getprogname: improvement on HP-UX

[Bruno Haible]

On HP-UX (hppa 64-bit), the test-xalloc-die.sh test fails:

*** -   Thu Oct 11 15:47:41 2018
--- err2        Thu Oct 11 15:55:06 2018
***************
*** 1 ****
! test-xalloc-die: memory exhausted
--- 1 ----
! test-xalloc-di: memory exhausted
FAIL test-xalloc-die.sh (exit status: 1)

The reason is a truncation of the program name to 14 characters. This can
be avoided in some cases. The command can be up to 63 characters and may
contain the program name.


2018-10-11  Bruno Haible  <address@hidden>

        getprogname: Work around program name truncation when possible.
        * lib/getprogname.c (getprogname) [HP-UX]: When pst_ucomm is truncated,
        possibly use pst_cmd instead.

diff --git a/lib/getprogname.c b/lib/getprogname.c
index 58625de..4f97df4 100644
--- a/lib/getprogname.c
+++ b/lib/getprogname.c
@@ -110,9 +110,33 @@ getprogname (void)
       first = 0;
       pid_t pid = getpid ();
       struct pst_status status;
-      p = (0 < pstat_getproc (&status, sizeof status, 0, pid)
-           ? strdup (status.pst_ucomm)
-           : NULL);
+      if (pstat_getproc (&status, sizeof status, 0, pid) > 0)
+        {
+          if (strlen (status.pst_ucomm) < PST_UCOMMLEN - 1)
+            p = status.pst_ucomm;
+          else
+            {
+              /* status.pst_ucomm is truncated to length PST_UCOMMLEN - 1.
+                 Look at status.pst_cmd instead.  */
+              char *space = strchr (status.pst_cmd, ' ');
+              if (space != NULL)
+                *space = '\0';
+              p = strrchr (status.pst_cmd, '/');
+              if (p != NULL)
+                p++;
+              else
+                p = status.pst_cmd;
+              if (strlen (p) > PST_UCOMMLEN - 1
+                  && memcmp (p, status.pst_ucomm, PST_UCOMMLEN - 1) == 0)
+                /* p is less truncated than status.pst_ucomm.  */
+                ;
+              else
+                p = status.pst_ucomm;
+            }
+          p = strdup (p);
+        }
+      else
+        p = NULL;
       if (!p)
         p = "?";
     }