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854 | bondari | 1 | /* |
2 | * Copyright (C) 2006 Sergey Bondari |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
910 | bondari | 29 | #include <elf.h> |
938 | jermar | 30 | #include <debug.h> |
31 | #include <arch/types.h> |
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32 | #include <typedefs.h> |
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33 | #include <mm/as.h> |
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34 | #include <mm/frame.h> |
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952 | jermar | 35 | #include <mm/slab.h> |
938 | jermar | 36 | #include <align.h> |
952 | jermar | 37 | #include <memstr.h> |
38 | #include <macros.h> |
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854 | bondari | 39 | |
938 | jermar | 40 | static char *error_codes[] = { |
41 | "no error", |
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42 | "invalid image", |
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43 | "address space error", |
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44 | "incompatible image", |
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45 | "unsupported image type", |
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46 | "irrecoverable error" |
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47 | }; |
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48 | |||
952 | jermar | 49 | static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as); |
50 | static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as); |
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51 | static int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as); |
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938 | jermar | 52 | |
53 | /** ELF loader |
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854 | bondari | 54 | * |
55 | * @param header Pointer to ELF header in memory |
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56 | * @param as Created and properly mapped address space |
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57 | * @return EE_OK on success |
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58 | */ |
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938 | jermar | 59 | int elf_load(elf_header_t *header, as_t * as) |
60 | { |
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61 | int i, rc; |
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910 | bondari | 62 | |
63 | /* Identify ELF */ |
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938 | jermar | 64 | if (header->e_ident[EI_MAG0] != ELFMAG0 || header->e_ident[EI_MAG1] != ELFMAG1 || |
65 | header->e_ident[EI_MAG2] != ELFMAG2 || header->e_ident[EI_MAG3] != ELFMAG3) { |
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910 | bondari | 66 | return EE_INVALID; |
67 | } |
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68 | |||
69 | /* Identify ELF compatibility */ |
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938 | jermar | 70 | if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || header->e_machine != ELF_MACHINE || |
71 | header->e_ident[EI_VERSION] != EV_CURRENT || header->e_version != EV_CURRENT || |
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72 | header->e_ident[EI_CLASS] != ELF_CLASS) { |
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73 | return EE_INCOMPATIBLE; |
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74 | } |
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75 | |||
952 | jermar | 76 | if (header->e_phentsize != sizeof(elf_segment_header_t)) |
938 | jermar | 77 | return EE_INCOMPATIBLE; |
78 | |||
952 | jermar | 79 | if (header->e_shentsize != sizeof(elf_section_header_t)) |
80 | return EE_INCOMPATIBLE; |
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81 | |||
938 | jermar | 82 | /* Check if the object type is supported. */ |
83 | if (header->e_type != ET_EXEC) |
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910 | bondari | 84 | return EE_UNSUPPORTED; |
938 | jermar | 85 | |
952 | jermar | 86 | /* Walk through all segment headers and process them. */ |
938 | jermar | 87 | for (i = 0; i < header->e_phnum; i++) { |
952 | jermar | 88 | rc = segment_header(&((elf_segment_header_t *)(((__u8 *) header) + header->e_phoff))[i], header, as); |
938 | jermar | 89 | if (rc != EE_OK) |
90 | return rc; |
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910 | bondari | 91 | } |
938 | jermar | 92 | |
952 | jermar | 93 | /* Inspect all section headers and proccess them. */ |
94 | for (i = 0; i < header->e_shnum; i++) { |
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95 | rc = section_header(&((elf_section_header_t *)(((__u8 *) header) + header->e_shoff))[i], header, as); |
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96 | if (rc != EE_OK) |
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97 | return rc; |
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98 | } |
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99 | |||
938 | jermar | 100 | return EE_OK; |
101 | } |
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102 | |||
103 | /** Print error message according to error code. |
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104 | * |
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105 | * @param rc Return code returned by elf_load(). |
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106 | * |
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107 | * @return NULL terminated description of error. |
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108 | */ |
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109 | char *elf_error(int rc) |
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110 | { |
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111 | ASSERT(rc < sizeof(error_codes)/sizeof(char *)); |
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112 | |||
113 | return error_codes[rc]; |
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114 | } |
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115 | |||
952 | jermar | 116 | /** Process segment header. |
938 | jermar | 117 | * |
952 | jermar | 118 | * @param entry Segment header. |
119 | * @param elf ELF header. |
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938 | jermar | 120 | * @param as Address space into wich the ELF is being loaded. |
121 | * |
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122 | * @return EE_OK on success, error code otherwise. |
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123 | */ |
