7ead136575
We return the size that includes \0 in order to preserve existing behaviour (return 0 when \0 haven't been seen, return positive number when it has been seen). * ucopy.c (umovestr_peekdata, umovestr): Return string length including \0 instead of 1 when \0 is found.
329 lines
8.8 KiB
C
329 lines
8.8 KiB
C
/*
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* Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
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* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
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* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
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* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
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* Copyright (c) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Linux for s390 port by D.J. Barrow
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* <barrow_dj@mail.yahoo.com,djbarrow@de.ibm.com>
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* Copyright (c) 1999-2017 The strace developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "defs.h"
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#include <sys/uio.h>
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#include <asm/unistd.h>
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#include "scno.h"
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#include "ptrace.h"
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static bool process_vm_readv_not_supported;
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#ifndef HAVE_PROCESS_VM_READV
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/*
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* Need to do this since process_vm_readv() is not yet available in libc.
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* When libc is updated, only "static bool process_vm_readv_not_supported"
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* line remains.
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* The name is different to avoid potential collision with OS headers.
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*/
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static ssize_t strace_process_vm_readv(pid_t pid,
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const struct iovec *lvec,
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unsigned long liovcnt,
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const struct iovec *rvec,
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unsigned long riovcnt,
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unsigned long flags)
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{
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return syscall(__NR_process_vm_readv,
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(long) pid, lvec, liovcnt, rvec, riovcnt, flags);
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}
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# define process_vm_readv strace_process_vm_readv
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#endif /* !HAVE_PROCESS_VM_READV */
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static ssize_t
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vm_read_mem(const pid_t pid, void *const laddr,
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const kernel_ulong_t raddr, const size_t len)
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{
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const unsigned long truncated_raddr = raddr;
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#if SIZEOF_LONG < SIZEOF_KERNEL_LONG_T
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if (raddr != (kernel_ulong_t) truncated_raddr) {
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errno = EIO;
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return -1;
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}
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#endif
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const struct iovec local = {
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.iov_base = laddr,
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.iov_len = len
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};
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const struct iovec remote = {
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.iov_base = (void *) truncated_raddr,
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.iov_len = len
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};
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const ssize_t rc = process_vm_readv(pid, &local, 1, &remote, 1, 0);
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if (rc < 0 && errno == ENOSYS)
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process_vm_readv_not_supported = true;
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return rc;
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}
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static bool
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tracee_addr_is_invalid(kernel_ulong_t addr)
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{
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return
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#if ANY_WORDSIZE_LESS_THAN_KERNEL_LONG
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current_wordsize < sizeof(addr) && addr & ~(kernel_ulong_t) -1U;
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#else
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false;
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#endif
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}
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/* legacy method of copying from tracee */
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static int
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umoven_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
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void *laddr)
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{
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unsigned int nread = 0;
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unsigned int residue = addr & (sizeof(long) - 1);
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while (len) {
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addr &= -sizeof(long); /* aligned address */
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errno = 0;
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union {
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long val;
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char x[sizeof(long)];
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} u = { .val = ptrace(PTRACE_PEEKDATA, pid, addr, 0) };
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switch (errno) {
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case 0:
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break;
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case ESRCH: case EINVAL:
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/* these could be seen if the process is gone */
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return -1;
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case EFAULT: case EIO: case EPERM:
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/* address space is inaccessible */
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if (nread) {
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perror_msg("umoven: short read (%u < %u) @0x%" PRI_klx,
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nread, nread + len, addr - nread);
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}
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return -1;
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default:
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/* all the rest is strange and should be reported */
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perror_msg("umoven: PTRACE_PEEKDATA pid:%d @0x%" PRI_klx,
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pid, addr);
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return -1;
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}
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unsigned int m = MIN(sizeof(long) - residue, len);
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memcpy(laddr, &u.x[residue], m);
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residue = 0;
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addr += sizeof(long);
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laddr += m;
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nread += m;
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len -= m;
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}
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return 0;
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}
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/*
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* Copy `len' bytes of data from process `pid'
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* at address `addr' to our space at `our_addr'.
