ref: 4d4deaa134b151e364f06c5731790b23dcd35233
parent: 68af611454400ea7ef8617c7c8b35d817e9caa50
author: kvik <kvik@a-b.xyz>
date: Thu Apr 15 15:05:47 EDT 2021
p9: implement non-throwing error reporting
--- a/fs.c
+++ b/fs.c
@@ -8,7 +8,7 @@
file = luaL_checkstring(L, 1);
mode = luaL_checkinteger(L, 2);
if((fd = open(file, mode)) == -1)
- lerror(L, "open");
+ return error(L, "open: %r");
lua_pushinteger(L, fd);
return 1;
}
@@ -24,7 +24,7 @@
mode = luaL_checkinteger(L, 2);
perm = luaL_checkinteger(L, 3);
if((fd = create(file, mode, perm)) == -1)
- lerror(L, "create");
+ return error(L, "create: %r");
lua_pushinteger(L, fd);
return 1;
}
@@ -33,7 +33,7 @@
p9_close(lua_State *L)
{
if(close(luaL_checkinteger(L, 1)) == -1)
- lerror(L, "close");
+ return error(L, "close: %r");
return 0;
}
@@ -53,7 +53,7 @@
else
n = pread(fd, buf, nbytes, offset);
if(n == -1)
- lerror(L, "read");
+ return error(L, "read: %r");
lua_pushlstring(L, buf, n);
return 1;
}
@@ -75,7 +75,7 @@
else
n = pwrite(fd, buf, nbytes, offset);
if(n != nbytes)
- lerror(L, "write");
+ return error(L, "write: %r");
lua_pushinteger(L, n);
return 1;
}
@@ -90,7 +90,7 @@
n = luaL_checkinteger(L, 2);
type = luaL_checkinteger(L, 3);
if((off = seek(fd, n, type)) == -1)
- lerror(L, "seek");
+ return error(L, "seek: %r");
lua_pushinteger(L, off);
return 1;
}
@@ -102,7 +102,7 @@
file = luaL_checkstring(L, 1);
if(remove(file) == -1)
- lerror(L, "remove");
+ return error(L, "remove: %r");
lua_pushboolean(L, 1);
return 1;
}
@@ -116,7 +116,7 @@
fd = luaL_checkinteger(L, 1);
buf = getbuffer(L, 8192);
if(fd2path(fd, buf, 8192) != 0)
- lerror(L, "fd2path");
+ return error(L, "fd2path: %r");
lua_pushstring(L, buf);
return 1;
}
@@ -198,12 +198,8 @@
case LUA_TNUMBER:
d = dirfstat(lua_tonumber(L, 1)); break;
}
- if(d == nil){
- lua_pushnil(L);
- seterror(L, "stat: %r");
- pusherror(L);
- return 2;
- }
+ if(d == nil)
+ return error(L, "stat: %r");
createdirtable(L, d);
free(d);
return 1;
@@ -220,54 +216,51 @@
{
static int p9_walkout(lua_State*);
static int p9_walknext(lua_State*);
- int nargs;
+ int nargs, wstate;
Dir *d;
Walk *w;
nargs = lua_gettop(L);
w = lua_newuserdatauv(L, sizeof(Walk), 1);
+ wstate = nargs + 1;
w->fd = -1;
w->nleft = 0;
w->dirs = w->p = nil;
luaL_setmetatable(L, "p9-Walk");
if(nargs == 2){
- lua_insert(L, 2);
- lua_setiuservalue(L, -2, 1);
+ lua_pushvalue(L, 2);
+ lua_setiuservalue(L, wstate, 1);
}
if(lua_isnumber(L, 1))
w->fd = lua_tointeger(L, 1);
else{
if((w->fd = open(luaL_checkstring(L, 1), OREAD|OCEXEC)) == -1){
- seterror(L, "open: %r");
+ error(L, "open: %r");
goto Error;
}
}
if((d = dirfstat(w->fd)) == nil){
- seterror(L, "stat: %r");
+ error(L, "stat: %r");
goto Error;
}
int isdir = d->mode & DMDIR;
free(d);
if(!isdir){
- seterror(L, "walk in a non-directory");
+ error(L, "walk in a non-directory");
goto Error;
}
/* return p9_walknext, p9-Walk, nil, p9-Walk */
- int i = lua_gettop(L);
lua_pushcfunction(L, p9_walknext);
- lua_pushvalue(L, i);
+ lua_pushvalue(L, wstate);
lua_pushnil(L);
- lua_pushvalue(L, i);
+ lua_pushvalue(L, wstate);
return 4;
Error:
- lua_getiuservalue(L, -1, 1);
- if(lua_istable(L, -1)){
- pusherror(L);
- lua_setfield(L, -2, "error");
+ if(nargs == 2){
+ lua_setfield(L, 2, "error");
lua_pushcfunction(L, p9_walkout);
return 1;
}
- pusherror(L);
return lua_error(L);
}
@@ -290,7 +283,7 @@
w->dirs = nil;
}
if((w->nleft = dirread(w->fd, &w->dirs)) == -1){
- seterror(L, "dirread: %r");
+ error(L, "dirread: %r");
goto Error;
}
w->p = w->dirs;
@@ -302,13 +295,14 @@
createdirtable(L, d);
return 1;
Error:
- pusherror(L);
- if(lua_istable(L, lua_upvalueindex(1))){
- lua_setfield(L, lua_upvalueindex(1), "error");
+ if(lua_getiuservalue(L, 1, 1) == LUA_TTABLE){
+ lua_pushvalue(L, -2);
+ lua_setfield(L, -2, "error");
lua_pushnil(L);
return 1;
}
- return lua_error(L);
+ lua_pop(L, 1);
+ return 2;
}
static int
@@ -317,10 +311,14 @@
Walk *w;
w = luaL_checkudata(L, 1, "p9-Walk");
- free(w->dirs);
- w->dirs = nil;
- close(w->fd);
- w->fd = -1;
+ if(w->dirs != nil){
+ free(w->dirs);
+ w->dirs = nil;
+ }
+ if(w->fd != -1){
+ close(w->fd);
+ w->fd = -1;
+ }
return 0;
}
--- a/mod/init.lua
+++ b/mod/init.lua
@@ -413,41 +413,4 @@
end,
})
-
-
-
--- Lethal API
--- p9.lethal() returns a proxy table that is just like the
--- regular p9 module table, except that each function field
--- is wrapped such that any error raised during a call
--- results in program termination. An error is printed to
--- fd 2 and the same error is used for the program's exit status.
