Revamp posix_spawn() implementation

libc/stdio/posix_spawnp.c

@@ -0,0 +1,37 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/errno.h"
+#include "libc/stdio/posix_spawn.h"
+
+/**
+ * Spawns process the POSIX way w/ PATH search.
+ *
+ * @param pid is non-NULL and will be set to child pid in parent
+ * @param path of executable is PATH searched unless it contains a slash
+ * @return 0 on success or error number on failure
+ */
+int posix_spawnp(int *pid, const char *path,
+                 const posix_spawn_file_actions_t *file_actions,
+                 const posix_spawnattr_t *attrp, char *const argv[],
+                 char *const envp[]) {
+  char pathbuf[PATH_MAX];
+  if (!(path = commandv(path, pathbuf, sizeof(pathbuf)))) return errno;
+  return posix_spawn(pid, path, file_actions, attrp, argv, envp);
+}