WebSVN – HelenOS – Diff – /branches/dynload/uspace/srv/loader/elf_load.c


/*
 * Copyright (c) 2006 Sergey Bondari
 * Copyright (c) 2006 Jakub Jermar
 * Copyright (c) 2008 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup generic
 * @{
 */
 
/**
 * @file
 * @brief   Userspace ELF loader.
 *
 * This module allows loading ELF binaries (both executables and
 * shared objects) from VFS. The current implementation allocates
 * anonymous memory, fills it with segment data and then adjusts
 * the memory areas' flags to the final value. In the future,
 * the segments will be mapped directly from the file.
 */
 
#include <stdio.h>
#include <sys/types.h>
#include <align.h>
#include <assert.h>
#include <as.h>
#include <unistd.h>
#include <fcntl.h>
#include <smc.h>
#include <loader/pcb.h>
 
#include "elf.h"
#include "elf_load.h"
#include "arch.h"
 
static char *error_codes[] = {
    "no error",
    "invalid image",
    "address space error",
    "incompatible image",
    "unsupported image type",
    "irrecoverable error"
};
 
static unsigned int elf_load(elf_ld_t *elf, size_t so_bias);
static int segment_header(elf_ld_t *elf, elf_segment_header_t *entry);
static int section_header(elf_ld_t *elf, elf_section_header_t *entry);
static int load_segment(elf_ld_t *elf, elf_segment_header_t *entry);
 
/** Read until the buffer is read in its entirety. */
static int my_read(int fd, char *buf, size_t len)
{
    int cnt = 0;
    do {
        buf += cnt;
        len -= cnt;
        cnt = read(fd, buf, len);
    } while ((cnt > 0) && ((len - cnt) > 0));
 
    return cnt;
}
 
/** Load ELF binary from a file.
 *
 * Load an ELF binary from the specified file. If the file is
 * an executable program, it is loaded unbiased. If it is a shared
 * object, it is loaded with the bias @a so_bias. Some information
 * extracted from the binary is stored in a elf_info_t structure
 * pointed to by @a info.
 *
 * @param file_name Path to the ELF file.
 * @param so_bias   Bias to use if the file is a shared object.
 * @param info      Pointer to a structure for storing information
 *          extracted from the binary.
 *
 * @return EOK on success or negative error code.
 */
int elf_load_file(char *file_name, size_t so_bias, eld_flags_t flags,
    elf_info_t *info)
{
    elf_ld_t elf;
 
    int fd;
    int rc;
 
//  printf("open and read '%s'...\n", file_name);
 
    fd = open(file_name, O_RDONLY);
    if (fd < 0) {
        printf("failed opening file (error %d)\n", fd);
        return -1;
    }
 
    elf.fd = fd;
    elf.info = info;
    elf.flags = flags;
 
    rc = elf_load(&elf, so_bias);
 
    close(fd);
 
    return rc;
}
 
/** Run an ELF executable.
 *
 * Transfers control to the entry point of an ELF executable loaded
 * earlier with elf_load_file(). This function does not return.
 *
 * @param info  Info structure filled earlier by elf_load_file()
 */
void elf_run(elf_info_t *info, pcb_t *pcb)
{
    program_run(info->entry, pcb);
 
    /* not reached */
}
 
/** Create the program control block (PCB).
 *
 * Fills the program control block @a pcb with information from
 * @a info.
 *
 * @param info  Program info structure
 * @return EOK on success or negative error code
 */
void elf_create_pcb(elf_info_t *info, pcb_t *pcb)
{
    pcb->entry = info->entry;
    pcb->dynamic = info->dynamic;
}
 
 
/** Load an ELF binary.
 *
 * The @a elf structure contains the loader state, including
 * an open file, from which the binary will be loaded,
 * a pointer to the @c info structure etc.
 *
 * @param elf       Pointer to loader state buffer.
 * @param so_bias   Bias to use if the file is a shared object.
 * @return EE_OK on success or EE_xx error code.
 */
static unsigned int elf_load(elf_ld_t *elf, size_t so_bias)
{
    elf_header_t header_buf;
    elf_header_t *header = &header_buf;
    int i, rc;
 
    rc = my_read(elf->fd, header, sizeof(elf_header_t));
    if (rc < 0) {
        printf("read error\n");
        return EE_INVALID;
    }
 
    elf->header = header;
 
//  printf("ELF-load:");
    /* Identify ELF */
    if (header->e_ident[EI_MAG0] != ELFMAG0 ||
        header->e_ident[EI_MAG1] != ELFMAG1 ||
        header->e_ident[EI_MAG2] != ELFMAG2 ||
        header->e_ident[EI_MAG3] != ELFMAG3) {
        printf("invalid header\n");
        return EE_INVALID;
    }
   
    /* Identify ELF compatibility */
    if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING ||
        header->e_machine != ELF_MACHINE ||
        header->e_ident[EI_VERSION] != EV_CURRENT ||
        header->e_version != EV_CURRENT ||
        header->e_ident[EI_CLASS] != ELF_CLASS) {
        printf("incompatible data/version/class\n");
        return EE_INCOMPATIBLE;
    }
 
    if (header->e_phentsize != sizeof(elf_segment_header_t)) {
        printf("e_phentsize:%d != %d\n", header->e_phentsize,
            sizeof(elf_segment_header_t));
        return EE_INCOMPATIBLE;
    }
 
    if (header->e_shentsize != sizeof(elf_section_header_t)) {
        printf("e_shentsize:%d != %d\n", header->e_shentsize,
            sizeof(elf_section_header_t));
        return EE_INCOMPATIBLE;
    }
 
