example: handle uclient connection errors
[project/uclient.git] / uclient-example.c
index a54aa88..144696c 100644 (file)
 
 #include <unistd.h>
 #include <stdio.h>
+#include <dlfcn.h>
+#include <getopt.h>
+#include <fcntl.h>
 
 #include <libubox/blobmsg.h>
 
 #include "uclient.h"
 
+#ifdef __APPLE__
+#define LIB_EXT "dylib"
+#else
+#define LIB_EXT "so"
+#endif
+
+static struct ustream_ssl_ctx *ssl_ctx;
+static const struct ustream_ssl_ops *ssl_ops;
+static int quiet = false;
+static bool verify = true;
+static const char *output_file;
+static int output_fd = -1;
+static int error_ret;
+
+static int open_output_file(const char *path, bool create)
+{
+       const char *str;
+       char *filename;
+       int len;
+       int flags = O_WRONLY;
+
+       if (create)
+               flags |= O_CREAT;
+
+       if (output_file) {
+               if (!strcmp(output_file, "-"))
+                       return STDOUT_FILENO;
+
+               return open(output_file, flags, 0644);
+       }
+
+       /* Don't automatically overwrite files if the name is derived from the URL */
+       if (create)
+               flags |= O_EXCL;
+
+       len = strcspn(path, ";&");
+       while (len > 0 && path[len - 1] == '/')
+               len--;
+
+       for (str = path + len - 1; str >= path; str--) {
+               if (*str == '/')
+                       break;
+       }
+
+       str++;
+       len -= str - path;
+
+       if (len > 0) {
+               filename = alloca(len + 1);
+               strncpy(filename, str, len);
+               filename[len] = 0;
+       } else {
+               filename = "index.html";
+       }
+
+       return open(filename, flags, 0644);
+}
+
+static void request_done(struct uclient *cl)
+{
+       if (output_fd >= 0) {
+               close(output_fd);
+               output_fd = -1;
+       }
+       uclient_disconnect(cl);
+       uloop_end();
+}
 
 static void example_header_done(struct uclient *cl)
 {
+       static int retries;
+
        struct blob_attr *cur;
-       char local[INET6_ADDRSTRLEN], remote[INET6_ADDRSTRLEN];
-       int local_port, remote_port;
        int rem;
 
-       uclient_get_addr(local, &local_port, &cl->local_addr);
-       uclient_get_addr(remote, &remote_port, &cl->remote_addr);
+       if (retries < 10 && uclient_http_redirect(cl)) {
+               if (!quiet)
+                       fprintf(stderr, "Redirected to %s on %s\n", cl->url->location, cl->url->host);
 
-       fprintf(stderr, "Connected: %s:%d -> %s:%d\n",
-               local, local_port, remote, remote_port);
+               retries++;
+               return;
+       }
 
-       printf("Headers (%d): \n", cl->status_code);
-       blobmsg_for_each_attr(cur, cl->meta, rem) {
-               printf("%s=%s\n", blobmsg_name(cur), (char *) blobmsg_data(cur));
+       retries = 0;
+       if (!quiet) {
+               fprintf(stderr, "Headers (%d): \n", cl->status_code);
+               blobmsg_for_each_attr(cur, cl->meta, rem) {
+                       fprintf(stderr, "%s=%s\n", blobmsg_name(cur), (char *) blobmsg_data(cur));
+               }
        }
 
-       printf("Contents:\n");
+       switch (cl->status_code) {
+       case 204:
+       case 200:
+               output_fd = open_output_file(cl->url->location, true);
+               if (output_fd < 0) {
+                       if (!quiet)
+                               perror("Cannot open output file");
+                       error_ret = 3;
+                       request_done(cl);
+               }
+               break;
+
+       default:
+               request_done(cl);
+               error_ret = 8;
+               break;
+       }
 }
 
 static void example_read_data(struct uclient *cl)
@@ -50,91 +141,160 @@ static void example_read_data(struct uclient *cl)
        char buf[256];
        int len;
 
+       if (output_fd < 0)
+               return;
+
        while (1) {
                len = uclient_read(cl, buf, sizeof(buf));
                if (!len)
                        return;
 
-               write(STDOUT_FILENO, buf, len);
+               write(output_fd, buf, len);
        }
 }
 
-static void example_request_sm(struct uclient *cl)
+static void msg_connecting(struct uclient *cl)
 {
-       static int i = 0;
+       char addr[INET6_ADDRSTRLEN];
+       int port;
 
-       switch (i++) {
-       case 0:
-               uclient_connect(cl);
-               uclient_http_set_request_type(cl, "HEAD");
-               uclient_request(cl);
-               break;
-       case 1:
-               uclient_connect(cl);
-               uclient_http_set_request_type(cl, "GET");
-               uclient_request(cl);
-               break;
-       default:
-               uloop_end();
-               break;
-       };
+       if (quiet)
+               return;
+
+       uclient_get_addr(addr, &port, &cl->remote_addr);
+       fprintf(stderr, "Connecting to %s %s:%d\n", cl->url->host, addr, port);
+}
+
+static void init_request(struct uclient *cl)
+{
+       uclient_connect(cl);
+       msg_connecting(cl);
+       uclient_http_set_request_type(cl, "GET");
+       uclient_request(cl);
 }
 
 static void example_eof(struct uclient *cl)
 {
-       static int retries;
+       request_done(cl);
+}
 
