12 /* We load ELF binaries. The following definitions are taken
13 from the ELF specification more-or-less verbatim. */
16 typedef uint32_t Elf32_Word, Elf32_Addr, Elf32_Off;
17 typedef uint16_t Elf32_Half;
25 This appears at the very beginning of an ELF binary. */
28 unsigned char e_ident[16];
37 Elf32_Half e_phentsize;
39 Elf32_Half e_shentsize;
41 Elf32_Half e_shstrndx;
45 There are e_phnum of these, starting at file offset e_phoff. */
58 /* Values for p_type. */
59 #define PT_NULL 0 /* Ignore. */
60 #define PT_LOAD 1 /* Loadable segment. */
61 #define PT_DYNAMIC 2 /* Dynamic linking info. */
62 #define PT_INTERP 3 /* Name of dynamic loader. */
63 #define PT_NOTE 4 /* Auxiliary info. */
64 #define PT_SHLIB 5 /* Reserved. */
65 #define PT_PHDR 6 /* Program header table. */
66 #define PT_STACK 0x6474e551 /* Stack segment. */
68 /* Flags for p_flags. */
69 #define PF_X 1 /* Executable. */
70 #define PF_W 2 /* Writable. */
71 #define PF_R 4 /* Readable. */
73 #define LOAD_ERROR(MSG) \
75 printk ("addrspace_load: %s: ", filename); \
82 load_segment (struct addrspace *as, struct file *file,
83 const struct Elf32_Phdr *phdr)
90 ASSERT (file != NULL);
91 ASSERT (phdr != NULL);
92 ASSERT (phdr->p_type == PT_LOAD);
94 /* p_offset and p_vaddr must be congruent modulo NBPG. */
95 if (phdr->p_offset % NBPG != phdr->p_vaddr % NBPG)
97 printk ("%#08"PE32Ox" and %#08"PE32Ax" not congruent modulo %#x\n",
98 phdr->p_offset, phdr->p_vaddr, (unsigned) NBPG);
102 /* p_memsz must be at least as big as p_filesz. */
103 if (phdr->p_memsz < phdr->p_filesz)
105 printk ("p_memsz (%08"PE32Wx") < p_filesz (%08"PE32Wx")\n",
106 phdr->p_memsz, phdr->p_filesz);
110 /* Validate virtual memory region to be mapped. */
111 start = PGROUNDDOWN (phdr->p_vaddr);
112 end = PGROUNDUP (phdr->p_vaddr + phdr->p_memsz);
113 if (start >= PHYS_BASE || end >= PHYS_BASE || end < start)
115 printk ("bad virtual region %08lx...%08lx\n",
116 (unsigned long) start, (unsigned long) end);
120 filesz_left = phdr->p_filesz + (phdr->p_vaddr - start);
121 file_seek (file, ROUND_DOWN (phdr->p_offset, NBPG));
122 for (upage = (uint8_t *) start; upage < (uint8_t *) end; upage += NBPG)
124 size_t read_bytes = filesz_left >= NBPG ? NBPG : filesz_left;
125 size_t zero_bytes = NBPG - read_bytes;
126 uint8_t *kpage = palloc_get (0);
130 if (file_read (file, kpage, read_bytes) != (int) read_bytes)
132 memset (kpage + read_bytes, 0, zero_bytes);
133 filesz_left -= read_bytes;
135 if (pagedir_get_page (as->pagedir, upage))
140 pagedir_set_page (as->pagedir, upage, kpage, true);
147 addrspace_load (struct addrspace *as, const char *filename)
149 struct Elf32_Ehdr ehdr;
150 struct file *file = NULL;
152 bool success = false;
155 as->pagedir = pagedir_create ();
157 file = filesys_open (filename);
159 LOAD_ERROR (("open failed"));
161 /* Read and verify executable header. */
162 if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr)
163 LOAD_ERROR (("error reading executable header"));
164 if (memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7) != 0)
165 LOAD_ERROR (("file is not ELF"));
166 if (ehdr.e_type != 2)
167 LOAD_ERROR (("ELF file is not an executable"));
168 if (ehdr.e_machine != 3)
169 LOAD_ERROR (("ELF executable is not x86"));
170 if (ehdr.e_version != 1)
171 LOAD_ERROR (("ELF executable hasunknown version %d",
172 (int) ehdr.e_version));
173 if (ehdr.e_phentsize != sizeof (struct Elf32_Phdr))
174 LOAD_ERROR (("bad ELF program header size"));
175 if (ehdr.e_phnum > 1024)
176 LOAD_ERROR (("too many ELF program headers"));
178 /* Read program headers. */
179 file_ofs = ehdr.e_phoff;
180 printk ("e_phnum=%d\n", ehdr.e_phnum);
181 for (i = 0; i < ehdr.e_phnum; i++)
183 struct Elf32_Phdr phdr;
185 file_seek (file, file_ofs);
186 if (file_read (file, &phdr, sizeof phdr) != sizeof phdr)
187 LOAD_ERROR (("error reading program header"));
188 printk ("%x: %08x, %08x %08x %08x %05x %05x\n",
191 phdr.p_offset, phdr.p_vaddr, phdr.p_paddr,
192 phdr.p_filesz, phdr.p_memsz);
193 file_ofs += sizeof phdr;
199 case PT_STACK: /* Stack segment. */
200 /* Ignore this segment. */
205 /* Reject the executable. */
206 LOAD_ERROR (("unsupported ELF segment type %d\n", phdr.p_type));
209 printk ("unknown ELF segment type %08x\n", phdr.p_type);
212 if (!load_segment (as, file, &phdr))
223 addrspace_destroy (as);
228 addrspace_destroy (struct addrspace *as)
230 if (as != NULL && as->pagedir != NULL)
231 pagedir_destroy (as->pagedir);