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/* This is part of um-ViewOS
* The user-mode implementation of OSVIEW -- A Process with a View
*
* viewsu user command
*
* Copyright 2010 Renzo Davoli University of Bologna - Italy
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2 or
* (at your option) any later version, as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* $Id: um_add_service.c 775 2009-09-01 21:15:23Z rd235 $
*
*/
#include <config.h>
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <getopt.h>
#include <pwd.h>
#include <grp.h>
#include <string.h>
#include <libgen.h>
#include <um_lib.h>
static struct option long_options[] = {
{"command", 1, 0, 'c'},
{"login", 0, 0, 'l'},
{"shell", 1, 0, 's'},
{"preserve-environment", 0, 0, 'p'},
{"help", 1, 0, 'h'},
{0, 0, 0, 0}
};
char *command;
int login;
char *shell;
int preserve_environment;
char *user;
int uid;
int gid;
char *arg0;
int ngroups;
gid_t *groups;
void usage(char *argv0)
{
char *name=basename(argv0);
fprintf(stderr,
"Usage: %s [options] [LOGIN]\n"
"\n"
"Options:\n"
" -c, --command COMMAND pass COMMAND to the invoked shell\n"
" -h, --help display this help message and exit\n"
" -, -l, --login make the shell a login shell\n"
//" -m, -p,\n"
//" --preserve-environment do not reset environment variables, and\n"
" keep the same shell\n"
" -s, --shell SHELL use SHELL instead of the default in passwd\n"
"\n",
name
);
exit(2);
}
void setpath(void)
{
char buf[1024];
char *tag=(uid==0)?"ENV_SUPATH":"ENV_PATH";
FILE *f=fopen("/etc/login.defs","r");
char *path;
if (f) {
char *s;
while((s=fgets(buf,1024,f)) != NULL) {
while (*s==' ' || *s=='\t') s++;
if (*s=='#') continue;
if (strncmp(tag,s,strlen(tag))!=0) continue;
s+=strlen(tag);
if (*s != ' ' && *s != '\t') continue;
while (*s==' ' || *s=='\t') s++;
if (strncmp("PATH=",s,5)!=0) continue;
s+=5;
s[strlen(s)-1]=0;
path=s;
break;
}
fclose(f);
}
if (!path) {
if (uid)
path="/bin:/usr/bin";
else
path="/sbin:/bin:/usr/sbin:/usr/bin";
}
setenv("PATH",path,1);
}
int main(int argc, char *argv[])
{
pid_t pid;
int status;
int c;
struct passwd *pwd;
/* outside viewos use su(1) */
if (um_check_viewos()==0)
execvp("su",argv);
while (1) {
int option_index = 0;
c = getopt_long(argc, argv, "c:ls:mph",
long_options, &option_index);
if (c == -1)
break;
switch (c) {
case 'c': command=optarg;
break;
case 'l': login=1;
break;
case 's': shell=optarg;
break;
// case 'm':
// case 'p': preserve_environment=1;
// break;
case 'h': usage(argv[0]);
break;
}
}
if (argc > optind+1)
usage(argv[0]);
if (argc > optind) {
if (strcmp(argv[optind],"-")==0)
login=1;
else
user=argv[optind];
}
//if (!preserve_environment)
//clearenv();
if (user) {
pwd=getpwnam(user);
if (pwd == NULL) {
fprintf(stderr,"Unknown id: %s\n",user);
exit(1);
}
uid=pwd->pw_uid;
gid=pwd->pw_gid;
if (shell == NULL)
shell=pwd->pw_shell;
} else {
user="root";
pwd=getpwuid(0);
if(pwd && shell == NULL)
shell=pwd->pw_shell;
}
if (pwd)
setenv("HOME",pwd->pw_dir,1);
if (shell == NULL)
shell="/bin/sh";
setenv("SHELL",shell,1);
if (login)
asprintf(&arg0,"-%s",shell);
else
arg0=shell;
getgrouplist(user,gid,NULL,&ngroups);
groups=malloc(ngroups * sizeof (gid_t));
if (groups == NULL)
ngroups=0;
else
getgrouplist(user,gid,groups,&ngroups);
switch (pid=fork()) {
case -1: exit(1);
case 0:
if (setresuid(uid,uid,uid) < 0)
perror(argv[0]);
else {
setresgid(gid,gid,gid);
setgroups(ngroups,groups);
setpath();
if (command)
execl(shell,arg0,"-c",command,(char *)0);
else
execl(shell,arg0,(char *)0);
perror(arg0);
}
exit(1);
break;
default:
waitpid(pid,&status,0);
exit(WEXITSTATUS(status));
}
return 0;
}
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