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2928 | svoboda | 1 | /* |
2 | * Copyright (c) 2006 Sergey Bondari |
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3 | * Copyright (c) 2006 Jakub Jermar |
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4 | * Copyright (c) 2008 Jiri Svoboda |
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5 | * All rights reserved. |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions |
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9 | * are met: |
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10 | * |
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11 | * - Redistributions of source code must retain the above copyright |
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12 | * notice, this list of conditions and the following disclaimer. |
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13 | * - Redistributions in binary form must reproduce the above copyright |
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14 | * notice, this list of conditions and the following disclaimer in the |
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15 | * documentation and/or other materials provided with the distribution. |
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16 | * - The name of the author may not be used to endorse or promote products |
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17 | * derived from this software without specific prior written permission. |
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18 | * |
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19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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20 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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21 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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22 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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23 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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24 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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25 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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26 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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27 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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28 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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29 | */ |
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30 | |||
31 | /** @addtogroup generic |
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32 | * @{ |
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33 | */ |
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34 | |||
35 | /** |
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36 | * @file |
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37 | * @brief Kernel ELF loader. |
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38 | */ |
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39 | |||
40 | #include <stdio.h> |
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41 | #include <sys/types.h> |
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42 | #include <align.h> |
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43 | #include <assert.h> |
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44 | #include <as.h> |
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45 | #include "elf.h" |
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46 | |||
2932 | svoboda | 47 | #define RTLD_BIAS 0x80000 |
2928 | svoboda | 48 | |
49 | static char *error_codes[] = { |
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50 | "no error", |
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51 | "invalid image", |
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52 | "address space error", |
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53 | "incompatible image", |
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54 | "unsupported image type", |
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55 | "irrecoverable error" |
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56 | }; |
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57 | |||
58 | static int segment_header(int fd, elf_header_t *elf); |
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59 | static int section_header(elf_section_header_t *entry, elf_header_t *elf); |
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60 | static int load_segment(int fd, elf_segment_header_t *entry, elf_header_t *elf); |
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61 | |||
62 | typedef void (*epoint_t)(void); |
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63 | |||
64 | /** ELF loader |
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65 | * |
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66 | * @param header Pointer to ELF header in memory |
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67 | * @return EE_OK on success |
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68 | */ |
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69 | unsigned int elf_load(int fd, elf_header_t *header) |
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70 | { |
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71 | int i, rc; |
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72 | |||
73 | rc = read(fd, header, sizeof(elf_header_t)); |
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74 | if (rc < 0) { |
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75 | printf("read error\n"); |
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76 | return EE_INVALID; |
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77 | } |
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78 | |||
79 | printf("ELF-load:"); |
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80 | /* Identify ELF */ |
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81 | if (header->e_ident[EI_MAG0] != ELFMAG0 || |
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82 | header->e_ident[EI_MAG1] != ELFMAG1 || |
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83 | header->e_ident[EI_MAG2] != ELFMAG2 || |
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84 | header->e_ident[EI_MAG3] != ELFMAG3) { |
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85 | printf("invalid header\n"); |
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86 | return EE_INVALID; |
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87 | } |
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88 | |||
89 | /* Identify ELF compatibility */ |
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90 | if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || |
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91 | header->e_machine != ELF_MACHINE || |
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92 | header->e_ident[EI_VERSION] != EV_CURRENT || |
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93 | header->e_version != EV_CURRENT || |
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94 | header->e_ident[EI_CLASS] != ELF_CLASS) { |