-       if (retries < 10 && uclient_http_redirect(cl)) {
-               retries++;
-               return;
+static void handle_uclient_error(struct uclient *cl, int code)
+{
+       const char *type = "Unknown error";
+       bool ignore = false;
+
+       switch(code) {
+       case UCLIENT_ERROR_CONNECT:
+               type = "Connection failed";
+               error_ret = 4;
+               break;
+       case UCLIENT_ERROR_SSL_INVALID_CERT:
+               type = "Invalid SSL certificate";
+               ignore = !verify;
+               error_ret = 5;
+               break;
+       case UCLIENT_ERROR_SSL_CN_MISMATCH:
+               type = "Server hostname does not match SSL certificate";
+               ignore = !verify;
+               error_ret = 5;
+               break;
+       default:
+               error_ret = 1;
+               break;
        }
 
-       retries = 0;
-       example_request_sm(cl);
-}
+       if (!quiet)
+               fprintf(stderr, "Connection error: %s%s\n", type, ignore ? " (ignored)" : "");
 
-static void example_error(struct uclient *cl, int code)
-{
-       fprintf(stderr, "Error %d!\n", code);
-       example_request_sm(cl);
+       if (ignore)
+               error_ret = 0;
+       else
+               request_done(cl);
 }
 
 static const struct uclient_cb cb = {
        .header_done = example_header_done,
        .data_read = example_read_data,
        .data_eof = example_eof,
-       .error = example_error,
+       .error = handle_uclient_error,
 };
 
 static int usage(const char *progname)
 {
        fprintf(stderr,
-               "Usage: %s [options] <hostname> <port>\n"
+               "Usage: %s [options] <URL>\n"
                "Options:\n"
-               "       -c <cert>:         Load CA certificates from file <cert>\n"
-               "       -C:                Skip certificate CN verification against hostname\n"
+               "       -O <file>:                      Redirect output to file (use \"-\" for stdout)\n"
+               "\n"
+               "HTTPS options:\n"
+               "       --ca-certificate=<cert>:        Load CA certificates from file <cert>\n"
+               "       --no-check-certificate:         don't validate the server's certificate\n"
                "\n", progname);
        return 1;
 }
 
 
+static void init_ustream_ssl(void)
+{
+       void *dlh;
+
+       dlh = dlopen("libustream-ssl." LIB_EXT, RTLD_LAZY | RTLD_LOCAL);
+       if (!dlh)
+               return;
+
+       ssl_ops = dlsym(dlh, "ustream_ssl_ops");
+       if (!ssl_ops)
+               return;
+
+       ssl_ctx = ssl_ops->context_new(false);
+}
+
+static int no_ssl(const char *progname)
+{
+       fprintf(stderr, "%s: SSL support not available, please install ustream-ssl\n", progname);
+       return 1;
+}
+
+enum {
+       L_NO_CHECK_CERTIFICATE,
+       L_CA_CERTIFICATE,
+};
+
+static const struct option longopts[] = {
+       [L_NO_CHECK_CERTIFICATE] = { "no-check-certificate", no_argument },
+       [L_CA_CERTIFICATE] = { "ca-certificate", required_argument },
+       {}
+};
+
 int main(int argc, char **argv)
 {
-       struct ustream_ssl_ctx *ctx;
        const char *progname = argv[0];
        struct uclient *cl;
-       bool verify = true;
        int ch;
+       int longopt_idx = 0;
 
-       ctx = ustream_ssl_context_new(false);
+       init_ustream_ssl();
 
-       while ((ch = getopt(argc, argv, "Cc:")) != -1) {
+       while ((ch = getopt_long(argc, argv, "qO:", longopts, &longopt_idx)) != -1) {
                switch(ch) {
-               case 'c':
-                       ustream_ssl_context_add_ca_crt_file(ctx, optarg);
+               case 0:
+                       switch (longopt_idx) {
+                       case L_NO_CHECK_CERTIFICATE:
+                               verify = false;
+                               break;
+                       case L_CA_CERTIFICATE:
+                               if (ssl_ctx)
+                                       ssl_ops->context_add_ca_crt_file(ssl_ctx, optarg);
+                               break;
+                       default:
+                               return usage(progname);
+                       }
+                       break;
+               case 'O':
+                       output_file = optarg;
                        break;
-               case 'C':
-                       verify = false;
+               case 'q':
+                       quiet = true;
                        break;
                default:
                        return usage(progname);
@@ -147,6 +307,9 @@ int main(int argc, char **argv)
        if (argc != 1)
                return usage(progname);
 
+       if (!strncmp(argv[0], "https", 5) && !ssl_ctx)
+               return no_ssl(progname);
+
        uloop_init();
 
        cl = uclient_new(argv[0], NULL, &cb);
@@ -155,14 +318,17 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       uclient_http_set_ssl_ctx(cl, ctx, verify);
-       example_request_sm(cl);
+       if (ssl_ctx)
+               uclient_http_set_ssl_ctx(cl, ssl_ops, ssl_ctx, verify);
+
+       init_request(cl);
        uloop_run();
        uloop_done();
 
        uclient_free(cl);
-       ustream_ssl_context_free(ctx);
 
+       if (ssl_ctx)
+               ssl_ops->context_free(ssl_ctx);
 
-       return 0;
+       return error_ret;
 }