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source: trunk/kernel/libk/elf.c @ 274

Last change on this file since 274 was 270, checked in by max@…, 7 years ago
Comment out EI_OSABI, and use ELFCLASS.
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	{
	88	uint32_t count;
[1]	89
[156]	90	// load .elf header
[265]	91	count = vfs_move( true, // to_buffer
	92	false, // is_user
[156]	93	file_xp,
	94	buffer,
	95	size );
[1]	96
	97	if( count != size )
	98	{
[265]	99	printk("\n[ERROR] in %s : cannot read ELF header size : %d / done = %d\n",
	100	__FUNCTION__ , size , count );
[1]	101	return -1;
	102	}
	103
[227]	104	Elf_Ehdr * header = (Elf_Ehdr *)buffer;
[156]	105
[1]	106	if( (header->e_ident[EI_MAG0] != ELFMAG0) \|\|
	107	(header->e_ident[EI_MAG1] != ELFMAG1) \|\|
	108	(header->e_ident[EI_MAG2] != ELFMAG2) \|\|
	109	(header->e_ident[EI_MAG3] != ELFMAG3) )
	110	{
	111	printk("\n[ERROR] in %s : file %s not in ELF format\n", __FUNCTION__ );
	112	return -1;
	113	}
	114
	115	if( !(elf_isValidHeader( header ) ) )
	116	{
	117	printk("\n[ERROR] in %s : not supported Elf\n", __FUNCTION__ );
	118	return -1;
	119	}
	120	return 0;
	121
[204]	122	} // end elf_header_load()
	123
[1]	124	///////////////////////////////////////////////////////////////////////////////////////
	125	// This function registers in the process VMM the CODE and DATA segments.
[204]	126	///////////////////////////////////////////////////////////////////////////////////////
[1]	127	// @ file : extended pointer on the remote file descriptor.
	128	// @ segs_base : local pointer on buffer containing the segments descriptors array
	129	// @ segs_nr : number of segments in segment descriptors array.
	130	// @ process : local pointer on process descriptor.
	131	///////////////////////////////////////////////////////////////////////////////////////
	132	static error_t elf_segments_load( xptr_t file_xp,
[156]	133	void * segs_base,
[1]	134	uint32_t nb_segs,
[156]	135	process_t * process )
[1]	136	{
	137	error_t error;
	138	uint32_t index;
	139	uint32_t file_size;
[156]	140	uint32_t mem_size;
[1]	141	intptr_t start;
	142	uint32_t type;
	143	uint32_t flags;
	144	uint32_t offset;
[156]	145	vseg_t * vseg;
[1]	146
[227]	147	Elf_Phdr * seg_ptr = (Elf_Phdr *)segs_base;
[1]	148
[156]	149	// loop on segments
	150	for( index = 0 ; index < nb_segs ; index++ , seg_ptr++ )
	151	{
	152	if( seg_ptr->p_type != PT_LOAD)
	153	continue;
	154
	155	// get segment attributes
[1]	156	start = seg_ptr->p_vaddr;
[156]	157	offset = seg_ptr->p_offset;
	158	file_size = seg_ptr->p_filesz;
	159	mem_size = seg_ptr->p_memsz;
	160	flags = seg_ptr->p_flags;
[1]	161
[156]	162	// check alignment
[1]	163	if( start & CONFIG_PPM_PAGE_MASK )
	164	{
	165	printk("\n[WARNING] in %s : segment base not aligned = %x\n",
	166	__FUNCTION__, start );
	167	}
	168
[156]	169	// check size
	170	if( file_size != mem_size )
[1]	171	{
	172	printk("\n[WARNING] in %s : base = %x / mem_size = %x / file_size = %x\n",
	173	__FUNCTION__, start , mem_size , file_size);
	174	}
	175
[156]	176	// set seek on segment base in file
[23]	177	error = vfs_lseek( file_xp,
[156]	178	offset,
	179	SEEK_SET,
	180	NULL );
[1]	181
	182	if( error )
	183	{
	184	printk("\n[ERROR] in %s : failed to seek\n", __FUNCTION__ );
	185	return -1;
	186	}
	187
	188	if( flags & PF_X ) // found CODE segment
	189	{
[156]	190	type = VSEG_TYPE_CODE;
[1]	191	process->vmm.code_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
	192
	193	elf_dmsg("\n[INFO] %s found CODE vseg / base = %x / size = %x\n",
[156]	194	__FUNCTION__ , start , mem_size );
[1]	195	}
[156]	196	else // found DATA segment
[1]	197	{
[156]	198	type = VSEG_TYPE_DATA;
[1]	199	process->vmm.data_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
	200
	201	elf_dmsg("\n[INFO] %s found DATA vseg / base = %x / size = %x\n",
[156]	202	__FUNCTION__, start , mem_size );
[1]	203	}
	204
[156]	205	// register vseg in VMM
	206	vseg = (vseg_t *)vmm_create_vseg( process,
	207	start,
	208	mem_size,
	209	type );
[1]	210	if( vseg == NULL )
	211	{
	212	printk("\n[ERROR] in %s : cannot map segment / base = %x / size = %x\n",
	213	__FUNCTION__ , start , mem_size );
	214	return -1;
	215	}
	216
	217	vfs_file_count_up( file_xp );
