Added proper platform fallback, a sanity test, and some documentation.

CMakeLists.txt

@@ -108,21 +108,26 @@ else ()
         # Don't add the exact path to CoreFoundation as this would hardcode the SDK version
         list(APPEND PLATFORM_LIBS dl Threads::Threads "-framework CoreFoundation")
         list (APPEND AWS_COMMON_OS_SRC "source/darwin/*.c") # OS specific includes
-        list (APPEND AWS_COMMON_OS_SRC "source/linux/*.c") # just for the moment
-
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
     elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Linux") # Android does not link to libpthread nor librt, so this is fine
         list(APPEND PLATFORM_LIBS dl m Threads::Threads rt)
         list (APPEND AWS_COMMON_OS_SRC "source/linux/*.c") # OS specific includes
     elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
         list(APPEND PLATFORM_LIBS dl m thr execinfo)
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "NetBSD")
         list(APPEND PLATFORM_LIBS dl m Threads::Threads execinfo)
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
         list(APPEND PLATFORM_LIBS m Threads::Threads execinfo)
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
     elseif(CMAKE_SYSTEM_NAME STREQUAL "Android")
         list(APPEND PLATFORM_LIBS log)
         file(GLOB ANDROID_SRC "source/android/*.c")
         list(APPEND AWS_COMMON_OS_SRC "${ANDROID_SRC}")
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
+    else()
+        list (APPEND AWS_COMMON_OS_SRC "source/platform_fallback_stubs/system_info.c")
     endif()
 
 endif()

bin/system_info/CMakeLists.txt

@@ -16,10 +16,3 @@ target_include_directories(${SI_PROJECT_NAME} PUBLIC
         $<INSTALL_INTERFACE:include>)
 
 target_link_libraries(${SI_PROJECT_NAME} PRIVATE aws-c-common)
-
-install(TARGETS ${SI_PROJECT_NAME}
-        EXPORT ${SI_PROJECT_NAME}-targets
-        COMPONENT Runtime
-        RUNTIME
-        DESTINATION bin
-        COMPONENT Runtime)

include/aws/common/private/system_info_priv.h

@@ -5,9 +5,9 @@
  * SPDX-License-Identifier: Apache-2.0.
  */
 
-#include <aws/common/system_info.h>
 #include <aws/common/byte_buf.h>
 #include <aws/common/string.h>
+#include <aws/common/system_info.h>
 
 struct aws_system_environment {
     struct aws_allocator *allocator;
@@ -19,7 +19,18 @@ struct aws_system_environment {
     void *additional_impl_data;
 };
 
+/**
+ * For internal implementors. Fill in info in env that you're able to grab, such as dmi info, os version strings etc...
+ * in here. The default just returns AWS_OP_SUCCESS. This is currently only implemented for linux.
+ *
+ * Returns AWS_OP_ERR if the implementation wasn't able to fill in required information for the platform.
+ */
 int aws_system_environment_load_platform_impl(struct aws_system_environment *env);
+
+/**
+ * For internal implementors. Cleans up anything allocated in aws_system_environment_load_platform_impl,
+ * but does not release the memory for env.
+ */
 void aws_system_environment_destroy_platform_impl(struct aws_system_environment *env);
 
 #endif /* AWS_COMMON_SYSTEM_INFO_PRIV_H */

include/aws/common/system_info.h

@@ -25,22 +25,41 @@ struct aws_system_environment;
 
 AWS_EXTERN_C_BEGIN
 
+/**
+ * Allocates and initializes information about the system the current process is executing on.
+ * If successful returns an instance of aws_system_environment. If it fails, it will return NULL.
+ */
 AWS_COMMON_API
 struct aws_system_environment *aws_system_environment_load(struct aws_allocator *allocator);
 
 AWS_COMMON_API
 void aws_system_environment_destroy(struct aws_system_environment *env);
 
-
+/**
+ * Returns the virtualization vendor for the specified compute environment, e.g. "Xen, Amazon EC2, etc..."
+ *
+ * The return value may be empty and in that case no vendor was detected.
+ */
 AWS_COMMON_API
 struct aws_byte_cursor aws_system_environment_get_virtualization_vendor(const struct aws_system_environment *env);
 
+/**
+ * Returns the product name for the specified compute environment. For example, the Amazon EC2 Instance type.
+ *
+ * The return value may be empty and in that case no vendor was detected.
+ */
 AWS_COMMON_API
 struct aws_byte_cursor aws_system_environment_get_virtualization_product_name(const struct aws_system_environment *env);
 
+/**
+ * Returns the number of processors for the specified compute environment.
+ */
 AWS_COMMON_API
 size_t aws_system_environment_get_processor_count(struct aws_system_environment *env);
 
