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/* -*- mode:c; tab-width:8; c-basic-offset:8; indent-tabs-mode:nil; -*- */
/*
Copyright (C) 2024 by Ronnie Sahlberg <ronniesahlberg@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#define _GNU_SOURCE
#include <asm/fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/uio.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <dlfcn.h>
int readv_close = -1;
int (*real_readv)(int fd, const struct iovec *iov, int iovcnt);
ssize_t readv(int fd, const struct iovec *iov, int iovcnt)
{
static int call_idx = 0;
call_idx++;
if (call_idx == readv_close) {
/* write some garbage */
write(fd, &call_idx, sizeof(call_idx));
errno = EBADF;
return -1;
}
return real_readv(fd, iov, iovcnt);
}
static void __attribute__((constructor))
_init(void)
{
/* Close the socket at this call to readv */
if (getenv("READV_CLOSE") != NULL) {
readv_close = atoi(getenv("READV_CLOSE"));
}
real_readv = dlsym(RTLD_NEXT, "readv");
}
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