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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 | /* * 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 <asm/pgtable.h> #include <asm/uaccess.h> /* * Access another process' address space, one page at a time. */ static int access_one_page(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long addr, void *buf, int len, int write) { pgd_t * pgdir; pmd_t * pgmiddle; pte_t * pgtable; unsigned long mapnr; unsigned long maddr; struct page *page; repeat: 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; mapnr = pte_pagenr(*pgtable); if (write && (!pte_write(*pgtable) || !pte_dirty(*pgtable))) goto fault_in_page; if (mapnr >= max_mapnr) return 0; page = mem_map + mapnr; flush_cache_page(vma, addr); if (write) { maddr = kmap(page, KM_WRITE); memcpy((char *)maddr + (addr & ~PAGE_MASK), buf, len); flush_page_to_ram(page); kunmap(maddr, KM_WRITE); } else { maddr = kmap(page, KM_READ); memcpy(buf, (char *)maddr + (addr & ~PAGE_MASK), len); flush_page_to_ram(page); kunmap(maddr, KM_READ); } return len; fault_in_page: /* -1: out of memory. 0 - unmapped page */ if (handle_mm_fault(tsk, vma, addr, write) > 0) goto repeat; return 0; bad_pgd: pgd_ERROR(*pgdir); return 0; bad_pmd: pmd_ERROR(*pgmiddle); return 0; } int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) { int copied; struct vm_area_struct * vma; down(&tsk->mm->mmap_sem); vma = find_extend_vma(tsk, addr); if (!vma) { up(&tsk->mm->mmap_sem); return 0; } 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(tsk, 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; } up(&tsk->mm->mmap_sem); 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; } |