+/**
+ * Returns the number of separate cpu groupings (multi-socket configurations or NUMA).
+ */
 AWS_COMMON_API
 size_t aws_system_environment_get_cpu_group_count(struct aws_system_environment *env);
 

source/linux/system_info.c

@@ -1,9 +1,14 @@
-
-#include <aws/common/private/system_info_priv.h>
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
 #include <aws/common/file.h>
+#include <aws/common/private/system_info_priv.h>
 
 int aws_system_environment_load_platform_impl(struct aws_system_environment *env) {
     aws_byte_buf_init_from_file(&env->virtualization_vendor, env->allocator, "/sys/devices/virtual/dmi/id/sys_vendor");
+    /* whether this one works depends on if this is a sysfs filesystem. If it fails, it will just be empty
+     * and these APIs are a best effort at the moment. We can add fallbacks as the loaders get more complicated. */
     aws_byte_buf_init_from_file(&env->product_name, env->allocator, "/sys/devices/virtual/dmi/id/product_name");
 
     return AWS_OP_SUCCESS;
@@ -13,4 +18,3 @@ void aws_system_environment_destroy_platform_impl(struct aws_system_environment
     aws_byte_buf_clean_up(&env->virtualization_vendor);
     aws_byte_buf_clean_up(&env->product_name);
 }
-

source/platform_fallback_stubs/system_info.c

@@ -0,0 +1,21 @@
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+#include <aws/common/private/system_info_priv.h>
+
+#include <aws/common/logging.h>
+
+int aws_system_environment_load_platform_impl(struct aws_system_environment *env) {
+    (void)env;
+    AWS_LOGF_DEBUG(
+        AWS_LS_COMMON_GENERAL,
+        "id=%p: platform specific environment loading is not implemented for this platform.",
+        (void *)env);
+
+    return AWS_OP_SUCCESS;
+}
+
+void aws_system_environment_destroy_platform_impl(struct aws_system_environment *env) {
+    (void)env;
+}

source/system_info.c

@@ -1,17 +1,35 @@
 /**
-* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
-* SPDX-License-Identifier: Apache-2.0.
-*/
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
 #include <aws/common/private/system_info_priv.h>
 
+#include <aws/common/logging.h>
+
 struct aws_system_environment *aws_system_environment_load(struct aws_allocator *allocator) {
     struct aws_system_environment *env = aws_mem_calloc(allocator, 1, sizeof(struct aws_system_environment));
     env->allocator = allocator;
 
     if (aws_system_environment_load_platform_impl(env)) {
+        AWS_LOGF_ERROR(
+            AWS_LS_COMMON_GENERAL,
+            "id=%p: failed to load system environment with error %s.",
+            (void *)env,
+            aws_error_debug_str(aws_last_error()));
         goto error;
     }
 
+    AWS_LOGF_TRACE(
+        AWS_LS_COMMON_GENERAL,
+        "id=%p: virtualization vendor detected as \"" PRInSTR "\"",
+        (void *)env,
+        AWS_BYTE_CURSOR_PRI(aws_system_environment_get_virtualization_vendor(env)));
+    AWS_LOGF_TRACE(
+        AWS_LS_COMMON_GENERAL,
+        "id=%p: virtualization product name detected as \"" PRInSTR " \"",
+        (void *)env,
+        AWS_BYTE_CURSOR_PRI(aws_system_environment_get_virtualization_vendor(env)));
+
     env->os = aws_get_platform_build_os();
     env->cpu_count = aws_system_info_processor_count();
     env->cpu_group_count = aws_get_cpu_group_count();
@@ -35,7 +53,8 @@ struct aws_byte_cursor aws_system_environment_get_virtualization_vendor(const st
     return aws_byte_cursor_trim_pred(&vendor_string, aws_char_is_space);
 }
 
-struct aws_byte_cursor aws_system_environment_get_virtualization_product_name(const struct aws_system_environment *env) {
+struct aws_byte_cursor aws_system_environment_get_virtualization_product_name(
+    const struct aws_system_environment *env) {
     struct aws_byte_cursor product_name_str = aws_byte_cursor_from_buf(&env->product_name);
     return aws_byte_cursor_trim_pred(&product_name_str, aws_char_is_space);
 }

tests/CMakeLists.txt

@@ -304,6 +304,7 @@ add_test_case(test_cpu_count_at_least_works_superficially)
 add_test_case(test_stack_trace_decoding)
 add_test_case(test_platform_build_os)
 add_test_case(test_sanity_check_numa_discovery)
+add_test_case(test_sanity_check_environment_loader)
 
 add_test_case(test_realloc_fallback)
 add_test_case(test_realloc_passthrough)

tests/system_info_tests.c

@@ -166,3 +166,22 @@ static int s_test_sanity_check_numa_discovery(struct aws_allocator *allocator, v
 }
 
 AWS_TEST_CASE(test_sanity_check_numa_discovery, s_test_sanity_check_numa_discovery)
+
+static int s_test_sanity_check_environment_loader(struct aws_allocator *allocator, void *ctx) {
+    (void)ctx;
+
+    aws_common_library_init(allocator);
+    struct aws_system_environment *env = aws_system_environment_load(allocator);
+    ASSERT_NOT_NULL(env);
+    struct aws_byte_cursor virt_vendor = aws_system_environment_get_virtualization_vendor(env);
+    ASSERT_TRUE(aws_byte_cursor_is_valid(&virt_vendor));
+    struct aws_byte_cursor virt_product = aws_system_environment_get_virtualization_product_name(env);
+    ASSERT_TRUE(aws_byte_cursor_is_valid(&virt_product));
+
+    aws_system_environment_destroy(env);
+
+    aws_common_library_clean_up();
+    return 0;
+}
+
+AWS_TEST_CASE(test_sanity_check_environment_loader, s_test_sanity_check_environment_loader)