1//=- RPCChannel.inc - LLVM out-of-process JIT execution for Unix --=//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Implementation of the Unix-specific parts of the RPCChannel class
11// which executes JITed code in a separate process from where it was built.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Support/Errno.h"
16#include "llvm/Support/raw_ostream.h"
17#include <stdio.h>
18#include <stdlib.h>
19#include <sys/wait.h>
20#include <unistd.h>
21
22namespace {
23
24struct ConnectionData_t {
25  int InputPipe;
26  int OutputPipe;
27
28  ConnectionData_t(int in, int out) : InputPipe(in), OutputPipe(out) {}
29};
30
31} // namespace
32
33namespace llvm {
34
35bool RPCChannel::createServer() {
36  int PipeFD[2][2];
37  pid_t ChildPID;
38
39  // Create two pipes.
40  if (pipe(PipeFD[0]) != 0 || pipe(PipeFD[1]) != 0)
41    perror("Error creating pipe: ");
42
43  ChildPID = fork();
44
45  if (ChildPID == 0) {
46    // In the child...
47
48    // Close the parent ends of the pipes
49    close(PipeFD[0][1]);
50    close(PipeFD[1][0]);
51
52    // Use our pipes as stdin and stdout
53    if (PipeFD[0][0] != STDIN_FILENO) {
54      dup2(PipeFD[0][0], STDIN_FILENO);
55      close(PipeFD[0][0]);
56    }
57    if (PipeFD[1][1] != STDOUT_FILENO) {
58      dup2(PipeFD[1][1], STDOUT_FILENO);
59      close(PipeFD[1][1]);
60    }
61
62    // Execute the child process.
63    char *args[1] = { nullptr };
64    int rc = execv(ChildName.c_str(), args);
65    if (rc != 0)
66      perror("Error executing child process: ");
67  } else {
68    // In the parent...
69
70    // Close the child ends of the pipes
71    close(PipeFD[0][0]);
72    close(PipeFD[1][1]);
73
74    // Store the parent ends of the pipes
75    ConnectionData = (void *)new ConnectionData_t(PipeFD[1][0], PipeFD[0][1]);
76    return true;
77  }
78  return false;
79}
80
81bool RPCChannel::createClient() {
82  // Store the parent ends of the pipes
83  ConnectionData = (void *)new ConnectionData_t(STDIN_FILENO, STDOUT_FILENO);
84  return true;
85}
86
87void RPCChannel::Wait() { wait(nullptr); }
88
89static bool CheckError(int rc, size_t Size, const char *Desc) {
90  if (rc < 0) {
91    llvm::errs() << "IO Error: " << Desc << ": " << sys::StrError() << '\n';
92    return false;
93  } else if ((size_t)rc != Size) {
94    std::string ErrorMsg;
95    char Number[10] = { 0 };
96    ErrorMsg += "Expecting ";
97    sprintf(Number, "%d", (uint32_t)Size);
98    ErrorMsg += Number;
99    ErrorMsg += " bytes, Got ";
100    sprintf(Number, "%d", rc);
101    ErrorMsg += Number;
102    llvm::errs() << "RPC Error: " << Desc << ": " << ErrorMsg << '\n';
103    return false;
104  }
105  return true;
106}
107
108bool RPCChannel::WriteBytes(const void *Data, size_t Size) {
109  int rc = write(((ConnectionData_t *)ConnectionData)->OutputPipe, Data, Size);
110  return CheckError(rc, Size, "WriteBytes");
111}
112
113bool RPCChannel::ReadBytes(void *Data, size_t Size) {
114  int rc = read(((ConnectionData_t *)ConnectionData)->InputPipe, Data, Size);
115  return CheckError(rc, Size, "ReadBytes");
116}
117
118RPCChannel::~RPCChannel() {
119  delete static_cast<ConnectionData_t *>(ConnectionData);
120}
121
122} // namespace llvm
123