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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 | /* * linux/fs/proc/mem.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <linux/types.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/proc_fs.h> #include <asm/page.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/pgtable.h> /* * mem_write isn't really a good idea right now. It needs * to check a lot more: if the process we try to write to * dies in the middle right now, mem_write will overwrite * kernel memory.. This disables it altogether. */ #define mem_write NULL static int check_range(struct mm_struct * mm, unsigned long addr, int count) { struct vm_area_struct *vma; int retval; vma = find_vma(mm, addr); if (!vma) return -EACCES; if (vma->vm_start > addr) return -EACCES; if (!(vma->vm_flags & VM_READ)) return -EACCES; while ((retval = vma->vm_end - addr) < count) { struct vm_area_struct *next = vma->vm_next; if (!next) break; if (vma->vm_end != next->vm_start) break; if (!(next->vm_flags & VM_READ)) break; vma = next; } if (retval > count) retval = count; return retval; } static struct task_struct * get_task(int pid) { struct task_struct * tsk = current; if (pid != tsk->pid) { tsk = find_task_by_pid(pid); /* Allow accesses only under the same circumstances * that we would allow ptrace to work. */ if (tsk) { if (!(tsk->flags & PF_PTRACED) || tsk->state != TASK_STOPPED || tsk->p_pptr != current) tsk = NULL; } } return tsk; } static ssize_t mem_read(struct file * file, char * buf, size_t count, loff_t *ppos) { struct inode * inode = file->f_dentry->d_inode; pgd_t *page_dir; pmd_t *page_middle; pte_t pte; char * page; struct task_struct * tsk; unsigned long addr; char *tmp; ssize_t scount, i; read_lock(&tasklist_lock); tsk = get_task(inode->i_ino >> 16); read_unlock(&tasklist_lock); /* FIXME: This should really be done only afetr not using tsk any more!!! */ if (!tsk) return -ESRCH; addr = *ppos; scount = check_range(tsk->mm, addr, count); if (scount < 0) return scount; tmp = buf; while (scount > 0) { if (signal_pending(current)) break; page_dir = pgd_offset(tsk->mm,addr); if (pgd_none(*page_dir)) break; if (pgd_bad(*page_dir)) { printk("Bad page dir entry %08lx\n", pgd_val(*page_dir)); pgd_clear(page_dir); break; } page_middle = pmd_offset(page_dir,addr); if (pmd_none(*page_middle)) break; if (pmd_bad(*page_middle)) { printk("Bad page middle entry %08lx\n", pmd_val(*page_middle)); pmd_clear(page_middle); break; } pte = *pte_offset(page_middle,addr); if (!pte_present(pte)) break; page = (char *) pte_page(pte) + (addr & ~PAGE_MASK); i = PAGE_SIZE-(addr & ~PAGE_MASK); if (i > scount) i = scount; copy_to_user(tmp, page, i); addr += i; tmp += i; scount -= i; } *ppos = addr; return tmp-buf; } #ifndef mem_write static ssize_t mem_write(struct file * file, char * buf, size_t count, loff_t *ppos) { struct inode * inode = file->f_dentry->d_inode; pgd_t *page_dir; pmd_t *page_middle; pte_t pte; char * page; struct task_struct * tsk; unsigned long addr; char *tmp; long i; addr = *ppos; tsk = get_task(inode->i_ino >> 16); if (!tsk) return -ESRCH; tmp = buf; while (count > 0) { if (signal_pending(current)) break; page_dir = pgd_offset(tsk,addr); if (pgd_none(*page_dir)) break; if (pgd_bad(*page_dir)) { printk("Bad page dir entry %08lx\n", pgd_val(*page_dir)); pgd_clear(page_dir); break; } page_middle = pmd_offset(page_dir,addr); if (pmd_none(*page_middle)) break; if (pmd_bad(*page_middle)) { printk("Bad page middle entry %08lx\n", pmd_val(*page_middle)); pmd_clear(page_middle); break; } pte = *pte_offset(page_middle,addr); if (!pte_present(pte)) break; if (!pte_write(pte)) break; page = (char *) pte_page(pte) + (addr & ~PAGE_MASK); i = PAGE_SIZE-(addr & ~PAGE_MASK); if (i > count) i = count; copy_from_user(page, tmp, i); addr += i; tmp += i; count -= i; } *ppos = addr; if (tmp != buf) return tmp-buf; if (signal_pending(current)) return -ERESTARTSYS; return 0; } #endif static long long mem_lseek(struct file * file, long long offset, int orig) { switch (orig) { case 0: file->f_pos = offset; return file->f_pos; case 1: file->f_pos += offset; return file->f_pos; default: return -EINVAL; } } /* * This isn't really reliable by any means.. */ int mem_mmap(struct file * file, struct vm_area_struct * vma) { struct task_struct *tsk; pgd_t *src_dir, *dest_dir; pmd_t *src_middle, *dest_middle; pte_t *src_table, *dest_table; unsigned long stmp, dtmp, mapnr; struct vm_area_struct *src_vma = NULL; struct inode *inode = file->f_dentry->d_inode; /* Get the source's task information */ tsk = get_task(inode->i_ino >> 16); if (!tsk) return -ESRCH; /* Ensure that we have a valid source area. (Has to be mmap'ed and have valid page information.) We can't map shared memory at the moment because working out the vm_area_struct & nattach stuff isn't worth it. */ src_vma = tsk->mm->mmap; stmp = vma->vm_offset; while (stmp < vma->vm_offset + (vma->vm_end - vma->vm_start)) { while (src_vma && stmp > src_vma->vm_end) src_vma = src_vma->vm_next; if (!src_vma || (src_vma->vm_flags & VM_SHM)) return -EINVAL; src_dir = pgd_offset(tsk->mm, stmp); if (pgd_none(*src_dir)) return -EINVAL; if (pgd_bad(*src_dir)) { printk("Bad source page dir entry %08lx\n", pgd_val(*src_dir)); return -EINVAL; } src_middle = pmd_offset(src_dir, stmp); if (pmd_none(*src_middle)) return -EINVAL; if (pmd_bad(*src_middle)) { printk("Bad source page middle entry %08lx\n", pmd_val(*src_middle)); return -EINVAL; } src_table = pte_offset(src_middle, stmp); if (pte_none(*src_table)) return -EINVAL; if (stmp < src_vma->vm_start) { if (!(src_vma->vm_flags & VM_GROWSDOWN)) return -EINVAL; if (src_vma->vm_end - stmp > current->rlim[RLIMIT_STACK].rlim_cur) return -EINVAL; } stmp += PAGE_SIZE; } src_vma = tsk->mm->mmap; stmp = vma->vm_offset; dtmp = vma->vm_start; flush_cache_range(vma->vm_mm, vma->vm_start, vma->vm_end); flush_cache_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end); while (dtmp < vma->vm_end) { while (src_vma && stmp > src_vma->vm_end) src_vma = src_vma->vm_next; src_dir = pgd_offset(tsk->mm, stmp); src_middle = pmd_offset(src_dir, stmp); src_table = pte_offset(src_middle, stmp); dest_dir = pgd_offset(current->mm, dtmp); dest_middle = pmd_alloc(dest_dir, dtmp); if (!dest_middle) return -ENOMEM; dest_table = pte_alloc(dest_middle, dtmp); if (!dest_table) return -ENOMEM; if (!pte_present(*src_table)) handle_mm_fault(tsk, src_vma, stmp, 1); if ((vma->vm_flags & VM_WRITE) && !pte_write(*src_table)) handle_mm_fault(tsk, src_vma, stmp, 1); set_pte(src_table, pte_mkdirty(*src_table)); set_pte(dest_table, *src_table); mapnr = MAP_NR(pte_page(*src_table)); if (mapnr < max_mapnr) get_page(mem_map + MAP_NR(pte_page(*src_table))); stmp += PAGE_SIZE; dtmp += PAGE_SIZE; } flush_tlb_range(vma->vm_mm, vma->vm_start, vma->vm_end); flush_tlb_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end); return 0; } static struct file_operations proc_mem_operations = { mem_lseek, mem_read, mem_write, NULL, /* mem_readdir */ NULL, /* mem_poll */ NULL, /* mem_ioctl */ mem_mmap, /* mmap */ NULL, /* no special open code */ NULL, /* flush */ NULL, /* no special release code */ NULL /* can't fsync */ }; struct inode_operations proc_mem_inode_operations = { &proc_mem_operations, /* default base directory file-ops */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ NULL, /* get_block */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* flushpage */ NULL, /* truncate */ proc_permission, /* permission */ NULL, /* smap */ NULL /* revalidate */ }; |