/* Caller must allocate exec_path of size at least MTCP_MAX_PATH */
char *mtcp_find_executable(char *executable, const char* path_env,
char exec_path[PATH_MAX])
{
char *path;
const char *tmp_env;
int len;
if (path_env == NULL) {
path_env = ""; // Will try stdpath later in this function
}
tmp_env = path_env;
while (*tmp_env != '\0') {
path = exec_path;
len = 0;
while (*tmp_env != ':' && *tmp_env != '\0' && ++len < PATH_MAX - 1)
*path++ = *tmp_env++;
if (*tmp_env == ':') /* but if *tmp_env == '\0', will exit while loop */
tmp_env++;
*path++ = '/'; /* '...//... is same as .../... in POSIX */
len++;
*path++ = '\0';
mtcp_strncat(exec_path, executable, PATH_MAX - len - 1);
if (mtcp_is_executable(exec_path))
return exec_path;
}
// In case we're running with PATH environment variable unset:
const char * stdpath = "/usr/local/bin:/usr/bin:/bin";
if (mtcp_strcmp(path_env, stdpath) == 0) {
return NULL; // Already tried stdpath
} else {
return mtcp_find_executable(executable, stdpath, exec_path);
}
}
/**
* This function will open the checkpoint file stored at the given filename.
* It will check the magic number and take the appropriate action. If the
* magic number is unknown, we will abort. The fd returned points to the
* beginning of the uncompressed data.
* NOTE: related code in ../dmtcp/src/connectionmanager.cpp:open_ckpt_to_read()
*
* @param filename the name of the checkpoint file
* @return the fd to use
*/
static int open_ckpt_to_read(char *filename, char *envp[])
{
int fd;
int fds[2];
char fc;
char *gzip_cmd = "gzip";
static char *gzip_args[] = { "gzip", "-d", "-", NULL };
#ifdef HBICT_DELTACOMP
char *hbict_cmd = "hbict";
static char *hbict_args[] = { "hbict", "-r", NULL };
#endif
char decomp_path[PATH_MAX];
static char **decomp_args;
pid_t cpid;
fc = first_char(filename);
fd = mtcp_sys_open(filename, O_RDONLY, 0);
if(fd < 0) {
MTCP_PRINTF("ERROR: Cannot open checkpoint file %s\n", filename);
mtcp_abort();
}
if (fc == MAGIC_FIRST || fc == 'D') /* no compression ('D' from DMTCP) */
return fd;
else if (fc == GZIP_FIRST
#ifdef HBICT_DELTACOMP
|| fc == HBICT_FIRST
#endif
) { /* Set prog_path */
if( fc == GZIP_FIRST ){
decomp_args = gzip_args;
if( mtcp_find_executable(gzip_cmd, getenv("PATH"),
decomp_path) == NULL ) {
MTCP_PRINTF("ERROR: Cannot find gunzip to decompress ckpt file!\n");
mtcp_abort();
}
}
#ifdef HBICT_DELTACOMP
if( fc == HBICT_FIRST ){
decomp_args = hbict_args;
if( mtcp_find_executable(hbict_cmd, getenv("PATH"),
decomp_path) == NULL ) {
MTCP_PRINTF("ERROR: Cannot find hbict to decompress ckpt file!\n");
mtcp_abort();
}
}
#endif
if (mtcp_sys_pipe(fds) == -1) {
MTCP_PRINTF("ERROR: Cannot create pipe to execute gunzip to decompress"
" checkpoint file!\n");
mtcp_abort();
}
cpid = mtcp_sys_fork();
if(cpid == -1) {
MTCP_PRINTF("ERROR: Cannot fork to execute gunzip to decompress"
" checkpoint file!\n");
mtcp_abort();
}
else if(cpid > 0) /* parent process */ {
decomp_child_pid = cpid;
mtcp_sys_close(fd);
mtcp_sys_close(fds[1]);
return fds[0];
}
else /* child process */ {
fd = mtcp_sys_dup(mtcp_sys_dup(mtcp_sys_dup(fd)));
if (fd == -1) {
MTCP_PRINTF("ERROR: dup() failed! No restoration will be performed!"
" Cancel now!\n");
mtcp_abort();
}
fds[1] = mtcp_sys_dup(fds[1]);
mtcp_sys_close(fds[0]);
if (mtcp_sys_dup2(fd, STDIN_FILENO) != STDIN_FILENO) {
MTCP_PRINTF("ERROR: dup2() failed! No restoration will be performed!"
" Cancel now!\n");
mtcp_abort();
}
mtcp_sys_close(fd);
mtcp_sys_dup2(fds[1], STDOUT_FILENO);
mtcp_sys_close(fds[1]);
mtcp_sys_execve(decomp_path, decomp_args, envp);
/* should not get here */
MTCP_PRINTF("ERROR: Decompression failed! No restoration will be"
" performed! Cancel now!\n");
mtcp_abort();
}
}
else /* invalid magic number */ {
MTCP_PRINTF("ERROR: Invalid magic number in this checkpoint file!\n");
mtcp_abort();
}
}
