vim-patch:8.2.2586: process id may be invalid

Problem:    Process id may be invalid.
Solution:   Use sysinfo.uptime to check for recent reboot. (suggested by Hugo
            van der Sanden, closes vim/vim#7947)

f52f0606ed

test_override() is N/A.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/memline.c

@@ -72,7 +72,7 @@
 #include "nvim/memory.h"
 #include "nvim/message.h"
 #include "nvim/option.h"
-#include "nvim/os/fs_defs.h"
+#include "nvim/os/fs.h"
 #include "nvim/os/input.h"
 #include "nvim/os/os.h"
 #include "nvim/os/process.h"
@@ -698,6 +698,23 @@ static void add_b0_fenc(ZERO_BL *b0p, buf_T *buf)
   }
 }
 
+/// Return true if the process with number "b0p->b0_pid" is still running.
+/// "swap_fname" is the name of the swap file, if it's from before a reboot then
+/// the result is false;
+static bool swapfile_process_running(const ZERO_BL *b0p, const char *swap_fname)
+{
+  FileInfo st;
+  double uptime;
+  // If the system rebooted after when the swap file was written then the
+  // process can't be running now.
+  if (os_fileinfo(swap_fname, &st)
+      && uv_uptime(&uptime) == 0
+      && (Timestamp)st.stat.st_mtim.tv_sec < os_time() - (Timestamp)uptime) {
+    return false;
+  }
+  return os_proc_running((int)char_to_long(b0p->b0_pid));
+}
+
 /// Try to recover curbuf from the .swp file.
 ///
 /// @param checkext  if true, check the extension and detect whether it is a
@@ -1139,7 +1156,7 @@ void ml_recover(bool checkext)
       msg(_("Recovery completed. Buffer contents equals file contents."));
     }
     msg_puts(_("\nYou may want to delete the .swp file now."));
-    if (os_proc_running((int)char_to_long(b0p->b0_pid))) {
+    if (swapfile_process_running(b0p, fname_used)) {
       // Warn there could be an active Vim on the same file, the user may
       // want to kill it.
       msg_puts(_("\nNote: process STILL RUNNING: "));
@@ -1485,7 +1502,7 @@ static time_t swapfile_info(char_u *fname)
         if (char_to_long(b0.b0_pid) != 0L) {
           msg_puts(_("\n        process ID: "));
           msg_outnum(char_to_long(b0.b0_pid));
-          if (os_proc_running((int)char_to_long(b0.b0_pid))) {
+          if (swapfile_process_running(&b0, (const char *)fname)) {
             msg_puts(_(" (STILL RUNNING)"));
             process_still_running = true;
           }
@@ -1555,8 +1572,7 @@ static bool swapfile_unchanged(char *fname)
   }
 
   // process must be known and not running.
-  long pid = char_to_long(b0.b0_pid);
-  if (pid == 0L || os_proc_running((int)pid)) {
+  if (char_to_long(b0.b0_pid) == 0L || swapfile_process_running(&b0, fname)) {
     ret = false;
   }
 

src/nvim/testdir/test_recover.vim

@@ -1,5 +1,7 @@
 " Test :recover
 
+source check.vim
+
 func Test_recover_root_dir()
   " This used to access invalid memory.
   split Xtest
@@ -23,6 +25,21 @@ func Test_recover_root_dir()
   set dir&
 endfunc
 
+" Make a copy of the current swap file to "Xswap".
+" Return the name of the swap file.
+func CopySwapfile()
+  preserve
+  " get the name of the swap file
+  let swname = split(execute("swapname"))[0]
+  let swname = substitute(swname, '[[:blank:][:cntrl:]]*\(.\{-}\)[[:blank:][:cntrl:]]*$', '\1', '')
+  " make a copy of the swap file in Xswap
+  set binary
+  exe 'sp ' . swname
+  w! Xswap
+  set nobinary
+  return swname
+endfunc
+
 " Inserts 10000 lines with text to fill the swap file with two levels of pointer
 " blocks.  Then recovers from the swap file and checks all text is restored.
 "
@@ -40,15 +57,9 @@ func Test_swap_file()
     let i += 1
   endwhile
   $delete
-  preserve
-  " get the name of the swap file
-  let swname = split(execute("swapname"))[0]
-  let swname = substitute(swname, '[[:blank:][:cntrl:]]*\(.\{-}\)[[:blank:][:cntrl:]]*$', '\1', '')
-  " make a copy of the swap file in Xswap
-  set binary
-  exe 'sp ' . swname
-  w! Xswap
-  set nobinary
+
+  let swname = CopySwapfile()
+
   new
   only!
   bwipe! Xtest
@@ -69,3 +80,53 @@ func Test_swap_file()
   set undolevels&
   enew! | only
 endfunc
+
+func Test_nocatch_process_still_running()
+  " assume Unix means sysinfo.uptime can be used
+  CheckUnix
+  CheckNotGui
+
+  " don't intercept existing swap file here
+  au! SwapExists
+
+  " Edit a file and grab its swapfile.
+  edit Xswaptest
+  call setline(1, ['a', 'b', 'c'])
+  let swname = CopySwapfile()
+
+  " Forget we edited this file
+  new
+  only!
+  bwipe! Xswaptest
+
+  call rename('Xswap', swname)
+  call feedkeys('e', 'tL')
+  redir => editOutput
+  edit Xswaptest
+  redir END
+  call assert_match('E325: ATTENTION', editOutput)
+  call assert_match('file name: .*Xswaptest', editOutput)
+  call assert_match('process ID: \d* (STILL RUNNING)', editOutput)
+
+  " Forget we edited this file
+  new
+  only!
+  bwipe! Xswaptest
+
+  " pretend we rebooted
+  call test_override("uptime", 0)
+  sleep 1
+
+  call rename('Xswap', swname)
+  call feedkeys('e', 'tL')
+  redir => editOutput
+  edit Xswaptest
+  redir END
+  call assert_match('E325: ATTENTION', editOutput)
+  call assert_notmatch('(STILL RUNNING)', editOutput)
+
+  call test_override("ALL", 0)
+  call delete(swname)
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab