ps: Stop crash if using test fields

I'm not sure if anyone actually uses these things, but if you
selected test fields on the command line ps would crash.

$ ps/pscommand -o _left
Signal 11 (SEGV) caught by pscommand (3.3.11.877-0488).
/home/csmall/Projects/procps/procps/ps/.libs/pscommand:ps/display.c:66: please report this bug
Segmentation fault

Anyway, it doesn't now:
$ ps/pscommand -o pid,_left,_left2,_right,_unlimited 1
    PID LLLLLLLL L2L2L2L2 RRRRRRRRRRR U
      1 tty7     3270/tty4      59:59 [123456789-12345] <defunct>

diff --git a/ps/output.c b/ps/output.c
index 20f9a5340dff486d7e00125a30e9e201ada94459..cbb0e6e23e9c93c214fe5072cd10f250779f4b80 100644 (file)
--- a/ps/output.c
+++ b/ps/output.c
@@ -1415,12 +1415,14 @@ setREL1(ID_TGID)
 // like "args"
 static int pr_t_unlimited(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"[123456789-12345] <defunct>","ps","123456789-123456"};
+  if (!outbuf) return 0;
   (void)pp;
   snprintf(outbuf, max_rightward+1, "%s", vals[lines_to_next_header%3u]);
   return strlen(outbuf);
 }
 static int pr_t_unlimited2(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"unlimited", "[123456789-12345] <defunct>","ps","123456789-123456"};
+  if (!outbuf) return 0;
   (void)pp;
   snprintf(outbuf, max_rightward+1, "%s", vals[lines_to_next_header%4u]);
   return strlen(outbuf);
@@ -1429,11 +1431,13 @@ static int pr_t_unlimited2(char *restrict const outbuf, const proc_t *restrict c
 // like "etime"
 static int pr_t_right(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"999-23:59:59","99-23:59:59","9-23:59:59","59:59"};
+  if (!outbuf) return 0;
   (void)pp;
   return snprintf(outbuf, COLWID, "%s", vals[lines_to_next_header%4u]);
 }
 static int pr_t_right2(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"999-23:59:59","99-23:59:59","9-23:59:59"};
+  if (!outbuf) return 0;
   (void)pp;
   return snprintf(outbuf, COLWID, "%s", vals[lines_to_next_header%3u]);
 }
@@ -1441,11 +1445,13 @@ static int pr_t_right2(char *restrict const outbuf, const proc_t *restrict const
 // like "tty"
 static int pr_t_left(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"tty7","pts/9999","iseries/vtty42","ttySMX0","3270/tty4"};
+  if (!outbuf) return 0;
   (void)pp;
   return snprintf(outbuf, COLWID, "%s", vals[lines_to_next_header%5u]);
 }
 static int pr_t_left2(char *restrict const outbuf, const proc_t *restrict const pp){
   static const char *const vals[] = {"tty7","pts/9999","ttySMX0","3270/tty4"};
+  if (!outbuf) return 0;
   (void)pp;
   return snprintf(outbuf, COLWID, "%s", vals[lines_to_next_header%4u]);
 }