Move IPC helpers to separate files

src/CMakeLists.txt

@@ -109,6 +109,7 @@ add_executable (manage-utils-test
 
                 debug_utils.c
                 gvmd.c gmpd.c
+                ipc.c
                 manage.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c
@@ -140,6 +141,7 @@ add_executable (manage-test
 
                 debug_utils.c
                 gvmd.c gmpd.c
+                ipc.c
                 manage_utils.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c
@@ -171,6 +173,7 @@ add_executable (manage-sql-test
 
                 debug_utils.c
                 gvmd.c gmpd.c
+                ipc.c
                 manage_utils.c manage.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c
@@ -202,6 +205,7 @@ add_executable (gmp-tickets-test
 
                 debug_utils.c
                 gvmd.c gmpd.c
+                ipc.c
                 manage_utils.c manage.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c
@@ -233,6 +237,7 @@ add_executable (utils-test
 
                 debug_utils.c
                 gvmd.c gmpd.c
+                ipc.c
                 manage_utils.c manage.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c
@@ -281,6 +286,7 @@ add_executable (gvmd
                 main.c gvmd.c
                 debug_utils.c
                 gmpd.c
+                ipc.c
                 manage_utils.c manage.c sql.c
                 manage_acl.c manage_configs.c manage_get.c
                 manage_license.c

src/gvmd.c

@@ -102,6 +102,7 @@
 #include <gvm/util/ldaputils.h>
 
 #include "debug_utils.h"
+#include "ipc.h"
 #include "manage.h"
 #include "manage_sql_nvts.h"
 #include "manage_sql_secinfo.h"

src/ipc.c

@@ -0,0 +1,160 @@
+/* Copyright (C) 2024 Greenbone AG
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file ipc.c
+ * @brief Inter-process communitcation (IPC)
+ */
+
+/**
+ * @brief Enable extra GNU functions.
+ *
+ * semtimedop needs this
+ */
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <sys/sem.h>
+
+#include "ipc.h"
+#include "manage.h"
+
+
+/**
+ * @brief System V semaphore set key for gvmd actions.
+ */
+static key_t semaphore_set_key = -1;
+
+/**
+ * @brief System V semaphore set id for gvmd actions.
+ */
+static int semaphore_set = -1;
+
+/**
+ * @brief Union type for values of semctl actions
+ */
+union semun {
+    int              val;    ///< Value for SETVAL
+    struct semid_ds *buf;    ///< Buffer for IPC_STAT, IPC_SET
+    unsigned short  *array;  ///< Array for GETALL, SETALL
+    struct seminfo  *__buf;  ///< Buffer for IPC_INFO (Linux-specific)
+};
+
+/**
+ * @brief Initializes the semaphore set for gvmd actions.
+ *
+ * Needs max_concurrent_scan_updates to be set.
+ *
+ * @return 0 success, -1 error
+ */
+int
+init_semaphore_set ()
+{
+  // Ensure semaphore set file exists
+  gchar *key_file_name = g_build_filename (GVM_STATE_DIR, "gvmd.sem", NULL);
+  FILE *key_file = fopen (key_file_name, "a");
+  union semun sem_value;
+  if (key_file == NULL)
+    {
+      g_warning ("%s: error creating semaphore file %s: %s",
+                 __func__, key_file_name, strerror (errno));
+      g_free (key_file_name);
+      return -1;
+    }
+  fclose (key_file);
+  semaphore_set_key = ftok (key_file_name, 0);
+  if (semaphore_set_key < 0)
+    {
+      g_warning ("%s: error creating semaphore key for file %s: %s",
+                 __func__, key_file_name, strerror (errno));
+      g_free (key_file_name);
+      return -1;
+    }
+
+  semaphore_set = semget (semaphore_set_key, 1, 0660 | IPC_CREAT);
+  if (semaphore_set < 0)
+    {
+      g_warning ("%s: error getting semaphore set: %s",
+                 __func__, strerror (errno));
+      g_free (key_file_name);
+      return -1;
+    }
+
+  g_debug ("%s: Semaphore set created for file '%s', key %x",
+             __func__, key_file_name, semaphore_set_key);
+  g_free (key_file_name);
+
+  sem_value.val = get_max_concurrent_scan_updates () ?: 1;
+  if (semctl (semaphore_set, SEMAPHORE_SCAN_UPDATE, SETVAL, sem_value) == -1)
+    {
+      g_warning ("%s: error initializing scan update semaphore: %s",
+                 __func__, strerror (errno));
+      return -1;
+    }
+
+  return 0;
+}
+
+/**
+ * @brief Performs a semaphore operation (signal or wait).
+ *
+ * A negative op_value will try to decrease the semaphore value
+ *  and wait if needed.
+ * A positive op_value will increase the semaphore value.
+ * Zero as op_value will wait for the semaphore value to become zero.
+ *
+ * (See semop from sys/sem.h)
+ *
+ * @param[in]  semaphore_index  The index of the semaphore in the gvmd set.
+ * @param[in]  op_value   The operation value
+ * @param[in]  timeout    Timeout in seconds, 0 for unlimited
+ *
+ * @return 0 success, 1 timed out, -1 error
+ */
+int
+semaphore_op (semaphore_index_t semaphore_index,
+              short int op_value,
+              time_t timeout)
+{
+  int ret;
+  struct sembuf op = {
+    sem_num: semaphore_index,
+    sem_op: op_value,
+    sem_flg: SEM_UNDO
+  };
+
+  struct timespec ts = {
+    tv_nsec: 0,
+    tv_sec: timeout,
+  };
+
+  ret = semtimedop (semaphore_set, &op, 1, timeout > 0 ? &ts : NULL);
+  if (ret)
+    {
+      if (errno == EAGAIN)
+        return 1;
+      else
+        {
+          g_warning ("%s: semaphore operation failed: %s",
+                     __func__, strerror (errno));
+          return -1;
+        }
+    }
+
+  return 0;
+}

src/ipc.h

@@ -0,0 +1,37 @@
+/* Copyright (C) 2024 Greenbone AG
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file ipc.h
+ * @brief Headers for inter-process communitcation (IPC)
+ */
+
+#ifndef _GVMD_IPC_H
+#define _GVMD_IPC_H
+
+typedef enum {
+  SEMAPHORE_SCAN_UPDATE = 0
+} semaphore_index_t;
+
+int
+init_semaphore_set ();
+
+int
+semaphore_op (semaphore_index_t, short int, time_t);
+
+#endif /* not _GVMD_IPC_H */