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shairport-sync/common.c
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/*
* Utility routines. This file is part of Shairport.
* Copyright (c) James Laird 2013
* The volume to attenuation function vol2attn copyright (c) Mike Brady 2014
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <memory.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <popt.h>
#include <poll.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <assert.h>
#include "common.h"
#ifdef COMPILE_FOR_OSX
#include <CoreServices/CoreServices.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#endif
#ifdef HAVE_LIBSSL
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#endif
#ifdef HAVE_LIBPOLARSSL
#include <polarssl/version.h>
#include <polarssl/base64.h>
#include <polarssl/x509.h>
#include <polarssl/md.h>
#include "polarssl/entropy.h"
#include "polarssl/ctr_drbg.h"
#if POLARSSL_VERSION_NUMBER >= 0x01030000
#include "polarssl/compat-1.2.h"
#endif
#endif
#include "common.h"
#include <libdaemon/dlog.h>
// true if Shairport Sync is supposed to be sending output to the output device, false otherwise
static volatile int requested_connection_state_to_output = 1;
shairport_cfg config;
int debuglev = 0;
int get_requested_connection_state_to_output() { return requested_connection_state_to_output; }
void set_requested_connection_state_to_output(int v) { requested_connection_state_to_output = v; }
void die(char *format, ...) {
char s[1024];
s[0] = 0;
va_list args;
va_start(args, format);
vsprintf(s, format, args);
va_end(args);
daemon_log(LOG_EMERG, "%s", s);
shairport_shutdown();
exit(1);
}
void warn(char *format, ...) {
char s[1024];
s[0] = 0;
va_list args;
va_start(args, format);
vsprintf(s, format, args);
va_end(args);
daemon_log(LOG_WARNING, "%s", s);
}
void debug(int level, char *format, ...) {
if (level > debuglev)
return;
char s[1024];
s[0] = 0;
va_list args;
va_start(args, format);
vsprintf(s, format, args);
va_end(args);
daemon_log(LOG_DEBUG, "%s", s);
}
void inform(char *format, ...) {
char s[1024];
s[0] = 0;
va_list args;
va_start(args, format);
vsprintf(s, format, args);
va_end(args);
daemon_log(LOG_INFO, "%s", s);
}
#ifdef HAVE_LIBPOLARSSL
char *base64_enc(uint8_t *input, int length) {
char *buf = NULL;
size_t dlen = 0;
int rc = base64_encode(NULL, &dlen, input, length);
if (rc && (rc != POLARSSL_ERR_BASE64_BUFFER_TOO_SMALL))
debug(1, "Error %d getting length of base64 encode.", rc);
else {
buf = (char *)malloc(dlen);
rc = base64_encode((unsigned char *)buf, &dlen, input, length);
if (rc != 0)
debug(1, "Error %d encoding base64.", rc);
}
return buf;
}
uint8_t *base64_dec(char *input, int *outlen) {
// slight problem here is that Apple cut the padding off their challenges. We must restore it
// before passing it in to the decoder, it seems
uint8_t *buf = NULL;
size_t dlen = 0;
int inbufsize = ((strlen(input) + 3) / 4) * 4; // this is the size of the input buffer we will
// send to the decoder, but we need space for 3
// extra "="s and a NULL
char *inbuf = malloc(inbufsize + 4);
