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#include <string.h>
#include <errno.h>
#include "file.h"
#include "pk.h"
#include "frontend.h"
#include "pcr.h"
#define MAX_FDS 32
file_t* fds[MAX_FDS];
#define MAX_FILES 32
file_t files[MAX_FILES] = {[0 ... MAX_FILES-1] = {-1,{0}}};
file_t *stdout, *stdin, *stderr;
static void file_incref(file_t* f)
{
atomic_add(&f->refcnt,1);
}
void file_decref(file_t* f)
{
if(atomic_add(&f->refcnt,-1) == 2)
{
if(f->kfd != -1)
{
frontend_syscall(SYS_close,f->kfd,0,0,0);
f->kfd = -1;
}
atomic_add(&f->refcnt,-1); // I think this could just be atomic_set(..,0)
}
}
static file_t* file_get_free()
{
for(int i = 0; i < MAX_FILES; i++)
{
if(atomic_read(&files[i].refcnt) == 0)
{
if(atomic_add(&files[i].refcnt,1) == 0)
{
atomic_add(&files[i].refcnt,1);
return &files[i];
}
file_decref(&files[i]);
}
}
return NULL;
}
static int fd_get_free()
{
for(int i = 0; i < MAX_FDS; i++)
if(fds[i] == NULL)
return i;
return -1;
}
int file_dup(file_t* f)
{
int fd = fd_get_free();
if(fd == -1)
return -1;
file_incref(f);
fds[fd] = f;
return fd;
}
void file_init()
{
stdin = file_get_free();
stdout = file_get_free();
stderr = file_get_free();
stdin->kfd = 0;
stdout->kfd = 1;
stderr->kfd = 2;
// create user FDs 0, 1, and 2
file_dup(stdin);
file_dup(stdout);
file_dup(stderr);
}
file_t* file_get(int fd)
{
return fd < 0 || fd >= MAX_FDS ? NULL : fds[fd];
}
sysret_t file_open(const char* fn, size_t len, int flags, int mode)
{
file_t* f = file_get_free();
if(!f)
return (sysret_t){-1,ENOMEM};
sysret_t ret = frontend_syscall(SYS_open,(long)fn,len,flags,mode);
if(ret.result != -1)
{
f->kfd = ret.result;
ret.result = (long)f;
}
else
file_decref(f);
return ret;
}
int fd_close(int fd)
{
file_t* f = file_get(fd);
if(!f)
return -1;
fds[fd] = NULL;
file_decref(f);
return 0;
}
sysret_t file_read(file_t* f, char* buf, size_t size)
{
return frontend_syscall(SYS_read,f->kfd,(long)buf,size,0);
}
sysret_t file_pread(file_t* f, char* buf, size_t size, off_t offset)
{
return frontend_syscall(SYS_pread,f->kfd,(long)buf,size,offset);
}
sysret_t file_write(file_t* f, const char* buf, size_t size)
{
return frontend_syscall(SYS_write,f->kfd,(long)buf,size,0);
}
sysret_t file_pwrite(file_t* f, const char* buf, size_t size, off_t offset)
{
return frontend_syscall(SYS_pwrite,f->kfd,(long)buf,size,offset);
}
sysret_t file_stat(file_t* f, struct stat* s)
{
return frontend_syscall(SYS_fstat,f->kfd,(long)s,0,0);
}
sysret_t file_lseek(file_t* f, size_t ptr, int dir)
{
return frontend_syscall(SYS_lseek,f->kfd,ptr,dir,0);
}
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