Add IQ file recording and IQ file viewer to ImScope

This commit introduces the following changes to ImScope:
 - Added the ability to record IQ data using the same mechanism as ImScope.
 - Added a new executable target `imscope_iq_file_viewer` for viewing IQ files.
 - Introduced a command line argument `--imscope-record` that enables data recording mode.
 - Refactored a lot of the scope code

Usage:
 - To record IQ data, run a modem with `--imscope-record` flag.
   The recording happens whenever a modem calls dumpScopeData, which currently is
   done only in gNB on PUSCH DTX and PUSCH CRC NOK.
   There is a limit of ~1GB of files written by the thread in a signle run to avoid
   accidentally exhausting disk space.
   If a directory `imscope-dump` is available the data will be recorded there in .imscope
   files. Otherwise files are written to the directory the modem was run. This is done so that
   the directory can be mapped in a docker container.

 - To view recorded IQ files, use the new executable `imscope_iq_file_viewer`. This can be done by running:
      ```
      ./imscope_iq_file_viewer <path_to_iq_file>
      ```
   Replace `<path_to_iq_file>` with the path to the IQ file you want to view.

openair1/PHY/TOOLS/imscope/imscope_record.cpp

@@ -0,0 +1,131 @@
+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#include "imscope_internal.h"
+#include "openair1/PHY/TOOLS/phy_scope_interface.h"
+#include <sys/stat.h>
+
+#define NUM_CACHED_DATA 4
+// Set maximum number of kilobytes written per recording session to 1GB. This is a safeguard against
+// recoding thread writing too many files and exhausting disk space.
+#define MAX_KBYTES_WRITTEN_PER_SESSION (1000 * 1000)
+
+ImScopeDataWrapper scope_array[EXTRA_SCOPE_TYPES];
+volatile int slot_to_dump = -1;
+volatile int frame_to_dump = -1;
+
+extern "C" void imscope_record_autoinit(void *dataptr)
+{
+  AssertFatal(IS_SOFTMODEM_5GUE ||  IS_SOFTMODEM_GNB,
+              "Scope cannot find NRUE or GNB context");
+  LOG_A(PHY, "Imscope recording started\n");
+
+  for (auto i = 0U; i < EXTRA_SCOPE_TYPES; i++) {
+    scope_array[i].is_data_ready = false;
+    scope_array[i].data.scope_graph_data = nullptr;
+    scope_array[i].data.meta = {-1, -1};
+  }
+
+  scopeData_t *scope = (scopeData_t *)calloc(1, sizeof(scopeData_t));
+  scope->copyData = copyDataThreadSafe;
+  scope->tryLockScopeData = tryLockScopeData;
+  scope->copyDataUnsafeWithOffset = copyDataUnsafeWithOffset;
+  scope->unlockScopeData = unlockScopeData;
+  scope->copyData = copyDataThreadSafe;
+  scope->dumpScopeData = dumpScopeData;
+  if (IS_SOFTMODEM_GNB) {
+    scopeParms_t *scope_params = (scopeParms_t *)dataptr;
+    scope_params->gNB->scopeData = scope;
+    scope_params->ru->scopeData = scope;
+  } else {
+    PHY_VARS_NR_UE *ue = (PHY_VARS_NR_UE *)dataptr;
+    ue->scopeData = scope;
+  }
+
+  pthread_t thread;
+  threadCreate(&thread, imscope_record_thread, dataptr, (char *)"imscope_record", -1, sched_get_priority_min(SCHED_RR));
+}
+
+void dumpScopeData(int slot, int frame) {
+  if (slot_to_dump == -1) {
+    LOG_E(PHY, "Will dump scope data\n");
+    frame_to_dump = frame;
+    slot_to_dump = slot;
+  }
+}
+
+void *imscope_record_thread(void *data_void_ptr)
+{
+  const char *path = "imscope-dump";
+  struct stat info;
+  bool has_dir = false;
+  if (stat(path, &info) == 0) {
+    if (info.st_mode & S_IFDIR) {
+      has_dir = true;
+    }
+  }
+  if (has_dir) {
+    LOG_A(PHY, "ImScope recorder thread starts, recording data to %s\n", path);
+  } else {
+    LOG_A(PHY, "ImScope recorder thread starts, recording data to cwd\n");
+  }
+  ImScopeData scope_cache[EXTRA_SCOPE_TYPES][NUM_CACHED_DATA];
+  memset(scope_cache, 0, sizeof(scope_cache));
+  uint scope_cache_index[EXTRA_SCOPE_TYPES] = {0};
+  float kbytes_written = 0.0f;
+  while (kbytes_written < MAX_KBYTES_WRITTEN_PER_SESSION) {
+    if (slot_to_dump != -1) {
+      std::string filename = std::string(path);
+      filename += has_dir ? "/" : "-";
+      filename += std::to_string(frame_to_dump) + std::string("-") + std::to_string(slot_to_dump) + std::string(".imscope");
+      std::ofstream outf(filename, std::ios_base::out | std::ios_base::binary);
+      if (!outf) {
+        LOG_E(PHY, "Could not open file %s for writing\n", filename.c_str());
+        break;
+      }
+      for (auto i = 0U; i < EXTRA_SCOPE_TYPES; i++) {
+        for (auto j = 0U; j < NUM_CACHED_DATA; j++) {
+          ImScopeData &scope_data = scope_cache[i][j];
+          if (scope_data.meta.frame == frame_to_dump && scope_data.meta.slot == slot_to_dump) {
+            scope_data.dump_to_file(outf);
+          }
+        }
+      }
+      long pos = outf.tellp();
+      kbytes_written += pos / 1000.0f;
+      outf.close();
+      LOG_D(PHY, "ImScope done writing to %s\n", filename.c_str());
+      slot_to_dump = -1;
+    }
+    for (auto i = 0U; i < EXTRA_SCOPE_TYPES; i++) {
+      ImScopeDataWrapper &scope_data = scope_array[i];
+      if (scope_data.is_data_ready) {
+        uint cache_index = scope_cache_index[i]++ % NUM_CACHED_DATA;
+        ImScopeData tmp = scope_cache[i][cache_index];
+        scope_cache[i][cache_index] = scope_data.data;
+        scope_data.data = tmp;
+        scope_data.is_data_ready = false;
+      }
+    }
+  }
+  LOG_E(PHY, "ImScope recorder thread exits!\n");
+  return nullptr;
+}