I'm an experienced programmer but new to curl. I have implemented a fuse filesystem that send notifications on open/close mkdir/rmdir events via curl to a web logic server, by emulating a SOAP/XML request, and it gets a response back via the write function callback. My test case is a recursive copy of a filesystem with lots of small files. Using curl 7.29.0, compiled manually for OEL5 (RHEL5), since the dependency list for the binary got complicated.

This consistently crashes after while, and I get a SEGV but the stack is somewhat mangled, but is always the same... Is this a known issue that is fixed? Would you like more information?

(gdb) where
#0 0x00007fd213f452b2 in addbyter () from /usr/local/lib/libcurl.so.4
#1 0x00007fd213f45bac in dprintf_formatf () from /usr/local/lib/libcurl.so.4
#2 0x00007fd213f46bf5 in curl_mvsnprintf () from /usr/local/lib/libcurl.so.4
#3 0x00007fd213f45473 in curl_msnprintf () from /usr/local/lib/libcurl.so.4
#4 0x00007fd213f32eae in Curl_failf () from /usr/local/lib/libcurl.so.4
#5 0x00007fd213f29d91 in Curl_resolv_timeout () from /usr/local/lib/libcurl.so.4
#6 0x00007fd213f39ed8 in resolve_server () from /usr/local/lib/libcurl.so.4
#7 0x00007fd213f3c095 in create_conn () from /usr/local/lib/libcurl.so.4
#8 0x00007fd2043b6a90 in ?? ()
#9 0x0000000100000000 in ?? ()
#10 0x00007fd2141751b8 in Curl_cmalloc () from /usr/local/lib/libcurl.so.4
#11 0x0000000100000000 in ?? ()
#12 0x00007fd204448c20 in ?? ()
#13 0x0000000100000000 in ?? ()
#14 0x00007fd2044a6550 in ?? ()
#15 0x00007fd200000000 in ?? ()
#16 0x0000000000000015 in ?? ()
#17 0x0000000100000000 in ?? ()
#18 0x00007fd204594330 in ?? ()
#19 0x0000000100000000 in ?? ()
#20 0x00007fd2044a6550 in ?? ()
#21 0x0000000000000038 in ?? ()
#22 0x0000000000000007 in ?? ()
#23 0x0000000100000000 in ?? ()
#24 0x00007fd2141751b8 in Curl_cmalloc () from /usr/local/lib/libcurl.so.4
#25 0x00007fd213f16000 in ?? ()
#26 0x0000000000000020 in ?? ()
#27 0x0000000000000020 in ?? ()
#28 0x00007fd204574410 in ?? ()
#29 0x0000000000000020 in ?? ()
#30 0x00007fd2141751b8 in Curl_cmalloc () from /usr/local/lib/libcurl.so.4
#31 0x00007fd213f16000 in ?? ()
#32 0x00007fd204574410 in ?? ()
#33 0x00007fd2141751b8 in Curl_cmalloc () from /usr/local/lib/libcurl.so.4
#34 0x0000000000000000 in ?? ()
(gdb)

Here is my curl send/receive code:

static char *afs_uri_str = NULL;
static char *afs_hostname = NULL;
static char *afs_port_str = NULL;

struct MemoryStruct {
  char *memory;
  size_t size;
  size_t max_size;
};

static size_t getWriteDataCallback(void *contents, size_t size,
    size_t nmemb, void *userp)
{
        size_t realsize = size * nmemb;
        struct MemoryStruct *mem = (struct MemoryStruct *)userp;

        // -1 because we need room for the null termination.
        // mem->size can not be greater that mem->max_size -1
        if (mem->size >= (mem->max_size - 1)) // if already full
        {
                LOG_WARN("Server returned message larger than buffer size!");
                return 0;
        }
        if ((mem->size + realsize) >= mem->max_size)
        {
                LOG_WARN("Server message larger than buffer size!");
                realsize = mem->max_size - mem->size - 1; // fill the buffer
        }
        memcpy(&(mem->memory[mem->size]), contents, realsize);
        mem->size += realsize;
        mem->memory[mem->size] = '\0';
        return realsize;
}

