git: 5437b0ff6d55 - main - flua: clean up lposix argument checking
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Date: Sun, 11 May 2025 13:47:45 UTC
The branch main has been updated by emaste:
URL: https://cgit.FreeBSD.org/src/commit/?id=5437b0ff6d557daf6c35e1307a5737139bc12f9a
commit 5437b0ff6d557daf6c35e1307a5737139bc12f9a
Author: Isaac Freund <ifreund@freebsdfoundation.org>
AuthorDate: 2025-05-09 14:29:37 +0000
Commit: Ed Maste <emaste@FreeBSD.org>
CommitDate: 2025-05-11 13:46:20 +0000
flua: clean up lposix argument checking
The key insight here is that the luaL_check*() and luaL_opt*() functions
will happily take indexes that are larger than the stack top and print a
useful error message.
This means that there is no need to check if too few arguments have been
received prior to checking the types of individual arguments.
This patch also replaces a couple reimplementations of luaL_opt*()
functions with the luaL helpers.
References: https://www.lua.org/manual/5.4/manual.html#4.1.2
Reviewed by: emaste, kevans
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D50273
---
libexec/flua/modules/lposix.c | 111 ++++++++++++++++--------------------------
1 file changed, 43 insertions(+), 68 deletions(-)
diff --git a/libexec/flua/modules/lposix.c b/libexec/flua/modules/lposix.c
index 0f3ea7722d4d..d69f1aa546c1 100644
--- a/libexec/flua/modules/lposix.c
+++ b/libexec/flua/modules/lposix.c
@@ -21,18 +21,26 @@
#include "lauxlib.h"
#include "lposix.h"
+static void
+enforce_max_args(lua_State *L, int max)
+{
+ int narg;
+
+ narg = lua_gettop(L);
+ luaL_argcheck(L, narg <= max, max + 1, "too many arguments");
+}
+
/*
* Minimal implementation of luaposix needed for internal FreeBSD bits.
*/
static int
lua__exit(lua_State *L)
{
- int code, narg;
-
- narg = lua_gettop(L);
- luaL_argcheck(L, narg == 1, 1, "_exit takes exactly one argument");
+ int code;
+ enforce_max_args(L, 1);
code = luaL_checkinteger(L, 1);
+
_exit(code);
}
@@ -40,10 +48,8 @@ static int
lua_basename(lua_State *L)
{
char *inpath, *outpath;
- int narg;
- narg = lua_gettop(L);
- luaL_argcheck(L, narg > 0, 1, "at least one argument required");
+ enforce_max_args(L, 1);
inpath = strdup(luaL_checkstring(L, 1));
if (inpath == NULL) {
lua_pushnil(L);
@@ -61,15 +67,13 @@ lua_basename(lua_State *L)
static int
lua_chmod(lua_State *L)
{
- int n;
const char *path;
mode_t mode;
- n = lua_gettop(L);
- luaL_argcheck(L, n == 2, n > 2 ? 3 : n,
- "chmod takes exactly two arguments");
+ enforce_max_args(L, 2);
path = luaL_checkstring(L, 1);
mode = (mode_t)luaL_checkinteger(L, 2);
+
if (chmod(path, mode) == -1) {
lua_pushnil(L);
lua_pushstring(L, strerror(errno));
@@ -83,14 +87,12 @@ lua_chmod(lua_State *L)
static int
lua_chown(lua_State *L)
{
- int n;
const char *path;
uid_t owner = (uid_t) -1;
gid_t group = (gid_t) -1;
- n = lua_gettop(L);
- luaL_argcheck(L, n > 1, n,
- "chown takes at least two arguments");
+ enforce_max_args(L, 3);
+
path = luaL_checkstring(L, 1);
if (lua_isinteger(L, 2))
owner = (uid_t) lua_tointeger(L, 2);
@@ -139,11 +141,9 @@ lua_chown(lua_State *L)
static int
lua_pclose(lua_State *L)
{
- int error, fd, n;
+ int error, fd;
- n = lua_gettop(L);
- luaL_argcheck(L, n == 1, 1,
- "close takes exactly one argument (fd)");
+ enforce_max_args(L, 1);
fd = luaL_checkinteger(L, 1);
if (fd < 0) {
@@ -169,14 +169,13 @@ static int
lua_fnmatch(lua_State *L)
{
const char *pattern, *string;
- int flags, n;
-
- n = lua_gettop(L);
