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/*===- StorageProxy.c - OS implementation of the caching interface --------===*\
* *
* This file implements the interface that we will expect operating *
* systems to implement if they wish to support offline cachine. *
* *
\*===----------------------------------------------------------------------===*/
#include "OSInterface.h"
#include "SysUtils.h"
#include "llvm/Config/fcntl.h"
#include "llvm/Config/unistd.h"
#include "llvm/Config/sys/types.h"
#include "llvm/Config/sys/stat.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static const char CacheRoot[] = "/tmp/LLVMCache";
static const char ExeSuffix[] = ".exe";
char* computeCachedFile(const char *key) {
/* CacheRoot + "/" + std::string(key) + ExeSuffix; */
char *cacheFile = (char*) malloc(strlen(CacheRoot) + 1 + strlen(key) +
strlen(ExeSuffix) + 1);
char *pCacheFile = cacheFile;
if (!cacheFile) return 0;
memcpy(cacheFile, CacheRoot, strlen(CacheRoot));
pCacheFile += strlen(CacheRoot);
*pCacheFile++ = '/';
memcpy(pCacheFile, key, strlen(key));
pCacheFile += strlen(key);
memcpy(pCacheFile, ExeSuffix, strlen(ExeSuffix));
pCacheFile += strlen(ExeSuffix);
*pCacheFile = 0; // Null-terminate
return cacheFile;
}
/*
* llvmStat - equivalent to stat(3), except the key may not necessarily
* correspond to a file by that name, implementation is up to the OS.
* Values returned in buf are similar as they are in Unix.
*/
void llvmStat(const char *key, struct stat *buf) {
char* cacheFile = computeCachedFile(key);
fprintf(stderr, "llvmStat(%s)\n", cacheFile);
stat(cacheFile, buf);
free(cacheFile);
}
/*
* llvmWriteFile - implements a 'save' of a file in the OS. 'key' may not
* necessarily map to a file of the same name.
* Returns:
* 0 - success
* non-zero - error
*/
int llvmWriteFile(const char *key, const void *data, size_t len)
{
char* cacheFile = computeCachedFile(key);
int fd = open(cacheFile, O_CREAT|O_WRONLY|O_TRUNC);
free(cacheFile);
if (fd < 0) return -1; // encountered an error
if (write(fd, data, len)) return -1;
if (fsync(fd)) return -1;
if (close(fd)) return -1;
return 0;
}
/*
* llvmReadFile - tells the OS to load data corresponding to a particular key
* somewhere into memory.
* Returns:
* 0 - failure
* non-zero - address of loaded file
*
* Value of size is the length of data loaded into memory.
*/
void* llvmReadFile(const char *key, size_t *size) {
char* cacheFile = computeCachedFile(key);
if (!cacheFile) return 0;
struct stat buf;
stat(cacheFile, &buf);
int fd = open(cacheFile, O_RDONLY);
if (fd < 0) return 0; // encountered an error
void* data = malloc(buf.st_size);
if (read(fd, data, buf.st_size)) {
free(data);
return 0;
}
*size = buf.st_size;
return data;
}
/*
* llvmExecve - execute a file from cache. This is a temporary proof-of-concept
* because we do not relocate what we can read from disk.
*/
int llvmExecve(const char *filename, char *const argv[], char *const envp[]) {
char* cacheFile = computeCachedFile(filename);
executeProgram(cacheFile, argv, envp);
}
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