static void afs_curl_build_payload(char *payload, size_t payload_max_size,
                const char *msg, const char *action, payload_type_t payload_type)
{
        (void) payload_type; // stop compiler complaining

        snprintf(payload, payload_max_size,
            "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
                "<env:Envelope xmlns:env=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:ns1=\"%s\">\n"
                " <env:Header />\n"
                " <env:Body>\n"
                " <ns1:%s>\n"
                " <arg0>%s</arg0>\n"
                " </ns1:%s>\n"
                " </env:Body>\n"
                "</env:Envelope>\n", AFS_NAME_SPACE, action, msg, action);
        return;
}
/* Common init routine between send and send_recieve */
static CURL *afs_curl_send_common(int debug_flag)
{
    CURL *curl = curl_easy_init(); // calls global init

    if (!curl)
    {
        LOG_ERROR("ERROR: Curl library init failed!");
        return NULL;
    }

        if (afs_uri_str == NULL)
        {
                afs_uri_str = calloc(1, AFS_MAX_PATH);
                if (!afs_uri_str)
                {
                        return -ENOMEM;
                }
                curl_global_init(CURL_GLOBAL_ALL); // do this once...
        }
        sprintf(afs_uri_str, "http://%s:%s/%s", afs_hostname,
            afs_port_str, AFS_CURL_DEFAULT_ENDPOINT);

    if (debug_flag)
    {
        /* The DEBUGFUNCTION has no effect until we enable VERBOSE */
        curl_easy_setopt(curl, CURLOPT_HEADER, 1L); // Include header in output
        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    } // DEBUG
    //curl_easy_setopt(curl, CURLOPT_NOPROXY, afs_hostname); // works for 7.29 not 7.15
    curl_easy_setopt(curl, CURLOPT_URL, afs_uri_str);
    return curl;
}

int afs_curl_send_receive(const char *msg, char *outmsg,
        size_t outmsg_max_len, char *action)
{
        struct curl_slist * headers=NULL;
        char payload[PAYLOAD_SIZE];
        struct MemoryStruct responseDataChunk;
        int rc;
        CURLcode res;

        CURL *curl = afs_curl_send_common(afs_debug_flag);
        if (curl == NULL)
        {
                return -1;
        }
        /* Build the SOAP request message payload */
        afs_curl_build_payload(payload, PAYLOAD_SIZE, msg, action, PAYLOAD_TYPE_NO_HTTP_HEADERS);

        /* Set up response function to collect all return data */
        responseDataChunk.memory = outmsg;
        responseDataChunk.size = 0; // amount of data received
        responseDataChunk.max_size = outmsg_max_len;
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, getWriteDataCallback);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseDataChunk);

        /* pass our list of custom made headers */
        //Note: Can't set the POST line using the CURLOPT_HTTPHEADER
        //headers = curl_slist_append(headers,
        // "POST http://bluefire:7111/OurayFuseWS/OurayFuseServicePort HTTP/1.1");
        headers = curl_slist_append(headers, "Content-Type: application/soap+xml; charset=UTF-8");
        headers = curl_slist_append(headers, "SOAPAction: \"\"");
        headers = curl_slist_append(headers, "Action:"); // remove this, we have soap action (this does not work?)
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, payload);
        LOG_DEBUG("Performing curl sync send");
        //LOG_DEBUG("###Send curl async:\n%s\n###End sent data", payload);
        res = curl_easy_perform(curl);
        if (CURLE_OK != res)
        {
                LOG_ERROR("ERROR:curl connect failed %s", curl_easy_strerror(res));
                rc = -2;
        }
        LOG_DEBUG("### Received (%ld, max %ld) bytes:\n%s\n### /Received",
            responseDataChunk.size, PAYLOAD_SIZE, responseDataChunk.memory);
        //LOG_DEBUG("curl async send completed, free resources");
        curl_slist_free_all(headers);
        curl_easy_cleanup(curl);
        return rc;
}

Ceri Davies | Principal Software Engineer | Ceri.Davies_at_Oracle.com
Work: +1 3032727810 x77810 | Home: +1 3035321116 | Cell: +1 3038706743
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Received on 2013-04-19