- luaL_argcheck(L, n == 2 || n == 3, 4, "need 2 or 3 arguments");
+ int flags;
+ enforce_max_args(L, 3);
pattern = luaL_checkstring(L, 1);
string = luaL_checkstring(L, 2);
flags = luaL_optinteger(L, 3, 0);
+
lua_pushinteger(L, fnmatch(pattern, string, flags));
return (1);
@@ -186,10 +185,9 @@ static int
lua_uname(lua_State *L)
{
struct utsname name;
- int error, n;
+ int error;
- n = lua_gettop(L);
- luaL_argcheck(L, n == 0, 1, "too many arguments");
+ enforce_max_args(L, 0);
error = uname(&name);
if (error != 0) {
@@ -219,11 +217,9 @@ static int
lua_dirname(lua_State *L)
{
char *inpath, *outpath;
- int narg;
- narg = lua_gettop(L);
- luaL_argcheck(L, narg > 0, 1,
- "dirname takes at least one argument (path)");
+ enforce_max_args(L, 1);
+
inpath = strdup(luaL_checkstring(L, 1));
if (inpath == NULL) {
lua_pushnil(L);
@@ -242,10 +238,8 @@ static int
lua_fork(lua_State *L)
{
pid_t pid;
- int narg;
- narg = lua_gettop(L);
- luaL_argcheck(L, narg == 0, 1, "too many arguments");
+ enforce_max_args(L, 0);
pid = fork();
if (pid < 0) {
@@ -262,10 +256,8 @@ lua_fork(lua_State *L)
static int
lua_getpid(lua_State *L)
{
- int narg;
+ enforce_max_args(L, 0);
- narg = lua_gettop(L);
- luaL_argcheck(L, narg == 0, 1, "too many arguments");
lua_pushinteger(L, getpid());
return (1);
}
@@ -273,10 +265,9 @@ lua_getpid(lua_State *L)
static int
lua_pipe(lua_State *L)
{
- int error, fd[2], narg;
+ int error, fd[2];
- narg = lua_gettop(L);
- luaL_argcheck(L, narg == 0, 1, "too many arguments");
+ enforce_max_args(L, 0);
error = pipe(fd);
if (error != 0) {
@@ -297,12 +288,9 @@ lua_read(lua_State *L)
char *buf;
ssize_t ret;
size_t sz;
- int error, fd, narg;
-
- narg = lua_gettop(L);
- luaL_argcheck(L, narg == 2, 1,
- "read takes exactly two arguments (fd, size)");
+ int error, fd;
+ enforce_max_args(L, 2);
fd = luaL_checkinteger(L, 1);
sz = luaL_checkinteger(L, 2);
@@ -343,10 +331,8 @@ lua_realpath(lua_State *L)
{
const char *inpath;
char *outpath;
- int narg;
- narg = lua_gettop(L);
- luaL_argcheck(L, narg > 0, 1, "at least one argument required");
+ enforce_max_args(L, 1);
inpath = luaL_checkstring(L, 1);
outpath = realpath(inpath, NULL);
@@ -367,17 +353,12 @@ lua_wait(lua_State *L)
{
pid_t pid;
int options, status;
- int narg;
- narg = lua_gettop(L);
-
- pid = -1;
- status = options = 0;
- if (narg >= 1 && !lua_isnil(L, 1))
- pid = luaL_checkinteger(L, 1);
- if (narg >= 2 && !lua_isnil(L, 2))
- options = luaL_checkinteger(L, 2);
+ enforce_max_args(L, 2);
+ pid = luaL_optinteger(L, 1, -1);
+ options = luaL_optinteger(L, 2, 0);
+ status = 0;
pid = waitpid(pid, &status, options);
if (pid < 0) {
lua_pushnil(L);
@@ -419,13 +400,9 @@ lua_write(lua_State *L)
size_t bufsz, sz;
ssize_t ret;
off_t offset;
- int error, fd, narg;
+ int error, fd;
- narg = lua_gettop(L);
- luaL_argcheck(L, narg >= 2, 1,
- "write takes at least two arguments (fd, buf, sz, off)");
- luaL_argcheck(L, narg <= 4, 5,
- "write takes no more than four arguments (fd, buf, sz, off)");
+ enforce_max_args(L, 4);
fd = luaL_checkinteger(L, 1);
if (fd < 0) {
@@ -435,13 +412,11 @@ lua_write(lua_State *L)
buf = luaL_checkstring(L, 2);
- bufsz = sz = lua_rawlen(L, 2);
- if (narg >= 3 && !lua_isnil(L, 3))
- sz = luaL_checkinteger(L, 3);
+ bufsz = lua_rawlen(L, 2);
+ sz = luaL_optinteger(L, 3, bufsz);
+
+ offset = luaL_optinteger(L, 4, 0);
- offset = 0;
- if (narg >= 4 && !lua_isnil(L, 4))
- offset = luaL_checkinteger(L, 4);
if ((size_t)offset > bufsz || offset + sz > bufsz) {
lua_pushnil(L);