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//===-- ExecveHandler.c - Replaces execve() to run LLVM files -------------===//
//
// This file implements a replacement execve() to spawn off LLVM programs to run
// transparently, without needing to be (JIT-)compiled manually by the user.
//
//===----------------------------------------------------------------------===//
#include "SysUtils.h"
#include "Config/unistd.h"
#include <errno.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
/*
* This is the expected header for all valid LLVM bytecode files.
* The first four characters must be exactly this.
*/
static const char llvmHeader[] = "llvm";
/*
* This replacement execve() function first checks the file to be executed
* to see if it is a valid LLVM bytecode file, and then either invokes our
* execution environment or passes it on to the system execve() call.
*/
int execve(const char *filename, char *const argv[], char *const envp[])
{
/* Open the file, test to see if first four characters are "llvm" */
size_t headerSize = strlen(llvmHeader);
char header[headerSize];
char* realFilename = 0;
/*
* If the program is specified with a relative or absolute path,
* then just use the path and filename as is, otherwise search for it.
*/
if (filename[0] != '.' && filename[0] != '/')
realFilename = FindExecutable(filename);
else
realFilename = (char*) filename;
if (!realFilename) {
fprintf(stderr, "Cannot find path to `%s', exiting.\n", filename);
return -1;
}
errno = 0;
int file = open(realFilename, O_RDONLY);
/* Check validity of `file' */
if (errno) return EIO;
/* Read the header from the file */
ssize_t bytesRead = read(file, header, headerSize);
close(file);
if (bytesRead != (ssize_t)headerSize) return EIO;
if (!memcmp(llvmHeader, header, headerSize)) {
/*
* This is a bytecode file, so execute the JIT with the program and
* parameters.
*/
unsigned argvSize, idx;
for (argvSize = 0, idx = 0; argv[idx] && argv[idx][0]; ++idx)
++argvSize;
char **LLIargs = (char**) malloc(sizeof(char*) * (argvSize+2));
char *LLIpath = FindExecutable("lli");
if (!LLIpath) {
fprintf(stderr, "Cannot find path to `lli', exiting.\n");
return -1;
}
LLIargs[0] = LLIpath;
LLIargs[1] = realFilename;
for (idx = 1; idx != argvSize; ++idx)
LLIargs[idx+1] = argv[idx];
LLIargs[argvSize + 1] = '\0';
return executeProgram(LLIpath, LLIargs, envp);
}
return executeProgram(filename, argv, envp);
}
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