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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
// Copyright (C) 2016 The Qt Company Ltd.
// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include <QtCore/private/qglobal_p.h>
#include "qcore_unix_p.h"
#include "qelapsedtimer.h"
#include <stdlib.h>
#ifdef __GLIBC__
# include <sys/syscall.h>
# include <pthread.h>
# include <unistd.h>
#endif
#ifdef Q_OS_MAC
#include <mach/mach_time.h>
#endif
QT_BEGIN_NAMESPACE
QByteArray qt_readlink(const char *path)
{
#ifndef PATH_MAX
// suitably large value that won't consume too much memory
# define PATH_MAX 1024*1024
#endif
QByteArray buf(256, Qt::Uninitialized);
ssize_t len = ::readlink(path, buf.data(), buf.size());
while (len == buf.size()) {
// readlink(2) will fill our buffer and not necessarily terminate with NUL;
if (buf.size() >= PATH_MAX) {
errno = ENAMETOOLONG;
return QByteArray();
}
// double the size and try again
buf.resize(buf.size() * 2);
len = ::readlink(path, buf.data(), buf.size());
}
if (len == -1)
return QByteArray();
buf.resize(len);
return buf;
}
#if defined(Q_PROCESSOR_X86_32) && defined(__GLIBC__)
# if !__GLIBC_PREREQ(2, 22)
// glibc prior to release 2.22 had a bug that suppresses the third argument to
// open() / open64() / openat(), causing file creation with O_TMPFILE to have
// the wrong permissions. So we bypass the glibc implementation and go straight
// for the syscall. See
// https://sourceware.org/git/?p=glibc.git;a=commit;h=65f6f938cd562a614a68e15d0581a34b177ec29d
int qt_open64(const char *pathname, int flags, mode_t mode)
{
return syscall(SYS_open, pathname, flags | O_LARGEFILE, mode);
}
# endif
#endif
#ifndef QT_BOOTSTRAPPED
#if QT_CONFIG(poll_pollts)
# define ppoll pollts
#endif
static inline bool time_update(struct timespec *tv, const struct timespec &start,
const struct timespec &timeout)
{
// clock source is (hopefully) monotonic, so we can recalculate how much timeout is left;
// if it isn't monotonic, we'll simply hope that it hasn't jumped, because we have no alternative
struct timespec now = qt_gettime();
*tv = timeout + start - now;
return tv->tv_sec >= 0;
}
#if QT_CONFIG(poll_poll)
static inline int timespecToMillisecs(const struct timespec *ts)
{
return (ts == NULL) ? -1 :
(ts->tv_sec * 1000) + (ts->tv_nsec / 1000000);
}
#endif
// defined in qpoll.cpp
int qt_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts);
static inline int qt_ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts)
{
#if QT_CONFIG(poll_ppoll) || QT_CONFIG(poll_pollts)
return ::ppoll(fds, nfds, timeout_ts, nullptr);
#elif QT_CONFIG(poll_poll)
return ::poll(fds, nfds, timespecToMillisecs(timeout_ts));
#elif QT_CONFIG(poll_select)
return qt_poll(fds, nfds, timeout_ts);
#else
// configure.json reports an error when everything is not available
#endif
}
/*!
\internal
Behaves as close to POSIX poll(2) as practical but may be implemented
using select(2) where necessary. In that case, returns -1 and sets errno
to EINVAL if passed any descriptor greater than or equal to FD_SETSIZE.
*/
int qt_safe_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts)
{
if (!timeout_ts) {
// no timeout -> block forever
int ret;
EINTR_LOOP(ret, qt_ppoll(fds, nfds, nullptr));
return ret;
}
timespec start = qt_gettime();
timespec timeout = *timeout_ts;
// loop and recalculate the timeout as needed
forever {
const int ret = qt_ppoll(fds, nfds, &timeout);
if (ret != -1 || errno != EINTR)
return ret;
// recalculate the timeout
if (!time_update(&timeout, start, *timeout_ts)) {
// timeout during update
// or clock reset, fake timeout error
return 0;
}
}
}
#endif // QT_BOOTSTRAPPED
QT_END_NAMESPACE
|