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95 | printf("incompatible data/version/class\n"); |
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96 | return EE_INCOMPATIBLE; |
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97 | } |
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98 | |||
99 | if (header->e_phentsize != sizeof(elf_segment_header_t)) |
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100 | return EE_INCOMPATIBLE; |
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101 | |||
102 | if (header->e_shentsize != sizeof(elf_section_header_t)) |
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103 | return EE_INCOMPATIBLE; |
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104 | |||
105 | /* Check if the object type is supported. */ |
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106 | if (header->e_type != ET_EXEC && header->e_type != ET_DYN) { |
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107 | printf("Object type %d is not supported\n", header->e_type); |
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108 | return EE_UNSUPPORTED; |
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109 | } |
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2932 | svoboda | 110 | if (header->e_type == ET_DYN) header->e_entry += RTLD_BIAS; |
2928 | svoboda | 111 | |
112 | printf("parse segments\n"); |
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113 | |||
114 | /* Walk through all segment headers and process them. */ |
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115 | for (i = 0; i < header->e_phnum; i++) { |
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116 | |||
117 | /* Seek to start of header */ |
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118 | lseek(fd, header->e_phoff + i * sizeof(elf_segment_header_t), SEEK_SET); |
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119 | |||
120 | rc = segment_header(fd, header); |
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121 | if (rc != EE_OK) |
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122 | return rc; |
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123 | } |
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124 | |||
125 | printf("parse sections\n"); |
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126 | |||
127 | /* Inspect all section headers and proccess them. */ |
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128 | for (i = 0; i < header->e_shnum; i++) { |
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129 | /* elf_section_header_t *sechdr; |
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130 | |||
131 | sechdr = &((elf_section_header_t *)(((uint8_t *) header) + |
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132 | header->e_shoff))[i]; |
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133 | rc = section_header(sechdr, header); |
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134 | if (rc != EE_OK) |
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135 | return rc;*/ |
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136 | } |
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137 | |||
138 | printf("done\n"); |
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139 | |||
140 | return EE_OK; |
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141 | } |
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142 | |||
143 | /** Print error message according to error code. |
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144 | * |
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145 | * @param rc Return code returned by elf_load(). |
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146 | * |
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147 | * @return NULL terminated description of error. |
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148 | */ |
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149 | char *elf_error(unsigned int rc) |
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150 | { |
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151 | assert(rc < sizeof(error_codes) / sizeof(char *)); |
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152 | |||
153 | return error_codes[rc]; |
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154 | } |
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155 | |||
156 | /** Process segment header. |
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157 | * |
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158 | * @param entry Segment header. |
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159 | * @param elf ELF header. |
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160 | * |
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161 | * @return EE_OK on success, error code otherwise. |
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162 | */ |
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163 | static int segment_header(int fd, elf_header_t *elf) |
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164 | { |
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165 | static elf_segment_header_t entry_buf; |
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166 | elf_segment_header_t *entry = &entry_buf; |
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167 | int rc; |
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168 | |||
169 | rc = read(fd, entry, sizeof(elf_segment_header_t)); |
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170 | if (rc < 0) { printf("read error\n"); return EE_INVALID; } |
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171 | |||
172 | switch (entry->p_type) { |
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173 | case PT_NULL: |
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174 | case PT_PHDR: |
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175 | break; |
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176 | case PT_LOAD: |
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177 | return load_segment(fd, entry, elf); |
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178 | break; |
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179 | case PT_DYNAMIC: |
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180 | case PT_INTERP: |
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181 | case PT_SHLIB: |
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182 | case PT_NOTE: |
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183 | case PT_LOPROC: |
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184 | case PT_HIPROC: |
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185 | default: |
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186 | printf("segment p_type %d unknown\n", entry->p_type); |
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187 | return EE_UNSUPPORTED; |
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188 | break; |
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189 | } |
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190 | return EE_OK; |
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191 | } |
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192 | |||
193 | /** Load segment described by program header entry. |
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194 | * |
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195 | * @param entry Program header entry describing segment to be loaded. |
