From 61197ecc317410d991fe643683a3ac49f8b2a7da Mon Sep 17 00:00:00 2001
From: Sam Bingner <sam@bingner.com>
Date: Mon, 6 Apr 2020 09:43:46 -1000
Subject: Actually fix strange metadata.cb0 crashes

---
 Cytore.hpp     | 28 ++++++++++++++++------------
 MobileCydia.mm | 14 ++++++++++++--
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/Cytore.hpp b/Cytore.hpp
index c0bad09..fb17aaa 100644
--- a/Cytore.hpp
+++ b/Cytore.hpp
@@ -140,6 +140,15 @@ class File {
             blocks_.push_back(bytes + Block_ * i);
     }
 
+    void Close_() {
+        for (typename MappingVector_::const_iterator map(maps_.begin()); map != maps_.end(); ++map)
+            munmap(map->data_, map->size_);
+        maps_.clear();
+        blocks_.clear();
+        close(file_);
+        file_ = -1;
+    }
+
     bool Truncate_(size_t capacity) {
         capacity = Round(capacity, Block_);
 
@@ -164,9 +173,7 @@ class File {
     }
 
     ~File() {
-        for (typename MappingVector_::const_iterator map(maps_.begin()); map != maps_.end(); ++map)
-            munmap(map->data_, map->size_);
-        close(file_);
+        Close_();
     }
 
     void Sync() {
@@ -182,6 +189,8 @@ class File {
         _assert(file_ == -1);
         file_ = open(path, O_RDWR | O_CREAT | O_EXLOCK, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
         _assert(file_ != -1);
+        _assert(file_ != STDOUT_FILENO);
+        _assert(file_ != STDERR_FILENO);
 
         struct stat stat;
         _assert(fstat(file_, &stat) == 0);
@@ -197,16 +206,11 @@ class File {
 
             Header_().magic_ = Magic;
             Size_() = core;
-        } else if (size < core) {
-            close(file_);
-            file_ = -1;
-            unlink(path);
+        // XXX: this involves an unneccessary call to ftruncate()
+        } else if (size < core || !Truncate_(size) || Header_().magic_ != Magic || Header_().version_ != 0) {
+            Close_();
+            _assert(unlink(path) == 0);
             goto open;
-        } else {
-            // XXX: this involves an unneccessary call to ftruncate()
-            _assert(Truncate_(size));
-            _assert(Header_().magic_ == Magic);
-            _assert(Header_().version_ == 0);
         }
     }
 
diff --git a/MobileCydia.mm b/MobileCydia.mm
index 25e8907..b038aa0 100644
--- a/MobileCydia.mm
+++ b/MobileCydia.mm
@@ -9303,9 +9303,19 @@ int main(int argc, char *argv[]) {
     if ([WebPreferences respondsToSelector:@selector(setWebKitLinkTimeVersion:)])
                 [WebPreferences setWebKitLinkTimeVersion:PACKED_VERSION(3453,0,0)];
 
+    // Ensure we have a stdout and stderr
     int fd(open("/tmp/cydia.log", O_WRONLY | O_APPEND | O_CREAT, 0644));
-    dup2(fd, 2);
-    close(fd);
+    // Added this because stderr output ended up in metadata.cb0 somehow once
+    // Perhaps we were spawned with stderr or stdout closed?
+    //
+    // Ensure we have a stdout and stderr
+    if (fcntl(STDOUT_FILENO, F_GETFD) == -1) {
+        dup2(fd, STDOUT_FILENO);
+    }
+    dup2(fd, STDERR_FILENO);
+    if (fd > STDERR_FILENO) {
+        close(fd);
+    }
 
     NSAutoreleasePool *pool([[NSAutoreleasePool alloc] init]);
 
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