From 56066f332fe60c4b83a0cbb3430a723cbf5dd441 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Thu, 17 Aug 2023 11:20:32 +0200
Subject: [PATCH] wind: Handle ftruncate() and mmap() errors properly

---
 wind/IPC.cpp | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/wind/IPC.cpp b/wind/IPC.cpp
index 3a4e5e59..d3ba6475 100644
--- a/wind/IPC.cpp
+++ b/wind/IPC.cpp
@@ -26,29 +26,32 @@ static Result<u32*> create_shm_region(const char* path, int* outfd, ui::Rect rec
     int fd = shm_open(path, O_RDWR | O_CREAT | O_EXCL, 0600);
     if (fd < 0)
     {
-        os::eprintln("wind: could not create shared memory region: shm_open failed (%s) - %s", path, strerror(errno));
-        return err(errno);
+        int olderr = errno;
+        os::eprintln("wind: could not create shared memory region: shm_open failed (%s) - %s", path, strerror(olderr));
+        return err(olderr);
     }
 
     usize size = align_up<PAGE_SIZE>(rect.width * rect.height * 4); // 4 bytes per pixel
 
     if (ftruncate(fd, size) < 0)
     {
+        int olderr = errno;
         os::eprintln("wind: could not create shared memory region: ftruncate failed (%d, %zu) - %s", fd, size,
-                     strerror(errno));
+                     strerror(olderr));
         shm_unlink(path);
         close(fd);
-        return 0;
+        return err(olderr);
     }
 
     void* p = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
     if (p == MAP_FAILED)
     {
+        int olderr = errno;
         os::eprintln("wind: could not create shared memory region: mmap failed (%zu, %d) - %s", size, fd,
-                     strerror(errno));
+                     strerror(olderr));
         shm_unlink(path);
         close(fd);
-        return 0;
+        return err(olderr);
     }
 
     if (outfd) *outfd = fd;