Switch out sockets IPC for a named pipe. Just like SysV does.

diff --git a/Makefile b/Makefile
index 561f3c380746c7c812900fbe6b91ece33cc505d4..b6f94ccda94ef7fb3f65ab99d02f1ae4c450bc62 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 # Doesn't need to be more complex than this
 
 init-ng: init-ng.c
-       gcc -std=c99 -g init-ng.c -o init-ng
+       gcc -std=c99 -g -D_DEFAULT_SOURCE init-ng.c -o init-ng
 

diff --git a/init-ng.c b/init-ng.c
index d161b844b71a08e8f3f5fa177cc2de222161d1ab..cc517777e68bc35c48546063338984709477bdd3 100644 (file)
--- a/init-ng.c
+++ b/init-ng.c
@@ -10,7 +10,6 @@
 // (C) 2017 Underground Software
 //
 
-#define _DEFAULT_SOURCE                // Without this, functions in unistd.h go missing
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
@@ -19,12 +18,12 @@
 #include <string.h>
 #include <sys/reboot.h>
 #include <sys/syscall.h>
-#include <sys/socket.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/un.h>
 #include <sys/wait.h>
 
-static const char socketPath[] = "/run/initctl";
+static const char fifoPath[] = "/dev/initctl";
 static int shuttingDown = 0;
 static int verbose = 0;                // N.B.: There is no mechanism to set this ATM
 static struct sigaction action;
@@ -54,7 +53,7 @@ int FindMonitoredPID(pid_t pid)
 //
 // Remove the given process from the MPL by index
 //
-void RemoveEntry(int entry)
+static void RemoveEntry(int entry)
 {
        free(processCmd[entry]);
        free(processName[entry]);
@@ -68,7 +67,7 @@ void RemoveEntry(int entry)
 //
 // Add a process to the MPL
 //
-void AddEntry(pid_t pid, char * name, char * command)
+static void AddEntry(pid_t pid, char * name, char * command)
 {
        int i;
 
@@ -91,7 +90,7 @@ void AddEntry(pid_t pid, char * name, char * command)
 // Take a given space delimited string and turn it into an array of strings
 // suitable for execv().
 //
-void MakeArgumentList(char * s)
+static void MakeArgumentList(char * s)
 {
        char buf[4096];
        char * tokSave;
@@ -120,7 +119,7 @@ void MakeArgumentList(char * s)
 // monitor: Tells Launch whether or not this process should be monitored
 //          and respawned if it goes away (0 = no, 1 = yes)
 //
-pid_t Launch(char * name, char * command, int monitor)
+static pid_t Launch(char * name, char * command, int monitor)
 {
        if (verbose)
                printf("Starting %s (%smonitored)...\n", name, (monitor ? "" : "un"));
@@ -158,7 +157,7 @@ pid_t Launch(char * name, char * command, int monitor)
 // At some point, we'll read inittab instead of recording just our own internal
 // processes...
 //
-void HandleSIGCHLD(int signum, siginfo_t * info, void * ptr)
+static void HandleSIGCHLD(int signum)
 {
        while (1)
        {
@@ -196,9 +195,9 @@ void HandleSIGCHLD(int signum, siginfo_t * info, void * ptr)
 //
 // Start up the system, using the awesome power of OpenRC
 //
-void Init(void)
+static void Init(void)
 {
-       printf("*** init-ng v1.0.0 starting...\n");
+       printf("*** init-ng v1.0.1 starting...\n");
 
        pid_t pid = Launch("openrc", "/sbin/rc sysinit", 0);
        waitpid(pid, NULL, 0);
@@ -211,7 +210,7 @@ void Init(void)
 }
 
 
-void ShutDown(int cmd)
+static void ShutDown(int cmd)
 {
        shuttingDown = 1;
        pid_t pid = Launch("openrc", "/sbin/rc reboot", 0);
@@ -227,34 +226,20 @@ void ShutDown(int cmd)
 
