Add a Unix socket connection

Unix-domain sockets have less overhead than TCP.

DOC/src/html/sif.html

@@ -25,6 +25,12 @@ default may be overridden when pigpio starts by the <a href=
 call.&nbsp; The pigpio daemon uses this function to provide an
 option to change the port number.<br>
 <br>
+pigpio also listens for connections on "/var/run/pigpio.sock" by
+default.&nbsp; This default may be overridden when pigpio starts
+by the <a href= "cif.html#gpioCfgSocketPath">gpioCfgSocketPath</a>
+function call.&nbsp; The pigpio daemon uses this function to provide an
+option to change the socket file name.<br>
+<br>
 The pigs utility is an example of using the socket interface from
 C.<span style="font-weight: bold;"><br></span>
 <h3><a name="Request" id="Request"></a>Request</h3>

command.c

@@ -567,6 +567,7 @@ static errInfo_t errInfo[]=
    {PI_CMD_INTERRUPTED  , "command interrupted, Python"},
    {PI_NOT_ON_BCM2711   , "not available on BCM2711"},
    {PI_ONLY_ON_BCM2711  , "only available on BCM2711"},
+   {PI_BAD_SOCKET_PATH  , "socket path empty"},
 
 };
 

pigpio.3

@@ -706,6 +706,8 @@ gpioCfgInterfaces          Configure user interfaces
 .br
 gpioCfgSocketPort          Configure socket port
 .br
+gpioCfgSocketPath          Configure socket path
+.br
 gpioCfgMemAlloc            Configure DMA memory allocation mode
 .br
 gpioCfgNetAddr             Configure allowed network addresses
@@ -7802,6 +7804,30 @@ port: 1024-32000
 .br
 The default setting is to use port 8888.
 
+.IP "\fBint gpioCfgSocketPath(const char*)\fP"
+.IP "" 4
+Configures pigpio to use the specified Unix socket.
+
+.br
+
+.br
+This function is only effective if called before \fBgpioInitialise\fP.
+
+.br
+
+.br
+
+.EX
+path: path to the socket.
+.br
+
+.EE
+
+.br
+
+.br
+The default is "/var/run/pigpio.sock".
+
 .IP "\fBint gpioCfgInterfaces(unsigned ifFlags)\fP"
 .IP "" 4
 Configures pigpio support of the fifo and socket interfaces.
@@ -8945,6 +8971,8 @@ These functions are only effective if called before \fBgpioInitialise\fP.
 .br
 \fBgpioCfgSocketPort\fP
 .br
+\fBgpioCfgSocketPath\fP
+.br
 \fBgpioCfgMemAlloc\fP
 
 .br
@@ -11040,6 +11068,8 @@ A 16-bit word value.
 .br
 #define PI_ONLY_ON_BCM2711 -146 // only available on BCM2711
 .br
+#define PI_BAD_SOCKET_PORT -147 // socket path empty
+.br
 
 .br
 #define PI_PIGIF_ERR_0    -2000

pigpio.c

@@ -58,6 +58,7 @@ For more information, please refer to <http://unlicense.org/>
 #include <sys/socket.h>
 #include <sys/sysmacros.h>
 #include <netinet/tcp.h>
+#include <sys/un.h>
 #include <arpa/inet.h>
 #include <sys/select.h>
 #include <fnmatch.h>
@@ -1096,6 +1097,7 @@ typedef struct
    unsigned DMAprimaryChannel;
    unsigned DMAsecondaryChannel;
    unsigned socketPort;
+   const char * socketPath;
    unsigned ifFlags;
    unsigned memAllocMode;
    unsigned dbgLevel;
@@ -1292,6 +1294,7 @@ static volatile int runState = PI_STARTING;
 static int pthAlertRunning  = PI_THREAD_NONE;
 static int pthFifoRunning   = PI_THREAD_NONE;
 static int pthSocketRunning = PI_THREAD_NONE;
+static int pthUnixRunning   = PI_THREAD_NONE;
 
 static gpioAlert_t      gpioAlert  [PI_MAX_USER_GPIO+1];
 
