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/*
* Copyright (c) 2020-2021 Dmitry V. Levin <ldv@strace.io>
* All rights reserved.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include "xgetdents.h"
#include "kernel_dirent.h"
static void
decode_dents(struct tcb *const tcp, kernel_ulong_t addr, unsigned int len,
const unsigned int header_size,
const decode_dentry_head_fn decode_dentry_head,
const decode_dentry_tail_fn decode_dentry_tail)
{
union {
kernel_dirent_t ent;
kernel_dirent64_t ent64;
} dent;
unsigned int count = 0;
if (abbrev(tcp))
printaddr(addr);
for (;;) {
if (len < header_size) {
if (!abbrev(tcp)) {
if (!len) {
tprint_array_begin();
++count;
} else {
printstr_ex(tcp, addr, len,
QUOTE_FORCE_HEX);
}
}
break;
}
/* len >= header_size after this point. */
if (!tfetch_mem(tcp, addr, header_size, &dent)) {
if (!abbrev(tcp)) {
if (count) {
tprint_more_data_follows();
printaddr_comment(addr);
} else {
printaddr(addr);
}
}
break;
}
if (!abbrev(tcp)) {
if (!count)
tprint_array_begin();
}
++count;
kernel_ulong_t next_addr = 0;
unsigned int next_len = 0;
unsigned int d_reclen = decode_dentry_head(tcp, &dent);
if (d_reclen > len) {
/* cannot happen? */
tprintf_comment("%s%u bytes overflow",
(abbrev(tcp) ? "d_reclen " : ""),
d_reclen - len);
d_reclen = len;
} else if (d_reclen < header_size) {
/* cannot happen? */
tprintf_comment("%s%u bytes underflow",
(abbrev(tcp) ? "d_reclen " : ""),
header_size - d_reclen);
d_reclen = header_size;
next_len = len - header_size;
} else {
next_len = len - d_reclen;
if (next_len) {
if (addr + d_reclen > addr) {
next_addr = addr + d_reclen;
} else {
/* cannot happen? */
tprints_comment("address overflow");
}
}
}
len = next_len;
/* Do not use len inside the loop after this point. */
if (!abbrev(tcp)) {
int rc = decode_dentry_tail(tcp, addr + header_size,
&dent,
d_reclen - header_size);
if (next_addr) {
tprint_array_next();
if (rc < 0) {
tprint_more_data_follows();
break;
}
}
}
if (!next_addr)
break;
addr = next_addr;
}
if (!abbrev(tcp)) {
if (count)
tprint_array_end();
} else {
tprintf_comment("%u%s entries", count, len ? "+" : "");
}
}
int
xgetdents(struct tcb *const tcp, const unsigned int header_size,
const decode_dentry_head_fn decode_dentry_head,
const decode_dentry_tail_fn decode_dentry_tail)
{
if (entering(tcp)) {
/* fd */
printfd(tcp, tcp->u_arg[0]);
tprint_arg_next();
return 0;
}
const unsigned int count = tcp->u_arg[2];
if (syserror(tcp) || !verbose(tcp) ||
(kernel_ulong_t) tcp->u_rval > count /* kernel gone bananas? */) {
printaddr(tcp->u_arg[1]);
} else {
decode_dents(tcp, tcp->u_arg[1], tcp->u_rval, header_size,
decode_dentry_head, decode_dentry_tail);
}
tprint_arg_next();
PRINT_VAL_U(count);
return 0;
}
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