boinc/client/switcher.cpp

79 lines
2.4 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/>.
// switcher.C
//
// When run as
// switcher Full-Path Executable-Name X1 ... Xn
// runs program at Full-Path with args X1. ... Xn
// note that the executable name nust be specified twice:
// once as part of the Full_Path and again as just the name
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <cerrno>
#include <sys/param.h> // for MAXPATHLEN
#include <pwd.h> // getpwuid
#include <grp.h>
int main(int argc, char** argv) {
passwd *pw;
group *grp;
char user_name[256], group_name[256];
strcpy(user_name, "boinc_project");
strcpy(group_name, "boinc_project");
#if 0 // For debugging only
char current_dir[MAXPATHLEN];
getcwd( current_dir, sizeof(current_dir));
fprintf(stderr, "current directory = %s\n", current_dir);
for (int i=0; i<argc; i++) {
fprintf(stderr, "switcher arg %d: %s\n", i, argv[i]);
}
fflush(stderr);
#endif
#if 0 // For debugging only
// Allow debugging without running as user or group boinc_project
pw = getpwuid(getuid());
if (pw) strcpy(user_name, pw->pw_name);
grp = getgrgid(getgid());
if (grp) strcpy(group_name, grp->gr_gid);
#endif
// We are running setuid root, so setgid() sets real group ID,
// effective group ID and saved set_group-ID for this process
grp = getgrnam(group_name);
if (grp) setgid(grp->gr_gid);
// We are running setuid root, so setuid() sets real user ID,
// effective user ID and saved set_user-ID for this process
pw = getpwnam(user_name);
if (pw) setuid(pw->pw_uid);
execv(argv[1], argv+2);
// If we got here execv failed
fprintf(stderr, "Process creation (%s) failed: errno=%d\n", argv[1], errno);
}