[PATCH v2 2/4] help.c::exclude_cmds: realloc() before copy, plug a leak

[Tay Ray Chuan]

Copying with structural assignment may not take into account that the
LHS struct has sufficient memory, especially since the cmdname->name
member is nonfixed in size. Be unambiguous about it by realloc()'ing it
to be of sufficient size.

Additionally, free the unused cmdnames, which are no longer accessible
anyway.

Signed-off-by: Tay Ray Chuan <rcta...@gmail.com>
---
 help.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/help.c b/help.c
index 6991492..dfb2e9d 100644
--- a/help.c
+++ b/help.c
@@ -20,6 +20,17 @@ void add_cmdname(struct cmdnames *cmds, const char *name, 
int len)
        cmds->names[cmds->cnt++] = ent;
 }
 
+static void copy_cmdname(struct cmdname **dest, struct cmdname *src)
+{
+       struct cmdname *ent = xrealloc(*dest, sizeof(*ent) + src->len + 1);
+
+       ent->len = src->len;
+       memcpy(ent->name, src->name, src->len);
+       ent->name[src->len] = 0;
+
+       *dest = ent;
+}
+
 static void clean_cmdnames(struct cmdnames *cmds)
 {
        int i;
@@ -58,20 +69,25 @@ void exclude_cmds(struct cmdnames *cmds, struct cmdnames 
*excludes)
 {
        int ci, cj, ei;
        int cmp;
+       int last_cj;
 
        ci = cj = ei = 0;
        while (ci < cmds->cnt && ei < excludes->cnt) {
                cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
                if (cmp < 0)
-                       cmds->names[cj++] = cmds->names[ci++];
+                       copy_cmdname(&cmds->names[cj++], cmds->names[ci++]);
                else if (cmp == 0)
                        ci++, ei++;
                else if (cmp > 0)
                        ei++;
        }
+       last_cj = cj;
 
        while (ci < cmds->cnt)
-               cmds->names[cj++] = cmds->names[ci++];
+               copy_cmdname(&cmds->names[cj++], cmds->names[ci++]);
+
+       while (last_cj < cmds->cnt)
+               free(cmds->names[last_cj++]);
 
        cmds->cnt = cj;
 }
-- 
1.7.11.1.116.g8228a23

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