Add nix::execvpe

src/libutil/unix/exec.hh

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace nix {
+
+/**
+ * `execvpe` is a GNU extension, so we need to implement it for other POSIX
+ * platforms.
+ *
+ * We use our own implementation unconditionally for consistency.
+ */
+int execvpe(const char * file0, char * const argv[], char * const envp[]);
+
+}

src/libutil/unix/meson.build

@@ -13,6 +13,7 @@ sources += files(
 include_dirs += include_directories('.')
 
 headers += files(
+  'exec.hh',
   'monitor-fd.hh',
   'signals-impl.hh',
 )

src/libutil/unix/processes.cc

@@ -1,5 +1,6 @@
 #include "current-process.hh"
 #include "environment-variables.hh"
+#include "executable-path.hh"
 #include "signals.hh"
 #include "processes.hh"
 #include "finally.hh"
@@ -419,4 +420,10 @@ bool statusOk(int status)
     return WIFEXITED(status) && WEXITSTATUS(status) == 0;
 }
 
+int execvpe(const char * file0, char * const argv[], char * const envp[])
+{
+    auto file = ExecutablePath::load().findPath(file0).string();
+    return execve(file.c_str(), argv, envp);
+}
+
 }