From 2dee094a08ff4e244e8df046f3b1d6445e707b77 Mon Sep 17 00:00:00 2001
From: Xing Xue <xingxue@outlook.com>
Date: Thu, 16 May 2019 14:02:13 +0000
Subject: [PATCH] Fixes for builds that require strict X/Open and POSIX
 compatiblity

Summary:
- Use alternative to MAP_ANONYMOUS for allocating mapped memory if it isn't available
- Use strtok_r instead of strsep as part of getting program path
- Don't try to find the width of a terminal using "struct winsize" and TIOCGWINSZ on POSIX builds. These aren't defined under POSIX (even though some platforms make them available when they shouldn't), so just check if we are doing a X/Open or POSIX compliant build first.

Author: daltenty

Reviewers: hubert.reinterpretcast, xingxue, andusy

Reviewed By: hubert.reinterpretcast

Subscribers: MaskRay, jsji, hiraditya, kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61326

llvm-svn: 360898
---
 llvm/lib/Support/Unix/Memory.inc  | 32 ++++++++++++++++++++++++++++---
 llvm/lib/Support/Unix/Path.inc    | 15 ++++++++-------
 llvm/lib/Support/Unix/Process.inc |  3 ++-
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
index affdb7e70d952..05c5ccbdb3dec 100644
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -91,9 +91,24 @@ Memory::allocateMappedMemory(size_t NumBytes,
   if (NumBytes == 0)
     return MemoryBlock();
 
-  int fd = -1;
+  // On platforms that have it, we can use MAP_ANON to get a memory-mapped
+  // page without file backing, but we need a fallback of opening /dev/zero
+  // for strictly POSIX platforms instead.
+  int fd;
+#if defined(MAP_ANON)
+  fd = -1;
+#else
+  fd = open("/dev/zero", O_RDWR);
+  if (fd == -1) {
+    EC = std::error_code(errno, std::generic_category());
+    return MemoryBlock();
+  }
+#endif
 
-  int MMFlags = MAP_PRIVATE | MAP_ANON;
+  int MMFlags = MAP_PRIVATE;
+#if defined(MAP_ANON)
+  MMFlags |= MAP_ANON;
+#endif
   int Protect = getPosixProtectionFlags(PFlags);
 
 #if defined(__NetBSD__) && defined(PROT_MPROTECT)
@@ -111,13 +126,24 @@ Memory::allocateMappedMemory(size_t NumBytes,
   void *Addr = ::mmap(reinterpret_cast<void *>(Start), NumBytes, Protect,
                       MMFlags, fd, 0);
   if (Addr == MAP_FAILED) {
-    if (NearBlock) //Try again without a near hint
+    if (NearBlock) { //Try again without a near hint
+#if !defined(MAP_ANON)
+      close(fd);
+#endif
       return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
+    }
 
     EC = std::error_code(errno, std::generic_category());
+#if !defined(MAP_ANON)
+    close(fd);
+#endif
     return MemoryBlock();
   }
 
+#if !defined(MAP_ANON)
+  close(fd);
+#endif
+
   MemoryBlock Result;
   Result.Address = Addr;
   Result.Size = NumBytes;
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index c2f78e79b8768..359202fc3161a 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -132,8 +132,6 @@ test_dir(char ret[PATH_MAX], const char *dir, const char *bin)
 static char *
 getprogpath(char ret[PATH_MAX], const char *bin)
 {
-  char *pv, *s, *t;
-
   /* First approach: absolute path. */
   if (bin[0] == '/') {
     if (test_dir(ret, "/", bin) == 0)
@@ -152,18 +150,21 @@ getprogpath(char ret[PATH_MAX], const char *bin)
   }
 
   /* Third approach: $PATH */
+  char *pv;
   if ((pv = getenv("PATH")) == nullptr)
     return nullptr;
-  s = pv = strdup(pv);
-  if (!pv)
+  char *s = strdup(pv);
+  if (!s)
     return nullptr;
-  while ((t = strsep(&s, ":")) != nullptr) {
+  char *state;
+  for (char *t = strtok_r(s, ":", &state); t != nullptr;
+       t = strtok_r(nullptr, ":", &state)) {
     if (test_dir(ret, t, bin) == 0) {
-      free(pv);
+      free(s);
       return ret;
     }
   }
-  free(pv);
+  free(s);
   return nullptr;
 }
 #endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
diff --git a/llvm/lib/Support/Unix/Process.inc b/llvm/lib/Support/Unix/Process.inc
index 78c123493e1db..4115ee3965822 100644
--- a/llvm/lib/Support/Unix/Process.inc
+++ b/llvm/lib/Support/Unix/Process.inc
@@ -291,7 +291,8 @@ static unsigned getColumns(int FileID) {
 
   unsigned Columns = 0;
 
-#if defined(HAVE_SYS_IOCTL_H) && defined(HAVE_TERMIOS_H)
+#if defined(HAVE_SYS_IOCTL_H) && defined(HAVE_TERMIOS_H) \
+  && !(defined(_XOPEN_SOURCE) || defined(_POSIX_C_SOURCE))
   // Try to determine the width of the terminal.
   struct winsize ws;
   if (ioctl(FileID, TIOCGWINSZ, &ws) == 0)