if (inbuf == 0)
debug(1, "Can't malloc memory for inbuf in base64_decode.");
else {
strcpy(inbuf, input);
strcat(inbuf, "===");
// debug(1,"base64_dec called with string \"%s\", length %d, filled string: \"%s\", length
// %d.",input,strlen(input),inbuf,inbufsize);
int rc = base64_decode(buf, &dlen, (unsigned char *)inbuf, inbufsize);
if (rc && (rc != POLARSSL_ERR_BASE64_BUFFER_TOO_SMALL))
debug(1, "Error %d getting decode length, result is %d.", rc, dlen);
else {
// debug(1,"Decode size is %d.",dlen);
buf = malloc(dlen);
if (buf == 0)
debug(1, "Can't allocate memory in base64_dec.");
else {
rc = base64_decode(buf, &dlen, (unsigned char *)inbuf, inbufsize);
if (rc != 0)
debug(1, "Error %d in base64_dec.", rc);
}
}
free(inbuf);
}
*outlen = dlen;
return buf;
}
#endif
#ifdef HAVE_LIBSSL
char *base64_enc(uint8_t *input, int length) {
BIO *bmem, *b64;
BUF_MEM *bptr;
b64 = BIO_new(BIO_f_base64());
bmem = BIO_new(BIO_s_mem());
b64 = BIO_push(b64, bmem);
BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
BIO_write(b64, input, length);
BIO_flush(b64);
BIO_get_mem_ptr(b64, &bptr);
char *buf = (char *)malloc(bptr->length);
if (bptr->length) {
memcpy(buf, bptr->data, bptr->length - 1);
buf[bptr->length - 1] = 0;
}
BIO_free_all(bmem);
return buf;
}
uint8_t *base64_dec(char *input, int *outlen) {
BIO *bmem, *b64;
int inlen = strlen(input);
b64 = BIO_new(BIO_f_base64());
BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
bmem = BIO_new(BIO_s_mem());
b64 = BIO_push(b64, bmem);
// Apple cut the padding off their challenges; restore it
BIO_write(bmem, input, inlen);
while (inlen++ & 3)
BIO_write(bmem, "=", 1);
BIO_flush(bmem);
int bufsize = strlen(input) * 3 / 4 + 1;
uint8_t *buf = malloc(bufsize);
int nread;
nread = BIO_read(b64, buf, bufsize);
BIO_free_all(bmem);
*outlen = nread;
return buf;
}
#endif
static char super_secret_key[] =
"-----BEGIN RSA PRIVATE KEY-----\n"
"MIIEpQIBAAKCAQEA59dE8qLieItsH1WgjrcFRKj6eUWqi+bGLOX1HL3U3GhC/j0Qg90u3sG/1CUt\n"
"wC5vOYvfDmFI6oSFXi5ELabWJmT2dKHzBJKa3k9ok+8t9ucRqMd6DZHJ2YCCLlDRKSKv6kDqnw4U\n"
"wPdpOMXziC/AMj3Z/lUVX1G7WSHCAWKf1zNS1eLvqr+boEjXuBOitnZ/bDzPHrTOZz0Dew0uowxf\n"
"/+sG+NCK3eQJVxqcaJ/vEHKIVd2M+5qL71yJQ+87X6oV3eaYvt3zWZYD6z5vYTcrtij2VZ9Zmni/\n"
"UAaHqn9JdsBWLUEpVviYnhimNVvYFZeCXg/IdTQ+x4IRdiXNv5hEewIDAQABAoIBAQDl8Axy9XfW\n"
"BLmkzkEiqoSwF0PsmVrPzH9KsnwLGH+QZlvjWd8SWYGN7u1507HvhF5N3drJoVU3O14nDY4TFQAa\n"
"LlJ9VM35AApXaLyY1ERrN7u9ALKd2LUwYhM7Km539O4yUFYikE2nIPscEsA5ltpxOgUGCY7b7ez5\n"
"NtD6nL1ZKauw7aNXmVAvmJTcuPxWmoktF3gDJKK2wxZuNGcJE0uFQEG4Z3BrWP7yoNuSK3dii2jm\n"
"lpPHr0O/KnPQtzI3eguhe0TwUem/eYSdyzMyVx/YpwkzwtYL3sR5k0o9rKQLtvLzfAqdBxBurciz\n"
"aaA/L0HIgAmOit1GJA2saMxTVPNhAoGBAPfgv1oeZxgxmotiCcMXFEQEWflzhWYTsXrhUIuz5jFu\n"
"a39GLS99ZEErhLdrwj8rDDViRVJ5skOp9zFvlYAHs0xh92ji1E7V/ysnKBfsMrPkk5KSKPrnjndM\n"
"oPdevWnVkgJ5jxFuNgxkOLMuG9i53B4yMvDTCRiIPMQ++N2iLDaRAoGBAO9v//mU8eVkQaoANf0Z\n"
"oMjW8CN4xwWA2cSEIHkd9AfFkftuv8oyLDCG3ZAf0vrhrrtkrfa7ef+AUb69DNggq4mHQAYBp7L+\n"
"k5DKzJrKuO0r+R0YbY9pZD1+/g9dVt91d6LQNepUE/yY2PP5CNoFmjedpLHMOPFdVgqDzDFxU8hL\n"
"AoGBANDrr7xAJbqBjHVwIzQ4To9pb4BNeqDndk5Qe7fT3+/H1njGaC0/rXE0Qb7q5ySgnsCb3DvA\n"
