1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
using BlockFlags = Thread::FileBlocker::BlockFlags;
KResultOr<ssize_t> Process::sys$readv(int fd, Userspace<const struct iovec*> iov, int iov_count)
{
REQUIRE_PROMISE(stdio);
if (iov_count < 0)
return EINVAL;
// Arbitrary pain threshold.
if (iov_count > (int)MiB)
return EFAULT;
u64 total_length = 0;
Vector<iovec, 32> vecs;
if (!vecs.try_resize(iov_count))
return ENOMEM;
if (!copy_n_from_user(vecs.data(), iov, iov_count))
return EFAULT;
for (auto& vec : vecs) {
total_length += vec.iov_len;
if (total_length > NumericLimits<i32>::max())
return EINVAL;
}
auto description = file_description(fd);
if (!description)
return EBADF;
if (!description->is_readable())
return EBADF;
if (description->is_directory())
return EISDIR;
int nread = 0;
for (auto& vec : vecs) {
if (description->is_blocking()) {
if (!description->can_read()) {
auto unblock_flags = BlockFlags::None;
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
return EINTR;
if (!has_flag(unblock_flags, BlockFlags::Read))
return EAGAIN;
// TODO: handle exceptions in unblock_flags
}
}
auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
if (!buffer.has_value())
return EFAULT;
auto result = description->read(buffer.value(), vec.iov_len);
if (result.is_error())
return result.error();
nread += result.value();
}
return nread;
}
KResultOr<ssize_t> Process::sys$read(int fd, Userspace<u8*> buffer, ssize_t size)
{
REQUIRE_PROMISE(stdio);
if (size < 0)
return EINVAL;
if (size == 0)
return 0;
dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
auto description = file_description(fd);
if (!description)
return EBADF;
if (!description->is_readable())
return EBADF;
if (description->is_directory())
return EISDIR;
if (description->is_blocking()) {
if (!description->can_read()) {
auto unblock_flags = BlockFlags::None;
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
return EINTR;
if (!has_flag(unblock_flags, BlockFlags::Read))
return EAGAIN;
// TODO: handle exceptions in unblock_flags
}
}
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
return EFAULT;
auto result = description->read(user_buffer.value(), size);
if (result.is_error())
return result.error();
return result.value();
}
}
|