@@ -1328,6 +1331,7 @@ static FILE * outFifo = NULL;
 static int fdLock       = -1;
 static int fdMem        = -1;
 static int fdSock       = -1;
+static int fdUnix       = -1;
 static int fdPmap       = -1;
 static int fdMbox       = -1;
 
@@ -1369,6 +1373,7 @@ static volatile gpioCfg_t gpioCfg =
    PI_DEFAULT_DMA_NOT_SET, /* primary DMA */
    PI_DEFAULT_DMA_NOT_SET, /* secondary DMA */
    PI_DEFAULT_SOCKET_PORT,
+   PI_DEFAULT_SOCKET_PATH,
    PI_DEFAULT_IF_FLAGS,
    PI_DEFAULT_MEM_ALLOC_MODE,
    0, /* dbgLevel */
@@ -1384,6 +1389,7 @@ static unsigned bufferCycles; /* number of cycles */
 static pthread_t pthAlert;
 static pthread_t pthFifo;
 static pthread_t pthSocket;
+static pthread_t pthUnix;
 
 static uint32_t spi_dummy;
 
@@ -7260,6 +7266,61 @@ static void * pthSocketThread(void *x)
    return 0;
 }
 
+static void * pthUnixThread(void *x)
+{
+   int fdC=0, c, *sock;
+   struct sockaddr_storage client;
+   pthread_attr_t attr;
+
+   if (pthread_attr_init(&attr))
+      SOFT_ERROR((void*)PI_INIT_FAILED,
+         "pthread_attr_init failed (%m)");
+
+   if (pthread_attr_setstacksize(&attr, STACK_SIZE))
+      SOFT_ERROR((void*)PI_INIT_FAILED,
+         "pthread_attr_setstacksize failed (%m)");
+
+   if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED))
+      SOFT_ERROR((void*)PI_INIT_FAILED,
+         "pthread_attr_setdetachstate failed (%m)");
+
+   /* fdUnix opened in gpioInitialise so that we can treat
+      failure to bind as fatal. */
+
+   listen(fdUnix, 100);
+
+   c = sizeof(client);
+
+   /* don't start until DMA started */
+
+   spinWhileStarting();
+
+   while (fdC >= 0)
+   {
+      pthread_t thr;
+
+      fdC = accept(fdUnix, (struct sockaddr *)&client, (socklen_t*)&c);
+
+      closeOrphanedNotifications(-1, fdC);
+
+      DBG(DBG_USER, "Connection accepted on socket %d", fdC);
+
+      sock = malloc(sizeof(int));
+
+      *sock = fdC;
+
+      if (pthread_create
+         (&thr, &attr, pthSocketThreadHandler, (void*) sock) < 0)
+         SOFT_ERROR((void*)PI_INIT_FAILED,
+            "socket pthread_create failed (%m)");
+   }
+
+   if (fdC < 0)
+      SOFT_ERROR((void*)PI_INIT_FAILED, "accept failed (%m)");
+
+   return 0;
+}
+
 /* ======================================================================= */
 
 static void initCheckLockFile(void)
@@ -7969,6 +8030,7 @@ static void initClearGlobals(void)
    pthAlertRunning  = PI_THREAD_NONE;
    pthFifoRunning   = PI_THREAD_NONE;
    pthSocketRunning = PI_THREAD_NONE;
+   pthUnixRunning   = PI_THREAD_NONE;
 
    wfc[0] = 0;
    wfc[1] = 0;
@@ -8051,6 +8113,7 @@ static void initClearGlobals(void)
    fdLock       = -1;
    fdMem        = -1;
    fdSock       = -1;
+   fdUnix       = -1;
 
    dmaMboxBlk = MAP_FAILED;
    dmaPMapBlk = MAP_FAILED;
@@ -8120,6 +8183,13 @@ static void initReleaseResources(void)
       pthSocketRunning = PI_THREAD_NONE;
    }
 
