From 43c5b3372d7c17b2c196e90115fb6058b813b003 Mon Sep 17 00:00:00 2001
From: Adam Dickmeiss <adam@indexdata.dk>
Date: Tue, 28 Mar 1995 08:01:23 +0000
Subject: [PATCH] FIFO existence is used to test for a running kernel.

---
 kernel/eti.c  |  112 +++++++++++++++++++++++++++++++++++----------------------
 kernel/main.c |   40 +++++----------------
 kernel/urp.c  |    7 ++--
 3 files changed, 84 insertions(+), 75 deletions(-)

diff --git a/kernel/eti.c b/kernel/eti.c
index 183f0e3..0398f56 100644
--- a/kernel/eti.c
+++ b/kernel/eti.c
@@ -2,7 +2,10 @@
  * Europagate, 1995
  *
  * $Log: eti.c,v $
- * Revision 1.2  1995/03/27 12:51:05  adam
+ * Revision 1.3  1995/03/28 08:01:23  adam
+ * FIFO existence is used to test for a running kernel.
+ *
+ * Revision 1.2  1995/03/27  12:51:05  adam
  * New log level in use: GW_LOG_ERRNO.
  *
  * Revision 1.1  1995/03/27  08:24:00  adam
@@ -18,6 +21,8 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <setjmp.h>
+#include <signal.h>
 
 #include <gw-log.h>
 #include <gw-db.h>
@@ -27,6 +32,12 @@
 static char line_buf[LINE_MAX+1];
 
 static char *module = "eti";
+static jmp_buf retry_jmp;
+
+static void pipe_handle (int dummy)
+{
+    longjmp (retry_jmp, 1);
+}
 
 static int email_header (FILE *inf, char *from_str, char *subject_str)
 {
@@ -45,17 +56,39 @@ static int email_header (FILE *inf, char *from_str, char *subject_str)
     return 1;
 }
 
-static int kernel_active (int id)
+static void start_kernel (int argc, char **argv, int id)
 {
-    char active_name[1024];
-    int fd;
+    pid_t pid;
+    int i;
+    char **argv_p;
+    char userid_option[20];
 
-    sprintf (active_name, "kernel.pid.%d", id);
-    fd = open (active_name, O_RDONLY);
-    if (fd == -1)
-        return 0;
-    close (fd);
-    return 1;
+    argv_p = malloc (sizeof(*argv_p)*(argc+2));
+    if (!argv_p)
+    {
+	gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "malloc fail");
+	exit (1);
+    }
+    argv_p[0] = "kernel";
+    for (i = 1; i<argc; i++)
+        argv_p[i] = argv[i];
+    sprintf (userid_option, "-i%d", id);
+    argv_p[i++] = userid_option;
+    argv_p[i++] = NULL;
+
+    gw_log (GW_LOG_DEBUG, module, "Starting kernel");
+    pid = fork ();
+    if (pid == -1)
+    {
+	gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "fork");
+	exit (1);
+    }
+    if (!pid)
+    {
+        execvp ("kernel", argv_p);
+	gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "execvp");
+	exit (1);
+    }
 }
 
 int main (int argc, char **argv)
@@ -69,6 +102,7 @@ int main (int argc, char **argv)
     size_t info_length;
     int  id;
     int  r;
+    static int pass = 0;
     char fifo_client_name[1024];
     char fifo_server_name[1024];
 
@@ -112,48 +146,42 @@ int main (int argc, char **argv)
     sprintf (fifo_client_name, "fifo.c.%d", id);
 
