How does http_find_header() work?

[Roy Smith]

I'm trying to modify haproxy-1.4.11 (on Ubuntu) to do some additional logging.  
I've added to http_sess_log(), some experimental code:

--- a/src/proto_http.c  Sat Mar 26 12:38:10 2011 -0400
+++ b/src/proto_http.c  Sat Mar 26 19:18:30 2011 -0400
@@ -1081,6 +1081,7 @@
        static char tmpline[MAX_SYSLOG_LEN];
        int t_request;
        int hdr;
+       struct hdr_ctx ctx;

        /* if we don't want to log normal traffic, return now */
        err = (s->flags & (SN_ERR_MASK | SN_REDISP)) ||
@@ -1149,6 +1150,14 @@
                                  '#', url_encode_map, uri);
                *(h++) = '"';
        }
+
+       if (http_find_header("X-Unique-ID", txn->req.sol, &txn->hdr_idx, &ctx)) 
{
+                // if (h < tmpline + ctx.vlen - 4) {
+                //         memcpy(tmpline, ctx.val, ctx.vlen);
+                //         h += ctx.vlen;
+                // }
+        }
+
        *h = '\0';

        svid = (tolog & LW_SVID) ?

when this code runs, I get a segfault as soon as it tries to log anything.  I'm 
obviously calling http_find_header() wrong, but I can't figure out  what I 
should be doing.  When I look at the resulting core file with gdb, it shows 
that txn->req.sol is not initialized.

#0  http_find_header2 (name=0x44d6af "X-Unique-ID", len=11, sol=0x1 <Address 
0x1 out of bounds>, idx=0x795960, ctx=0x7fff37575a80) at src/proto_http.c:513
513                     eol = sol + idx->v[cur_idx].len;

Is there something I need to be doing to initialize the sol element of the 
request?


--
Roy Smith
roy.sm...@s7labs.com