+   if (pthUnixRunning != PI_THREAD_NONE)
+   {
+      pthread_cancel(pthUnix);
+      pthread_join(pthUnix, NULL);
+      pthUnixRunning = PI_THREAD_NONE;
+   }
+
    /* release mmap'd memory */
 
    if (auxReg  != MAP_FAILED) munmap((void *)auxReg,  AUX_LEN);
@@ -8224,6 +8294,12 @@ static void initReleaseResources(void)
       fdSock = -1;
    }
 
+   if (fdUnix != -1)
+   {
+      close(fdUnix);
+      fdUnix = -1;
+   }
+
    if (fdPmap != -1)
    {
       close(fdPmap);
@@ -8248,7 +8324,9 @@ int initInitialise(void)
    unsigned rev, model;
    struct sockaddr_in server;
    struct sockaddr_in6 server6;
+   struct sockaddr_un serverU;
    char * portStr;
+   const char * sockStr;
    unsigned port;
    struct sched_param param;
    pthread_attr_t pthAttr;
@@ -8368,6 +8446,29 @@ int initInitialise(void)
       pthFifoRunning = PI_THREAD_STARTED;
    }
 
+   if (!(gpioCfg.ifFlags & PI_DISABLE_UNIX_IF))
+   {
+      sockStr = getenv(PI_ENVSOCK);
+      if (! sockStr) sockStr = gpioCfg.socketPath;
+
+      fdUnix = socket(AF_UNIX, SOCK_STREAM , 0);
+
+      if (fdUnix != -1)
+      {
+         bzero((char *)&serverU, sizeof(serverU));
+         serverU.sun_family = AF_UNIX;
+         strncpy (serverU.sun_path, sockStr, sizeof (serverU.sun_path) - 1);
+
+         if (bind(fdUnix,(struct sockaddr *)&serverU, sizeof(serverU)) < 0)
+            SOFT_ERROR(PI_INIT_FAILED, "bind to socket '%s' failed (%m)", sockStr);
+      }
+
+      if (pthread_create(&pthUnix, &pthAttr, pthUnixThread, &i))
+         SOFT_ERROR(PI_INIT_FAILED, "pthread_create unix failed (%m)");
+
+      pthUnixRunning = PI_THREAD_STARTED;
+   }
+
    if (!(gpioCfg.ifFlags & PI_DISABLE_SOCK_IF))
    {
       portStr = getenv(PI_ENVPORT);
@@ -13972,6 +14073,21 @@ int gpioCfgSocketPort(unsigned port)
 }
 
 
+int gpioCfgSocketPath(const char *path)
+{
+   DBG(DBG_USER, "path=%s", path);
+
+   CHECK_NOT_INITED;
+
+   if (!path || !*path)
+      SOFT_ERROR(PI_BAD_SOCKET_PATH, "bad path");
+
+   gpioCfg.socketPath = path;
+
+   return 0;
+}
+
+
 /* ----------------------------------------------------------------------- */
 
 int gpioCfgMemAlloc(unsigned memAllocMode)

pigpio.h

@@ -385,6 +385,7 @@ gpioCfgDMAchannels         Configure the DMA channels
 gpioCfgPermissions         Configure the GPIO access permissions
 gpioCfgInterfaces          Configure user interfaces
 gpioCfgSocketPort          Configure socket port
+gpioCfgSocketPath          Configure Unix socket path
 gpioCfgMemAlloc            Configure DMA memory allocation mode
 gpioCfgNetAddr             Configure allowed network addresses
 
@@ -415,6 +416,7 @@ OVERVIEW*/
 
 #define PI_ENVPORT "PIGPIO_PORT"
 #define PI_ENVADDR "PIGPIO_ADDR"
+#define PI_ENVSOCK "PIGPIO_SOCKET"
 
