/* * linux/fs/proc/mem.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include #include #include #include #include #include #include #include #include /* * 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 mem_read(struct inode * inode, struct file * file,char * buf, int count) { pgd_t *page_dir; pmd_t *page_middle; pte_t pte; char * page; struct task_struct * tsk; unsigned long addr, pid; char *tmp; int i; if (count < 0) return -EINVAL; pid = inode->i_ino; pid >>= 16; tsk = NULL; for (i = 1 ; i < NR_TASKS ; i++) if (task[i] && task[i]->pid == pid) { tsk = task[i]; break; } if (!tsk) return -EACCES; addr = file->f_pos; tmp = buf; while (count > 0) { if (current->signal & ~current->blocked) 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; page = (char *) pte_page(pte) + (addr & ~PAGE_MASK); i = PAGE_SIZE-(addr & ~PAGE_MASK); if (i > count) i = count; memcpy_tofs(tmp, page, i); addr += i; tmp += i; count -= i; } file->f_pos = addr; return tmp-buf; } #ifndef mem_write static int mem_write(struct inode * inode, struct file * file,char * buf, int count) { pgd_t *page_dir; pmd_t *page_middle; pte_t pte; char * page; struct task_struct * tsk; unsigned long addr, pid; char *tmp; int i; if (count < 0) return -EINVAL; addr = file->f_pos; pid = inode->i_ino; pid >>= 16; tsk = NULL; for (i = 1 ; i < NR_TASKS ; i++) if (task[i] && task[i]->pid == pid) { tsk = task[i]; break; } if (!tsk) return -EACCES; tmp = buf; while (count > 0) { if (current->signal & ~current->blocked) 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; memcpy_fromfs(page, tmp, i); addr += i; tmp += i; count -= i; } file->f_pos = addr; if (tmp != buf) return tmp-buf; if (current->signal & ~current->blocked) return -ERESTARTSYS; return 0; } #endif static int mem_lseek(struct inode * inode, struct file * file, off_t 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 inode * inode, 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; struct vm_area_struct *src_vma = NULL; int i; /* Get the source's task information */ tsk = NULL; for (i = 1 ; i < NR_TASKS ; i++) if (task[i] && task[i]->pid == (inode->i_ino >> 16)) { tsk = task[i]; break; } if (!tsk) return -EACCES; /* 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, 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; while (dtmp < vma->vm_end) { while (src_vma && stmp > src_vma->vm_end) src_vma = src_vma->vm_next; src_dir = pgd_offset(tsk, stmp); src_middle = pmd_offset(src_dir, stmp); src_table = pte_offset(src_middle, stmp); dest_dir = pgd_offset(current, 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)) do_no_page(src_vma, stmp, 1); if ((vma->vm_flags & VM_WRITE) && !pte_write(*src_table)) do_wp_page(src_vma, stmp, 1); *src_table = pte_mkdirty(*src_table); *dest_table = *src_table; mem_map[MAP_NR(pte_page(*src_table))]++; stmp += PAGE_SIZE; dtmp += PAGE_SIZE; } invalidate(); return 0; } static struct file_operations proc_mem_operations = { mem_lseek, mem_read, mem_write, NULL, /* mem_readdir */ NULL, /* mem_select */ NULL, /* mem_ioctl */ mem_mmap, /* mmap */ NULL, /* no special open code */ 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, /* bmap */ NULL, /* truncate */ NULL /* permission */ };