    /* Check if the object type is supported. */
    if (header->e_type != ET_EXEC && header->e_type != ET_DYN) {
        printf("Object type %d is not supported\n", header->e_type);
        return EE_UNSUPPORTED;
    }
 
    /* Shared objects can be loaded with a bias */
//  printf("Object type: %d\n", header->e_type);
    if (header->e_type == ET_DYN)
        elf->bias = so_bias;
    else
        elf->bias = 0;
 
//  printf("Bias set to 0x%x\n", elf->bias);
    elf->info->interp = NULL;
    elf->info->dynamic = NULL;
 
//  printf("parse segments\n");
 
    /* Walk through all segment headers and process them. */
    for (i = 0; i < header->e_phnum; i++) {
        elf_segment_header_t segment_hdr;
 
        /* Seek to start of segment header */
        lseek(elf->fd, header->e_phoff
                + i * sizeof(elf_segment_header_t), SEEK_SET);
 
        rc = my_read(elf->fd, &segment_hdr,
            sizeof(elf_segment_header_t));
        if (rc < 0) {
            printf("read error\n");
            return EE_INVALID;
        }
 
        rc = segment_header(elf, &segment_hdr);
        if (rc != EE_OK)
            return rc;
    }
 
//  printf("parse sections\n");
 
    /* Inspect all section headers and proccess them. */
    for (i = 0; i < header->e_shnum; i++) {
        elf_section_header_t section_hdr;
 
        /* Seek to start of section header */
        lseek(elf->fd, header->e_shoff
            + i * sizeof(elf_section_header_t), SEEK_SET);
 
        rc = my_read(elf->fd, &section_hdr,
            sizeof(elf_section_header_t));
        if (rc < 0) {
            printf("read error\n");
            return EE_INVALID;
        }
 
        rc = section_header(elf, &section_hdr);
        if (rc != EE_OK)
            return rc;
    }
 
    elf->info->entry =
        (entry_point_t)((uint8_t *)header->e_entry + elf->bias);
 
//  printf("done\n");
 
    return EE_OK;
}
 
/** Print error message according to error code.
 *
 * @param rc Return code returned by elf_load().
 *
 * @return NULL terminated description of error.
 */
char *elf_error(unsigned int rc)
{
    assert(rc < sizeof(error_codes) / sizeof(char *));
 
    return error_codes[rc];
}
 
/** Process segment header.
 *
 * @param entry Segment header.
 *
 * @return EE_OK on success, error code otherwise.
 */
static int segment_header(elf_ld_t *elf, elf_segment_header_t *entry)
{
    switch (entry->p_type) {
    case PT_NULL:
    case PT_PHDR:
        break;
    case PT_LOAD:
        return load_segment(elf, entry);
        break;
    case PT_INTERP:
        /* Assume silently interp == "/lib/rtld" */
        elf->info->interp = "/lib/rtld";
        break;
    case PT_DYNAMIC:
    case PT_SHLIB:
    case PT_NOTE:
    case PT_LOPROC:
    case PT_HIPROC:
    default:
        printf("segment p_type %d unknown\n", entry->p_type);
        return EE_UNSUPPORTED;
        break;
    }
    return EE_OK;
}
 
/** Load segment described by program header entry.
 *
 * @param elf   Loader state.
 * @param entry Program header entry describing segment to be loaded.
 *
 * @return EE_OK on success, error code otherwise.
 */
int load_segment(elf_ld_t *elf, elf_segment_header_t *entry)
{
    void *a;
    int flags = 0;
    uintptr_t bias;
    uintptr_t base;
    size_t mem_sz;
    int rc;
 
//  printf("load segment at addr 0x%x, size 0x%x\n", entry->p_vaddr,
//      entry->p_memsz);
   
    bias = elf->bias;
 
    if (entry->p_align > 1) {
        if ((entry->p_offset % entry->p_align) !=
            (entry->p_vaddr % entry->p_align)) {
            printf("align check 1 failed offset%%align=%d, "
                "vaddr%%align=%d\n",
                entry->p_offset % entry->p_align,
                entry->p_vaddr % entry->p_align
            );
            return EE_INVALID;
        }
    }
 
    /* Final flags that will be set for the memory area */
 
    if (entry->p_flags & PF_X)
        flags |= AS_AREA_EXEC;
    if (entry->p_flags & PF_W)
        flags |= AS_AREA_WRITE;
    if (entry->p_flags & PF_R)
        flags |= AS_AREA_READ;
    flags |= AS_AREA_CACHEABLE;
   
    base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);
    mem_sz = entry->p_memsz + (entry->p_vaddr - base);
 
//  printf("map to p_vaddr=0x%x-0x%x...\n", entry->p_vaddr + bias,
//  entry->p_vaddr + bias + ALIGN_UP(entry->p_memsz, PAGE_SIZE));
 
    /*
     * For the course of loading, the area needs to be readable
     * and writeable.
     */
    a = as_area_create((uint8_t *)base + bias, mem_sz,
        AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE);
    if (a == (void *)(-1)) {
        printf("memory mapping failed\n");
        return EE_MEMORY;
    }
 
//  printf("as_area_create(0x%lx, 0x%x, %d) -> 0x%lx\n",
//      entry->p_vaddr+bias, entry->p_memsz, flags, (uintptr_t)a);
 
    /*
     * Load segment data
     */
//  printf("seek to %d\n", entry->p_offset);
    rc = lseek(elf->fd, entry->p_offset, SEEK_SET);
    if (rc < 0) {
        printf("seek error\n");
        return EE_INVALID;
    }
 