     gip = gipc_initialize (fifo_client_name);
-    if (kernel_active (id))
+
+    signal (SIGPIPE, pipe_handle);
+    setjmp (retry_jmp);
+    ++pass;
+    gw_log (GW_LOG_DEBUG, module, "Pass %d", pass);
+    if (pass == 1)
+        r = gipc_open (gip, fifo_server_name, 0);
+    else if (pass == 2)
     {
-        gw_log (GW_LOG_DEBUG, module, "Kernel already active");
-        gipc_open (gip, fifo_server_name, 0);
+        gipc_close (gip);
+        start_kernel (argc, argv, id);
+        r = gipc_open (gip, fifo_server_name, 1);
     }
-    else
+    else if (pass == 3)
     {
-        pid_t pid;
-	int i;
-	char **argv_p;
-	char userid_option[20];
-
-        argv_p = malloc (sizeof(*argv_p)*(argc+2));
-	if (!argv_p)
+        gw_log (GW_LOG_FATAL, module, "Cannot start kernel");
+	exit (1);
+    }
+    if (r < 0)
+        if (r == -2)
 	{
-	    gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "Malloc fail");
-	    exit (1);
+	    gw_log (GW_LOG_WARN|GW_LOG_ERRNO, module, "r==-2");
+	    longjmp (retry_jmp, 1);
 	}
-	argv_p[0] = "kernel";
-        for (i = 1; i<argc; i++)
-            argv_p[i] = argv[i];
-	sprintf (userid_option, "-i%d", id);
-	argv_p[i++] = userid_option;
-	argv_p[i++] = NULL;
-
-        gw_log (GW_LOG_DEBUG, module, "Kernel not active");
-	pid = fork ();
-	if (pid == -1)
+	else if (r == -1)
 	{
-	    gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "fork");
-	    exit (1);
+	    gw_log (GW_LOG_WARN|GW_LOG_ERRNO, module, "r==-1");
+	    longjmp (retry_jmp, 1);
 	}
-	if (!pid)
+	else
 	{
-            execvp ("kernel", argv_p);
-	    gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "execvp");
+	    gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, module, "gipc_open");
 	    exit (1);
 	}
-        gipc_open (gip, fifo_server_name, 1);
-    }
     /* deliver message ... */
-    gw_log (GW_LOG_DEBUG, module, "Deliver mail header");
+    gw_log (GW_LOG_DEBUG, module, "Delivering mail header");
     gip_wline (gip, "mail\n");
     gip_wline (gip, "From ");
     gip_wline (gip, from_str);
@@ -165,7 +193,7 @@ int main (int argc, char **argv)
 	gip_wline (gip, "\n");
     }
     gip_wline (gip, "\n");
-    gw_log (GW_LOG_DEBUG, module, "Deliver mail body");
+    gw_log (GW_LOG_DEBUG, module, "Delivering mail body");
     while (fgets (line_str, LINE_MAX, stdin))
         gip_wline (gip, line_str);
     gip_wline (gip, "\001");
diff --git a/kernel/main.c b/kernel/main.c
index 10dc733..fd6ef7e 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -2,7 +2,10 @@
  * Europagate, 1995
  *
  * $Log: main.c,v $
- * Revision 1.12  1995/03/27 12:51:05  adam
+ * Revision 1.13  1995/03/28 08:01:25  adam
+ * FIFO existence is used to test for a running kernel.
+ *
+ * Revision 1.12  1995/03/27  12:51:05  adam
  * New log level in use: GW_LOG_ERRNO.
  *
  * Revision 1.11  1995/03/27  08:24:02  adam
@@ -63,32 +66,6 @@ FILE *reply_fd = stdout;
 
 struct gw_kernel_info info;
 
-static void mk_active (int userid)
-{
-    char active_name[1024];
-    char pid_buf[30];
-    int fd;
-
-    sprintf (active_name, "kernel.pid.%d", userid);
-    fd = open (active_name, O_WRONLY|O_CREAT, 0666);
-    if (fd == -1)
-    {
-        gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, "Cannot create %s", active_name);
-	exit (1);
-    }
-    sprintf (pid_buf, "%ld", (long) getpid()); 
-    write (fd, pid_buf, strlen(pid_buf));
-    close (fd);
-}
-
-static void rm_active (int userid)
-{
-    char active_name[1024];
-
-    sprintf (active_name, "kernel.pid.%d", userid);
-    unlink (active_name);
-}
-
 static void kernel_events (int userid)
 {
     char fifo_client_name[1024];
@@ -131,7 +108,10 @@ static void kernel_events (int userid)
             char command[128], *cp;
 
 	    if (!(lgets (command, 127, gip_fd)))
+	    {
+	        gw_log (GW_LOG_WARN, KERNEL_LOG, "Unexpected close");
 	        break;
+	    }
 	    if ((cp = strchr (command, '\n')))
 	        *cp = '\0';
 	    gw_log (GW_LOG_STAT, KERNEL_LOG, "IPC: %s", command);
@@ -153,6 +133,8 @@ static void kernel_events (int userid)
     }
     gips_close (gip);
     gips_destroy (gip);
+    unlink (fifo_client_name);
+    unlink (fifo_server_name);
 }
 
 int main (int argc, char **argv)
@@ -308,11 +290,7 @@ int main (int argc, char **argv)
     }
     read_kernel_res ();
     if (userid != -1)
-    {
-        mk_active (userid);
         kernel_events (userid);
-	rm_active (userid);
-    }
     else
         urp (0);
     return 0;
diff --git a/kernel/urp.c b/kernel/urp.c
index 9f3b37e..5e2d9b1 100644
--- a/kernel/urp.c
+++ b/kernel/urp.c
@@ -2,7 +2,10 @@
  * Europagate, 1995
  *
  * $Log: urp.c,v $
- * Revision 1.22  1995/03/27 12:51:05  adam
+ * Revision 1.23  1995/03/28 08:01:28  adam
+ * FIFO existence is used to test for a running kernel.
+ *
+ * Revision 1.22  1995/03/27  12:51:05  adam
  * New log level in use: GW_LOG_ERRNO.
  *
  * Revision 1.21  1995/03/27  08:24:04  adam
@@ -817,7 +820,7 @@ int urp (int fd)
         
         mta_code = system (cmd);
         if (mta_code)
-            gw_log (GW_LOG_FATAL|GW_LOG_ERRNO, KERNEL_LOG,
+            gw_log (GW_LOG_FATAL, KERNEL_LOG,
                     "Reply '%s' got exit code %d", cmd, mta_code);
         unlink (reply_fname);        
         gw_log (GW_LOG_ACCT, KERNEL_LOG, "User end %s", from_str);
-- 
1.7.10.4