[llvm-commits] CVS: llvm/lib/System/Unix/Program.cpp

[Reid Spencer]

Changes in directory llvm/lib/System/Unix:

Program.cpp added (r1.1)
---
Log message:

Initial commit of an platform-indepdendent implementation for the
"Program" operating system concept (find and execute programs).


---
Diffs of the changes:  (+133 -0)

Index: llvm/lib/System/Unix/Program.cpp
diff -c /dev/null llvm/lib/System/Unix/Program.cpp:1.1
*** /dev/null	Sun Aug 29 14:20:51 2004
--- llvm/lib/System/Unix/Program.cpp	Sun Aug 29 14:20:41 2004
***************
*** 0 ****
--- 1,133 ----
+ //===- llvm/System/Unix/Program.cpp -----------------------------*- C++ -*-===//
+ // 
+ //                     The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Reid Spencer and is distributed under the 
+ // University of Illinois Open Source License. See LICENSE.TXT for details.
+ // 
+ //===----------------------------------------------------------------------===//
+ //
+ // This file implements the Unix specific portion of the Program class.
+ //
+ //===----------------------------------------------------------------------===//
+ 
+ //===----------------------------------------------------------------------===//
+ //=== WARNING: Implementation here must contain only generic UNIX code that
+ //===          is guaranteed to work on *all* UNIX variants.
+ //===----------------------------------------------------------------------===//
+ 
+ #include "Unix.h"
+ #include <sys/stat.h>
+ #include <fcntl.h>
+ #include <Config/config.h>
+ #ifdef HAVE_SYS_WAIT_H
+ #include <sys/wait.h>
+ #endif
+ 
+ namespace llvm {
+ using namespace sys;
+ 
+ // This function just uses the PATH environment variable to find the program.
+ Program
+ Program::FindProgramByName(const std::string& progName) {
+ 
+   // Check some degenerate cases
+   if (progName.length() == 0) // no program
+     return Program();
+   Program temp;
+   if (!temp.set_file(progName)) // invalid name
+     return Program();
+   if (temp.executable()) // already executable as is
+     return temp;
+ 
+   // At this point, the file name is valid and its not executable
+  
+   // Get the path. If its empty, we can't do anything to find it.
+   const char *PathStr = getenv("PATH");
+   if (PathStr == 0) 
+     return Program();
+ 
+   // Now we have a colon separated list of directories to search; try them.
+   unsigned PathLen = strlen(PathStr);
+   while (PathLen) {
+     // Find the first colon...
+     const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
+ 
+     // Check to see if this first directory contains the executable...
+     Program FilePath;
+     if (FilePath.set_directory(std::string(PathStr,Colon))) {
+       FilePath.append_file(progName);
+       if (FilePath.executable())
+         return FilePath;                    // Found the executable!
+     }
+ 
+     // Nope it wasn't in this directory, check the next path in the list!
+     PathLen -= Colon-PathStr;
+     PathStr = Colon;
+ 
+     // Advance past duplicate colons
+     while (*PathStr == ':') {
+       PathStr++;
+       PathLen--;
+     }
+   }
+   return Program();
+ }
+ 
+ //
+ int 
+ Program::ExecuteAndWait(const std::vector<std::string>& args) const {
+   if (!executable())
+     throw get() + " is not executable"; 
+ 
+ #ifdef HAVE_SYS_WAIT_H
+   // Create local versions of the parameters that can be passed into execve()
+   // without creating const problems.
+   const char* argv[ args.size() + 2 ];
+   unsigned index = 0;
+   std::string progname(this->getLast());
+   argv[index++] = progname.c_str();
+   for (unsigned i = 0; i < args.size(); i++)
+     argv[index++] = args[i].c_str();
+   argv[index] = 0;
+ 
+   // Create a child process.
+   switch (fork()) {
+     // An error occured:  Return to the caller.
+     case -1:
+       ThrowErrno(std::string("Couldn't execute program '") + get() + "'");
+       break;
+ 
+     // Child process: Execute the program.
+     case 0:
+       execve (get().c_str(), (char** const)argv, environ);
+       // If the execve() failed, we should exit and let the parent pick up
+       // our non-zero exit status.
+       exit (errno);
+ 
+     // Parent process: Break out of the switch to do our processing.
+     default:
+       break;
+   }
+ 
+   // Parent process: Wait for the child process to terminate.
+   int status;
+   if ((::wait (&status)) == -1)
+     ThrowErrno(std::string("Failed waiting for program '") + get() + "'");
+ 
+   // If the program exited normally with a zero exit status, return success!
+   if (WIFEXITED (status))
+     return WEXITSTATUS(status);
+   else if (WIFSIGNALED(status))
+     throw std::string("Program '") + get() + "' received terminating signal.";
+   else
+     return 0;
+     
+ #else
+   throw std::string("Program::ExecuteAndWait not implemented on this platform!\n");
+ #endif
+ 
+ }
+ 
+ }
+ // vim: sw=2 smartindent smarttab tw=80 autoindent expandtab