//  printf("read 0x%x bytes to address 0x%x\n", entry->p_filesz, entry->p_vaddr+bias);
/*  rc = read(fd, (void *)(entry->p_vaddr + bias), entry->p_filesz);
    if (rc < 0) { printf("read error\n"); return EE_INVALID; }*/
 
    /* Long reads are not possible yet. Load segment picewise */
 
    unsigned left, now;
    uint8_t *dp;
 
    left = entry->p_filesz;
    dp = (uint8_t *)(entry->p_vaddr + bias);
 
    while (left > 0) {
        now = 16384;
        if (now > left) now = left;
 
//      printf("read %d...", now);
        rc = my_read(elf->fd, dp, now);
//      printf("->%d\n", rc);
 
        if (rc < 0) {
            printf("read error\n");
            return EE_INVALID;
        }
 
        left -= now;
        dp += now;
    }
 
    /*
     * The caller wants to modify the segments first. He will then
     * need to set the right access mode and ensure SMC coherence.
     */
    if ((elf->flags & ELDF_RW) != 0) return EE_OK;
 
    printf("set area flags to %d\n", flags);
    rc = as_area_change_flags((uint8_t *)entry->p_vaddr + bias, flags);
    if (rc != 0) {
        printf("failed to set memory area flags\n");
        return EE_MEMORY;
    }
 
    if (flags & AS_AREA_EXEC) {
        /* Enforce SMC coherence for the segment */
        if (smc_coherence(entry->p_vaddr + bias, entry->p_filesz))
            return EE_MEMORY;
    }
 
    return EE_OK;
}
 
/** Process section header.
 *
 * @param elf   Loader state.
 * @param entry Segment header.
 *
 * @return EE_OK on success, error code otherwise.
 */
static int section_header(elf_ld_t *elf, elf_section_header_t *entry)
{
    switch (entry->sh_type) {
    case SHT_PROGBITS:
        if (entry->sh_flags & SHF_TLS) {
            /* .tdata */
        }
        break;
    case SHT_NOBITS:
        if (entry->sh_flags & SHF_TLS) {
            /* .tbss */
        }
        break;
    case SHT_DYNAMIC:
        /* Record pointer to dynamic section into info structure */
        elf->info->dynamic =
            (void *)((uint8_t *)entry->sh_addr + elf->bias);
        printf("dynamic section found at 0x%x\n",
            (uintptr_t)elf->info->dynamic);
        break;
    default:
        break;
    }
   