	218	}
	219
	220	return 0;
	221
[204]	222	} // end elf_segments_load()
	223
[1]	224	///////////////////////////////////////////////
	225	error_t elf_load_process( char * pathname,
	226	process_t * process)
	227	{
	228	kmem_req_t req; // kmem request for program header
[227]	229	Elf_Ehdr header; // local buffer for .elf header
[1]	230	void * segs_base; // pointer on buffer for segment descriptors array
[156]	231	uint32_t segs_size; // size of buffer for segment descriptors array
[1]	232	xptr_t file_xp; // extended pointer on created file descriptor
[156]	233	uint32_t file_id; // file descriptor index (unused)
	234	uint32_t count; // bytes counter
[1]	235	error_t error;
	236
[265]	237	elf_dmsg("\n[INFO] %s : enters for <%s>\n", __FUNCTION__ , pathname );
[1]	238
[204]	239	// avoid GCC warning
	240	file_xp = XPTR_NULL;
	241	file_id = -1;
[1]	242
[156]	243	// open file
	244	error = vfs_open( process->vfs_cwd_xp,
[204]	245	pathname,
[156]	246	O_RDONLY,
	247	0,
	248	&file_xp,
	249	&file_id );
[1]	250	if( error )
	251	{
[204]	252	printk("\n[ERROR] in %s : failed to open file %s\n", __FUNCTION__ , pathname );
[1]	253	return -1;
	254	}
	255
[265]	256	elf_dmsg("\n[INFO] %s : file <%s> open\n", __FUNCTION__ , pathname );
[204]	257
[156]	258	// load header in local buffer
[204]	259	error = elf_header_load( file_xp ,
[156]	260	&header,
[227]	261	sizeof(Elf_Ehdr) );
[156]	262	if( error )
	263	{
[204]	264	printk("\n[ERROR] in %s : cannot get header file %s\n", __FUNCTION__ , pathname );
[156]	265	vfs_close( file_xp , file_id );
	266	return -1;
	267	}
[1]	268
[204]	269	elf_dmsg("\n[INFO] %s : loaded elf header for %s\n", __FUNCTION__ , pathname );
[1]	270
	271	if( header.e_phnum == 0 )
	272	{
	273	printk("\n[ERROR] in %s : no segments found\n", __FUNCTION__ );
[156]	274	vfs_close( file_xp , file_id );
[1]	275	return -1;
	276	}
	277
[156]	278	// compute buffer size for segment descriptors array
[227]	279	segs_size = sizeof(Elf_Phdr) * header.e_phnum;
[156]	280
	281	// allocate memory for segment descriptors array
[1]	282	req.type = KMEM_GENERIC;
	283	req.size = segs_size;
	284	req.flags = AF_KERNEL;
	285	segs_base = kmem_alloc( &req );
	286
	287	if( segs_base == NULL )
[156]	288	{
[1]	289	printk("\n[ERROR] in %s : no memory for segment descriptors\n", __FUNCTION__ );
[156]	290	vfs_close( file_xp , file_id );
	291	return -1;
	292	}
[1]	293
[156]	294	// set seek pointer in file descriptor to access segment descriptors array
[23]	295	error = vfs_lseek( file_xp , header.e_phoff, SEEK_SET , NULL );
[1]	296
	297	if( error )
	298	{
	299	printk("\n[ERROR] in %s : cannot seek for descriptors array\n", __FUNCTION__ );
[156]	300	vfs_close( file_xp , file_id );
	301	req.ptr = segs_base;
	302	kmem_free( &req );
[1]	303	return -1;
	304	}
	305
[156]	306	// load seg descriptors array to local buffer
[265]	307	count = vfs_move( true, // to_buffer
	308	false, // is_user
[156]	309	file_xp,
	310	segs_base,
	311	segs_size );
[1]	312
	313	if( count != segs_size )
	314	{
	315	printk("\n[ERROR] in %s : cannot read segments descriptors\n", __FUNCTION__ );
[156]	316	vfs_close( file_xp , file_id );
	317	req.ptr = segs_base;
	318	kmem_free( &req );
[1]	319	return -1;
	320	}
	321
[204]	322	elf_dmsg("\n[INFO] %s loaded segments descriptors for %s \n", __FUNCTION__ , pathname );
[1]	323
[156]	324	// register loadable segments in process VMM
	325	error = elf_segments_load( file_xp,
	326	segs_base,
	327	header.e_phnum,
	328	process );
[1]	329	if( error )
[156]	330	{
	331	vfs_close( file_xp , file_id );
	332	req.ptr = segs_base;
	333	kmem_free( &req );
[1]	334	return -1;
[156]	335	}
[1]	336
[156]	337	// register process entry point in VMM
[1]	338	process->vmm.entry_point = (intptr_t)header.e_entry;
	339
[156]	340	// register extended pointer on .elf file descriptor
	341	process->vfs_bin_xp = file_xp;
[1]	342
[156]	343	// release allocated memory for program header
[1]	344	req.ptr = segs_base;
	345	kmem_free(&req);
	346
[156]	347	elf_dmsg("\n[INFO] %s successfully completed / entry point = %x for %s]\n",
[204]	348	__FUNCTION__, (uint32_t) header.e_entry , pathname );
[1]	349
	350	return 0;
	351
[204]	352	} // end elf_load_process()
	353

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