 #define PI_LOCKFILE "/var/run/pigpio.pid"
 
@@ -890,6 +892,7 @@ typedef void *(gpioThreadFunc_t) (void *);
 #define PI_DISABLE_SOCK_IF   2
 #define PI_LOCALHOST_SOCK_IF 4
 #define PI_DISABLE_ALERT     8
+#define PI_DISABLE_UNIX_IF   16
 
 /* memAllocMode */
 
@@ -4919,6 +4922,21 @@ The default setting is to use port 8888.
 D*/
 
 
+/*F*/
+int gpioCfgSocketPath(const char * path);
+/*D
+Configures pigpio to use the specified Unix socket.
+
+This function is only effective if called before [*gpioInitialise*].
+
+. .
+port: path to the socket file.
+. .
+
+The default is "/var/run/pigpio.sock".
+D*/
+
+
 /*F*/
 int gpioCfgInterfaces(unsigned ifFlags);
 /*D
@@ -5538,6 +5556,7 @@ These functions are only effective if called before [*gpioInitialise*].
 [*gpioCfgPermissions*] 
 [*gpioCfgInterfaces*] 
 [*gpioCfgSocketPort*] 
+[*gpioCfgSocketPath*] 
 [*gpioCfgMemAlloc*]
 
 gpioGetSamplesFunc_t::
@@ -6528,6 +6547,7 @@ after this command is issued.
 #define PI_CMD_INTERRUPTED -144 // Used by Python
 #define PI_NOT_ON_BCM2711  -145 // not available on BCM2711
 #define PI_ONLY_ON_BCM2711 -146 // only available on BCM2711
+#define PI_BAD_SOCKET_PATH -147 // socket path empty
 
 #define PI_PIGIF_ERR_0    -2000
 #define PI_PIGIF_ERR_99   -2099
@@ -6550,6 +6570,7 @@ after this command is issued.
 #define PI_DEFAULT_DMA_PRIMARY_CH_2711     7
 #define PI_DEFAULT_DMA_SECONDARY_CH_2711   6
 #define PI_DEFAULT_DMA_NOT_SET             15
+#define PI_DEFAULT_SOCKET_PATH             "/var/run/pigpio.sock"
 #define PI_DEFAULT_SOCKET_PORT             8888
 #define PI_DEFAULT_SOCKET_PORT_STR         "8888"
 #define PI_DEFAULT_SOCKET_ADDR_STR         "localhost"

pigpio.py

@@ -723,6 +723,7 @@ PI_BAD_EVENT_ID     =-143
 PI_CMD_INTERRUPTED  =-144
 PI_NOT_ON_BCM2711   =-145
 PI_ONLY_ON_BCM2711  =-146
+_PI_BAD_SOCKET_PATH =-147
 
 # pigpio error text
 
@@ -871,6 +872,7 @@ _errors=[
    [PI_CMD_INTERRUPTED   , "pigpio command interrupted"],
    [PI_NOT_ON_BCM2711    , "not available on BCM2711"],
    [PI_ONLY_ON_BCM2711   , "only available on BCM2711"],
+   [_PI_BAD_SOCKET_PATH  , "socket path empty"],
 ]
 
 _except_a = "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n{}"
@@ -5177,6 +5179,7 @@ class pi():
    def __init__(self,
                 host = os.getenv("PIGPIO_ADDR", 'localhost'),
                 port = os.getenv("PIGPIO_PORT", 8888),
+                sock = os.getenv("PIGPIO_SOCKET", None),
                 show_errors = True):
       """
       Grants access to a Pi's GPIO.
@@ -5201,6 +5204,7 @@ class pi():
       pi = pigio.pi()              # use defaults
       pi = pigpio.pi('mypi')       # specify host, default port
       pi = pigpio.pi('mypi', 7777) # specify host and port
+      pi = pigpio.pi(sock='/run/pigpio.sock') # specify a Unix socket
 
       pi = pigpio.pi()             # exit script if no connection
       if not pi.connected:
@@ -5212,19 +5216,24 @@ class pi():
       self.sl = _socklock()
       self._notify  = None
 