    return EE_OK;
}
 
/** @}
 */
 

Rev 3403	Rev 3552
1	/*	1	/*
2	* Copyright (c) 2006 Sergey Bondari	2	* Copyright (c) 2006 Sergey Bondari
3	* Copyright (c) 2006 Jakub Jermar	3	* Copyright (c) 2006 Jakub Jermar
4	* Copyright (c) 2008 Jiri Svoboda	4	* Copyright (c) 2008 Jiri Svoboda
5	* All rights reserved.	5	* All rights reserved.
6	*	6	*
7	* Redistribution and use in source and binary forms, with or without	7	* Redistribution and use in source and binary forms, with or without
8	* modification, are permitted provided that the following conditions	8	* modification, are permitted provided that the following conditions
9	* are met:	9	* are met:
10	*	10	*
11	* - Redistributions of source code must retain the above copyright	11	* - Redistributions of source code must retain the above copyright
12	* notice, this list of conditions and the following disclaimer.	12	* notice, this list of conditions and the following disclaimer.
13	* - Redistributions in binary form must reproduce the above copyright	13	* - Redistributions in binary form must reproduce the above copyright
14	* notice, this list of conditions and the following disclaimer in the	14	* notice, this list of conditions and the following disclaimer in the
15	* documentation and/or other materials provided with the distribution.	15	* documentation and/or other materials provided with the distribution.
16	* - The name of the author may not be used to endorse or promote products	16	* - The name of the author may not be used to endorse or promote products
17	* derived from this software without specific prior written permission.	17	* derived from this software without specific prior written permission.
18	*	18	*
19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	20	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	21	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	22	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	23	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	24	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	25	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	26	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	27	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	28	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29	*/	29	*/
30		30
31	/** @addtogroup generic	31	/** @addtogroup generic
32	* @{	32	* @{
33	*/	33	*/
34		34
35	/**	35	/**
36	* @file	36	* @file
37	* @brief Userspace ELF loader.	37	* @brief Userspace ELF loader.
38	*	38	*
39	* This module allows loading ELF binaries (both executables and	39	* This module allows loading ELF binaries (both executables and
40	* shared objects) from VFS. The current implementation allocates	40	* shared objects) from VFS. The current implementation allocates
41	* anonymous memory, fills it with segment data and then adjusts	41	* anonymous memory, fills it with segment data and then adjusts
42	* the memory areas' flags to the final value. In the future,	42	* the memory areas' flags to the final value. In the future,
43	* the segments will be mapped directly from the file.	43	* the segments will be mapped directly from the file.
44	*/	44	*/
45		45
46	#include <stdio.h>	46	#include <stdio.h>
47	#include <sys/types.h>	47	#include <sys/types.h>
48	#include <align.h>	48	#include <align.h>
49	#include <assert.h>	49	#include <assert.h>
50	#include <as.h>	50	#include <as.h>
51	#include <unistd.h>	51	#include <unistd.h>
52	#include <fcntl.h>	52	#include <fcntl.h>
53	#include <smc.h>	53	#include <smc.h>
54	#include <loader/pcb.h>	54	#include <loader/pcb.h>
55		55
56	#include "elf.h"	56	#include "elf.h"
57	#include "elf_load.h"	57	#include "elf_load.h"
58	#include "arch.h"	58	#include "arch.h"
59		59
60	static char *error_codes[] = {	60	static char *error_codes[] = {
61	"no error",	61	"no error",
62	"invalid image",	62	"invalid image",
63	"address space error",	63	"address space error",
64	"incompatible image",	64	"incompatible image",
65	"unsupported image type",	65	"unsupported image type",
66	"irrecoverable error"	66	"irrecoverable error"
67	};	67	};
68		68
69	static unsigned int elf_load(elf_ld_t *elf, size_t so_bias);	69	static unsigned int elf_load(elf_ld_t *elf, size_t so_bias);
70	static int segment_header(elf_ld_t elf, elf_segment_header_t entry);	70	static int segment_header(elf_ld_t elf, elf_segment_header_t entry);
71	static int section_header(elf_ld_t elf, elf_section_header_t entry);	71	static int section_header(elf_ld_t elf, elf_section_header_t entry);
72	static int load_segment(elf_ld_t elf, elf_segment_header_t entry);	72	static int load_segment(elf_ld_t elf, elf_segment_header_t entry);
73		73
74	/** Read until the buffer is read in its entirety. */	74	/** Read until the buffer is read in its entirety. */
75	static int my_read(int fd, char *buf, size_t len)	75	static int my_read(int fd, char *buf, size_t len)
76	{	76	{
77	int cnt = 0;	77	int cnt = 0;
78	do {	78	do {
79	buf += cnt;	79	buf += cnt;
80	len -= cnt;	80	len -= cnt;
81	cnt = read(fd, buf, len);	81	cnt = read(fd, buf, len);
82	} while ((cnt > 0) && ((len - cnt) > 0));	82	} while ((cnt > 0) && ((len - cnt) > 0));
83		83
84	return cnt;	84	return cnt;
85	}	85	}
86		86
87	/** Load ELF binary from a file.	87	/** Load ELF binary from a file.
88	*	88	*
