unix,win: add ability to retrieve all env variables

Fixes: https://github.com/libuv/libuv/issues/2400

PR-URL: https://github.com/libuv/libuv/pull/2404
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

docs/src/misc.rst

@@ -180,6 +180,17 @@ Data types
             char machine[256];
         } uv_utsname_t;
 
+.. c:type:: uv_env_item_t
+
+    Data type for environment variable storage.
+
+    ::
+
+    typedef struct uv_env_item_s {
+        char* name;
+        char* value;
+    } uv_env_item_t;
+
 
 API
 ---
@@ -523,6 +534,23 @@ API
 
     .. versionadded:: 1.8.0
 
+.. c:function:: int uv_os_environ(uv_env_item_t** envitems, int* count)
+
+    Retrieves all environment variables. This function will allocate memory
+    which must be freed by calling :c:func:`uv_os_free_environ`.
+
+    .. warning::
+        This function is not thread safe.
+
+    .. versionadded:: 1.31.0
+
+.. c:function:: void uv_os_free_environ(uv_env_item_t* envitems, int count);
+
+    Frees the memory allocated for the environment variables by
+    :c:func:`uv_os_environ`.
+
+    .. versionadded:: 1.31.0
+
 .. c:function:: int uv_os_getenv(const char* name, char* buffer, size_t* size)
 
     Retrieves the environment variable specified by `name`, copies its value

include/uv.h

@@ -231,6 +231,7 @@ typedef struct uv_fs_s uv_fs_t;
 typedef struct uv_work_s uv_work_t;
 
 /* None of the above. */
+typedef struct uv_env_item_s uv_env_item_t;
 typedef struct uv_cpu_info_s uv_cpu_info_t;
 typedef struct uv_interface_address_s uv_interface_address_t;
 typedef struct uv_dirent_s uv_dirent_t;
@@ -1162,6 +1163,13 @@ UV_EXTERN int uv_interface_addresses(uv_interface_address_t** addresses,
 UV_EXTERN void uv_free_interface_addresses(uv_interface_address_t* addresses,
                                            int count);
 
+struct uv_env_item_s {
+  char* name;
+  char* value;
+};
+
+UV_EXTERN int uv_os_environ(uv_env_item_t** envitems, int* count);
+UV_EXTERN void uv_os_free_environ(uv_env_item_t* envitems, int count);
 UV_EXTERN int uv_os_getenv(const char* name, char* buffer, size_t* size);
 UV_EXTERN int uv_os_setenv(const char* name, const char* value);
 UV_EXTERN int uv_os_unsetenv(const char* name);

src/unix/core.c

@@ -50,11 +50,15 @@
 #endif
 
 #ifdef __APPLE__
+# include <crt_externs.h>
 # include <mach-o/dyld.h> /* _NSGetExecutablePath */
 # include <sys/filio.h>
 # if defined(O_CLOEXEC)
 #  define UV__O_CLOEXEC O_CLOEXEC
 # endif
+# define environ (*_NSGetEnviron())
+#else
+extern char** environ;
 #endif
 
 #if defined(__DragonFly__)      || \
@@ -1284,6 +1288,62 @@ int uv_translate_sys_error(int sys_errno) {
 }
 
 
+int uv_os_environ(uv_env_item_t** envitems, int* count) {
+  int i, j, cnt;
+  uv_env_item_t* envitem;
+
+  *envitems = NULL;
+  *count = 0;
+
+  for (i = 0; environ[i] != NULL; i++);
+
+  *envitems = uv__calloc(i, sizeof(**envitems));
+
+  if (envitems == NULL)
+    return UV_ENOMEM;
+
+  for (j = 0, cnt = 0; j < i; j++) {
+    char* buf;
+    char* ptr;
+
+    if (environ[j] == NULL)
+      break;
+
+    buf = uv__strdup(environ[j]);
+    if (buf == NULL)
+      goto fail;
+
+    ptr = strchr(buf, '=');
+    if (ptr == NULL) {
+      uv__free(buf);
+      continue;
+    }
+
+    *ptr = '\0';
+
+    envitem = &(*envitems)[cnt];
+    envitem->name = buf;
+    envitem->value = ptr + 1;
+
+    cnt++;
+  }
+
+  *count = cnt;
+  return 0;
+
+fail:
+  for (i = 0; i < cnt; i++) {
+    envitem = &(*envitems)[cnt];
+    uv__free(envitem->name);
+  }
+  uv__free(*envitems);
+
+  *envitems = NULL;
+  *count = 0;
+  return UV_ENOMEM;
+}
+
+
 int uv_os_getenv(const char* name, char* buffer, size_t* size) {
   char* var;
   size_t len;

