From 5b7a2311d94ef65171055a571d5d7ddc6466e031 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@operamail.com>
Date: Sun, 31 Aug 2014 00:40:52 +0200
Subject: create and export process group
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

Signed-off-by: Mattias Andrée <maandree@operamail.com>
---
 src/libmdsserver/config.h |  9 +++++++++
 src/mds.c                 | 34 ++++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/libmdsserver/config.h b/src/libmdsserver/config.h
index dbd7655..b4a0087 100644
--- a/src/libmdsserver/config.h
+++ b/src/libmdsserver/config.h
@@ -190,6 +190,15 @@
 #endif
 
 
+/**
+ * The name of the environment variable that
+ * indicates the display server's process group
+ */
+#ifndef PGROUP_ENV
+#define PGROUP_ENV  "MDS_PGROUP"
+#endif
+
+
 /**
  * The minimum time that most have elapsed
  * for respawning to be allowed
diff --git a/src/mds.c b/src/mds.c
index cc6adfd..40d9a42 100644
--- a/src/mds.c
+++ b/src/mds.c
@@ -101,11 +101,11 @@ int main(int argc_, char** argv_)
   
   /* Set up to ignore SIGUPDATE, used in mds for re-exec, but we cannot re-exec. */
   if (xsigaction(SIGUPDATE, SIG_IGN) < 0)
-    perror(*argv);
+    xperror(*argv);
   
   /* Set up to ignore SIGDANGER. */
   if (xsigaction(SIGDANGER, SIG_IGN) < 0)
-    perror(*argv);
+    xperror(*argv);
   
   /* Create directory for socket files, PID files and such. */
   if (create_directory_root(MDS_RUNTIME_ROOT_DIRECTORY))
@@ -124,7 +124,7 @@ int main(int argc_, char** argv_)
 	  f = fopen(pathname, "r");
 	  if (f == NULL) /* Race, or error? */
 	    {
-	      perror(*argv);
+	      xperror(*argv);
 	      continue;
 	    }
 	  r = is_pid_file_reusable(f);
@@ -146,13 +146,13 @@ int main(int argc_, char** argv_)
     {
       fclose(f);
       if (unlink(pathname) < 0)
-	perror(*argv);
+	xperror(*argv);
       return 1;
     }
   fflush(f);
   fclose(f);
   if (chmod(pathname, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) < 0)
-    perror(*argv);
+    xperror(*argv);
   
   /* Create data storage directory. */
   xsnprintf(pathname,  "%s/%u.data", MDS_STORAGE_ROOT_DIRECTORY, display);
@@ -166,6 +166,12 @@ int main(int argc_, char** argv_)
 	    ":%u", display);
   fail_if (setenv(DISPLAY_ENV, pathname, 1) < 0);
   
+  /* Create a new process group and export MDS_PGROUP */
+  fail_if (setpgid(0, 0) < 0);
+  xsnprintf(pathname, /* Excuse the reuse without renaming. */
+	    "%ji", (intmax_t)getpgrp());
+  fail_if (setenv(PGROUP_ENV, pathname, 1) < 0);
+  
   /* Create display socket. */
   xsnprintf(pathname, "%s/%u.socket", MDS_RUNTIME_ROOT_DIRECTORY, display);
   address.sun_family = AF_UNIX;
@@ -204,7 +210,7 @@ int main(int argc_, char** argv_)
   return rc;
   
  pfail:
-  perror(*argv);
+  xperror(*argv);
   rc = 1;
   goto done;
 }
@@ -223,7 +229,7 @@ int is_pid_file_reusable(FILE* f)
   
   read_len = fread(piddata, 1, sizeof(piddata) / sizeof(char), f);
   if (ferror(f)) /* Failed to read. */
-    perror(*argv);
+    xperror(*argv);
   else if (feof(f) == 0) /* Did not read everything. */
     eprint("the content of a PID file is larger than expected.");
   else
@@ -337,7 +343,7 @@ int spawn_and_respawn_server(int fd)
   
   /* Get the current time. (Start of child process.) */
   if ((time_error = (monotone(&time_start) < 0)))
-    perror(*argv);
+    xperror(*argv);
   
   /* Wait for master server to die. */
   if (uninterruptable_waitpid(pid, &status, 0) == (pid_t)-1)
@@ -359,7 +365,7 @@ int spawn_and_respawn_server(int fd)
   /* Do not respawn if we could not read the time. */
   if (time_error)
     {
-      perror(*argv);
+      xperror(*argv);
       eprintf("`%s' died abnormally, not respawning because we could not read the time.", master_server);
       goto fail;
     }
@@ -396,7 +402,7 @@ int spawn_and_respawn_server(int fd)
   return rc;
   
  pfail:
-  perror(*argv);
+  xperror(*argv);
   goto fail;
 }
 
@@ -436,7 +442,7 @@ int create_directory_root(const char* pathname)
   return 0;
 
  pfail:
-  perror(*argv);
+  xperror(*argv);
   return 1;
 }
 
@@ -468,7 +474,7 @@ int create_directory_user(const char* pathname)
 	{
 	  if (errno != EEXIST) /* Unlikely race condition. */
 	    {
-	      perror(*argv);
+	      xperror(*argv);
 	      return 1;
 	    }
 	}
@@ -476,7 +482,7 @@ int create_directory_user(const char* pathname)
 	/* Set ownership. */
 	if (chown(pathname, getuid(), NOBODY_GROUP_GID) < 0)
 	  {
-	    perror(*argv);
+	    xperror(*argv);
 	    return 1;
 	  }
     }
@@ -530,7 +536,7 @@ int unlink_recursive(const char* pathname)
   
   
  pfail:
-  perror(*argv);
+  xperror(*argv);
   rc = -1;
   goto done;
 }
-- 
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