89	* Load an ELF binary from the specified file. If the file is	89	* Load an ELF binary from the specified file. If the file is
90	* an executable program, it is loaded unbiased. If it is a shared	90	* an executable program, it is loaded unbiased. If it is a shared
91	* object, it is loaded with the bias @a so_bias. Some information	91	* object, it is loaded with the bias @a so_bias. Some information
92	* extracted from the binary is stored in a elf_info_t structure	92	* extracted from the binary is stored in a elf_info_t structure
93	* pointed to by @a info.	93	* pointed to by @a info.
94	*	94	*
95	* @param file_name Path to the ELF file.	95	* @param file_name Path to the ELF file.
96	* @param so_bias Bias to use if the file is a shared object.	96	* @param so_bias Bias to use if the file is a shared object.
97	* @param info Pointer to a structure for storing information	97	* @param info Pointer to a structure for storing information
98	* extracted from the binary.	98	* extracted from the binary.
99	*	99	*
100	* @return EOK on success or negative error code.	100	* @return EOK on success or negative error code.
101	*/	101	*/
102	int elf_load_file(char file_name, size_t so_bias, elf_info_t info)	102	int elf_load_file(char *file_name, size_t so_bias, eld_flags_t flags,
-		103	elf_info_t *info)
103	{	104	{
104	elf_ld_t elf;	105	elf_ld_t elf;
105		106
106	int fd;	107	int fd;
107	int rc;	108	int rc;
108		109
109	// printf("open and read '%s'...\n", file_name);	110	// printf("open and read '%s'...\n", file_name);
110		111
111	fd = open(file_name, O_RDONLY);	112	fd = open(file_name, O_RDONLY);
112	if (fd < 0) {	113	if (fd < 0) {
113	printf("failed opening file (error %d)\n", fd);	114	printf("failed opening file (error %d)\n", fd);
114	return -1;	115	return -1;
115	}	116	}
116		117
117	elf.fd = fd;	118	elf.fd = fd;
118	elf.info = info;	119	elf.info = info;
-		120	elf.flags = flags;
119		121
120	rc = elf_load(&elf, so_bias);	122	rc = elf_load(&elf, so_bias);
121		123
122	close(fd);	124	close(fd);
123		125
124	return rc;	126	return rc;
125	}	127	}
126		128
127	/** Run an ELF executable.	129	/** Run an ELF executable.
128	*	130	*
129	* Transfers control to the entry point of an ELF executable loaded	131	* Transfers control to the entry point of an ELF executable loaded
130	* earlier with elf_load_file(). This function does not return.	132	* earlier with elf_load_file(). This function does not return.
131	*	133	*
132	* @param info Info structure filled earlier by elf_load_file()	134	* @param info Info structure filled earlier by elf_load_file()
133	*/	135	*/
134	void elf_run(elf_info_t info, pcb_t pcb)	136	void elf_run(elf_info_t info, pcb_t pcb)
135	{	137	{
136	program_run(info->entry, pcb);	138	program_run(info->entry, pcb);
137		139
138	/* not reached */	140	/* not reached */
139	}	141	}
140		142
141	/** Create the program control block (PCB).	143	/** Create the program control block (PCB).
142	*	144	*
143	* Fills the program control block @a pcb with information from	145	* Fills the program control block @a pcb with information from
144	* @a info.	146	* @a info.
145	*	147	*
146	* @param info Program info structure	148	* @param info Program info structure
147	* @return EOK on success or negative error code	149	* @return EOK on success or negative error code
148	*/	150	*/
149	void elf_create_pcb(elf_info_t info, pcb_t pcb)	151	void elf_create_pcb(elf_info_t info, pcb_t pcb)
150	{	152	{
151	pcb->entry = info->entry;	153	pcb->entry = info->entry;
152	pcb->dynamic = info->dynamic;	154	pcb->dynamic = info->dynamic;
153	}	155	}
154		156
155		157
156	/** Load an ELF binary.	158	/** Load an ELF binary.
157	*	159	*
158	* The @a elf structure contains the loader state, including	160	* The @a elf structure contains the loader state, including
159	* an open file, from which the binary will be loaded,	161	* an open file, from which the binary will be loaded,
160	* a pointer to the @c info structure etc.	162	* a pointer to the @c info structure etc.
161	*	163	*
162	* @param elf Pointer to loader state buffer.	164	* @param elf Pointer to loader state buffer.
163	* @param so_bias Bias to use if the file is a shared object.	165	* @param so_bias Bias to use if the file is a shared object.
164	* @return EE_OK on success or EE_xx error code.	166	* @return EE_OK on success or EE_xx error code.
165	*/	167	*/
166	static unsigned int elf_load(elf_ld_t *elf, size_t so_bias)	168	static unsigned int elf_load(elf_ld_t *elf, size_t so_bias)
167	{	169	{
168	elf_header_t header_buf;	170	elf_header_t header_buf;
169	elf_header_t *header = &header_buf;	171	elf_header_t *header = &header_buf;
170	int i, rc;	172	int i, rc;
171		173
172	rc = my_read(elf->fd, header, sizeof(elf_header_t));	174	rc = my_read(elf->fd, header, sizeof(elf_header_t));
173	if (rc < 0) {	175	if (rc < 0) {
174	printf("read error\n");	176	printf("read error\n");
175	return EE_INVALID;	177	return EE_INVALID;
176	}	178	}
177		179
178	elf->header = header;	180	elf->header = header;
179		181
180	// printf("ELF-load:");	182	// printf("ELF-load:");
181	/* Identify ELF */	183	/* Identify ELF */
182	if (header->e_ident[EI_MAG0] != ELFMAG0 \|\|	184	if (header->e_ident[EI_MAG0] != ELFMAG0 \|\|
183	header->e_ident[EI_MAG1] != ELFMAG1 \|\|	185	header->e_ident[EI_MAG1] != ELFMAG1 \|\|
