From: Alejandro Colomar <alx@kernel.org>
Date: Thu, 14 Nov 2024 18:58:54 +0000 (+0100)
Subject: lib/addgrps.c: add_groups(): Reallocate at once
X-Git-Tag: 4.17.3~37
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=aaaa3d41a5379aae745d53fae5870ec8678a889e;p=thirdparty%2Fshadow.git

lib/addgrps.c: add_groups(): Reallocate at once

We can calculate an upper bound of the number of added groups by
counting the number of delimiters in the string (plus one for the
element after the last delimiter).  This avoids reallocating +1 in a
loop.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---

diff --git a/lib/addgrps.c b/lib/addgrps.c
index 88a9710bc..603197543 100644
--- a/lib/addgrps.c
+++ b/lib/addgrps.c
@@ -22,8 +22,7 @@
 #include "alloc/reallocf.h"
 #include "search/l/lsearch.h"
 #include "shadowlog.h"
-
-#ident "$Id$"
+#include "string/strchr/strchrscnt.h"
 
 
 /*
@@ -59,6 +58,10 @@ add_groups(const char *list)
 	if (n0 == -1)
 		goto free_gids;
 
+	grouplist = REALLOCF(grouplist, n0 + strchrscnt(list, ",:") + 1, GETGROUPS_T);
+	if (grouplist == NULL)
+		return -1;
+
 	n = n0;
 	p = buf;
 	while (NULL != (g = strsep(&p, ",:"))) {
@@ -70,10 +73,6 @@ add_groups(const char *list)
 			continue;
 		}
 
-		grouplist = REALLOCF(grouplist, n + 1, GETGROUPS_T);
-		if (grouplist == NULL)
-			return -1;
-
 		LSEARCH(&grp->gr_gid, grouplist, &n);
 	}