/*
* ZeroTier One - Global Peer to Peer Ethernet
* Copyright (C) 2012-2013 ZeroTier Networks LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
/* Launcher for Linux/Unix/Mac */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include "launcher.h"
/* Must match first 16 bytes of EMBEDDED_VERSION_STAMP in Node.cpp */
static const unsigned char EMBEDDED_VERSION_STAMP_KEY[16] = { 0x6d,0xfe,0xff,0x01,0x90,0xfa,0x89,0x57,0x88,0xa1,0xaa,0xdc,0xdd,0xde,0xb0,0x33 };
const unsigned char EMBEDDED_LAUNCHER_VERSION_STAMP[20] = {
0x96,0xf0,0x00,0x08,0x18,0xff,0xc9,0xde,0xad,0xf0,0x0f,0xbe,0xef,0x30,0xce,0xa1, /* key */
ZT_LAUNCHER_VERSION_MAJOR,
ZT_LAUNCHER_VERSION_MINOR,
(unsigned char)(((unsigned int)ZT_LAUNCHER_VERSION_REVISION) & 0xff), /* little-endian */
(unsigned char)((((unsigned int)ZT_LAUNCHER_VERSION_REVISION) >> 8) & 0xff)
};
#define ZT_BINARY_NAME "zerotier-one"
#define ZT_BINARY_UPDATE_PREFIX "zerotier-one_update."
#define ZT_LAUNCHER_PIDFILE "zerotier-launcher.pid"
#define ZT_ONE_PIDFILE "zerotier-one.pid"
/* Load a file into newly malloc()'ed memory, len set to size */
static unsigned char *loadFile(const char *path,unsigned long *len)
{
unsigned char *fbuf = (unsigned char *)0;
FILE *f = fopen(path,"rb");
if (f) {
if (!fseek(f,0,SEEK_END)) {
long l = ftell(f);
if (l > 0) {
fseek(f,0,SEEK_SET);
fbuf = malloc(l);
if (fbuf) {
if (fread(fbuf,l,1,f) != 1) {
free(fbuf);
fbuf = (unsigned char *)0;
} else *len = (unsigned long)l;
}
}
}
fclose(f);
}
return fbuf;
}
/* Scans a ZeroTier binary and determines its version from its embedded version code */
static int findVersion(const unsigned char *bin,unsigned long len,unsigned int *major,unsigned int *minor,unsigned int *revision)
{
unsigned long i;
if (len > 20) {
for(i=0;i<(len - 20);++i) {
if ((bin[i] == EMBEDDED_VERSION_STAMP_KEY[0])&&(!memcmp(bin + i,EMBEDDED_VERSION_STAMP_KEY,16))) {
*major = bin[i + 16];
*minor = bin[i + 17];
*revision = ((unsigned int)bin[i + 18] & 0xff) | (((unsigned int)bin[i + 19] << 8) & 0xff00);
return 1;
}
}
}
return 0;
}
/* Scan for updates and, if found, replace the main binary if possible */
static int doUpdateBinaryIfNewer()
{
long pfxLen = strlen(ZT_BINARY_UPDATE_PREFIX);
struct dirent dbuf,*d;
int needUpdate;
unsigned int major = 0,minor = 0,revision = 0;
unsigned int existingMajor = 0,existingMinor = 0,existingRevision = 0;
unsigned long binLen;
unsigned char *bin;
char oldname[1024];
DIR *dir;
binLen = 0;
bin = loadFile(ZT_BINARY_NAME,&binLen);
if (!((bin)&&(binLen)&&(findVersion(bin,binLen,&existingMajor,&existingMinor,&existingRevision)))) {
if (bin)
free(bin);
return 0;
}
free(bin);
dir = opendir(".");
if (!dir)
return 0;
while (!readdir_r(dir,&dbuf,&d)) {
if (!d) break;
if (!strncasecmp(d->d_name,ZT_BINARY_UPDATE_PREFIX,pfxLen)) {
binLen = 0;
unsigned char *bin = loadFile(d->d_name,&binLen);
if ((bin)&&(binLen)&&(findVersion(bin,binLen,&major,&minor,&revision))) {
needUpdate = 0;
if (major > existingMajor)
needUpdate = 1;
else if (major == existingMajor) {
if (minor > existingMinor)
needUpdate = 1;
else if (minor == existingMinor) {
if (revision > existingRevision)
needUpdate = 1;
}
}
free(bin);
if (needUpdate) {
/* fprintf(stderr,"zerotier-launcher: replacing %s with %s\n",ZT_BINARY_NAME,d->d_name); */
sprintf(oldname,"%s.OLD",ZT_BINARY_NAME);
if (!rename(ZT_BINARY_NAME,oldname)) {
