#include <unistd.h>#include <stdlib.h>#include <errno.h>#include <sys/stat.h>#include <string.h>#include <stdio.h>#include "syscall.h" int execl(const char *path, const char *arg, ...){	return execv(path, (char *const*)&arg);} int execv(const char *path, char *const arg[]){	return execve(path, arg, environ);} int execve(const char *path, char *const arg[], char *const env[]){	return syscall(VXSYSEXEC, (int)path, (int)arg, (int)env, 0, 0);} int execlp(const char *path, const char *arg, ...){	return execvp(path, (char*const*)&arg);} int execvp(const char *file, char *const arg[]){	struct stat st; 	if(file[0] == '/' || (file[0] == '.' && file[1] == '/'))		return execv(file, arg); 	char buf[1024];	char *path = getenv("PATH");	if(path == NULL){		errno = ENOENT;		return -1;	}	char *p, *ep;	int n;	for(p=path; p; p=ep){		ep = strchr(p, ':');		if(ep)			n = ep++ - p;		else			n = strlen(p);		if(n+1+strlen(file)+1 > sizeof buf)			continue;		if(n == 0)			strcpy(buf, file);		else{			memmove(buf, p, n);			buf[n] = '/';			strcpy(buf+n+1, file);		}		if(stat(buf, &st) >= 0)			return execv(buf, arg);	}	errno = ENOENT;	return -1;}