"cJyRM9SJ7OKlGt0FMSdJD5KG0XPIpAVNwgpXXH5MDJg09KHeh0kXo+QA6viFBi21y340NonnEfdf\n"
"54PX4ZGS/Xac1UK+pLkBB+zRAoGAf0AY3H3qKS2lMEI4bzEFoHeK3G895pDaK3TFBVmD7fV0Zhov\n"
"17fegFPMwOII8MisYm9ZfT2Z0s5Ro3s5rkt+nvLAdfC/PYPKzTLalpGSwomSNYJcB9HNMlmhkGzc\n"
"1JnLYT4iyUyx6pcZBmCd8bD0iwY/FzcgNDaUmbX9+XDvRA0CgYEAkE7pIPlE71qvfJQgoA9em0gI\n"
"LAuE4Pu13aKiJnfft7hIjbK+5kyb3TysZvoyDnb3HOKvInK7vXbKuU4ISgxB2bB3HcYzQMGsz1qJ\n"
"2gG0N5hvJpzwwhbhXqFKA4zaaSrw622wDniAK5MlIE0tIAKKP4yxNGjoD2QYjhBGuhvkWKY=\n"
"-----END RSA PRIVATE KEY-----\0";
#ifdef HAVE_LIBSSL
uint8_t *rsa_apply(uint8_t *input, int inlen, int *outlen, int mode) {
static RSA *rsa = NULL;
if (!rsa) {
BIO *bmem = BIO_new_mem_buf(super_secret_key, -1);
rsa = PEM_read_bio_RSAPrivateKey(bmem, NULL, NULL, NULL);
BIO_free(bmem);
}
uint8_t *out = malloc(RSA_size(rsa));
switch (mode) {
case RSA_MODE_AUTH:
*outlen = RSA_private_encrypt(inlen, input, out, rsa, RSA_PKCS1_PADDING);
break;
case RSA_MODE_KEY:
*outlen = RSA_private_decrypt(inlen, input, out, rsa, RSA_PKCS1_OAEP_PADDING);
break;
default:
die("bad rsa mode");
}
return out;
}
#endif
#ifdef HAVE_LIBPOLARSSL
uint8_t *rsa_apply(uint8_t *input, int inlen, int *outlen, int mode) {
rsa_context trsa;
const char *pers = "rsa_encrypt";
int rc;
entropy_context entropy;
ctr_drbg_context ctr_drbg;
entropy_init(&entropy);
if ((rc = ctr_drbg_init(&ctr_drbg, entropy_func, &entropy, (const unsigned char *)pers,
strlen(pers))) != 0)
debug(1, "ctr_drbg_init returned %d\n", rc);
rsa_init(&trsa, RSA_PKCS_V21, POLARSSL_MD_SHA1); // padding and hash id get overwritten
// BTW, this seems to reset a lot of parameters in the rsa_context
rc = x509parse_key(&trsa, (unsigned char *)super_secret_key, strlen(super_secret_key), NULL, 0);
if (rc != 0)
debug(1, "Error %d reading the private key.");
uint8_t *out = NULL;
switch (mode) {
case RSA_MODE_AUTH:
trsa.padding = RSA_PKCS_V15;
trsa.hash_id = POLARSSL_MD_NONE;
debug(2, "rsa_apply encrypt");
out = malloc(trsa.len);
rc = rsa_pkcs1_encrypt(&trsa, ctr_drbg_random, &ctr_drbg, RSA_PRIVATE, inlen, input, out);
if (rc != 0)
debug(1, "rsa_pkcs1_encrypt error %d.", rc);
*outlen = trsa.len;
break;
case RSA_MODE_KEY:
debug(2, "rsa_apply decrypt");
trsa.padding = RSA_PKCS_V21;
trsa.hash_id = POLARSSL_MD_SHA1;
out = malloc(trsa.len);
#if POLARSSL_VERSION_NUMBER >= 0x01020900
rc = rsa_pkcs1_decrypt(&trsa, ctr_drbg_random, &ctr_drbg, RSA_PRIVATE, (size_t *)outlen, input,
out, trsa.len);
#else
rc = rsa_pkcs1_decrypt(&trsa, RSA_PRIVATE, outlen, input, out, trsa.len);
#endif
if (rc != 0)
debug(1, "decrypt error %d.", rc);
break;
default:
die("bad rsa mode");
}
rsa_free(&trsa);
debug(2, "rsa_apply exit");
return out;
}
#endif
void command_start(void) {
if (config.cmd_start) {
/*Spawn a child to run the program.*/
pid_t pid = fork();
if (pid == 0) { /* child process */
int argC;
char **argV;
// debug(1,"on-start command found.");
if (poptParseArgvString(config.cmd_start, &argC, (const char ***)&argV) !=
0) // note that argV should be free()'d after use, but we expect this fork to exit
// eventually.
