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/****************************************************************************
**
** Copyright (C) 2019 Luxoft Sweden AB
** Copyright (C) 2018 Pelagicore AG
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Luxoft Application Manager.
**
** $QT_BEGIN_LICENSE:LGPL-QTAS$
** Commercial License Usage
** Licensees holding valid commercial Qt Automotive Suite licenses may use
** this file in accordance with the commercial license agreement provided
** with the Software or, alternatively, in accordance with the terms
** contained in a written agreement between you and The Qt Company. For
** licensing terms and conditions see https://www.qt.io/terms-conditions.
** For further information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
** SPDX-License-Identifier: LGPL-3.0
**
****************************************************************************/
#include "processtitle.h"
#if !defined(Q_OS_LINUX)
QT_BEGIN_NAMESPACE_AM
void ProcessTitle::setTitle(const char *, ...) { }
const char *ProcessTitle::title() { return nullptr; }
QT_END_NAMESPACE_AM
#else
#include "logging.h"
#include <QVarLengthArray>
#include <QByteArray>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include <stdlib.h>
QT_BEGIN_NAMESPACE_AM
static char *startOfArgv = nullptr;
static size_t maxArgvSize = 0;
static char *originalArgv = nullptr;
static size_t originalArgvSize = 0;
/* \internal
Sadly, Linux has no setproctitle() call like the BSDs have...
You could just overwrite argv[0], but writing beyond the original length would overwrite the
environment.
*/
static void ProcessTitleInitialize(int argc, char *argv[], char *envp[])
{
// How this works:
// All argv[] and envp[] strings are in one continuous memory region that starts at argv[0]. All
// strings are simply separated by '\0'.
// In order to make room to extend argv[], we copy the environment somewhere else and can then
// use the "old" environment as a buffer to extend argv[]
// In addition, we need to replace the argv[i] pointers with a copy of the original strings,
// since the app's cmdline parser might want to access argv[i] after a setTitle call.
// char *start = argv[0];
// for (int i = 0; i < argc; ++i)
// fprintf(stderr, "ARGV[%d] = %p | len=%d | delta=%ld\n", i, argv[i], int(strlen(argv[i])), argv[i] - start);
// for (int i = 0; envp[i]; ++i)
// fprintf(stderr, "ENVP[%d] = %p | len=%d | delta=%ld\n", i, envp[i], int(strlen(envp[i])), envp[i] - start);
// sanity checks
if (argc <= 0 || !argv[0] || !envp)
return;
if (envp[0] && ((argv[argc - 1] + strlen(argv[argc - 1]) + 1) != envp[0]))
return;
// calculate the size of the available area
startOfArgv = argv[0];
originalArgvSize = size_t(envp[0] - argv[0]);
originalArgv = static_cast<char *>(malloc(originalArgvSize));
memcpy(originalArgv, argv[0], originalArgvSize);
char *envpEnd;
size_t envc = 0;
while (envp[envc])
++envc;
envpEnd = envp[envc - 1] + strlen(envp[envc - 1]) + 1;
maxArgvSize = size_t(envpEnd - startOfArgv);
// temporary copy of the list of pointers on the stack
QVarLengthArray<char *, 2048> oldenvp(static_cast<int>(envc));
memcpy(oldenvp.data(), envp, envc * sizeof(char *));
// this will only free the list of pointers, but not the contents!
clearenv();
// copy the environment via setenv() - do NOT use putenv() as this would just put the old
// pointer in the new table.
for (int i = 0; i < oldenvp.size(); ++i) {
// split into key/value pairs for setenv()
char *name = oldenvp[i];
char *value = strchr(name, '=');
if (!value) // entries without '=' should not exist
continue;
*value++ = 0;
if (setenv(name, value, 1) != 0) {
fprintf(stderr, "ERROR: could not copy the environment: %s\n", strerror(errno));
_exit(1);
}
}
// last step: make sure that argv[i] returns consistent pointers regardless of how many times
// setTitle() will be called
for (int i = argc - 1; i >= 0; --i)
argv[i] = originalArgv + (argv[i] - argv[0]);
// fprintf(stderr, "env is moved: testing $SHELL=%s\n", getenv("SHELL"));
}
// register as a a .init function that is automatically run before main()
decltype(ProcessTitleInitialize) *init_ProcessTitleInitialize
__attribute__((section(".init_array"))) = ProcessTitleInitialize;
/*! \internal
This function mimics the API of the setproctitle() function found in BSDs:
https://www.freebsd.org/cgi/man.cgi?query=setproctitle&sektion=3
*/
void ProcessTitle::setTitle(const char *fmt, ...)
{
if (!startOfArgv || maxArgvSize <= 0 || !originalArgv || originalArgvSize <= 0) {
qWarning(LogSystem) << "ProcessTitle::setTitle() failed, because its initialization function"
" was not called via an .init_array section at process startup.";
return;
}
char title[256];
char *ptr = title;
size_t len = 0;
if (!fmt) {
// reset to original argv[]
ptr = originalArgv;
len = originalArgvSize;
} else {
// BSD compatibility: the title will always start with the original argv[0] + ": ",
// unless the first character in the format string is a '-'
if (fmt[0] == '-') {
fmt++;
} else {
len = qMin(strlen(originalArgv), sizeof(title) - 3);
memcpy(title, originalArgv, len);
memcpy(title + len, ": \0", 3);
len += 2;
}
va_list ap;
va_start(ap, fmt);
size_t result = static_cast<size_t>(qvsnprintf(title + len, sizeof(title) - len, fmt, ap));
va_end(ap);
len += qMin(result, sizeof(title) - len); // clamp to buffer size in case of overflow
if ((len + 1) > maxArgvSize)
len = maxArgvSize - 1;
}
if (ptr && len) {
memcpy(startOfArgv, ptr, len);
memset(startOfArgv + len, 0, maxArgvSize - len);
}
}
const char *ProcessTitle::title()
{
return startOfArgv;
}
QT_END_NAMESPACE_AM
#endif
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