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https://github.com/c64scene-ar/llvm-6502.git
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0abaaf49fd
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7760 91177308-0d34-0410-b5e6-96231b3b80d8
93 lines
2.9 KiB
C
93 lines
2.9 KiB
C
//===-- ExecveHandler.c - Replaces execve() to run LLVM files -------------===//
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//
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// This file implements a replacement execve() to spawn off LLVM programs to run
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// transparently, without needing to be (JIT-)compiled manually by the user.
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//
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//===----------------------------------------------------------------------===//
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#include "SysUtils.h"
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#include <Config/dlfcn.h>
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#include <Config/errno.h>
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#include <Config/stdlib.h>
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#include <stdio.h>
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#include <string.h>
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/*
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* This is the expected header for all valid LLVM bytecode files.
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* The first four characters must be exactly this.
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*/
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static const char llvmHeader[] = "llvm";
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/*
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* The type of the execve() function is long and boring, but required.
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*/
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typedef int(*execveTy)(const char*, char *const[], char *const[]);
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/*
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* This method finds the real `execve' call in the C library and executes the
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* given program.
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*/
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int executeProgram(const char *filename, char *const argv[], char *const envp[])
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{
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/*
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* Find a pointer to the *real* execve() function starting the search in the
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* next library and forward, to avoid finding the one defined in this file.
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*/
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char *error;
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execveTy execvePtr = (execveTy) dlsym(RTLD_NEXT, "execve");
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if ((error = dlerror()) != NULL) {
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fprintf(stderr, "%s\n", error);
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return -1;
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}
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/* Really execute the program */
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return execvePtr(filename, argv, envp);
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}
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/*
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* This replacement execve() function first checks the file to be executed
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* to see if it is a valid LLVM bytecode file, and then either invokes our
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* execution environment or passes it on to the system execve() call.
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*/
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int execve(const char *filename, char *const argv[], char *const envp[])
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{
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/* Open the file, test to see if first four characters are "llvm" */
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char header[4];
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FILE *file = fopen(filename, "r");
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/* Check validity of `file' */
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if (errno) { return errno; }
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/* Read the header from the file */
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size_t headerSize = strlen(llvmHeader) - 1; // ignore the NULL terminator
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size_t bytesRead = fread(header, sizeof(char), headerSize, file);
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fclose(file);
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if (bytesRead != headerSize) {
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return EIO;
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}
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if (!strncmp(llvmHeader, header, headerSize)) {
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/*
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* This is a bytecode file, so execute the JIT with the program and
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* parameters.
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*/
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unsigned argvSize, idx;
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for (argvSize = 0, idx = 0; argv[idx] && argv[idx][0]; ++idx)
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++argvSize;
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char **LLIargs = (char**) malloc(sizeof(char*) * (argvSize+2));
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char *LLIpath = FindExecutable("lli");
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if (!LLIpath) {
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fprintf(stderr, "Cannot find path to `lli', exiting.\n");
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return -1;
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}
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LLIargs[0] = LLIpath;
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for (idx = 0; idx != argvSize; ++idx)
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LLIargs[idx+1] = argv[idx];
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LLIargs[argvSize + 1] = '\0';
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/*
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for (idx = 0; idx != argvSize+2; ++idx)
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printf("LLI args[%d] = \"%s\"\n", idx, LLIargs[idx]);
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*/
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return executeProgram(LLIpath, LLIargs, envp);
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}
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executeProgram(filename, argv, envp);
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return 0;
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}
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