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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 | /* * linux/kernel/ptrace.c * * (C) Copyright 1999 Linus Torvalds * * Common interfaces for "ptrace()" which we do not want * to continually duplicate across every architecture. */ #include <linux/sched.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/smp_lock.h> #include <asm/pgtable.h> #include <asm/uaccess.h> /* * Access another process' address space, one page at a time. */ static int access_one_page(struct mm_struct * mm, struct vm_area_struct * vma, unsigned long addr, void *buf, int len, int write) { pgd_t * pgdir; pmd_t * pgmiddle; pte_t * pgtable; char *maddr; struct page *page; repeat: spin_lock(&mm->page_table_lock); pgdir = pgd_offset(vma->vm_mm, addr); if (pgd_none(*pgdir)) goto fault_in_page; if (pgd_bad(*pgdir)) goto bad_pgd; pgmiddle = pmd_offset(pgdir, addr); if (pmd_none(*pgmiddle)) goto fault_in_page; if (pmd_bad(*pgmiddle)) goto bad_pmd; pgtable = pte_offset(pgmiddle, addr); if (!pte_present(*pgtable)) goto fault_in_page; if (write && (!pte_write(*pgtable) || !pte_dirty(*pgtable))) goto fault_in_page; page = pte_page(*pgtable); /* ZERO_PAGE is special: reads from it are ok even though it's marked reserved */ if (page != ZERO_PAGE(addr) || write) { if ((!VALID_PAGE(page)) || PageReserved(page)) { spin_unlock(&mm->page_table_lock); return 0; } } get_page(page); spin_unlock(&mm->page_table_lock); flush_cache_page(vma, addr); if (write) { maddr = kmap(page); memcpy(maddr + (addr & ~PAGE_MASK), buf, len); flush_page_to_ram(page); flush_icache_page(vma, page); kunmap(page); } else { maddr = kmap(page); memcpy(buf, maddr + (addr & ~PAGE_MASK), len); flush_page_to_ram(page); kunmap(page); } put_page(page); return len; fault_in_page: spin_unlock(&mm->page_table_lock); /* -1: out of memory. 0 - unmapped page */ if (handle_mm_fault(mm, vma, addr, write) > 0) goto repeat; return 0; bad_pgd: spin_unlock(&mm->page_table_lock); pgd_ERROR(*pgdir); return 0; bad_pmd: spin_unlock(&mm->page_table_lock); pmd_ERROR(*pgmiddle); return 0; } static int access_mm(struct mm_struct *mm, struct vm_area_struct * vma, unsigned long addr, void *buf, int len, int write) { int copied = 0; for (;;) { unsigned long offset = addr & ~PAGE_MASK; int this_len = PAGE_SIZE - offset; int retval; if (this_len > len) this_len = len; retval = access_one_page(mm, vma, addr, buf, this_len, write); copied += retval; if (retval != this_len) break; len -= retval; if (!len) break; addr += retval; buf += retval; if (addr < vma->vm_end) continue; if (!vma->vm_next) break; if (vma->vm_next->vm_start != vma->vm_end) break; vma = vma->vm_next; } return copied; } int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) { int copied; struct mm_struct *mm; struct vm_area_struct * vma; /* Worry about races with exit() */ task_lock(tsk); mm = tsk->mm; if (mm) atomic_inc(&mm->mm_users); task_unlock(tsk); if (!mm) return 0; down_read(&mm->mmap_sem); vma = find_extend_vma(mm, addr); copied = 0; if (vma) copied = access_mm(mm, vma, addr, buf, len, write); up_read(&mm->mmap_sem); mmput(mm); return copied; } int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int len) { int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; retval = access_process_vm(tsk, src, buf, this_len, 0); if (!retval) { if (copied) break; return -EIO; } if (copy_to_user(dst, buf, retval)) return -EFAULT; copied += retval; src += retval; dst += retval; len -= retval; } return copied; } int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int len) { int copied = 0; while (len > 0) { char buf[128]; int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; if (copy_from_user(buf, src, this_len)) return -EFAULT; retval = access_process_vm(tsk, dst, buf, this_len, 1); if (!retval) { if (copied) break; return -EIO; } copied += retval; src += retval; dst += retval; len -= retval; } return copied; } |