PATCH Re: Crash after history/fc -p if history size is set to 0 or non-numerical value

[Bart Schaefer <schaefer@brasslantern.com>]

On Oct 10, 12:47pm, Axel Beckert wrote:
}
} ~ -> zsh -f
} kiva6% fc -p a b
} kiva6% c
} [1]    4284 segmentation fault (core dumped)  zsh -f

This rejects non-integer values but also handles a zero value.  The hunk
in putoldhistentryontop() is just extra defensive programming, the small
change in prepnexthistent() is the real repair.


diff --git a/Src/builtin.c b/Src/builtin.c
index 4a10c7d..5b711ed 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -1363,10 +1363,19 @@ bin_fc(char *nam, char **argv, Options ops, int func)
 	if (*argv) {
 	    hf = *argv++;
 	    if (*argv) {
-		hs = zstrtol(*argv++, NULL, 10);
-		if (*argv)
-		    shs = zstrtol(*argv++, NULL, 10);
-		else
+		char *check;
+		hs = zstrtol(*argv++, &check, 10);
+		if (*check) {
+		    zwarnnam("fc", "HISTSIZE must be an integer");
+		    return 1;
+		}
+		if (*argv) {
+		    shs = zstrtol(*argv++, &check, 10);
+		    if (*check) {
+			zwarnnam("fc", "SAVEHIST must be an integer");
+			return 1;
+		    }
+		} else
 		    shs = hs;
 		if (*argv) {
 		    zwarnnam("fc", "too many arguments");
diff --git a/Src/hist.c b/Src/hist.c
index 4660fd0..0831756 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -1110,8 +1110,11 @@ static void
 putoldhistentryontop(short keep_going)
 {
     static Histent next = NULL;
-    Histent he = keep_going? next : hist_ring->down;
-    next = he->down;
+    Histent he = (keep_going || !hist_ring) ? next : hist_ring->down;
+    if (he)
+	next = he->down;
+    else
+	return;
     if (isset(HISTEXPIREDUPSFIRST) && !(he->node.flags & HIST_DUP)) {
 	static zlong max_unique_ct = 0;
 	if (!keep_going)
@@ -1151,7 +1154,7 @@ prepnexthistent(void)
 	freehistnode(&hist_ring->node);
     }
 
-    if (histlinect < histsiz) {
+    if (histlinect < histsiz || !hist_ring) {
 	he = (Histent)zshcalloc(sizeof *he);
 	if (!hist_ring)
 	    hist_ring = he->up = he->down = he;