src/uv-common.c

@@ -786,3 +786,14 @@ void uv_loop_delete(uv_loop_t* loop) {
   if (loop != default_loop)
     uv__free(loop);
 }
+
+
+void uv_os_free_environ(uv_env_item_t* envitems, int count) {
+  int i;
+
+  for (i = 0; i < count; i++) {
+    uv__free(envitems[i].name);
+  }
+
+  uv__free(envitems);
+}

src/win/util.c

@@ -1397,6 +1397,75 @@ int uv_os_get_passwd(uv_passwd_t* pwd) {
 }
 
 
+int uv_os_environ(uv_env_item_t** envitems, int* count) {
+  wchar_t* env;
+  wchar_t* penv;
+  int i, cnt;
+  uv_env_item_t* envitem;
+
+  *envitems = NULL;
+  *count = 0;
+
+  env = GetEnvironmentStringsW();
+  if (env == NULL)
+    return 0;
+
+  for (penv = env, i = 0; *penv != L'\0'; penv += wcslen(penv) + 1, i++);
+
+  *envitems = uv__calloc(i, sizeof(**envitems));
+  if (envitems == NULL) {
+    FreeEnvironmentStringsW(env);
+    return UV_ENOMEM;
+  }
+
+  penv = env;
+  cnt = 0;
+
+  while (*penv != L'\0' && cnt < i) {
+    char* buf;
+    char* ptr;
+
+    if (uv__convert_utf16_to_utf8(penv, -1, &buf) != 0)
+      goto fail;
+
+    ptr = strchr(buf, '=');
+    if (ptr == NULL) {
+      uv__free(buf);
+      goto do_continue;
+    }
+
+    *ptr = '\0';
+
+    envitem = &(*envitems)[cnt];
+    envitem->name = buf;
+    envitem->value = ptr + 1;
+
+    cnt++;
+
+  do_continue:
+    penv += wcslen(penv) + 1;
+  }
+
+  FreeEnvironmentStringsW(env);
+
+  *count = cnt;
+  return 0;
+
+fail:
+  FreeEnvironmentStringsW(env);
+
+  for (i = 0; i < cnt; i++) {
+    envitem = &(*envitems)[cnt];
+    uv__free(envitem->name);
+  }
+  uv__free(*envitems);
+
+  *envitems = NULL;
+  *count = 0;
+  return UV_ENOMEM;
+}
+
+
 int uv_os_getenv(const char* name, char* buffer, size_t* size) {
   wchar_t var[MAX_ENV_VAR_LENGTH];
   wchar_t* name_w;

test/test-env-vars.c

@@ -27,9 +27,11 @@
 
 TEST_IMPL(env_vars) {
   const char* name = "UV_TEST_FOO";
+  const char* name2 = "UV_TEST_FOO2";
   char buf[BUF_SIZE];
   size_t size;
-  int r;
+  int i, r, envcount, found;
+  uv_env_item_t* envitems;
 
   /* Reject invalid inputs when setting an environment variable */
   r = uv_os_setenv(NULL, "foo");
@@ -86,5 +88,38 @@ TEST_IMPL(env_vars) {
   r = uv_os_unsetenv(name);
   ASSERT(r == 0);
 
+  /* Check getting all env variables. */
+  r = uv_os_setenv(name, "123456789");
+  ASSERT(r == 0);
+  r = uv_os_setenv(name2, "");
+  ASSERT(r == 0);
+
+  r = uv_os_environ(&envitems, &envcount);
+  ASSERT(r == 0);
+  ASSERT(envcount > 0);
+
+  found = 0;
+
+  for (i = 0; i < envcount; i++) {
+    /* printf("Env: %s = %s\n", envitems[i].name, envitems[i].value); */
+    if (strcmp(envitems[i].name, name) == 0) {
+      found++;
+      ASSERT(strcmp(envitems[i].value, "123456789") == 0);
+    } else if (strcmp(envitems[i].name, name2) == 0) {
+      found++;
+      ASSERT(strlen(envitems[i].value) == 0);
+    }
+  }
+
+  ASSERT(found == 2);
+
+  uv_os_free_environ(envitems, envcount);
+
+  r = uv_os_unsetenv(name);
+  ASSERT(r == 0);
+
+  r = uv_os_unsetenv(name2);
+  ASSERT(r == 0);
+
   return 0;
 }