From 284a27675c5d3274965a4fc312d3f410c090f25f Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sat, 6 Nov 2021 20:10:42 -0500
Subject: [PATCH] Fix env properly: env -i uses old $PATH, but use new PATH=
 when redefined.

Also add QUIET macro to shut up gcc's "isn't actually used uninitalized"
warnings, instead of doing the "int x=x;" trick.
---
 lib/portability.h |  5 +++++
 tests/env.test    |  3 ++-
 toys/posix/env.c  | 30 +++++++++++++++++++++---------
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/lib/portability.h b/lib/portability.h
index 67727f9c..4286b7b0 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -29,6 +29,11 @@
 // Test for gcc (using compiler builtin #define)
 
 #ifdef __GNUC__
+#ifndef __clang__
+#define QUIET = 0 // shut up false positive "may be used uninitialized" warning
+#else
+#define QUIET
+#endif
 #define printf_format	__attribute__((format(printf, 1, 2)))
 #else
 #define printf_format
diff --git a/tests/env.test b/tests/env.test
index 30757be4..06ba680e 100755
--- a/tests/env.test
+++ b/tests/env.test
@@ -11,7 +11,8 @@ FILTER="| egrep '^(WALRUS|BANANA|LETTERS)=' | sort"
 testcmd "read" "$FILTER" "BANANA=hello\nLETTERS=\nWALRUS=42\n" "" ""
 testcmd "-u" "-u BANANA $FILTER" "LETTERS=\nWALRUS=42\n" "" ""
 testcmd "-uu" "-u LETTERS -u WALRUS $FILTER" "BANANA=hello\n" "" ""
-testcmd "-i" "-i \"$(which env)\"" "" "" ""
+testcmd "-i uses old \$PATH" "-i echo hello" "hello\n" "" ""
+testcmd "-i env" "-i env" "" "" ""
 testcmd "-i =" "-i one=two three=four $C | sort" \
   "one=two\nthree=four\n" "" ""
 testcmd "-0" "-i five=six seven=eight $C -0 | sort -z" "five=six\0seven=eight\0" "" ""
diff --git a/toys/posix/env.c b/toys/posix/env.c
index 750ba49a..8e560a25 100644
--- a/toys/posix/env.c
+++ b/toys/posix/env.c
@@ -4,6 +4,8 @@
  *
  * http://opengroup.org/onlinepubs/9699919799/utilities/env.html
  *
+ * Note: env bypasses shell builtins, so don't xexec().
+ *
  * Deviations from posix: "-" argument and -0
 
 USE_ENV(NEWTOY(env, "^i0u*", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_ARGFAIL(125)))
@@ -30,7 +32,8 @@ GLOBALS(
 
 void env_main(void)
 {
-  char **ev = toys.optargs;
+  char **ev = toys.optargs, **ee = 0, **set QUIET, *path = getenv("PATH");
+  struct string_list *sl = 0;
   struct arg_list *u;
 
   // If first nonoption argument is "-" treat it as -i
@@ -39,16 +42,25 @@ void env_main(void)
     ev++;
   }
 
-  if (FLAG(i)) xclearenv();
+  if (FLAG(i)) ee = set = xzalloc(sizeof(void *)*(toys.optc+1));
   else for (u = TT.u; u; u = u->next) xunsetenv(u->arg);
 
-  for (; *ev; ev++)
-    if (strchr(*ev, '=')) xsetenv(xstrdup(*ev), 0);
-    else {
-      // a common use of env is to bypass shell builtins
-      toys.stacktop = 0;
-      xexec(ev);
+  for (; *ev; ev++) {
+    if (strchr(*ev, '=')) {
+      if (FLAG(i)) *set++ = *ev;
+      else xsetenv(xstrdup(*ev), 0);
+      if (!strncmp(*ev, "PATH=", 5)) path=(*ev)+5;
+    } else {
+      // unfortunately, posix has no exec combining p and e, so do p ourselves
+      if (!strchr(*ev, '/') && path) {
+         errno = ENOENT;
+         for (sl = find_in_path(path, *ev); sl; sl = sl->next)
+           execve(sl->str, ev, ee ? : environ);
+      } else execve(*ev, ev, ee ? : environ);
+      perror_msg("exec %s", *ev);
+      _exit(126+(errno == ENOENT));
     }
+  }
 
-  for (ev = environ; *ev; ev++) xprintf("%s%c", *ev, '\n'*!FLAG(0));
+  for (ev = ee ? : environ; *ev; ev++) xprintf("%s%c", *ev, '\n'*!FLAG(0));
 }