ref: bc1f00d4e76ce69cff7b632cadf0df867d1bf5eb
dir: lu9-p9/fs.c
/*
* The File object
* p9.file(fd) takes an open file descriptor and returns a
* File object f which provides a convenient method interface
* to the usual file operations.
* p9.open and p9.create take a file name to open or create.
* The file descriptor stored in f.fd is garbage collected,
* that is, it will be automatically closed once the File
* object becomes unreachable. Note how this means that f.fd
* should be used sparringly and with much care. In particular
* you shouldn't store it outside of f, since the actual file
* descriptor number might become invalid (closed) or refer
* to a completely different file after f is collected.
*
* Store the File object in some global place to prevent it
* from being collected.
*/
static int
openmode(lua_State *L, char *s)
{
int i, n, mode;
char r, w, x;
char buf[64], *f[10], *p;
snprint(buf, sizeof buf, "%s", s);
mode = r = w = x = 0;
n = getfields(buf, f, sizeof f, 1, " \t\n");
if(n < 1)
return OREAD;
for(i = 0; p = f[i], i < n; i++){
if(strcmp(p, "r") == 0 || strcmp(p, "read") == 0)
r = 1;
else if(strcmp(p, "w") == 0 || strcmp(p, "write") == 0)
w = 1;
else if(strcmp(p, "rw") == 0 || strcmp(p, "rdwr") == 0)
r = w = 1;
else if(strcmp(p, "x") == 0 || strcmp(p, "exec") == 0)
x = 1;
else if(strcmp(p, "trunc") == 0)
mode |= OTRUNC;
else if(strcmp(p, "cexec") == 0)
mode |= OCEXEC;
else if(strcmp(p, "rclose") == 0)
mode |= ORCLOSE;
else if(strcmp(p, "excl") == 0)
mode |= OEXCL;
else
return luaL_error(L, "unknown mode flag '%s'", p);
}
if(x) mode |= OEXEC;
else if(r && w) mode |= ORDWR;
else if(r) mode |= OREAD;
else if(w) mode |= OWRITE;
return mode;
}
static ulong
createperm(lua_State *L, char *s)
{
int i, n;
ulong perm;
char buf[64], *f[10], *p;
snprint(buf, sizeof buf, "%s", s);
perm = 0;
n = getfields(buf, f, sizeof f, 1, " \t\n");
if(n < 1)
return 0644;
for(i = 0; p = f[i], i < n; i++){
if(isdigit(p[0]))
perm |= strtol(p, nil, 8);
else if(strcmp(p, "dir") == 0)
perm |= DMDIR;
else if(strcmp(p, "tmp") == 0)
perm |= DMTMP;
else if(strcmp(p, "excl") == 0)
perm |= DMEXCL;
else if(strcmp(p, "append") == 0)
perm |= DMAPPEND;
else
return luaL_error(L, "unknown permission flag '%s'", p);
}
return perm;
}
static int filenew(lua_State*, int);
static int fileclose(lua_State*);
static int filefd(lua_State*, int);
static int
filenew(lua_State *L, int fd)
{
int f;
lua_createtable(L, 0, 2);
f = lua_gettop(L);
lua_pushinteger(L, fd);
lua_setfield(L, f, "fd");
luaL_getmetatable(L, "p9-File");
lua_setfield(L, f, "__index");
lua_pushcfunction(L, fileclose);
lua_setfield(L, f, "__close");
lua_pushcfunction(L, fileclose);
lua_setfield(L, f, "__gc");
lua_pushvalue(L, f);
lua_setmetatable(L, f);
return 1;
}
static int
fileclose(lua_State *L)
{
int fd;
fd = filefd(L, 1);
if(fd == -1)
return 0;
lua_pushinteger(L, -1);
lua_setfield(L, 1, "fd");
close(fd);
return 0;
}
static int
filefd(lua_State *L, int idx)
{
int fd;
if(lua_getfield(L, idx, "fd") != LUA_TNUMBER)
return luaL_error(L, "fd must be integer");
