strace/mem.c
Dmitry V. Levin d54388e1ce print_array: enhance printing of unfetchable object addresses
When umoven_func invocation fails to fetch data, it prints the faulty
address.  If this happens to a subsequent umoven_func invocation,
the printed address may be undistinguishable from a valid data printed
by print_func, e.g. when the data is printed in a numeric form like
[0x1, 0x2, 0x3, 0xdefaced].

Fix this source of confusion by moving the printing of the faulty
address from umoven_func to print_array itself.  This change renames
umoven_func to tfetch_mem_func and changes its semantics, so that
 - tfetch_mem_func never prints anything;
 - tfetch_mem_func returns true if the fetch succeeded,
   and false otherwise.

* defs.h (print_array): Replace umoven_func argument with
tfetch_mem_func.
* util.c (print_array): Replace umoven_func argument with
tfetch_mem_func, document expected tfetch_mem_func return value
semantics.  When tfetch_mem_func returns false, print either addr
or "... /* addr */" depending on the context (inside the array or not).
* bpf.c (print_ebpf_prog, print_bpf_prog_info,
BEGIN_BPF_CMD_DECODER(BPF_PROG_QUERY)): Replace umoven_or_printaddr
argument of print_array with tfetch_mem.
* bpf_filter.c (print_bpf_fprog): Likewise.
* btrfs.c (btrfs_print_logical_ino_container,
btrfs_print_ino_path_container, btrfs_print_qgroup_inherit,
btrfs_ioctl): Likewise.
* dm.c (dm_decode_dm_target_deps): Likewise.
* epoll.c (epoll_wait_common): Likewise.
* file_ioctl.c (file_ioctl): Likewise.
* ipc_sem.c (tprint_sembuf_array): Likewise.
* kexec.c (print_kexec_segments): Likewise.
* mem.c (SYS_FUNC(subpage_prot)): Likewise.
* net.c (print_getsockopt): Likewise.
* netlink.c (decode_nlmsgerr_attr_cookie): Likewise.
* netlink_netlink_diag.c (decode_netlink_diag_groups): Likewise.
* netlink_packet_diag.c (decode_packet_diag_mclist): Likewise.
* netlink_unix_diag.c (decode_unix_diag_inode): Likewise.
* nlattr.c (decode_nla_meminfo): Likewise.
* numa.c (print_nodemask, SYS_FUNC(move_pages),
* perf_ioctl.c (perf_ioctl_query_bpf): Likewise.
* poll.c (decode_poll_entering): Likewise.
* printsiginfo.c (print_siginfo_array): Likewise.
* rtnl_tc.c (decode_tca_stab_data): Likewise.
* sock.c (decode_ifconf): Likewise.
* uid.c (print_groups): Likewise.
* io.c (SYS_FUNC(io_submit), SYS_FUNC(io_getevents)): Replace
umoven_or_printaddr argument of print_array with tfetch_mem.
(tprint_iov_upto): Replace umoven_or_printaddr_ignore_syserror
with tfetch_mem_ignore_syserror.
* v4l2.c (print_v4l2_format_fmt): Replace umoven_or_printaddr argument
of print_array with tfetch_mem.
(print_v4l2_ext_controls): Replace umoven_or_printaddr_ignore_syserror
with tfetch_mem_ignore_syserror.
* mmsghdr.c (fetch_struct_mmsghdr_or_printaddr): Rename
to fetch_struct_mmsghdr_for_print, do not print address, return bool.
(decode_mmsgvec): Replace fetch_struct_mmsghdr_or_printaddr
with fetch_struct_mmsghdr_for_print.
* tests/aio.c (main): Update expected output.
* tests/bpf.c (print_BPF_PROG_QUERY_attr5): Likewise.
* tests/ioctl_perf-success.c (main): Likewise.
* tests/ioctl_v4l2.c (main): Update expected output.
* tests/kexec_load.c (main): Likewise.
* tests/mmsg_name.c (test_mmsg_name): Update expected output.
* tests/move_pages.c (print_page_array, print_node_array): Likewise.
* tests/poll.c (print_pollfd_array_entering): Likewise.
* tests/preadv-pwritev.c (main): Likewise.
* tests/preadv2-pwritev2.c (dumpio): Likewise.
* tests/process_vm_readv_writev.c (print_iov): Likewise.
* tests/pwritev.c (print_iovec): Likewise.
* tests/readv.c (main): Likewise.
* tests/seccomp-filter-v.c
* tests/semop.c (main): Likewise.
* tests/set_mempolicy.c (print_nodes): Likewise.
* tests/setgroups.c (main): Likewise.
* tests/test_nlattr.h (print_nlattr) Likewise.

