From 29fae6aca64d5e1b0e82a88c23dc6b898702ed58 Mon Sep 17 00:00:00 2001
From: tkchia <tkchia-cosmo@gmx.com>
Date: Tue, 18 Oct 2022 23:12:21 +0000
Subject: [PATCH] [metal] Get zipos working

---
 libc/str/getzipcdir.c | 10 +++++++---
 libc/zipos/open.c     |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/libc/str/getzipcdir.c b/libc/str/getzipcdir.c
index 25ccdf17d..968275045 100644
--- a/libc/str/getzipcdir.c
+++ b/libc/str/getzipcdir.c
@@ -41,6 +41,7 @@ void *GetZipCdir(const uint8_t *p, size_t n) {
   size_t i, j;
   v8hi pk = {READ16LE("PK"), READ16LE("PK"), READ16LE("PK"), READ16LE("PK"),
              READ16LE("PK"), READ16LE("PK"), READ16LE("PK"), READ16LE("PK")};
+  uint32_t magic;
   i = n - 4;
   asm("" : "+x"(pk));
   do {
@@ -54,11 +55,14 @@ void *GetZipCdir(const uint8_t *p, size_t n) {
         continue;
       }
     }
-    if (READ32LE(p + i) == kZipCdir64LocatorMagic &&
+    while (magic = READ32LE(p + i),
+           magic != kZipCdir64LocatorMagic && magic != kZipCdirHdrMagic &&
+           i + 0x10000 + 0x1000 >= n) --i;
+    if (magic == kZipCdir64LocatorMagic &&
         i + kZipCdir64LocatorSize <= n &&
         IsZipCdir64(p, n, ZIP_LOCATE64_OFFSET(p + i))) {
       return p + ZIP_LOCATE64_OFFSET(p + i);
-    } else if (READ32LE(p + i) == kZipCdirHdrMagic && IsZipCdir32(p, n, i)) {
+    } else if (magic == kZipCdirHdrMagic && IsZipCdir32(p, n, i)) {
       j = i;
       do {
         if (READ32LE(p + j) == kZipCdir64LocatorMagic &&
@@ -69,6 +73,6 @@ void *GetZipCdir(const uint8_t *p, size_t n) {
       } while (j-- && i - j < 128);
       return p + i;
     }
-  } while (i--);
+  } while (i-- + 0x10000 + 0x1000 >= n);
   return 0;
 }
diff --git a/libc/zipos/open.c b/libc/zipos/open.c
index 097b4eb3f..0c37fe211 100644
--- a/libc/zipos/open.c
+++ b/libc/zipos/open.c
@@ -163,7 +163,7 @@ static int __zipos_load(struct Zipos *zipos, size_t cf, unsigned flags,
     minfd = 3;
     __fds_lock();
   TryAgain:
-    if (IsWindows()) {
+    if (IsWindows() || IsMetal()) {
       if ((fd = __reservefd_unlocked(-1)) != -1) {
         return __zipos_setfd(fd, h, flags, mode);
       }