184	header->e_ident[EI_MAG2] != ELFMAG2 \|\|	186	header->e_ident[EI_MAG2] != ELFMAG2 \|\|
185	header->e_ident[EI_MAG3] != ELFMAG3) {	187	header->e_ident[EI_MAG3] != ELFMAG3) {
186	printf("invalid header\n");	188	printf("invalid header\n");
187	return EE_INVALID;	189	return EE_INVALID;
188	}	190	}
189		191
190	/* Identify ELF compatibility */	192	/* Identify ELF compatibility */
191	if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING \|\|	193	if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING \|\|
192	header->e_machine != ELF_MACHINE \|\|	194	header->e_machine != ELF_MACHINE \|\|
193	header->e_ident[EI_VERSION] != EV_CURRENT \|\|	195	header->e_ident[EI_VERSION] != EV_CURRENT \|\|
194	header->e_version != EV_CURRENT \|\|	196	header->e_version != EV_CURRENT \|\|
195	header->e_ident[EI_CLASS] != ELF_CLASS) {	197	header->e_ident[EI_CLASS] != ELF_CLASS) {
196	printf("incompatible data/version/class\n");	198	printf("incompatible data/version/class\n");
197	return EE_INCOMPATIBLE;	199	return EE_INCOMPATIBLE;
198	}	200	}
199		201
200	if (header->e_phentsize != sizeof(elf_segment_header_t)) {	202	if (header->e_phentsize != sizeof(elf_segment_header_t)) {
201	printf("e_phentsize:%d != %d\n", header->e_phentsize,	203	printf("e_phentsize:%d != %d\n", header->e_phentsize,
202	sizeof(elf_segment_header_t));	204	sizeof(elf_segment_header_t));
203	return EE_INCOMPATIBLE;	205	return EE_INCOMPATIBLE;
204	}	206	}
205		207
206	if (header->e_shentsize != sizeof(elf_section_header_t)) {	208	if (header->e_shentsize != sizeof(elf_section_header_t)) {
207	printf("e_shentsize:%d != %d\n", header->e_shentsize,	209	printf("e_shentsize:%d != %d\n", header->e_shentsize,
208	sizeof(elf_section_header_t));	210	sizeof(elf_section_header_t));
209	return EE_INCOMPATIBLE;	211	return EE_INCOMPATIBLE;
210	}	212	}
211		213
212	/* Check if the object type is supported. */	214	/* Check if the object type is supported. */
213	if (header->e_type != ET_EXEC && header->e_type != ET_DYN) {	215	if (header->e_type != ET_EXEC && header->e_type != ET_DYN) {
214	printf("Object type %d is not supported\n", header->e_type);	216	printf("Object type %d is not supported\n", header->e_type);
215	return EE_UNSUPPORTED;	217	return EE_UNSUPPORTED;
216	}	218	}
217		219
218	/* Shared objects can be loaded with a bias */	220	/* Shared objects can be loaded with a bias */
219	// printf("Object type: %d\n", header->e_type);	221	// printf("Object type: %d\n", header->e_type);
220	if (header->e_type == ET_DYN)	222	if (header->e_type == ET_DYN)
221	elf->bias = so_bias;	223	elf->bias = so_bias;
222	else	224	else
223	elf->bias = 0;	225	elf->bias = 0;
224		226
225	// printf("Bias set to 0x%x\n", elf->bias);	227	// printf("Bias set to 0x%x\n", elf->bias);
226	elf->info->interp = NULL;	228	elf->info->interp = NULL;
227	elf->info->dynamic = NULL;	229	elf->info->dynamic = NULL;
228		230
229	// printf("parse segments\n");	231	// printf("parse segments\n");
230		232
231	/* Walk through all segment headers and process them. */	233	/* Walk through all segment headers and process them. */
232	for (i = 0; i < header->e_phnum; i++) {	234	for (i = 0; i < header->e_phnum; i++) {
233	elf_segment_header_t segment_hdr;	235	elf_segment_header_t segment_hdr;
234		236
235	/* Seek to start of segment header */	237	/* Seek to start of segment header */
236	lseek(elf->fd, header->e_phoff	238	lseek(elf->fd, header->e_phoff
237	+ i * sizeof(elf_segment_header_t), SEEK_SET);	239	+ i * sizeof(elf_segment_header_t), SEEK_SET);
238		240
239	rc = my_read(elf->fd, &segment_hdr,	241	rc = my_read(elf->fd, &segment_hdr,
240	sizeof(elf_segment_header_t));	242	sizeof(elf_segment_header_t));
241	if (rc < 0) {	243	if (rc < 0) {
242	printf("read error\n");	244	printf("read error\n");
243	return EE_INVALID;	245	return EE_INVALID;
244	}	246	}
245		247
246	rc = segment_header(elf, &segment_hdr);	248	rc = segment_header(elf, &segment_hdr);
247	if (rc != EE_OK)	249	if (rc != EE_OK)
248	return rc;	250	return rc;
249	}	251	}
250		252
251	// printf("parse sections\n");	253	// printf("parse sections\n");
252		254
253	/* Inspect all section headers and proccess them. */	255	/* Inspect all section headers and proccess them. */
254	for (i = 0; i < header->e_shnum; i++) {	256	for (i = 0; i < header->e_shnum; i++) {
255	elf_section_header_t section_hdr;	257	elf_section_header_t section_hdr;
256		258
257	/* Seek to start of section header */	259	/* Seek to start of section header */
258	lseek(elf->fd, header->e_shoff	260	lseek(elf->fd, header->e_shoff
259	+ i * sizeof(elf_section_header_t), SEEK_SET);	261	+ i * sizeof(elf_section_header_t), SEEK_SET);
260		262
261	rc = my_read(elf->fd, &section_hdr,	263	rc = my_read(elf->fd, &section_hdr,
262	sizeof(elf_section_header_t));	264	sizeof(elf_section_header_t));
263	if (rc < 0) {	265	if (rc < 0) {
264	printf("read error\n");	266	printf("read error\n");
265	return EE_INVALID;	267	return EE_INVALID;
266	}	268	}
267		269
268	rc = section_header(elf, &section_hdr);	270	rc = section_header(elf, &section_hdr);
269	if (rc != EE_OK)	271	if (rc != EE_OK)
270	return rc;	272	return rc;
271	}	273	}
272		274
273	elf->info->entry =	275	elf->info->entry =
274	(entry_point_t)((uint8_t *)header->e_entry + elf->bias);	276	(entry_point_t)((uint8_t *)header->e_entry + elf->bias);