-      port = int(port)
+      self._sock = sock
-
-      if host == '':
-         host = "localhost"
-
-      self._host = host
-      self._port = port
-
       try:
-         self.sl.s = socket.create_connection((host, port), None)
+         if sock:
+            self.sl.s = socket.socket(family=socket.AF_UNIX, type=socket.SOCK_STREAM)
+            self.sl.s.connect(sock)
+         else:
+            port = int(port)
 
-         # Disable the Nagle algorithm.
+            if host == '':
-         self.sl.s.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+               host = "localhost"
+
+            self._host = host
+            self._port = port
+
+            self.sl.s = socket.create_connection((host, port), None)
+
+            # Disable the Nagle algorithm.
+            self.sl.s.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
 
          self._notify = _callback_thread(self.sl, host, port)
 
@@ -5264,7 +5273,9 @@ class pi():
             print(_except_z)
 
    def __repr__(self):
-      return "<pipio.pi host={} port={}>".format(self._host, self._port)
+      if self._sock is None:
+         return "<pipio.pi host={} port={}>".format(self._host, self._port)
+      return "<pipio.pi sock={}>".format(self._sock)
 
    def stop(self):
       """Release pigpio resources.

pigpiod.c

@@ -59,6 +59,7 @@ static int      foreground             = PI_DEFAULT_FOREGROUND;
 static unsigned DMAprimaryChannel      = PI_DEFAULT_DMA_NOT_SET;
 static unsigned DMAsecondaryChannel    = PI_DEFAULT_DMA_NOT_SET;
 static unsigned socketPort             = PI_DEFAULT_SOCKET_PORT;
+static char *   socketPath             = PI_DEFAULT_SOCKET_PATH;
 static unsigned memAllocMode           = PI_DEFAULT_MEM_ALLOC_MODE;
 static uint64_t updateMask             = -1;
 
@@ -106,6 +107,7 @@ void usage()
       "   -n IP addr, allow address, name or dotted,     default allow all\n" \
       "   -p value,   socket port, 1024-32000,           default 8888\n" \
       "   -s value,   sample rate, 1, 2, 4, 5, 8, or 10, default 5\n" \
+      "   -S path,    Unix socket file,                  default /var/run/pigpio.sock\n" \
       "   -t value,   clock peripheral, 0=PWM 1=PCM,     default PCM\n" \
       "   -v, -V,     display pigpio version and exit\n" \
       "   -x mask,    GPIO which may be updated,         default board GPIO\n" \
@@ -163,7 +165,7 @@ static void initOpts(int argc, char *argv[])
    uint32_t addr;
    int64_t mask;
 
-   while ((opt = getopt(argc, argv, "a:b:c:d:e:fgkln:mp:s:t:x:vV")) != -1)
+   while ((opt = getopt(argc, argv, "a:b:c:d:e:fgkln:mp:s:S:t:x:vV")) != -1)
    {
       switch (opt)
       {
@@ -256,6 +258,12 @@ static void initOpts(int argc, char *argv[])
             }
             break;
 
+         case 'S':
+            if (!*optarg)
+               fatal("invalid -S option (empty string)");
+            socketPath = optarg;
+            break;
+
          case 't':
             i = getNum(optarg, &err);
             if ((i >= PI_CLOCK_PWM) && (i <= PI_CLOCK_PCM))
@@ -358,6 +366,8 @@ int main(int argc, char **argv)
 
    gpioCfgSocketPort(socketPort);
 
+   gpioCfgSocketPath(socketPath);
+
    gpioCfgMemAlloc(memAllocMode);
 
    if (updateMaskSet) gpioCfgPermissions(updateMask);