/* fprintf(stderr,"zerotier-launcher: %s -> %s\n",ZT_BINARY_NAME,oldname); */
if (!rename(d->d_name,ZT_BINARY_NAME)) {
/* fprintf(stderr,"zerotier-launcher: %s -> %s\nzerotier-launcher: delete %s\n",d->d_name,ZT_BINARY_NAME,oldname); */
chmod(ZT_BINARY_NAME,0755);
unlink(oldname);
return 1;
}
}
break;
}
}
if (bin)
free(bin);
}
}
closedir(dir);
return 0;
}
static volatile long childPid = 0;
static void sigRepeater(int sig)
{
if (childPid > 0)
kill(childPid,sig);
}
int main(int argc,char **argv)
{
const char *zerotierHome = ZT_DEFAULT_HOME;
FILE *pidf;
int status,exitCode;
unsigned long timeStart;
unsigned int numSubTwoSecondRuns;
/* Pass on certain signals transparently to the subprogram to do with as it will */
signal(SIGHUP,&sigRepeater);
signal(SIGPIPE,SIG_IGN);
signal(SIGUSR1,&sigRepeater);
signal(SIGUSR2,&sigRepeater);
signal(SIGALRM,SIG_IGN);
signal(SIGURG,SIG_IGN);
signal(SIGTERM,&sigRepeater);
signal(SIGQUIT,&sigRepeater);
if (argc == 2)
zerotierHome = argv[1];
if (chdir(zerotierHome)) {
fprintf(stderr,"%s: fatal error: could not chdir to %s\n",argv[0],zerotierHome);
return ZT_EXEC_RETURN_VALUE_UNRECOVERABLE_ERROR;
}
pidf = fopen(ZT_LAUNCHER_PIDFILE,"w");
if (pidf) {
fprintf(pidf,"%d",(int)getpid());
fclose(pidf);
}
numSubTwoSecondRuns = 0;
exitCode = ZT_EXEC_RETURN_VALUE_NORMAL_TERMINATION;
restart_subprogram:
/* We actually do this on every loop, which is fine. It picks up any
* newer versions that are waiting and swaps them out for the current
* running binary. */
doUpdateBinaryIfNewer();
timeStart = time(0);
childPid = fork();
if (childPid < 0) {
fprintf(stderr,"%s: fatal error: could not fork(): %s\n",argv[0],strerror(errno));
return ZT_EXEC_RETURN_VALUE_UNRECOVERABLE_ERROR;
} else if (childPid) {
pidf = fopen(ZT_ONE_PIDFILE,"w");
if (pidf) {
fprintf(pidf,"%d",(int)childPid);
fclose(pidf);
}
status = ZT_EXEC_RETURN_VALUE_NO_BINARY;
wait_for_subprogram_exit:
if ((long)waitpid(childPid,&status,0) >= 0) {
if (WIFEXITED(status)) {
unlink(ZT_ONE_PIDFILE);
if ((time(0) - timeStart) < 2) {
/* Terminate abnormally if we appear to be looping in a tight loop
* to avoid fork bombing if one exits abnormally without an abnormal
* exit code. */
if (++numSubTwoSecondRuns >= 16) {
fprintf(stderr,"%s: fatal error: program exiting immediately in infinite loop\n",argv[0]);
return ZT_EXEC_RETURN_VALUE_UNRECOVERABLE_ERROR;
}
}
switch(WEXITSTATUS(status)) {
case ZT_EXEC_RETURN_VALUE_NORMAL_TERMINATION:
exitCode = ZT_EXEC_RETURN_VALUE_NORMAL_TERMINATION;
goto exit_launcher;
case ZT_EXEC_RETURN_VALUE_NO_BINARY:
fprintf(stderr,"%s: fatal error: binary zerotier-one not found at %s\n",argv[0],zerotierHome);
exitCode = ZT_EXEC_RETURN_VALUE_UNRECOVERABLE_ERROR;
goto exit_launcher;
case ZT_EXEC_RETURN_VALUE_TERMINATED_FOR_UPGRADE:
case ZT_EXEC_RETURN_VALUE_PLEASE_RESTART:
goto restart_subprogram;
default:
exitCode = status;
goto exit_launcher;
}
}
} else if (errno != EINTR) {
fprintf(stderr,"%s: fatal error: waitpid() failed: %s\n",argv[0],strerror(errno));
exitCode = ZT_EXEC_RETURN_VALUE_UNRECOVERABLE_ERROR;
goto exit_launcher;
} else {
goto wait_for_subprogram_exit;
}
} else {
execl(ZT_BINARY_NAME,ZT_BINARY_NAME,zerotierHome,(char *)0);
exit(ZT_EXEC_RETURN_VALUE_NO_BINARY); /* only reached if execl succeeds */
}
exit_launcher:
unlink(ZT_LAUNCHER_PIDFILE);
return exitCode;
}