Add flag to compile gpr with compatibility for musl

binding.gyp

@@ -47,7 +47,11 @@
     # will let users recompile gRPC to work without ALPN.
     'grpc_alpn%': 'true',
     # Indicates that the library should be built with gcov.
-    'grpc_gcov%': 'false'
+    'grpc_gcov%': 'false',
+    # Indicates that the library should be built with compatibility for musl
+    # libc, so that it can run on Alpine Linux. This is only necessary if not
+    # building on Alpine Linux
+    'grpc_alpine%': 'false'
   },
   'target_defaults': {
     'configurations': {
@@ -115,6 +119,11 @@
             '-rdynamic',
         ],
       }],
+      ['grpc_alpine=="true"', {
+        'defines': [
+          'GPR_MUSL_LIBC_COMPAT'
+        ]
+      }],
       ['OS!="win" and runtime=="electron"', {
         "defines": [
           'OPENSSL_NO_THREADS'

include/grpc/impl/codegen/port_platform.h

@@ -189,7 +189,7 @@
 #ifdef __GLIBC__
 #define GPR_POSIX_CRASH_HANDLER 1
 #else /* musl libc */
-#define GRPC_MSG_IOVLEN_TYPE int
+#define GPR_MUSL_LIBC_COMPAT 1
 #endif
 #elif defined(__APPLE__)
 #include <Availability.h>

src/core/lib/iomgr/port.h

@@ -88,6 +88,7 @@
 #ifndef __GLIBC__
 #define GRPC_LINUX_EPOLL 1
 #define GRPC_LINUX_EVENTFD 1
+#define GRPC_MSG_IOVLEN_TYPE int
 #endif
 #ifndef GRPC_LINUX_EVENTFD
 #define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1

src/core/lib/support/cpu_linux.c

@@ -67,16 +67,16 @@ unsigned gpr_cpu_num_cores(void) {
 }
 
 unsigned gpr_cpu_current_cpu(void) {
-#ifdef __GLIBC__
+#ifdef GPR_MUSL_LIBC_COMPAT
+  // sched_getcpu() is undefined on musl
+  return 0;
+#else
   int cpu = sched_getcpu();
   if (cpu < 0) {
     gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
     return 0;
   }
   return (unsigned)cpu;
-#else
-  // sched_getcpu() is undefined on musl
-  return 0;
 #endif
 }
 

src/core/lib/support/wrap_memcpy.c

@@ -31,6 +31,8 @@
  *
  */
 
+#include <grpc/support/port_platform.h>
+
 #include <string.h>
 
 /* Provide a wrapped memcpy for targets that need to be backwards
@@ -40,7 +42,7 @@
  */
 
 #ifdef __linux__
-#if defined(__x86_64__) && defined(__GNU_LIBRARY__)
+#if defined(__x86_64__) && !defined(GPR_MUSL_LIBC_COMPAT)
 __asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
 void *__wrap_memcpy(void *destination, const void *source, size_t num) {
   return memcpy(destination, source, num);

templates/binding.gyp.template

@@ -49,7 +49,11 @@
       # will let users recompile gRPC to work without ALPN.
       'grpc_alpn%': 'true',
       # Indicates that the library should be built with gcov.
-      'grpc_gcov%': 'false'
+      'grpc_gcov%': 'false',
+      # Indicates that the library should be built with compatibility for musl
+      # libc, so that it can run on Alpine Linux. This is only necessary if not
+      # building on Alpine Linux
+      'grpc_alpine%': 'false'
     },
     'target_defaults': {
       'configurations': {
@@ -105,6 +109,11 @@
           %  endif
           % endfor
         }],
+        ['grpc_alpine=="true"', {
+          'defines': [
+            'GPR_MUSL_LIBC_COMPAT'
+          ]
+        }],
         ['OS!="win" and runtime=="electron"', {
           "defines": [
             'OPENSSL_NO_THREADS'

tools/run_tests/artifacts/build_artifact_node.sh

@@ -48,7 +48,7 @@ electron_versions=( 1.0.0 1.1.0 1.2.0 1.3.0 1.4.0 1.5.0 1.6.0 )
 
 for version in ${node_versions[@]}
 do
-  ./node_modules/.bin/node-pre-gyp configure rebuild package testpackage --target=$version --target_arch=$NODE_TARGET_ARCH
+  ./node_modules/.bin/node-pre-gyp configure rebuild package testpackage --target=$version --target_arch=$NODE_TARGET_ARCH --grpc_alpine=true
   cp -r build/stage/* artifacts/
 done