275		277
276	// printf("done\n");	278	// printf("done\n");
277		279
278	return EE_OK;	280	return EE_OK;
279	}	281	}
280		282
281	/** Print error message according to error code.	283	/** Print error message according to error code.
282	*	284	*
283	* @param rc Return code returned by elf_load().	285	* @param rc Return code returned by elf_load().
284	*	286	*
285	* @return NULL terminated description of error.	287	* @return NULL terminated description of error.
286	*/	288	*/
287	char *elf_error(unsigned int rc)	289	char *elf_error(unsigned int rc)
288	{	290	{
289	assert(rc < sizeof(error_codes) / sizeof(char *));	291	assert(rc < sizeof(error_codes) / sizeof(char *));
290		292
291	return error_codes[rc];	293	return error_codes[rc];
292	}	294	}
293		295
294	/** Process segment header.	296	/** Process segment header.
295	*	297	*
296	* @param entry Segment header.	298	* @param entry Segment header.
297	*	299	*
298	* @return EE_OK on success, error code otherwise.	300	* @return EE_OK on success, error code otherwise.
299	*/	301	*/
300	static int segment_header(elf_ld_t elf, elf_segment_header_t entry)	302	static int segment_header(elf_ld_t elf, elf_segment_header_t entry)
301	{	303	{
302	switch (entry->p_type) {	304	switch (entry->p_type) {
303	case PT_NULL:	305	case PT_NULL:
304	case PT_PHDR:	306	case PT_PHDR:
305	break;	307	break;
306	case PT_LOAD:	308	case PT_LOAD:
307	return load_segment(elf, entry);	309	return load_segment(elf, entry);
308	break;	310	break;
309	case PT_INTERP:	311	case PT_INTERP:
310	/* Assume silently interp == "/lib/rtld.so" */	312	/* Assume silently interp == "/lib/rtld" */
311	elf->info->interp = "/lib/rtld.so";	313	elf->info->interp = "/lib/rtld";
312	break;	314	break;
313	case PT_DYNAMIC:	315	case PT_DYNAMIC:
314	case PT_SHLIB:	316	case PT_SHLIB:
315	case PT_NOTE:	317	case PT_NOTE:
316	case PT_LOPROC:	318	case PT_LOPROC:
317	case PT_HIPROC:	319	case PT_HIPROC:
318	default:	320	default:
319	printf("segment p_type %d unknown\n", entry->p_type);	321	printf("segment p_type %d unknown\n", entry->p_type);
320	return EE_UNSUPPORTED;	322	return EE_UNSUPPORTED;
321	break;	323	break;
322	}	324	}
323	return EE_OK;	325	return EE_OK;
324	}	326	}
325		327
326	/** Load segment described by program header entry.	328	/** Load segment described by program header entry.
327	*	329	*
328	* @param elf Loader state.	330	* @param elf Loader state.
329	* @param entry Program header entry describing segment to be loaded.	331	* @param entry Program header entry describing segment to be loaded.
330	*	332	*
331	* @return EE_OK on success, error code otherwise.	333	* @return EE_OK on success, error code otherwise.
332	*/	334	*/
333	int load_segment(elf_ld_t elf, elf_segment_header_t entry)	335	int load_segment(elf_ld_t elf, elf_segment_header_t entry)
334	{	336	{
335	void *a;	337	void *a;
336	int flags = 0;	338	int flags = 0;
337	uintptr_t bias;	339	uintptr_t bias;
338	uintptr_t base;	340	uintptr_t base;
339	size_t mem_sz;	341	size_t mem_sz;
340	int rc;	342	int rc;
341		343
342	// printf("load segment at addr 0x%x, size 0x%x\n", entry->p_vaddr,	344	// printf("load segment at addr 0x%x, size 0x%x\n", entry->p_vaddr,
343	// entry->p_memsz);	345	// entry->p_memsz);
344		346
345	bias = elf->bias;	347	bias = elf->bias;
346		348
347	if (entry->p_align > 1) {	349	if (entry->p_align > 1) {
348	if ((entry->p_offset % entry->p_align) !=	350	if ((entry->p_offset % entry->p_align) !=
349	(entry->p_vaddr % entry->p_align)) {	351	(entry->p_vaddr % entry->p_align)) {
350	printf("align check 1 failed offset%%align=%d, "	352	printf("align check 1 failed offset%%align=%d, "
351	"vaddr%%align=%d\n",	353	"vaddr%%align=%d\n",
352	entry->p_offset % entry->p_align,	354	entry->p_offset % entry->p_align,
353	entry->p_vaddr % entry->p_align	355	entry->p_vaddr % entry->p_align
354	);	356	);
355	return EE_INVALID;	357	return EE_INVALID;
356	}	358	}
357	}	359	}
358		360
359	/* Final flags that will be set for the memory area */	361	/* Final flags that will be set for the memory area */
360		362
361	if (entry->p_flags & PF_X)	363	if (entry->p_flags & PF_X)
362	flags \|= AS_AREA_EXEC;	364	flags \|= AS_AREA_EXEC;
363	if (entry->p_flags & PF_W)	365	if (entry->p_flags & PF_W)
364	flags \|= AS_AREA_WRITE;	366	flags \|= AS_AREA_WRITE;
365	if (entry->p_flags & PF_R)	367	if (entry->p_flags & PF_R)
366	flags \|= AS_AREA_READ;	368	flags \|= AS_AREA_READ;
367	flags \|= AS_AREA_CACHEABLE;	369	flags \|= AS_AREA_CACHEABLE;
368		370
369	base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);	371	base = ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE);
370	mem_sz = entry->p_memsz + (entry->p_vaddr - base);	372	mem_sz = entry->p_memsz + (entry->p_vaddr - base);
371		373
372	// printf("map to p_vaddr=0x%x-0x%x...\n", entry->p_vaddr + bias,	374	// printf("map to p_vaddr=0x%x-0x%x...\n", entry->p_vaddr + bias,
373	// entry->p_vaddr + bias + ALIGN_UP(entry->p_memsz, PAGE_SIZE));	375	// entry->p_vaddr + bias + ALIGN_UP(entry->p_memsz, PAGE_SIZE));
374		376
375	/*	377	/*
376	* For the course of loading, the area needs to be readable	378	* For the course of loading, the area needs to be readable
377	* and writeable.	379	* and writeable.
378	*/	380	*/
379	a = as_area_create((uint8_t *)base + bias, mem_sz,	381	a = as_area_create((uint8_t *)base + bias, mem_sz,
