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//===-- Implementation of fcntl -------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/fcntl/fcntl.h"
#include "hdr/fcntl_macros.h"
#include "hdr/types/struct_f_owner_ex.h"
#include "hdr/types/struct_flock.h"
#include "hdr/types/struct_flock64.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/__support/common.h"
#include "src/errno/libc_errno.h"
#include <stdarg.h>
#include <sys/syscall.h> // For syscall numbers.
// The OFD file locks require special handling for LARGEFILES
namespace LIBC_NAMESPACE {
LLVM_LIBC_FUNCTION(int, fcntl, (int fd, int cmd, ...)) {
void *arg;
va_list varargs;
va_start(varargs, cmd);
arg = va_arg(varargs, void *);
va_end(varargs);
switch (cmd) {
case F_SETLKW:
return syscall_impl<int>(SYS_fcntl, fd, cmd, arg);
case F_OFD_SETLKW: {
struct flock *flk = reinterpret_cast<struct flock *>(arg);
// convert the struct to a flock64
struct flock64 flk64;
flk64.l_type = flk->l_type;
flk64.l_whence = flk->l_whence;
flk64.l_start = flk->l_start;
flk64.l_len = flk->l_len;
flk64.l_pid = flk->l_pid;
// create a syscall
return syscall_impl<int>(SYS_fcntl, fd, cmd, &flk64);
}
case F_OFD_GETLK:
case F_OFD_SETLK: {
struct flock *flk = reinterpret_cast<struct flock *>(arg);
// convert the struct to a flock64
struct flock64 flk64;
flk64.l_type = flk->l_type;
flk64.l_whence = flk->l_whence;
flk64.l_start = flk->l_start;
flk64.l_len = flk->l_len;
flk64.l_pid = flk->l_pid;
// create a syscall
int retVal = syscall_impl<int>(SYS_fcntl, fd, cmd, &flk64);
// On failure, return
if (retVal == -1)
return -1;
// Check for overflow, i.e. the offsets are not the same when cast
// to off_t from off64_t.
if (static_cast<off_t>(flk64.l_len) != flk64.l_len ||
static_cast<off_t>(flk64.l_start) != flk64.l_start) {
libc_errno = EOVERFLOW;
return -1;
}
// Now copy back into flk, in case flk64 got modified
flk->l_type = flk64.l_type;
flk->l_whence = flk64.l_whence;
flk->l_start = flk64.l_start;
flk->l_len = flk64.l_len;
flk->l_pid = flk64.l_pid;
return retVal;
}
case F_GETOWN: {
struct f_owner_ex fex;
int retVal = syscall_impl<int>(SYS_fcntl, fd, F_GETOWN_EX, &fex);
if (retVal == -EINVAL)
return syscall_impl<int>(SYS_fcntl, fd, cmd,
reinterpret_cast<void *>(arg));
if (static_cast<unsigned long>(retVal) <= -4096UL)
return fex.type == F_OWNER_PGRP ? -fex.pid : fex.pid;
libc_errno = -retVal;
return -1;
}
// The general case
default:
return syscall_impl<int>(SYS_fcntl, fd, cmd, reinterpret_cast<void *>(arg));
}
}
} // namespace LIBC_NAMESPACE
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