debug(1, "Can't decipher on-start command arguments");
else {
// debug(1,"Executing on-start command %s with %d arguments.",argV[0],argC);
execv(argV[0], argV);
warn("Execution of on-start command failed to start");
debug(1, "Error executing on-start command %s", config.cmd_start);
exit(127); /* only if execv fails */
}
} else {
if (config.cmd_blocking) { /* pid!=0 means parent process and if blocking is true, wait for
process to finish */
pid_t rc = waitpid(pid, 0, 0); /* wait for child to exit */
if (rc != pid) {
warn("Execution of on-start command returned an error.");
debug(1, "on-start command %s finished with error %d", config.cmd_start, errno);
}
}
// debug(1,"Continue after on-start command");
}
}
}
void command_stop(void) {
if (config.cmd_stop) {
/*Spawn a child to run the program.*/
pid_t pid = fork();
if (pid == 0) { /* child process */
int argC;
char **argV;
// debug(1,"on-stop command found.");
if (poptParseArgvString(config.cmd_stop, &argC, (const char ***)&argV) !=
0) // note that argV should be free()'d after use, but we expect this fork to exit
// eventually.
debug(1, "Can't decipher on-stop command arguments");
else {
// debug(1,"Executing on-stop command %s",config.cmd_stop);
execv(argV[0], argV);
warn("Execution of on-stop command failed to start");
debug(1, "Error executing on-stop command %s", config.cmd_stop);
exit(127); /* only if execv fails */
}
} else {
if (config.cmd_blocking) { /* pid!=0 means parent process and if blocking is true, wait for
process to finish */
pid_t rc = waitpid(pid, 0, 0); /* wait for child to exit */
if (rc != pid) {
warn("Execution of on-stop command returned an error.");
debug(1, "Stop command %s finished with error %d", config.cmd_stop, errno);
}
}
// debug(1,"Continue after on-stop command");
}
}
}
// this is for reading an unsigned 32 bit number, such as an RTP timestamp
uint32_t uatoi(const char *nptr) {
uint64_t llint = atoll(nptr);
uint32_t r = llint;
return r;
}
// Given a volume (0 to -30) and high and low attenuations available in the mixer in dB, return an
// attenuation depending on the volume and the function's transfer function
// See http://tangentsoft.net/audio/atten.html for data on good attenuators.
// We want a smooth attenuation function, like, for example, the ALPS RK27 Potentiometer transfer
// functions referred to at the link above.
// Note that the max_db and min_db are given as dB*100
double vol2attn(double vol, long max_db, long min_db) {
// We use a little coordinate geometry to build a transfer function from the volume passed in to the
// device's dynamic range.
// (See the diagram in the documents folder.)
// The x axis is the "volume in" which will be from -30 to 0. The y axis will be the "volume out"
// which will be from the bottom of the range to the top.
// We build the transfer function from one or more lines. We characterise each line with two
// numbers:
// the first is where on x the line starts when y=0 (x can be from 0 to -30); the second is where on
// y the line stops when when x is -30.
// thus, if the line was characterised as {0,-30}, it would be an identity transfer.