380	AS_AREA_READ \| AS_AREA_WRITE \| AS_AREA_CACHEABLE);	382	AS_AREA_READ \| AS_AREA_WRITE \| AS_AREA_CACHEABLE);
381	if (a == (void *)(-1)) {	383	if (a == (void *)(-1)) {
382	printf("memory mapping failed\n");	384	printf("memory mapping failed\n");
383	return EE_MEMORY;	385	return EE_MEMORY;
384	}	386	}
385		387
386	// printf("as_area_create(0x%lx, 0x%x, %d) -> 0x%lx\n",	388	// printf("as_area_create(0x%lx, 0x%x, %d) -> 0x%lx\n",
387	// entry->p_vaddr+bias, entry->p_memsz, flags, (uintptr_t)a);	389	// entry->p_vaddr+bias, entry->p_memsz, flags, (uintptr_t)a);
388		390
389	/*	391	/*
390	* Load segment data	392	* Load segment data
391	*/	393	*/
392	// printf("seek to %d\n", entry->p_offset);	394	// printf("seek to %d\n", entry->p_offset);
393	rc = lseek(elf->fd, entry->p_offset, SEEK_SET);	395	rc = lseek(elf->fd, entry->p_offset, SEEK_SET);
394	if (rc < 0) {	396	if (rc < 0) {
395	printf("seek error\n");	397	printf("seek error\n");
396	return EE_INVALID;	398	return EE_INVALID;
397	}	399	}
398		400
399	// printf("read 0x%x bytes to address 0x%x\n", entry->p_filesz, entry->p_vaddr+bias);	401	// printf("read 0x%x bytes to address 0x%x\n", entry->p_filesz, entry->p_vaddr+bias);
400	/* rc = read(fd, (void *)(entry->p_vaddr + bias), entry->p_filesz);	402	/* rc = read(fd, (void *)(entry->p_vaddr + bias), entry->p_filesz);
401	if (rc < 0) { printf("read error\n"); return EE_INVALID; }*/	403	if (rc < 0) { printf("read error\n"); return EE_INVALID; }*/
402		404
403	/* Long reads are not possible yet. Load segment picewise */	405	/* Long reads are not possible yet. Load segment picewise */
404		406
405	unsigned left, now;	407	unsigned left, now;
406	uint8_t *dp;	408	uint8_t *dp;
407		409
408	left = entry->p_filesz;	410	left = entry->p_filesz;
409	dp = (uint8_t *)(entry->p_vaddr + bias);	411	dp = (uint8_t *)(entry->p_vaddr + bias);
410		412
411	while (left > 0) {	413	while (left > 0) {
412	now = 16384;	414	now = 16384;
413	if (now > left) now = left;	415	if (now > left) now = left;
414		416
415	// printf("read %d...", now);	417	// printf("read %d...", now);
416	rc = my_read(elf->fd, dp, now);	418	rc = my_read(elf->fd, dp, now);
417	// printf("->%d\n", rc);	419	// printf("->%d\n", rc);
418		420
419	if (rc < 0) {	421	if (rc < 0) {
420	printf("read error\n");	422	printf("read error\n");
421	return EE_INVALID;	423	return EE_INVALID;
422	}	424	}
423		425
424	left -= now;	426	left -= now;
425	dp += now;	427	dp += now;
426	}	428	}
427		429
-		430	/*
-		431	* The caller wants to modify the segments first. He will then
-		432	* need to set the right access mode and ensure SMC coherence.
-		433	*/
-		434	if ((elf->flags & ELDF_RW) != 0) return EE_OK;
-		435
428	// printf("set area flags to %d\n", flags);	436	printf("set area flags to %d\n", flags);
429	rc = as_area_change_flags((uint8_t *)entry->p_vaddr + bias, flags);	437	rc = as_area_change_flags((uint8_t *)entry->p_vaddr + bias, flags);
430	if (rc != 0) {	438	if (rc != 0) {
431	printf("failed to set memory area flags\n");	439	printf("failed to set memory area flags\n");
432	return EE_MEMORY;	440	return EE_MEMORY;
433	}	441	}
434		442
435	if (flags & AS_AREA_EXEC) {	443	if (flags & AS_AREA_EXEC) {
436	/* Enforce SMC coherence for the segment */	444	/* Enforce SMC coherence for the segment */
437	if (smc_coherence(entry->p_vaddr + bias, entry->p_filesz))	445	if (smc_coherence(entry->p_vaddr + bias, entry->p_filesz))
438	return EE_MEMORY;	446	return EE_MEMORY;
439	}	447	}
440		448
441	return EE_OK;	449	return EE_OK;
442	}	450	}
443		451
444	/** Process section header.	452	/** Process section header.
445	*	453	*
446	* @param elf Loader state.	454	* @param elf Loader state.
447	* @param entry Segment header.	455	* @param entry Segment header.
448	*	456	*
449	* @return EE_OK on success, error code otherwise.	457	* @return EE_OK on success, error code otherwise.
450	*/	458	*/
451	static int section_header(elf_ld_t elf, elf_section_header_t entry)	459	static int section_header(elf_ld_t elf, elf_section_header_t entry)
452	{	460	{
453	switch (entry->sh_type) {	461	switch (entry->sh_type) {
454	case SHT_PROGBITS:	462	case SHT_PROGBITS:
455	if (entry->sh_flags & SHF_TLS) {	463	if (entry->sh_flags & SHF_TLS) {
456	/* .tdata */	464	/* .tdata */
457	}	465	}
458	break;	466	break;
459	case SHT_NOBITS:	467	case SHT_NOBITS:
460	if (entry->sh_flags & SHF_TLS) {	468	if (entry->sh_flags & SHF_TLS) {
461	/* .tbss */	469	/* .tbss */
462	}	470	}
463	break;	471	break;
464	case SHT_DYNAMIC:	472	case SHT_DYNAMIC:
465	/* Record pointer to dynamic section into info structure */	473	/* Record pointer to dynamic section into info structure */
466	elf->info->dynamic =	474	elf->info->dynamic =
467	(void )((uint8_t )entry->sh_addr + elf->bias);	475	(void )((uint8_t )entry->sh_addr + elf->bias);
468	printf("dynamic section found at 0x%x\n",	476	printf("dynamic section found at 0x%x\n",
469	(uintptr_t)elf->info->dynamic);	477	(uintptr_t)elf->info->dynamic);
470	break;	478	break;
471	default:	479	default:
472	break;	480	break;
473	}	481	}
474		482
475	return EE_OK;	483	return EE_OK;
476	}	484	}
477		485
478	/** @}	486	/** @}
479	*/	487	*/
480		488

Subversion Repositories HelenOS

(root)/branches/dynload/uspace/srv/loader/elf_load.c – Rev 3403 → 3552