gdb.txt: Running Vscode remotely

cmake_targets/gdb.txt

@@ -81,3 +81,75 @@ See launch.json for details about how vscode launches lte-softmodem for debuggin
 For example, in lte-softmodem.c, scroll to main() and click the line number to
 the left of main to add a breakpoint.  then do Run => Start debugging (F5) to
 run lte-softmodem in the debugger
+
+-------------------------------------------------------------------------------
+Running Vscode remotely.
+
+Currently, running Vscode remotely (via an X-Windows connection) does not work
+-- the Vscode window appears but remains blank.  Presumably the Vscode
+developers will fix this problem eventually.  Meanwhile, you can use `sshfs`
+to make the remote filesystem appear locally and then run Vscode locally.
+
+On the local machine:
+
+  $ remote=surfer      # or whatever the remote machine's name is
+  $ mkdir ~/openairinterface5g
+  $ sshfs $remote:openairinterface5g ~/openairinterface5g
+  $ ls ~/openairinterface5g
+   CHANGELOG.md    CONTRIBUTING.md   nfapi       openair3            targets
+  ...
+  $ code ~/openairinterface5g
+  $
+
+The remote and local pathnames of your openairinterface5g workspace should be
+the same.  If they're different, use a symlink on the local machine to make
+the remote pathnames work locally.  This part is important because executables
+built on $remote contain references to the source files and vscode & gdb will
+use those pathnames to find the source files.
+
+You may want to locally mount the remote logs directory, too:
+
+  $ mkdir ~/logs
+  $ sshfs $remote:logs ~/logs
+  $ ls -l ~/logs
+  total 40
+  lrwxrwxrwx 1 1002 1002   22 Jan 17 11:54 latest -> logs-2021-01-17-085419
+  drwxr-xr-x 1 1002 1002 4096 Jan 17 11:54 logs-2021-01-17-085419
+  $
+
+That will give you access to core files collected by lte_testscript.py, for
+example.
+
+  $ file ~/logs/latest/0001/coredump-6699
+  /home/michael/logs/latest/0001/coredump-6699: ELF 64-bit LSB core file,
+  x86-64, version 1 (SYSV), SVR4-style, from './ran_build/build/lte-softmodem
+  -O ../ci-scripts/conf_files/rcc.band7.tm1.nfapi', real uid: 0, effective
+  uid: 0, real gid: 0, effective gid: 0, execfn:
+  './ran_build/build/lte-softmodem', platform: 'x86_64'
+  $
+  $ file ~/openairinterface5g/cmake_targets/ran_build/build/lte-softmodem
+  /home/michael/openairinterface5g/cmake_targets/ran_build/build/lte-softmodem:
+  ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked,
+  interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32,
+  BuildID[sha1]=831400d4aae5d43b94ef3b22ebbd635107de48ae, with debug_info, not
+  stripped
+  $
+
+Verify gdb can access these remote files:
+
+  $ gdb ~/openairinterface5g/cmake_targets/ran_build/build/lte-softmodem \
+  ~/logs/latest/0001/coredump-6699
+  ...
+  Program terminated with signal SIGABRT, Aborted.
+  #0  0x00007f7fd7d11438 in ?? ()
+  [Current thread is 1 (LWP 39)]
+  (gdb)
+
+If this step is too slow, you may want to copy the executable and coredump
+files to the local machine first.
+
+  $ scp -C $remote:openairinterface5g/cmake_targets/ran_build/build/lte-softmodem .
+  $ scp -C $remote:logs/latest/0001/coredump-6699 .
+  $ gdb lte-softmodem coredump-6699
+
+-------------------------------------------------------------------------------