1 files changed, 117 insertions, 0 deletions

diff --git a/win32/env.c b/win32/env.c
new file mode 100644
index 000000000..f30ee62f6
--- /dev/null
+++ b/win32/env.c
@@ -0,0 +1,117 @@
+#include "libbb.h"
+
+#undef getenv
+#undef putenv
+
+char *mingw_getenv(const char *name)
+{
+        char *result = getenv(name);
+        if (!result) {
+                if (!strcmp(name, "TMPDIR")) {
+                        /* on Windows it is TMP and TEMP */
+                        result = getenv("TMP");
+                        if (!result)
+                                result = getenv("TEMP");
+                } else if (!strcmp(name, "HOME")) {
+                        struct passwd *p = getpwuid(getuid());
+                        if (p)
+                                result = p->pw_dir;
+                }
+        }
+        return result;
+}
+
+int setenv(const char *name, const char *value, int replace)
+{
+        int out;
+        char *envstr;
+
+        if (!name || !*name || strchr(name, '=') || !value) return -1;
+        if (!replace) {
+                if (getenv(name)) return 0;
+        }
+
+        envstr = xasprintf("%s=%s", name, value);
+        out = mingw_putenv(envstr);
+        free(envstr);
+
+        return out;
+}
+
+/*
+ * Removing an environment variable with WIN32 _putenv requires an argument
+ * like "NAME="; glibc omits the '='.  The implementations of unsetenv and
+ * clearenv allow for this.
+ *
+ * It isn't possible to create an environment variable with an empty value
+ * using WIN32 _putenv.
+ */
+int unsetenv(const char *name)
+{
+        char *envstr;
+        int ret;
+
+        if (!name || !*name || strchr(name, '=') ) {
+                return -1;
+        }
+
+        envstr = xasprintf("%s=", name);
+        ret = _putenv(envstr);
+        free(envstr);
+
+        return ret;
+}
+
+int clearenv(void)
+{
+        char *envp, *name, *s;
+
+        while ( environ && (envp=*environ) ) {
+                if ( (s=strchr(envp, '=')) != NULL ) {
+                        name = xstrndup(envp, s-envp+1);
+                        if (_putenv(name) == -1) {
+                                free(name);
+                                return -1;
+                        }
+                        free(name);
+                }
+                else {
+                        return -1;
+                }
+        }
+        return 0;
+}
+
+int mingw_putenv(const char *env)
+{
+        char *s, **envp;
+        int ret = 0;
+
+        if ( (s=strchr(env, '=')) == NULL ) {
+                return unsetenv(env);
+        }
+
+        if (s[1] != '\0') {
+                /* setting non-empty value is fine */
+                return _putenv(env);
+        }
+        else {
+                /* set empty value by setting a non-empty one then truncating */
+                char *envstr = xasprintf("%s0", env);
+                ret = _putenv(envstr);
+
+                for (envp = environ; *envp; ++envp) {
+                        if (strcmp(*envp, envstr) == 0) {
+                                (*envp)[s - env + 1] = '\0';
+                                break;
+                        }
+                }
+
+                /* tell the OS environment about the change */
+                envstr[s - env] = '\0';
+                SetEnvironmentVariable(envstr, "");
+                free(envstr);
+        }
+
+        return ret;
+}