// Assuming, for example, a dynamic range of lv=-60 to hv=0
// Typically we'll use three lines -- a three order transfer function
// First: {0,30} giving a gentle slope -- the 30 comes from half the dynamic range
// Second: {-5,-30-(lv+30)/2} giving a faster slope from y=0 at x=-12 to y=-42.5 at x=-30
// Third: {-17,lv} giving a fast slope from y=0 at x=-19 to y=-60 at x=-30
#define order 3
double vol_setting = max_db;
if ((vol <= 0.0) && (vol >= -30.0)) {
long range_db = max_db - min_db; // this will be a positive nunmber
// debug(1,"Volume min %ddB, max %ddB, range %ddB.",min_db,max_db,range_db);
// double first_slope = -3000.0; // this is the slope of the attenuation at the high end -- 30dB
// for the full rotation.
double first_slope =
-range_db /
2; // this is the slope of the attenuation at the high end -- 30dB for the full rotation.
if (-range_db > first_slope)
first_slope = range_db;
double lines[order][2] = {
{0, first_slope}, {-5, first_slope - (range_db + first_slope) / 2}, {-17, -range_db}};
int i;
for (i = 0; i < order; i++) {
if (vol <= lines[i][0]) {
double tvol = lines[i][1] * (vol - lines[i][0]) / (-30 - lines[i][0]);
// debug(1,"On line %d, end point of %f, input vol %f yields output vol
// %f.",i,lines[i][1],vol,tvol);
if (tvol < vol_setting)
vol_setting = tvol;
}
}
vol_setting += max_db;
} else if (vol != -144.0) {
debug(1, "Volume request value %f is out of range: should be from 0.0 to -30.0 or -144.0.",
vol);
} else {
vol_setting = min_db; // for safety, return the lowest setting...
}
// debug(1,"returning an attenuation of %f.",vol_setting);
return vol_setting;
}
uint64_t get_absolute_time_in_fp() {
uint64_t time_now_fp;
#ifdef COMPILE_FOR_LINUX_AND_FREEBSD_AND_CYGWIN
struct timespec tn;
// can't use CLOCK_MONOTONIC_RAW as it's not implemented in OpenWrt
clock_gettime(CLOCK_MONOTONIC, &tn);
time_now_fp = ((uint64_t)tn.tv_sec << 32) + ((uint64_t)tn.tv_nsec << 32) / 1000000000;
#endif
#ifdef COMPILE_FOR_OSX
uint64_t time_now_mach;
uint64_t elapsedNano;
static mach_timebase_info_data_t sTimebaseInfo = {0, 0};
time_now_mach = mach_absolute_time();
// If this is the first time we've run, get the timebase.
// We can use denom == 0 to indicate that sTimebaseInfo is
// uninitialised because it makes no sense to have a zero
// denominator in a fraction.
if (sTimebaseInfo.denom == 0) {
debug(1, "Mac initialise timebase info.");
(void)mach_timebase_info(&sTimebaseInfo);
}
// Do the maths. We hope that the multiplication doesn't
// overflow; the price you pay for working in fixed point.
// this gives us nanoseconds
uint64_t time_now_ns = time_now_mach * sTimebaseInfo.numer / sTimebaseInfo.denom;
// take the units and shift them to the upper half of the fp, and take the nanoseconds, shift them
// to the upper half and then divide the result to 1000000000
time_now_fp =
((time_now_ns / 1000000000) << 32) + (((time_now_ns % 1000000000) << 32) / 1000000000);
#endif
return time_now_fp;
}
ssize_t non_blocking_write(int fd, const void *buf, size_t count) {
// debug(1,"writing %u to pipe...",count);
// we are assuming that the count is always smaller than the FIFO's buffer
struct pollfd ufds[1];
ssize_t reply;
do {
ufds[0].fd = fd;
ufds[0].events = POLLOUT;
int rv = poll(ufds, 1, 5000);
if (rv == -1)
debug(1, "error waiting for pipe to unblock...");
if (rv == 0)
debug(1, "timeout waiting for pipe to unblock");
reply = write(fd, buf, count);
if ((reply == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK)))
debug(1, "writing to pipe will block...");
// else
// debug(1,"writing %u to pipe done...",reply);
} while ((reply == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK)));
return reply;
// return write(fd,buf,count);
}
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