1 /*===-- ExecveHandler.c - Replaces execve() to run LLVM files -------------===*\
3 * The LLVM Compiler Infrastructure
5 * This file was developed by the LLVM research group and is distributed under
6 * the University of Illinois Open Source License. See LICENSE.TXT for details.
8 *===----------------------------------------------------------------------===
10 * This file implements a replacement execve() to spawn off LLVM programs to run
11 * transparently, without needing to be (JIT-)compiled manually by the user.
13 \*===----------------------------------------------------------------------===*/
16 #include "llvm/Config/unistd.h"
24 * This is the expected header for all valid LLVM bytecode files.
25 * The first four characters must be exactly this.
27 static const char llvmHeader[] = "llvm";
30 * This replacement execve() function first checks the file to be executed
31 * to see if it is a valid LLVM bytecode file, and then either invokes our
32 * execution environment or passes it on to the system execve() call.
34 int execve(const char *filename, char *const argv[], char *const envp[])
36 /* Open the file, test to see if first four characters are "llvm" */
37 size_t headerSize = strlen(llvmHeader);
38 char header[headerSize];
39 char* realFilename = 0;
41 * If the program is specified with a relative or absolute path,
42 * then just use the path and filename as is, otherwise search for it.
44 if (filename[0] != '.' && filename[0] != '/')
45 realFilename = FindExecutable(filename);
47 realFilename = (char*) filename;
49 fprintf(stderr, "Cannot find path to `%s', exiting.\n", filename);
53 int file = open(realFilename, O_RDONLY);
54 /* Check validity of `file' */
55 if (errno) return EIO;
56 /* Read the header from the file */
57 ssize_t bytesRead = read(file, header, headerSize);
59 if (bytesRead != (ssize_t)headerSize) return EIO;
60 if (!memcmp(llvmHeader, header, headerSize)) {
62 * This is a bytecode file, so execute the JIT with the program and
65 unsigned argvSize, idx;
66 for (argvSize = 0, idx = 0; argv[idx] && argv[idx][0]; ++idx)
68 char **LLIargs = (char**) malloc(sizeof(char*) * (argvSize+2));
69 char *LLIpath = FindExecutable("lli");
71 fprintf(stderr, "Cannot find path to `lli', exiting.\n");
75 LLIargs[1] = realFilename;
76 for (idx = 1; idx != argvSize; ++idx)
77 LLIargs[idx+1] = argv[idx];
78 LLIargs[argvSize + 1] = '\0';
79 return executeProgram(LLIpath, LLIargs, envp);
81 return executeProgram(filename, argv, envp);