Avoid interleaved $(info ) output

Since $(info ) function output is written using two system calls for
the message and the newline, it's possible for output from another
parallel make job to sneak in between them.

Reported by Paul Eggert <eggert@cs.ucla.edu>, who saw the report from
Lars Ingebrigtsen <https://bugs.gnu.org/53358>.

* src/function.c (func_error): Paul provided a fix but instead I
rewrote the entire function: it's not possible for it to be invoked
with anything other than exactly one argument so don't worry about
re-combining the arguments.

diff --git a/src/function.c b/src/function.c
index c27f573bf8daf417196516e3ca474ce581abcdf9..d7c139234deb1ef121c55120652878fa9048f638 100644 (file)
--- a/src/function.c
+++ b/src/function.c
@@ -1171,41 +1171,25 @@ func_strip (char *o, char **argv, const char *funcname UNUSED)
 static char *
 func_error (char *o, char **argv, const char *funcname)
 {
-  char **argvp;
-  char *msg, *p;
-  size_t len;
-
-  /* The arguments will be broken on commas.  Rather than create yet
-     another special case where function arguments aren't broken up,
-     just create a format string that puts them back together.  */
-  for (len=0, argvp=argv; *argvp != 0; ++argvp)
-    len += strlen (*argvp) + 2;
-
-  p = msg = alloca (len + 1);
-  msg[0] = '\0';
-
-  for (argvp=argv; argvp[1] != 0; ++argvp)
-    {
-      strcpy (p, *argvp);
-      p += strlen (*argvp);
-      *(p++) = ',';
-      *(p++) = ' ';
-    }
-  strcpy (p, *argvp);
-
   switch (*funcname)
     {
     case 'e':
-      OS (fatal, reading_file, "%s", msg);
+      OS (fatal, reading_file, "%s", argv[0]);
 
     case 'w':
-      OS (error, reading_file, "%s", msg);
+      OS (error, reading_file, "%s", argv[0]);
       break;
 
     case 'i':
-      outputs (0, msg);
-      outputs (0, "\n");
-      break;
+      {
+        size_t len = strlen (argv[0]);
+        char *msg = alloca (len + 2);
+        strcpy (msg, argv[0]);
+        msg[len] = '\n';
+        msg[len + 1] = '\0';
+        outputs (0, msg);
+        break;
+      }
 
     default:
       OS (fatal, *expanding_var, "Internal error: func_error: '%s'", funcname);