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*/
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int
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umoven(struct tcb *const tcp, kernel_ulong_t addr, unsigned int len,
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void *const our_addr)
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{
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if (tracee_addr_is_invalid(addr))
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return -1;
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const int pid = tcp->pid;
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if (process_vm_readv_not_supported)
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return umoven_peekdata(pid, addr, len, our_addr);
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int r = vm_read_mem(pid, our_addr, addr, len);
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if ((unsigned int) r == len)
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return 0;
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if (r >= 0) {
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error_msg("umoven: short read (%u < %u) @0x%" PRI_klx,
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(unsigned int) r, len, addr);
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return -1;
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}
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switch (errno) {
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case ENOSYS:
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case EPERM:
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/* try PTRACE_PEEKDATA */
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return umoven_peekdata(pid, addr, len, our_addr);
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case ESRCH:
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/* the process is gone */
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return -1;
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case EFAULT: case EIO:
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/* address space is inaccessible */
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return -1;
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default:
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/* all the rest is strange and should be reported */
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perror_msg("process_vm_readv: pid:%d @0x%" PRI_klx,
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pid, addr);
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return -1;
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}
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}
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/*
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* Like umoven_peekdata but make the additional effort of looking
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* for a terminating zero byte.
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*/
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static int
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umovestr_peekdata(const int pid, kernel_ulong_t addr, unsigned int len,
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void *laddr)
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{
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unsigned int nread = 0;
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unsigned int residue = addr & (sizeof(long) - 1);
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void *const orig_addr = laddr;
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while (len) {
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addr &= -sizeof(long); /* aligned address */
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errno = 0;
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union {
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unsigned long val;
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char x[sizeof(long)];
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} u = { .val = ptrace(PTRACE_PEEKDATA, pid, addr, 0) };
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switch (errno) {
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case 0:
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break;
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case ESRCH: case EINVAL:
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/* these could be seen if the process is gone */
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return -1;
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case EFAULT: case EIO: case EPERM:
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/* address space is inaccessible */
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if (nread) {
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perror_msg("umovestr: short read (%d < %d) @0x%" PRI_klx,
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nread, nread + len, addr - nread);
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}
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return -1;
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default:
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/* all the rest is strange and should be reported */
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perror_msg("umovestr: PTRACE_PEEKDATA pid:%d @0x%" PRI_klx,
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pid, addr);
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return -1;
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}
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unsigned int m = MIN(sizeof(long) - residue, len);
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memcpy(laddr, &u.x[residue], m);
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while (residue < sizeof(long))
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if (u.x[residue++] == '\0')
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return (laddr - orig_addr) + residue;
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residue = 0;
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addr += sizeof(long);
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laddr += m;
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nread += m;
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len -= m;
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}
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return 0;
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}
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/*
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* Like `umove' but make the additional effort of looking
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* for a terminating zero byte.
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*
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* Returns < 0 on error, strlen + 1 if NUL was seen,
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* else 0 if len bytes were read but no NUL byte seen.
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*
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* Note: there is no guarantee we won't overwrite some bytes
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* in laddr[] _after_ terminating NUL (but, of course,
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* we never write past laddr[len-1]).
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*/
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int
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umovestr(struct tcb *const tcp, kernel_ulong_t addr, unsigned int len,
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char *laddr)
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{
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if (tracee_addr_is_invalid(addr))
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return -1;
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const int pid = tcp->pid;
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if (process_vm_readv_not_supported)
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return umovestr_peekdata(pid, addr, len, laddr);
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const size_t page_size = get_pagesize();
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const size_t page_mask = page_size - 1;
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unsigned int nread = 0;
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while (len) {
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/*
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* Don't cross pages, otherwise we can get EFAULT
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* and fail to notice that terminating NUL lies
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* in the existing (first) page.
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*/
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unsigned int chunk_len = len > page_size ? page_size : len;
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unsigned int end_in_page = (addr + chunk_len) & page_mask;
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if (chunk_len > end_in_page) /* crosses to the next page */
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chunk_len -= end_in_page;
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int r = vm_read_mem(pid, laddr, addr, chunk_len);
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if (r > 0) {
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char *nul_addr = memchr(laddr, '\0', r);
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if (nul_addr)
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return (nul_addr - laddr) + 1;
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addr += r;
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laddr += r;
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nread += r;
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len -= r;
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continue;
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}
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switch (errno) {
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case ENOSYS:
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case EPERM:
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/* try PTRACE_PEEKDATA */
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if (!nread)
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return umovestr_peekdata(pid, addr,
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len, laddr);
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/* fall through */
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case EFAULT: case EIO:
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/* address space is inaccessible */
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if (nread)
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perror_msg("umovestr: short read (%d < %d) @0x%" PRI_klx,
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nread, nread + len, addr - nread);
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return -1;
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case ESRCH:
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/* the process is gone */
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return -1;
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default:
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/* all the rest is strange and should be reported */
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perror_msg("process_vm_readv: pid:%d @0x%" PRI_klx,
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pid, addr);
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return -1;
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}
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}
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return 0;
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}
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