--- Note that this only mechanism only works for the fields
--- of the p9 module, like the p9.open and friends.
--- In particular, it doesn't apply to methods of File objects
--- nor to the p9.env object.
--- This limitation should be removed in the future.
-
-local lethalproxy = setmetatable({}, {
- __index = function(_, key)
- if type(p9[key]) ~= "function" then
- return p9[key]
- end
- return function(...)
- local res = table.pack(pcall(p9[key], ...))
- if not res[1] then
- p9.write(2, string.format("%s: %s\n", arg[0] or "lua", res[2]))
- os.exit(res[2])
- end
- table.remove(res, 1)
- return table.unpack(res)
- end
- end
-})
-
---- lethal() -> p9{}
-function p9.lethal()
- return lethalproxy
-end
-
return p9
--- a/ns.c
+++ b/ns.c
@@ -9,7 +9,7 @@
over = luaL_checkstring(L, 2);
flag = luaL_checkinteger(L, 3);
if((r = bind(this, over, flag)) == -1)
- lerror(L, "bind");
+ return error(L, "bind: %r");
lua_pushinteger(L, r);
return 1;
}
@@ -26,7 +26,7 @@
flag = luaL_checkinteger(L, 4);
aname = luaL_checkstring(L, 5);
if((r = mount(fd, afd, over, flag, aname)) == -1)
- lerror(L, "mount");
+ return error(L, "mount: %r");
lua_pushinteger(L, r);
return 1;
}
@@ -40,7 +40,7 @@
name = luaL_optstring(L, 1, nil);
over = luaL_checkstring(L, 2);
if((r = unmount(name, over)) == -1)
- lerror(L, "unmount");
+ return error(L, "unmount: %r");
lua_pushinteger(L, r);
return 1;
}
--- a/p9.c
+++ b/p9.c
@@ -5,8 +5,8 @@
#include <lua.h>
#include <lauxlib.h>
-static void
-seterror(lua_State *L, char *fmt, ...)
+static int
+error(lua_State *L, char *fmt, ...)
{
va_list varg;
int n;
@@ -13,29 +13,13 @@
char *buf;
luaL_Buffer b;
+ lua_pushnil(L);
buf = luaL_buffinitsize(L, &b, 512);
va_start(varg, fmt);
n = vsnprint(buf, 512, fmt, varg);
va_end(varg);
luaL_pushresultsize(&b, n);
- lua_setfield(L, LUA_REGISTRYINDEX, "p9-error");
-}
-
-static const char*
-pusherror(lua_State *L)
-{
- lua_getfield(L, LUA_REGISTRYINDEX, "p9-error");
- return lua_tostring(L, -1);
-}
-
-static void
-lerror(lua_State *L, char *call)
-{
- char err[ERRMAX];
-
- rerrstr(err, sizeof err);
- lua_pushfstring(L, "%s: %s", call, err);
- lua_error(L);
+ return 2;
}
/* Memory allocator associated with Lua state */
--- a/proc.c
+++ b/proc.c
@@ -6,7 +6,7 @@
flags = luaL_checkinteger(L, 1);
if((r = rfork(flags)) == -1)
- lerror(L, "rfork");
+ return error(L, "rfork %r");
lua_pushinteger(L, r);
return 1;
}
--- a/test.lua
+++ b/test.lua
@@ -75,7 +75,7 @@
local f <close> = p9.createfile(tmp())
fd = f.fd
end
-assert(pcall(p9.seek, fd, 0) == false)
+assert(p9.seek(fd, 0) == nil)
-- Make sure it's not closed
local fd
do
@@ -82,7 +82,7 @@
local f = p9.createfile(tmp())
fd = f.fd
end
-assert(pcall(p9.seek, fd, 0) == true)
+assert(p9.seek(fd, 0))
p9.close(fd)
-- Basic operations. These are the same as regular
@@ -173,18 +173,18 @@
-- Namespaces
-- bind and unmount work
-assert(pcall(function()
+assert(function()
local f
- p9.bind("#|", "/n/pipe")
- f = p9.openfile("/n/pipe/data")
- p9.unmount("/n/pipe")
- assert(pcall(p9.openfile, "/n/pipe/data") == false)
-end))
+ assert(p9.bind("#|", "/n/pipe"))
+ f = assert(p9.openfile("/n/pipe/data"))
+ assert(p9.unmount("/n/pipe"))
+ assert(p9.openfile("/n/pipe/data") == nil)
+end)
-- mount works
-assert(pcall(function()
+assert(function()
assert(p9.mount(p9.open("/srv/cwfs", "rw"), nil, "/n/test"))
assert(p9.openfile("/n/test/lib/glass"))
-end))
+end)
-- Process control