boinc/lib/unix_util.C

130 lines
3.8 KiB
C

// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>.
#include "unix_util.h"
#if 0
#ifndef HAVE_SETENV
#include <vector>
#include <cstring>
#include <cerrno>
#include <cstdlib>
static std::vector<char *> envstrings;
// In theory setenv() is posix, but some implementations of unix
// don't have it. The implementation isn't trivial because of
// differences in how putenv() behaves on different systems.
int setenv(const char *name, const char *value, int overwrite) {
char *buf;
int rv;
// Name can't contant an equal sign.
if (strchr(name,'=')) {
errno=EINVAL;
return -1;
}
// get any existing environment string.
buf=getenv(name);
if (!buf) {
// no existing string, allocate a new one.
buf=(char *)malloc(strlen(name)+strlen(value)+2);
if (buf) envstrings.push_back(buf);
} else {
// we do have an existing string.
// Are we allowed to overwrite it? If not return success.
if (!overwrite) return 0;
// is it long enough to hold our current string?
if (strlen(buf)<(strlen(name)+strlen(value)+1)) {
// no. See if we originally allocated this string.
std::vector<char *>::iterator i=envstrings.begin();
for (;i!=envstrings.end();i++) {
if (*i == buf) break;
}
if (i!=envstrings.end()) {
// we allocated this string. Reallocate it.
buf=(char *)realloc(buf,strlen(name)+strlen(value)+2);
*i=buf;
} else {
// someone else allocated the string. Allocate new memory.
buf=(char *)malloc(strlen(name)+strlen(value)+2);
if (buf) envstrings.push_back(buf);
}
}
}
if (!buf) {
errno=ENOMEM;
return -1;
}
sprintf(buf,"%s=%s",name,value);
rv=putenv(buf);
// Yes, there is a potential memory leak here. Some versions of operating
// systems copy the string into the environment, others make the
// existing string part of the environment. If we were to
// implement unsetenv(), it might be possible to recover some of
// this memory. But unsetenv() is even less trivial than setenv.
return rv;
}
#endif /* !HAVE_SETENV */
#endif
#ifndef HAVE_DAEMON
#include <cstdio>
#include <cstdlib>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
using std::FILE;
using std::freopen;
static FILE *stderr_null, *stdout_null;
int daemon(int nochdir, int noclose) {
pid_t childpid,sessionid;
if (!nochdir) {
chdir("/");
}
if (!noclose) {
stderr_null = freopen("/dev/null", "w", stderr);
stdout_null = freopen("/dev/null", "w", stdout);
}
childpid = fork();
if (childpid>0) {
// Fork successful. We are the parent process.
_exit(0);
}
if (childpid < 0) {
// Fork unsuccessful. Return -1
return -1;
}
// Fork successful, We are the child. Make us the lead process of a new
// session.
sessionid = setsid();
if (sessionid <= 0) {
// setsid() failed
return -1;
}
// success
return 0;
}
#endif /* !HAVE_DAEMON */