Co-Authored-by: Eugene Syromyatnikov <evgsyr@gmail.com>
2018-05-29 09:58:10 +00:00

368 lines
8.7 KiB
C

/*
* Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
* Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
* Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
* Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
* Copyright (c) 2000 PocketPenguins Inc. Linux for Hitachi SuperH
* port by Greg Banks <gbanks@pocketpenguins.com>
* Copyright (c) 1999-2018 The strace developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "defs.h"
#include <linux/mman.h>
#include <sys/mman.h>
unsigned long
get_pagesize(void)
{
static unsigned long pagesize;
if (!pagesize) {
long ret = sysconf(_SC_PAGESIZE);
if (ret < 0)
perror_func_msg_and_die("sysconf(_SC_PAGESIZE)");
if (ret == 0)
error_func_msg_and_die("sysconf(_SC_PAGESIZE) "
"returned 0");
pagesize = (unsigned long) ret;
}
return pagesize;
}
SYS_FUNC(brk)
{
printaddr(tcp->u_arg[0]);
return RVAL_DECODED | RVAL_HEX;
}
#include "xlat/mmap_prot.h"
#include "xlat/mmap_flags.h"
#ifndef MAP_HUGE_SHIFT
# define MAP_HUGE_SHIFT 26
#endif
#ifndef MAP_HUGE_MASK
# define MAP_HUGE_MASK 0x3f
#endif
static void
print_mmap_flags(kernel_ulong_t flags)
{
printxval64(mmap_flags, flags & MAP_TYPE, "MAP_???");
flags &= ~MAP_TYPE;
const unsigned int mask = MAP_HUGE_MASK << MAP_HUGE_SHIFT;
const unsigned int hugetlb_value = flags & mask;
flags &= ~mask;
if (flags) {
tprints("|");
printflags64(mmap_flags, flags, NULL);
}
if (hugetlb_value)
tprintf("|%u<<MAP_HUGE_SHIFT",
hugetlb_value >> MAP_HUGE_SHIFT);
}
static void
print_mmap(struct tcb *tcp, kernel_ulong_t *u_arg, unsigned long long offset)
{
const kernel_ulong_t addr = u_arg[0];
const kernel_ulong_t len = u_arg[1];
const kernel_ulong_t prot = u_arg[2];
const kernel_ulong_t flags = u_arg[3];
const int fd = u_arg[4];
printaddr(addr);
tprintf(", %" PRI_klu ", ", len);
printflags64(mmap_prot, prot, "PROT_???");
tprints(", ");
print_mmap_flags(flags);
tprints(", ");
printfd(tcp, fd);
tprintf(", %#llx", offset);
}
/* Syscall name<->function correspondence is messed up on many arches.
* For example:
* i386 has __NR_mmap == 90, and it is "old mmap", and
* also it has __NR_mmap2 == 192, which is a "new mmap with page offsets".
* But x86_64 has just one __NR_mmap == 9, a "new mmap with byte offsets".
* Confused? Me too!
*/
#if HAVE_ARCH_OLD_MMAP
/* Params are pointed to by u_arg[0], offset is in bytes */
SYS_FUNC(old_mmap)
{
kernel_ulong_t *args =
fetch_indirect_syscall_args(tcp, tcp->u_arg[0], 6);
if (args)
print_mmap(tcp, args, args[5]);
else
printaddr(tcp->u_arg[0]);
return RVAL_DECODED | RVAL_HEX;
}
# if HAVE_ARCH_OLD_MMAP_PGOFF
/* Params are pointed to by u_arg[0], offset is in pages */
SYS_FUNC(old_mmap_pgoff)
{
kernel_ulong_t *args =
fetch_indirect_syscall_args(tcp, tcp->u_arg[0], 6);
if (args) {
unsigned long long offset;
offset = args[5];
offset *= get_pagesize();
print_mmap(tcp, args, offset);
} else {
printaddr(tcp->u_arg[0]);
}
return RVAL_DECODED | RVAL_HEX;
}
# endif /* HAVE_ARCH_OLD_MMAP_PGOFF */
#endif /* HAVE_ARCH_OLD_MMAP */
/* Params are passed directly, offset is in bytes */
SYS_FUNC(mmap)
{
/* Example of kernel-side handling of this variety of mmap:
* arch/x86/kernel/sys_x86_64.c::SYSCALL_DEFINE6(mmap, ...) calls
* sys_mmap_pgoff(..., off >> PAGE_SHIFT); i.e. off is in bytes,
* since the above code converts off to pages.
*/
print_mmap(tcp, tcp->u_arg, tcp->u_arg[5]);
return RVAL_DECODED | RVAL_HEX;
}
/* Params are passed directly, offset is in pages */
SYS_FUNC(mmap_pgoff)
{
/* Try test/mmap_offset_decode.c */
unsigned long long offset;