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952 | jermar | 124 | static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as) |
938 | jermar | 125 | { |
126 | switch (entry->p_type) { |
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127 | case PT_NULL: |
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128 | case PT_PHDR: |
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129 | break; |
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130 | case PT_LOAD: |
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952 | jermar | 131 | return load_segment(entry, elf, as); |
938 | jermar | 132 | break; |
133 | case PT_DYNAMIC: |
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134 | case PT_INTERP: |
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135 | case PT_SHLIB: |
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136 | case PT_NOTE: |
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137 | case PT_LOPROC: |
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138 | case PT_HIPROC: |
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139 | default: |
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140 | return EE_UNSUPPORTED; |
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141 | break; |
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142 | } |
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143 | return EE_OK; |
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144 | } |
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145 | |||
146 | /** Load segment described by program header entry. |
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147 | * |
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148 | * @param entry Program header entry describing segment to be loaded. |
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952 | jermar | 149 | * @param elf ELF header. |
938 | jermar | 150 | * @parma as Address space into wich the ELF is being loaded. |
151 | * |
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152 | * @return EE_OK on success, error code otherwise. |
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153 | */ |
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952 | jermar | 154 | int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as) |
938 | jermar | 155 | { |
156 | as_area_t *a; |
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1026 | jermar | 157 | int i, flags = 0; |
952 | jermar | 158 | size_t segment_size; |
159 | __u8 *segment; |
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938 | jermar | 160 | |
161 | if (entry->p_align > 1) { |
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162 | if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) { |
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163 | return EE_INVALID; |
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164 | } |
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165 | } |
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166 | |||
1026 | jermar | 167 | if (entry->p_flags & PF_X) |
168 | flags |= AS_AREA_EXEC; |
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169 | if (entry->p_flags & PF_W) |
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170 | flags |= AS_AREA_WRITE; |
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171 | if (entry->p_flags & PF_R) |
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172 | flags |= AS_AREA_READ; |
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910 | bondari | 173 | |
952 | jermar | 174 | /* |
175 | * Check if the virtual address starts on page boundary. |
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176 | */ |
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177 | if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr) |
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178 | return EE_UNSUPPORTED; |
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179 | |||
180 | segment_size = ALIGN_UP(max(entry->p_filesz, entry->p_memsz), PAGE_SIZE); |
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973 | palkovsky | 181 | if ((entry->p_flags & PF_W)) { |
182 | /* If writable, copy data (should be COW in the future) */ |
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183 | segment = malloc(segment_size, 0); |
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952 | jermar | 184 | memsetb((__address) (segment + entry->p_filesz), segment_size - entry->p_filesz, 0); |
973 | palkovsky | 185 | memcpy(segment, (void *) (((__address) elf) + entry->p_offset), entry->p_filesz); |
186 | } else /* Map identically original data */ |
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187 | segment = ((void *) elf) + entry->p_offset; |
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952 | jermar | 188 | |
1239 | jermar | 189 | a = as_area_create(as, flags, entry->p_memsz, entry->p_vaddr, AS_AREA_ATTR_NONE); |
938 | jermar | 190 | if (!a) |
1070 | jermar | 191 | return EE_MEMORY; |
938 | jermar | 192 | |
193 | for (i = 0; i < SIZE2FRAMES(entry->p_filesz); i++) { |
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952 | jermar | 194 | as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) segment) + i*PAGE_SIZE)); |
938 | jermar | 195 | } |
196 | |||
197 | return EE_OK; |
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854 | bondari | 198 | } |
952 | jermar | 199 | |
200 | /** Process section header. |
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201 | * |
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202 | * @param entry Segment header. |
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203 | * @param elf ELF header. |
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204 | * @param as Address space into wich the ELF is being loaded. |
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205 | * |
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206 | * @return EE_OK on success, error code otherwise. |
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207 | */ |
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208 | static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as) |
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209 | { |
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210 | switch (entry->sh_type) { |
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211 | default: |
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212 | break; |
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213 | } |
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214 | |||
215 | return EE_OK; |
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216 | } |