[1]	304	return -1;
	305	}
	306
[204]	307	elf_dmsg("\n[INFO] %s loaded segments descriptors for %s \n", __FUNCTION__ , pathname );
[1]	308
[156]	309	// register loadable segments in process VMM
[313]	310	error = elf_segments_register( file_xp,
	311	segs_base,
	312	header.e_phnum,
	313	process );
[1]	314	if( error )
[156]	315	{
	316	vfs_close( file_xp , file_id );
	317	req.ptr = segs_base;
	318	kmem_free( &req );
[1]	319	return -1;
[156]	320	}
[1]	321
[156]	322	// register process entry point in VMM
[1]	323	process->vmm.entry_point = (intptr_t)header.e_entry;
	324
[156]	325	// register extended pointer on .elf file descriptor
	326	process->vfs_bin_xp = file_xp;
[1]	327
[156]	328	// release allocated memory for program header
[1]	329	req.ptr = segs_base;
	330	kmem_free(&req);
	331
[156]	332	elf_dmsg("\n[INFO] %s successfully completed / entry point = %x for %s]\n",
[204]	333	__FUNCTION__, (uint32_t) header.e_entry , pathname );
[1]	334
	335	return 0;
	336
[204]	337	} // end elf_load_process()
	338

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