offset = tcp->u_arg[5];
offset *= get_pagesize();
print_mmap(tcp, tcp->u_arg, offset);
return RVAL_DECODED | RVAL_HEX;
}
/* Params are passed directly, offset is in 4k units */
SYS_FUNC(mmap_4koff)
{
unsigned long long offset;
offset = tcp->u_arg[5];
offset <<= 12;
print_mmap(tcp, tcp->u_arg, offset);
return RVAL_DECODED | RVAL_HEX;
}
SYS_FUNC(munmap)
{
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu, tcp->u_arg[1]);
return RVAL_DECODED;
}
static int
do_mprotect(struct tcb *tcp, bool has_pkey)
{
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
printflags64(mmap_prot, tcp->u_arg[2], "PROT_???");
if (has_pkey)
tprintf(", %d", (int) tcp->u_arg[3]);
return RVAL_DECODED;
}
SYS_FUNC(mprotect)
{
return do_mprotect(tcp, false);
}
SYS_FUNC(pkey_mprotect)
{
return do_mprotect(tcp, true);
}
#include "xlat/mremap_flags.h"
SYS_FUNC(mremap)
{
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu ", %" PRI_klu ", ", tcp->u_arg[1], tcp->u_arg[2]);
printflags64(mremap_flags, tcp->u_arg[3], "MREMAP_???");
#ifdef MREMAP_FIXED
if ((tcp->u_arg[3] & (MREMAP_MAYMOVE | MREMAP_FIXED)) ==
(MREMAP_MAYMOVE | MREMAP_FIXED)) {
tprints(", ");
printaddr(tcp->u_arg[4]);
}
#endif
return RVAL_DECODED | RVAL_HEX;
}
#include "xlat/madvise_cmds.h"
SYS_FUNC(madvise)
{
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
printxval(madvise_cmds, tcp->u_arg[2], "MADV_???");
return RVAL_DECODED;
}
#include "xlat/mlockall_flags.h"
SYS_FUNC(mlockall)
{
printflags(mlockall_flags, tcp->u_arg[0], "MCL_???");
return RVAL_DECODED;
}
#include "xlat/mctl_sync.h"
SYS_FUNC(msync)
{
/* addr */
printaddr(tcp->u_arg[0]);
/* len */
tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
/* flags */
printflags(mctl_sync, tcp->u_arg[2], "MS_???");
return RVAL_DECODED;
}
#include "xlat/mlock_flags.h"
SYS_FUNC(mlock2)
{
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
printflags(mlock_flags, tcp->u_arg[2], "MLOCK_???");
return RVAL_DECODED;
}
SYS_FUNC(mincore)
{
if (entering(tcp)) {
printaddr(tcp->u_arg[0]);
tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
} else {
const unsigned long page_size = get_pagesize();
const unsigned long page_mask = page_size - 1;
unsigned long len = tcp->u_arg[1];
unsigned char *vec = NULL;
len = len / page_size + (len & page_mask ? 1 : 0);
if (syserror(tcp) || !verbose(tcp) ||
!tcp->u_arg[2] || !(vec = malloc(len)) ||
umoven(tcp, tcp->u_arg[2], len, vec) < 0)
printaddr(tcp->u_arg[2]);
else {
unsigned long i;
tprints("[");
for (i = 0; i < len; i++) {
if (i)
tprints(", ");
if (abbrev(tcp) && i >= max_strlen) {
tprints("...");
break;
}
tprints((vec[i] & 1) ? "1" : "0");
}
tprints("]");
}
free(vec);
}
return 0;
}
SYS_FUNC(remap_file_pages)
{
const kernel_ulong_t addr = tcp->u_arg[0];
const kernel_ulong_t size = tcp->u_arg[1];
const kernel_ulong_t prot = tcp->u_arg[2];
const kernel_ulong_t pgoff = tcp->u_arg[3];
const kernel_ulong_t flags = tcp->u_arg[4];
printaddr(addr);
tprintf(", %" PRI_klu ", ", size);
printflags64(mmap_prot, prot, "PROT_???");
tprintf(", %" PRI_klu ", ", pgoff);
print_mmap_flags(flags);
return RVAL_DECODED;
}
#if defined(POWERPC)
static bool
print_protmap_entry(struct tcb *tcp, void *elem_buf, size_t elem_size, void *data)
{
tprintf("%#08x", *(unsigned int *) elem_buf);
return true;
}
SYS_FUNC(subpage_prot)
{
kernel_ulong_t addr = tcp->u_arg[0];
kernel_ulong_t len = tcp->u_arg[1];
kernel_ulong_t nmemb = len >> 16;
kernel_ulong_t map = tcp->u_arg[2];
printaddr(addr);
tprintf(", %" PRI_klu ", ", len);
unsigned int entry;
print_array(tcp, map, nmemb, &entry, sizeof(entry),
tfetch_mem, print_protmap_entry, 0);
return RVAL_DECODED;
}
#endif