[#215] Process title length

This is a brute force approach to set the process title with the
appropriate length.
The idea is to compute the size of the process title as it has been
requested, and set it to the computed size.

This works on Rocky Linux release 8.6 (Green Obsidian).

It could break some aggressive security-enforced environments.

This commit introduces the function
`pgagroal_set_connection_proc_title()` that builds a process title
with the form:

      user@host:port/database

using in turn the `pgagroal_set_proc_title` function.
The `pgagroal_set_connection_proc_title` function is used only by the
`worker` process stuff and required to identify the primary server (to
get the hostname and port).

Close #215.

src/include/utils.h

@@ -254,6 +254,20 @@ pgagroal_base64_decode(char* encoded, size_t encoded_length, char** raw, int* ra
 void
 pgagroal_set_proc_title(int argc, char** argv, char* s1, char* s2);
 
+/**
+ * Sets the process title for a given connection.
+ *
+ * Uses `pgagroal_set_proc_title` to build an information string
+ * with the form
+ *    user@host:port/database
+ *
+ * @param argc the number of arguments
+ * @param argv command line arguments
+ * @param connection the struct connection pointer for the established connection.
+ */
+void
+pgagroal_set_connection_proc_title(int argc, char** argv, struct connection* connection);
+
 #ifdef DEBUG
 
 /**

src/libpgagroal/utils.c

@@ -30,6 +30,7 @@
 #include <pgagroal.h>
 #include <logging.h>
 #include <utils.h>
+#include <server.h>
 
 /* system */
 #include <ev.h>
@@ -55,7 +56,7 @@
 extern char** environ;
 #ifdef HAVE_LINUX
 static bool env_changed = false;
-static int max_process_title_size = -1;
+static int max_process_title_size = 0;
 #endif
 
 int32_t
@@ -754,50 +755,62 @@ pgagroal_set_proc_title(int argc, char** argv, char* s1, char* s2)
       env_changed = true;
    }
 
-   if (max_process_title_size == -1)
+   // compute how long was the command line
+   // when the application was started
+   if (max_process_title_size == 0)
    {
-      int m = 0;
-
       for (int i = 0; i < argc; i++)
       {
-         m += strlen(argv[i]);
-         m += 1;
+         max_process_title_size += strlen(argv[i]) + 1;
       }
-
-      max_process_title_size = m;
-      memset(*argv, 0, max_process_title_size);
    }
 
+   // compose the new title
    memset(&title, 0, sizeof(title));
+   snprintf(title, sizeof(title) - 1, "pgagroal: %s%s%s",
+            s1 != NULL ? s1 : "",
+            s1 != NULL && s2 != NULL ? "/" : "",
+            s2 != NULL ? s2 : "");
 
-   if (s1 != NULL && s2 != NULL)
-   {
-      snprintf(title, sizeof(title) - 1, "pgagroal: %s/%s", s1, s2);
-   }
-   else
-   {
-      snprintf(title, sizeof(title) - 1, "pgagroal: %s", s1);
-   }
+   size = strlen(title) + 1;
 
-   size = MIN(max_process_title_size, sizeof(title));
-   size = MIN(size, strlen(title) + 1);
+   // nuke the command line info
+   memset(*argv, 0, max_process_title_size);
 
    memcpy(*argv, title, size);
    memset(*argv + size, 0, 1);
 
+   // keep track of how long is now the title
+   max_process_title_size = size;
+
 #else
-   if (s1 != NULL && s2 != NULL)
-   {
-      setproctitle("-pgagroal: %s/%s", s1, s2);
-   }
-   else
-   {
-      setproctitle("-pgagroal: %s", s1);
-   }
+   setproctitle("-pgagroal: %s%s%s",
+                s1 != NULL ? s1 : "",
+                s1 != NULL && s2 != NULL ? "/" : "",
+                s2 != NULL ? s2 : "");
 
 #endif
 }
 
+void
+pgagroal_set_connection_proc_title(int argc, char** argv, struct connection* connection)
+{
+   struct configuration* config;
+   int primary;
+   char info[MISC_LENGTH];
+
+   config = (struct configuration*)shmem;
+
+   pgagroal_get_primary(&primary);
+
+   snprintf(info, MISC_LENGTH, "%s@%s:%d",
+            connection->username,
+            config->servers[primary].host,
+            config->servers[primary].port);
+
+   pgagroal_set_proc_title(argc, argv, info, connection->database);
+}
+
 #ifdef DEBUG
 
 int

src/libpgagroal/worker.c

@@ -106,7 +106,7 @@ pgagroal_worker(int client_fd, char* address, char** argv)
       pgagroal_prometheus_client_active_add();
 
       pgagroal_pool_status();
-      pgagroal_set_proc_title(1, argv, config->connections[slot].username, config->connections[slot].database);
+      pgagroal_set_connection_proc_title(1, argv, &config->connections[slot]);
 
       if (config->pipeline == PIPELINE_PERFORMANCE)
       {