fix: check for libcurl version and feature AsynchDNS

CHANGELOG.md

@@ -5,6 +5,7 @@
 **Fixes**:
 
 - Remove OpenSSL as direct dependency for the crashpad backend on Linux. ([#812](https://github.com/getsentry/sentry-native/pull/812), [crashpad#81](https://github.com/getsentry/crashpad/pull/81))
+- Check `libcurl` for feature `AsynchDNS` at compile- and runtime. ([#813](https://github.com/getsentry/sentry-native/pull/813))
 
 ## 0.6.0
 

CMakeLists.txt

@@ -274,7 +274,7 @@ endif()
 
 if(SENTRY_TRANSPORT_CURL)
 	if(NOT CURL_FOUND) # Some other lib might bring libcurl already
-		find_package(CURL REQUIRED)
+		find_package(CURL REQUIRED COMPONENTS AsynchDNS)
 	endif()
 
 	if(TARGET CURL::libcurl) # Only available in cmake 3.12+

src/sentry_utils.c

@@ -529,3 +529,20 @@ sentry__snprintf_c(char *buf, size_t buf_size, const char *fmt, ...)
     va_end(args);
     return rv;
 }
+
+bool
+sentry__check_min_version(sentry_version_t actual, sentry_version_t expected)
+{
+    if (actual.major < expected.major) {
+        return false;
+    }
+    if (actual.major == expected.major && actual.minor < expected.minor) {
+        return false;
+    }
+    if (actual.major == expected.major && actual.minor == expected.minor
+        && actual.patch < expected.patch) {
+        return false;
+    }
+
+    return true;
+}

src/sentry_utils.h

@@ -198,4 +198,20 @@ double sentry__strtod_c(const char *ptr, char **endptr);
  */
 int sentry__snprintf_c(char *buf, size_t buf_size, const char *fmt, ...);
 
+/**
+ * Represents a version of a software artifact.
+ */
+typedef struct {
+    unsigned int major;
+    unsigned int minor;
+    unsigned int patch;
+} sentry_version_t;
+
+/**
+ * Checks whether `actual` is the same or a later version than `expected`.
+ * Returns `true` if that is the case.
+ */
+bool sentry__check_min_version(
+    sentry_version_t actual, sentry_version_t expected);
+
 #endif

src/transports/sentry_transport_curl.c

@@ -11,7 +11,6 @@
 
 #include <curl/curl.h>
 #include <curl/easy.h>
-#include <stdlib.h>
 #include <string.h>
 
 typedef struct curl_transport_state_s {
@@ -67,6 +66,32 @@ sentry__curl_transport_start(
             SENTRY_WARNF("`curl_global_init` failed with code `%d`", (int)rv);
             return 1;
         }
+
+        curl_version_info_data *version_data
+            = curl_version_info(CURLVERSION_NOW);
+
+        if (!version_data) {
+            SENTRY_WARN("Failed to retrieve `curl_version_info`");
+            return 1;
+        }
+
+        sentry_version_t curl_version = {
+            .major = (version_data->version_num >> 16) & 0xff,
+            .minor = (version_data->version_num >> 8) & 0xff,
+            .patch = version_data->version_num & 0xff,
+        };
+
+        if (!sentry__check_min_version(
+                curl_version, (sentry_version_t) { 7, 10, 7 })) {
+            SENTRY_WARNF("`libcurl` is at unsupported version `%u.%u.%u`",
+                curl_version.major, curl_version.minor, curl_version.patch);
+            return 1;
+        }
+
+        if ((version_data->features & CURL_VERSION_ASYNCHDNS) == 0) {
+            SENTRY_WARN("`libcurl` was not compiled with feature `AsynchDNS`");
+            return 1;
+        }
     }
 
     sentry_bgworker_t *bgworker = (sentry_bgworker_t *)transport_state;

tests/unit/test_utils.c

@@ -221,3 +221,32 @@ SENTRY_TEST(os)
 
     sentry_value_decref(os);
 }
+
+SENTRY_TEST(check_version)
+{
+    TEST_CHECK(sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 11, .patch = 7 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 8 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(sentry__check_min_version(
+        (sentry_version_t) { .major = 8, .minor = 9, .patch = 7 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 11, .patch = 6 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+
+    TEST_CHECK(!sentry__check_min_version(
+        (sentry_version_t) { .major = 6, .minor = 10, .patch = 7 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(!sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 9, .patch = 7 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+    TEST_CHECK(!sentry__check_min_version(
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 6 },
+        (sentry_version_t) { .major = 7, .minor = 10, .patch = 7 }));
+}

tests/unit/tests.inc

@@ -14,20 +14,21 @@ XX(basic_tracing_context)
 XX(basic_transaction)
 XX(bgworker_flush)
 XX(build_id_parser)
+XX(check_version)
 XX(child_spans)
 XX(concurrent_init)
 XX(concurrent_uninit)
 XX(count_sampled_events)
-XX(crashed_last_run)
 XX(crash_marker)
+XX(crashed_last_run)
 XX(custom_logger)
 XX(discarding_before_send)
 XX(distributed_headers)
 XX(drop_unfinished_spans)
 XX(dsn_parsing_complete)
 XX(dsn_parsing_invalid)
-XX(dsn_store_url_without_path)
 XX(dsn_store_url_with_path)
+XX(dsn_store_url_without_path)
 XX(empty_transport)
 XX(fuzz_json)
 XX(init_failure)