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196 | * @param elf ELF header. |
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197 | * |
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198 | * @return EE_OK on success, error code otherwise. |
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199 | */ |
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200 | int load_segment(int fd, elf_segment_header_t *entry, elf_header_t *elf) |
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201 | { |
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202 | void *a; |
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203 | int flags = 0; |
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2932 | svoboda | 204 | uintptr_t bias; |
2928 | svoboda | 205 | int rc; |
206 | |||
207 | printf("load segment at addr 0x%x, size 0x%x\n", entry->p_vaddr, |
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208 | entry->p_memsz); |
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209 | |||
2932 | svoboda | 210 | bias = (elf->e_type == ET_DYN) ? RTLD_BIAS : 0; |
2928 | svoboda | 211 | |
212 | if (entry->p_align > 1) { |
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213 | if ((entry->p_offset % entry->p_align) != |
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214 | (entry->p_vaddr % entry->p_align)) { |
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215 | printf("align check 1 failed offset%%align=%d, vaddr%%align=%d\n", |
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216 | entry->p_offset % entry->p_align, |
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217 | entry->p_vaddr % entry->p_align |
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218 | ); |
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219 | return EE_INVALID; |
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220 | } |
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221 | } |
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222 | |||
223 | /* if (entry->p_flags & PF_X) |
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224 | flags |= AS_AREA_EXEC; |
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225 | if (entry->p_flags & PF_W) |
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226 | flags |= AS_AREA_WRITE; |
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227 | if (entry->p_flags & PF_R) |
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228 | flags |= AS_AREA_READ; |
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229 | flags |= AS_AREA_CACHEABLE; |
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230 | */ |
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231 | /* FIXME: Kernel won't normally allow this, unless you "patch" it */ |
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232 | flags = AS_AREA_READ | AS_AREA_WRITE | AS_AREA_EXEC | AS_AREA_CACHEABLE; |
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233 | |||
234 | /* |
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235 | * Check if the virtual address starts on page boundary. |
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236 | */ |
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237 | if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr) { |
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238 | printf("align check 2 failed - not page-aligned\n"); |
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239 | printf("vaddr = 0x%x, should be 0x%x\n", |
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240 | entry->p_vaddr, ALIGN_UP(entry->p_vaddr, PAGE_SIZE)); |
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241 | return EE_UNSUPPORTED; |
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242 | } |
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243 | |||
2932 | svoboda | 244 | printf("map to p_vaddr=0x%x-0x%x...\n", entry->p_vaddr + bias, |
245 | entry->p_vaddr + bias + ALIGN_UP(entry->p_memsz, PAGE_SIZE)); |
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2928 | svoboda | 246 | |
2932 | svoboda | 247 | a = as_area_create((uint8_t *)entry->p_vaddr + bias, |
2928 | svoboda | 248 | entry->p_memsz, flags); |
249 | if (a == (void *)(-1)) { |
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250 | printf("memory mapping failed\n"); |
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251 | return EE_MEMORY; |
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252 | } |
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253 | |||
254 | printf("as_area_create() -> 0x%x\n", (unsigned)a); |
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255 | |||
256 | /* |
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257 | * Load segment data |
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258 | */ |
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259 | rc = lseek(fd, entry->p_offset, SEEK_SET); |
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260 | if (rc < 0) { printf("seek error\n"); return EE_INVALID; } |
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261 | |||
2932 | svoboda | 262 | rc = read(fd, (void *)(entry->p_vaddr + bias), entry->p_filesz); |
2928 | svoboda | 263 | if (rc < 0) { printf("read error\n"); return EE_INVALID; } |
264 | |||
265 | return EE_OK; |
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266 | } |
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267 | |||
268 | /** Process section header. |
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269 | * |
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270 | * @param entry Segment header. |
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271 | * @param elf ELF header. |
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272 | * |
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273 | * @return EE_OK on success, error code otherwise. |
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274 | */ |
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275 | static int section_header(elf_section_header_t *entry, elf_header_t *elf) |
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276 | { |
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277 | switch (entry->sh_type) { |
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278 | case SHT_PROGBITS: |
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279 | if (entry->sh_flags & SHF_TLS) { |
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280 | /* .tdata */ |
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281 | } |
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282 | break; |
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283 | case SHT_NOBITS: |
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284 | if (entry->sh_flags & SHF_TLS) { |
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285 | /* .tbss */ |
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286 | } |
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287 | break; |
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288 | default: |
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289 | break; |
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290 | } |
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291 | |||
292 | return EE_OK; |
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293 | } |
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294 | |||
295 | /** @} |
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296 | */ |