Initial checkin of the LLEE, the (LL)VM (E)xecution (E)nvironment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7760 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 81 insertions, 0 deletions

diff --git a/tools/llee/SysUtils.c b/tools/llee/SysUtils.c
new file mode 100644
index 0000000000..1c3aa85e5c
--- /dev/null
+++ b/tools/llee/SysUtils.c
@@ -0,0 +1,81 @@
+//===- SystemUtils.h - Utilities to do low-level system stuff --*- C++ -*--===//
+//
+// This file contains functions used to do a variety of low-level, often
+// system-specific, tasks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SysUtils.h"
+#include "Config/sys/types.h"
+#include "Config/sys/stat.h"
+#include "Config/fcntl.h"
+#include "Config/sys/wait.h"
+#include "Config/unistd.h"
+#include "Config/errno.h"
+#include <stdlib.h>
+#include <string.h>
+
+/// isExecutableFile - This function returns true if the filename specified
+/// exists and is executable.
+///
+bool isExecutableFile(const char *ExeFileName) {
+  struct stat Buf;
+  if (stat(ExeFileName, &Buf))
+    return false;  // Must not be executable!
+
+  if (!(Buf.st_mode & S_IFREG))
+    return false;                    // Not a regular file?
+
+  if (Buf.st_uid == getuid())        // Owner of file?
+    return Buf.st_mode & S_IXUSR;
+  else if (Buf.st_gid == getgid())   // In group of file?
+    return Buf.st_mode & S_IXGRP;
+  else                               // Unrelated to file?
+    return Buf.st_mode & S_IXOTH;
+}
+
+/// FindExecutable - Find a named executable in the directories listed in $PATH.
+/// If the executable cannot be found, returns NULL.
+/// 
+char *FindExecutable(const char *ExeName) {
+  /* Try to find the executable in the path */
+  const char *PathStr = getenv("PATH");
+  if (PathStr == 0) return "";
+
+  // Now we have a colon separated list of directories to search... try them...
+  unsigned PathLen = strlen(PathStr);
+  while (PathLen) {
+    /* Find the next colon */
+    const char *Colon = strchr(PathStr, ':');
+    
+    /* Check to see if this first directory contains the executable... */
+    unsigned DirLen = Colon ? (Colon-PathStr) : strlen(PathStr);
+    char *FilePath = alloca(sizeof(char) * (DirLen+1+strlen(ExeName)+1));
+    unsigned i, e;
+    for (i = 0; i != DirLen; ++i)
+      FilePath[i] = PathStr[i];
+    FilePath[i] = '/';
+    for (i = 0, e = strlen(ExeName); i != e; ++i)
+      FilePath[DirLen + 1 + i] = ExeName[i];
+    FilePath[DirLen + 1 + i] = '\0';
+    if (isExecutableFile(FilePath))
+      return strdup(FilePath); /* Found the executable! */
+
+    /* If Colon is NULL, there are no more colon separators and no more dirs */
+    if (!Colon) break;
+
+    /* Nope, it wasn't in this directory, check the next range! */
+    PathLen -= DirLen;
+    PathStr = Colon;
+    while (*PathStr == ':') {   /* Advance past colons */
+      PathStr++;
+      PathLen--;
+    }
+
+    /* Advance past the colon */
+    ++Colon;
+  }
+
+  // If we fell out, we ran out of directories in PATH to search, return failure
+  return NULL;
+}