strace/epoll.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

119 lines
3.4 KiB
C

/*
* Copyright (c) 2004-2007 Ulrich Drepper <drepper@redhat.com>
* Copyright (c) 2004 Roland McGrath <roland@redhat.com>
* Copyright (c) 2005-2015 Dmitry V. Levin <ldv@altlinux.org>
* Copyright (c) 2015-2017 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 <fcntl.h>
#include <sys/epoll.h>
SYS_FUNC(epoll_create)
{
tprintf("%d", (int) tcp->u_arg[0]);
return RVAL_DECODED | RVAL_FD;
}
#include "xlat/epollflags.h"
SYS_FUNC(epoll_create1)
{
printflags(epollflags, tcp->u_arg[0], "EPOLL_???");
return RVAL_DECODED | RVAL_FD;
}
#include "xlat/epollevents.h"
static bool
print_epoll_event(struct tcb *tcp, void *elem_buf, size_t elem_size, void *data)
{
const struct epoll_event *ev = elem_buf;
tprints("{");
printflags(epollevents, ev->events, "EPOLL???");
/* We cannot know what format the program uses, so print u32 and u64
which will cover every value. */
tprintf(", {u32=%" PRIu32 ", u64=%" PRIu64 "}}",
ev->data.u32, ev->data.u64);
return true;
}
#include "xlat/epollctls.h"
SYS_FUNC(epoll_ctl)
{
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
const unsigned int op = tcp->u_arg[1];
printxval(epollctls, op, "EPOLL_CTL_???");
tprints(", ");
printfd(tcp, tcp->u_arg[2]);
tprints(", ");
struct epoll_event ev;
if (EPOLL_CTL_DEL == op)
printaddr(tcp->u_arg[3]);
else if (!umove_or_printaddr(tcp, tcp->u_arg[3], &ev))
print_epoll_event(tcp, &ev, sizeof(ev), 0);
return RVAL_DECODED;
}
static void
epoll_wait_common(struct tcb *tcp)
{
if (entering(tcp)) {
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
} else {
struct epoll_event ev;
print_array(tcp, tcp->u_arg[1], tcp->u_rval, &ev, sizeof(ev),
tfetch_mem, print_epoll_event, 0);
tprintf(", %d, %d", (int) tcp->u_arg[2], (int) tcp->u_arg[3]);
}
}
SYS_FUNC(epoll_wait)
{
epoll_wait_common(tcp);
return 0;
}
SYS_FUNC(epoll_pwait)
{
epoll_wait_common(tcp);
if (exiting(tcp)) {
tprints(", ");
/* NB: kernel requires arg[5] == NSIG_BYTES */
print_sigset_addr_len(tcp, tcp->u_arg[4], tcp->u_arg[5]);
tprintf(", %" PRI_klu, tcp->u_arg[5]);
}
return 0;
}