 
 //
-// Connect to PID 1's socket to send a command
+// Connect to PID 1's FIFO to send a command
 //
-void DoCmd(char * cmd)
+static void DoCmd(char * cmd)
 {
-       struct sockaddr_un remote;
-       int s = socket(AF_UNIX, SOCK_STREAM, 0);
+       FILE * file = fopen(fifoPath, "w");
 
-       if (s == -1)
+       if (file == NULL)
        {
-               // Handle error
-               printf("Could not get socket in DoCmd()...\n");
+               perror("DoCmd: fopen");
                return;
        }
 
-       remote.sun_family = AF_UNIX;
-       strcpy(remote.sun_path, socketPath);
-       int len = strlen(remote.sun_path) + sizeof(remote.sun_family);
-       int s2 = connect(s, (struct sockaddr *)&remote, len);
-
-       if (s2 == -1)
-       {
-               // Handle error
-               printf("Could not connect in DoCmd()...\n");
-               return;
-       }
-
-       send(s, cmd, strlen(cmd), 0);
-       close(s);
+       size_t ignored = fwrite(cmd, 1, strlen(cmd), file);
+       fclose(file);
 }
 
 
@@ -303,61 +288,40 @@ int main(int argc, char * argv[])
 
        // Install SIGCHLD signal handler to do process monitoring
        memset(&action, 0, sizeof(action));
-       action.sa_sigaction = HandleSIGCHLD;
+       action.sa_handler = HandleSIGCHLD;
        action.sa_flags = SA_SIGINFO;
        sigaction(SIGCHLD, &action, NULL);
 
-       // Create socket to listen on for commands...
-       struct sockaddr_un local, remote;
-       unsigned int s = socket(AF_UNIX, SOCK_STREAM, 0);
-
-       if (s == -1)
+       // Create a named pipe to listen on for commands
+       if (mkfifo(fifoPath, 0600) == -1)
        {
-               perror("socket");
-               printf("init-ng: socket() failed!\n");
-       }
-
-       local.sun_family = AF_UNIX;
-       strcpy(local.sun_path, socketPath);
-       unlink(local.sun_path);
-       int len = strlen(local.sun_path) + sizeof(local.sun_family);
-
-       if (bind(s, (struct sockaddr *)&local, len) == -1)
-       {
-               perror("bind");
-               printf("init-ng: bind() failed!\n");
-       }
-
-       // Queue size of 20 ought to be enough for anybody ;-)
-       if (listen(s, 20) == -1)
-       {
-               perror("listen");
-               printf("init-ng: listen() failed!\n");
+               // This is bad... If this happens, we have no comms
+               perror("mkfifo");
        }
 
        // Main loop for PID 1. All commands are received and acted upon from here.
        while (1)
        {
-               int t = sizeof(remote);
-               unsigned int s2 = accept(s, (struct sockaddr *)&remote, &t);
+               // This will block until a command is sent down the pipe...
+               FILE * file = fopen(fifoPath, "r");
 
-               if (s2 == -1)
+               if (file == NULL)
                {
                        // Check to see if the signal handler blew things up on us
                        if (errno == EINTR)
                                continue;
 
-                       // An unanticipated error occurred, handle it
-                       perror("accept");
-                       printf("init-ng: accept() failed!\n");
+                       perror("fopen");
+                       continue;
                }
 
-               // Get the message from the socket
-               int n = recv(s2, buf, 2048, 0);
-               buf[n] = 0;
+               // Grab whatever was shoved into the FIFO
+               size_t read = fread(buf, 1, 2047, file);
+               buf[read] = 0;
+               fclose(file);
 
                if (verbose)
-                       printf("PID1: Received \"%s\" from socket...\n", buf);
+                       printf("PID1: Received \"%s\" from FIFO...\n", buf);
 
                // Now do something with it...
                if (strcmp(buf, "poweroff") == 0)
@@ -376,8 +340,6 @@ int main(int argc, char * argv[])
                {
                        printf("[Status placeholder]\n");
                }
-
-               close(s2);
        }
 
        // We should never get here...