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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt 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 Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#ifdef __sun
# define PT_TRACE_ME 0
# define PT_DETACH 7
#else
# include <sys/ptrace.h>
#endif
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
/* For OpenBSD */
#ifndef EPROTO
# define EPROTO EINVAL
#endif
extern char **environ;
static int qtcFd;
static char *sleepMsg;
static void __attribute__((noreturn)) doExit(int code)
{
tcsetpgrp(0, getpid());
puts(sleepMsg);
fgets(sleepMsg, 2, stdin); /* Minimal size to make it wait */
exit(code);
}
static void sendMsg(const char *msg, int num)
{
int pidStrLen;
int ioRet;
char pidStr[64];
pidStrLen = sprintf(pidStr, msg, num);
if ((ioRet = write(qtcFd, pidStr, pidStrLen)) != pidStrLen) {
fprintf(stderr, "Cannot write to creator comm socket: %s\n",
(ioRet < 0) ? strerror(errno) : "short write");
doExit(3);
}
}
enum {
ArgCmd = 0,
ArgAction,
ArgSocket,
ArgMsg,
ArgDir,
ArgEnv,
ArgExe
};
/* syntax: $0 {"run"|"debug"} <pid-socket> <continuation-msg> <workdir> <env-file> <exe> <args...> */
/* exit codes: 0 = ok, 1 = invocation error, 3 = internal error */
int main(int argc, char *argv[])
{
int errNo;
int chldPid;
int chldStatus;
int chldPipe[2];
char **env = 0;
struct sockaddr_un sau;
if (argc < ArgEnv) {
fprintf(stderr, "This is an internal helper of Qt Creator. Do not run it manually.\n");
return 1;
}
sleepMsg = argv[ArgMsg];
/* Connect to the master, i.e. Creator. */
if ((qtcFd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
perror("Cannot create creator comm socket");
doExit(3);
}
memset(&sau, 0, sizeof(sau));
sau.sun_family = AF_UNIX;
strncpy(sau.sun_path, argv[ArgSocket], sizeof(sau.sun_path) - 1);
if (connect(qtcFd, (struct sockaddr *)&sau, sizeof(sau))) {
fprintf(stderr, "Cannot connect creator comm socket %s: %s\n", sau.sun_path, strerror(errno));
doExit(1);
}
if (*argv[ArgDir] && chdir(argv[ArgDir])) {
/* Only expected error: no such file or direcotry */
sendMsg("err:chdir %d\n", errno);
return 1;
}
if (*argv[ArgEnv]) {
FILE *envFd;
char *envdata, *edp;
long size;
int count;
if (!(envFd = fopen(argv[ArgEnv], "r"))) {
fprintf(stderr, "Cannot read creator env file %s: %s\n",
argv[ArgEnv], strerror(errno));
doExit(1);
}
fseek(envFd, 0, SEEK_END);
size = ftell(envFd);
rewind(envFd);
envdata = malloc(size);
if (fread(envdata, 1, size, envFd) != (size_t)size) {
perror("Failed to read env file");
doExit(1);
}
fclose(envFd);
for (count = 0, edp = envdata; edp < envdata + size; ++count)
edp += strlen(edp) + 1;
env = malloc((count + 1) * sizeof(char *));
for (count = 0, edp = envdata; edp < envdata + size; ++count) {
env[count] = edp;
edp += strlen(edp) + 1;
}
env[count] = 0;
}
/* Ignore SIGTTOU. Without this, calling tcsetpgrp() from a background
* process group (in which we will be, once as child and once as parent)
* generates the mentioned signal and stops the concerned process. */
signal(SIGTTOU, SIG_IGN);
/* Create execution result notification pipe. */
if (pipe(chldPipe)) {
perror("Cannot create status pipe");
doExit(3);
}
/* The debugged program is not supposed to inherit these handles. But we cannot
* close the writing end before calling exec(). Just handle both ends the same way ... */
fcntl(chldPipe[0], F_SETFD, FD_CLOEXEC);
fcntl(chldPipe[1], F_SETFD, FD_CLOEXEC);
switch ((chldPid = fork())) {
case -1:
perror("Cannot fork child process");
doExit(3);
case 0:
close(qtcFd);
/* Put the process into an own process group and make it the foregroud
* group on this terminal, so it will receive ctrl-c events, etc.
* This is the main reason for *all* this stub magic in the first place. */
/* If one of these calls fails, the world is about to end anyway, so
* don't bother checking the return values. */
setpgid(0, 0);
tcsetpgrp(0, getpid());
/* Get a SIGTRAP after exec() has loaded the new program. */
#ifdef __linux__
ptrace(PTRACE_TRACEME);
#else
ptrace(PT_TRACE_ME, 0, 0, 0);
#endif
if (env)
environ = env;
execvp(argv[ArgExe], argv + ArgExe);
/* Only expected error: no such file or direcotry, i.e. executable not found */
errNo = errno;
write(chldPipe[1], &errNo, sizeof(errNo)); /* Only realistic error case is SIGPIPE */
_exit(0);
default:
for (;;) {
if (wait(&chldStatus) < 0) {
perror("Cannot obtain exit status of child process");
doExit(3);
}
if (WIFSTOPPED(chldStatus)) {
/* The child stopped. This can be only the result of ptrace(TRACE_ME). */
/* We won't need the notification pipe any more, as we know that
* the exec() succeeded. */
close(chldPipe[0]);
close(chldPipe[1]);
chldPipe[0] = -1;
/* If we are not debugging, just skip the "handover enabler".
* This is suboptimal, as it makes us ignore setuid/-gid bits. */
if (!strcmp(argv[ArgAction], "debug")) {
/* Stop the child after we detach from it, so we can hand it over to gdb.
* If the signal delivery is not queued, things will go awry. It works on
* Linux and MacOSX ... */
kill(chldPid, SIGSTOP);
}
#ifdef __linux__
ptrace(PTRACE_DETACH, chldPid, 0, 0);
#else
ptrace(PT_DETACH, chldPid, 0, 0);
#endif
sendMsg("pid %d\n", chldPid);
} else if (WIFEXITED(chldStatus)) {
/* The child exited normally. */
if (chldPipe[0] >= 0) {
/* The child exited before being stopped by ptrace(). That can only
* mean that the exec() failed. */
switch (read(chldPipe[0], &errNo, sizeof(errNo))) {
default:
/* Read of unknown length. Should never happen ... */
errno = EPROTO;
case -1:
/* Read failed. Should never happen, either ... */
perror("Cannot read status from child process");
doExit(3);
case sizeof(errNo):
/* Child telling us the errno from exec(). */
sendMsg("err:exec %d\n", errNo);
return 3;
}
}
sendMsg("exit %d\n", WEXITSTATUS(chldStatus));
doExit(0);
} else {
sendMsg("crash %d\n", WTERMSIG(chldStatus));
doExit(0);
}
}
break;
}
}
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