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Re: A strange problem while using variable allocated by ber_memalloc_x().

Chen, Shi Jun SLC CT PEK wrote:
I encount a strange problem while using variable allocated by ber_memalloc_x().
For each operation request, slapd will malloc a buffer to contain the DN and NDN by using ber_memalloc_x() for fields o_req_dn & o_req_ndn in struct operation.
Now I want to rewrite the DN and NDN myself, and below is the code.
I always get segment fault while running it.
But when I set MALLOC_CHECK_, the code does work and will not be crashed.
So what's the matter of my code?

Your realloc is one byte too short. This is the typical off-by-one error that all beginning C programmers make.
-Shijun Chen-
wrap_dn(op->o_req_dn, op->o_tmpmemctx);
wrap_dn(struct berval *dn, void *ctx)
char *tmp_buf=NULL, *psub=NULL;
int len_tmp_buf=0;
lem_tmp_buf = dn->bv_len + 5;
dn->bv_val = LDAP_REALLOCX(dn->bv_val, len_tmp_buf, ctx);
dn->bv_len = len_tmp_buf;
tmp_buf = malloc(len_tmp_buf + 1);
memset(tmp_buf, 0, len_tmp_buf + 1);
memcpy(tmp_buf, dn->bv_val, len_tmp_buf);
psub = strcasestr(tmp_buf, "dc=com");
assert( psub != NULL);
sprintf(p_sub, "dc=1,%s", "dc=com");
memcpy(dn->bv_val, tmp_buf, len_tmp_buf);

  -- Howard Chu
  Chief Architect, Symas Corp.  http://www.symas.com
  Director, Highland Sun        http://highlandsun.com/hyc
  OpenLDAP Core Team            http://www.openldap.org/project/