fd = lua_tonumber(L, -1);
lua_pop(L, 1);
return fd;
}
static int
p9_file(lua_State *L)
{
int fd;
fd = luaL_checkinteger(L, 1);
return filenew(L, fd);
}
static int
p9_open(lua_State *L)
{
const char *file;
int mode;
int fd;
file = luaL_checkstring(L, 1);
mode = openmode(L, luaL_optstring(L, 2, "read"));
if((fd = open(file, mode)) == -1)
return error(L, "open: %r");
return filenew(L, fd);
}
static int
p9_create(lua_State *L)
{
const char *file;
int fd, mode;
ulong perm;
file = luaL_checkstring(L, 1);
mode = openmode(L, luaL_optstring(L, 2, "rdwr"));
perm = createperm(L, luaL_optstring(L, 3, "644"));
if((fd = create(file, mode, perm)) == -1)
return error(L, "create: %r");
return filenew(L, fd);
}
static int
p9_close(lua_State *L)
{
if(close(filefd(L, 1)) == -1)
return error(L, "close: %r");
return 0;
}
static int
seekmode(lua_State *L, char *s)
{
if(strcmp(s, "set") == 0)
return 0;
if(strcmp(s, "cur") == 0)
return 1;
if(strcmp(s, "end") == 0)
return 2;
return luaL_error(L, "unknown seek mode '%s'", s);
}
static int
p9_seek(lua_State *L)
{
int fd, type;
vlong n, off;
fd = filefd(L, 1);
n = luaL_checkinteger(L, 2);
type = seekmode(L, luaL_optstring(L, 3, "set"));
if((off = seek(fd, n, type)) == -1)
return error(L, "seek: %r");
lua_pushinteger(L, off);
return 1;
}
static int
p9_read(lua_State *L)
{
int fd;
long n, nbytes;
vlong offset;
char *buf;
fd = filefd(L, 1);
nbytes = luaL_optinteger(L, 2, Iosize);
offset = luaL_optinteger(L, 3, -1);
buf = getbuffer(L, nbytes);
if(offset == -1)
n = read(fd, buf, nbytes);
else
n = pread(fd, buf, nbytes, offset);
if(n == -1)
return error(L, "read: %r");
lua_pushlstring(L, buf, n);
return 1;
}
static int
slurp(lua_State *L, int fd, long nbytes)
{
int all;
long n, nr, tot;
char *buf;
luaL_Buffer b;
all = (nbytes == -1) ? 1 : 0;
luaL_buffinit(L, &b);
for(tot = 0; all || tot < nbytes; tot += nr){
n = all ? Iosize : min(Iosize, nbytes - tot);
buf = luaL_prepbuffsize(&b, n);
if((nr = read(fd, buf, n)) == -1)
return error(L, "read: %r");
if(nr == 0)
break;
luaL_addsize(&b, nr);
}
luaL_pushresult(&b);
return 1;
}
static int
p9_slurp(lua_State *L)
{
int fd;
long nbytes;
fd = filefd(L, 1);
nbytes = luaL_optinteger(L, 2, -1);
slurp(L, fd, nbytes);
return 1;
}
static int
p9_write(lua_State *L)
{
lua_Integer fd, offset;
size_t nbytes;
const char *buf;
long n;
fd = filefd(L, 1);
buf = luaL_checklstring(L, 2, &nbytes);
nbytes = luaL_optinteger(L, 3, nbytes);
offset = luaL_optinteger(L, 4, -1);
if(offset == -1)
n = write(fd, buf, nbytes);
else
n = pwrite(fd, buf, nbytes, offset);
if(n != nbytes)
return error(L, "write: %r");
lua_pushinteger(L, n);
return 1;
}
static int
p9_remove(lua_State *L)
{
const char *file;
file = luaL_checkstring(L, 1);
if(remove(file) == -1)
return error(L, "remove: %r");
lua_pushboolean(L, 1);
return 1;
}
static int
p9_fd2path(lua_State *L)
{
lua_Integer fd;
char *buf;
fd = luaL_checkinteger(L, 1);
buf = getbuffer(L, Iosize);
if(fd2path(fd, buf, Iosize) != 0)
return error(L, "fd2path: %r");
lua_pushstring(L, buf);
return 1;
}