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Fix lua lseek command / io lib

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lua would not return or set arbitrary file positions
file:seek("set", 0) worked file:seek("cur") worked
but setting an offset or file:seek("end") failed

I tracked this down to a bug checking the return of rb->lseek

on error lseek returns a negative number and returns the file
position otherwise, the function was checking for if(N) instead of
if(N < 0)

Fixed - limited size of lseek to size of signed LuaNumber

Fixed - io:lines() stopped after first line containing only a newline
        instead of returning a blank line and continuing till EOF
        this fixes file:read("*l") as well

Fixed - ssize_t for read() with error checking

Change-Id: Ie859b288fb8f6814f1b3ae30992ecf78f2669de7
This commit is contained in:
William Wilgus 2018-01-29 08:13:37 +01:00
parent 1f63604e2c
commit 0d41e13cf4
1 changed files with 14 additions and 11 deletions
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25
apps/plugins/lua/liolib.c
View file

@ -18,7 +18,7 @@
#include "lualib.h" #include "lualib.h"
#include "rocklibc.h" #include "rocklibc.h"
#include "llimits.h"
#define IO_INPUT 1 #define IO_INPUT 1
#define IO_OUTPUT 2 #define IO_OUTPUT 2
@ -256,9 +256,9 @@ static int read_number (lua_State *L, int *f) {
static int test_eof (lua_State *L, int *f) { static int test_eof (lua_State *L, int *f) {
ssize_t s = rb->lseek(*f, 0, SEEK_CUR); off_t s = rb->lseek(*f, 0, SEEK_CUR);
lua_pushlstring(L, NULL, 0); lua_pushlstring(L, NULL, 0);
return s != rb->filesize(*f); return s < rb->filesize(*f);
} }
@ -268,10 +268,11 @@ static int _read_line (lua_State *L, int *f) {
luaL_buffinit(L, &b); luaL_buffinit(L, &b);
for (;;) { for (;;) {
size_t l; size_t l;
size_t r; off_t r;
char *p = luaL_prepbuffer(&b); char *p = luaL_prepbuffer(&b);
r = rb->read_line(*f, p, LUAL_BUFFERSIZE); r = rb->read_line(*f, p, LUAL_BUFFERSIZE);
l = strlen(p); l = strlen(p);
if (l == 0 || p[l-1] != '\n') if (l == 0 || p[l-1] != '\n')
luaL_addsize(&b, l); luaL_addsize(&b, l);
else { else {
@ -281,7 +282,7 @@ static int _read_line (lua_State *L, int *f) {
} }
if (r < LUAL_BUFFERSIZE) { /* eof? */ if (r < LUAL_BUFFERSIZE) { /* eof? */
luaL_pushresult(&b); /* close buffer */ luaL_pushresult(&b); /* close buffer */
return (lua_objlen(L, -1) > 0); /* check whether read something */ return (r > 0); /* check whether read something */
} }
} }
} }
@ -289,7 +290,7 @@ static int _read_line (lua_State *L, int *f) {
static int read_chars (lua_State *L, int *f, size_t n) { static int read_chars (lua_State *L, int *f, size_t n) {
size_t rlen; /* how much to read */ size_t rlen; /* how much to read */
size_t nr; /* number of chars actually read */ ssize_t nr; /* number of chars actually read */
luaL_Buffer b; luaL_Buffer b;
luaL_buffinit(L, &b); luaL_buffinit(L, &b);
rlen = LUAL_BUFFERSIZE; /* try to read that much each time */ rlen = LUAL_BUFFERSIZE; /* try to read that much each time */
@ -297,9 +298,11 @@ static int read_chars (lua_State *L, int *f, size_t n) {
char *p = luaL_prepbuffer(&b); char *p = luaL_prepbuffer(&b);
if (rlen > n) rlen = n; /* cannot read more than asked */ if (rlen > n) rlen = n; /* cannot read more than asked */
nr = rb->read(*f, p, rlen); nr = rb->read(*f, p, rlen);
if (nr < 0)
luaL_error(L, "error reading file");
luaL_addsize(&b, nr); luaL_addsize(&b, nr);
n -= nr; /* still have to read `n' chars */ n -= nr; /* still have to read `n' chars */
} while (n > 0 && nr == rlen); /* until end of count or eof */ } while (n > 0 && nr == (ssize_t) rlen); /* until end of count or eof */
luaL_pushresult(&b); /* close buffer */ luaL_pushresult(&b); /* close buffer */
return (n == 0 || lua_objlen(L, -1) > 0); return (n == 0 || lua_objlen(L, -1) > 0);
} }
@ -414,11 +417,11 @@ static int f_seek (lua_State *L) {
int f = *tofile(L); int f = *tofile(L);
int op = luaL_checkoption(L, 2, "cur", modenames); int op = luaL_checkoption(L, 2, "cur", modenames);
long offset = luaL_optlong(L, 3, 0); long offset = luaL_optlong(L, 3, 0);
op = rb->lseek(f, offset, mode[op]); off_t size = rb->lseek(f, offset, mode[op]);
if (op) if (size < 0 || size > MAX_INT) /* signed limit */
return pushresult(L, 0, NULL); /* error */ return pushresult(L, 0, NULL); /* error */
else { else {
lua_pushinteger(L, rb->lseek(f, 0, SEEK_CUR)); lua_pushinteger(L, (LUA_INTEGER) size );
return 1; return 1;
} }
} }
@ -465,4 +468,4 @@ LUALIB_API int luaopen_io (lua_State *L) {
/* create (and set) default files */ /* create (and set) default files */
lua_pop(L, 1); /* pop environment for default files */ lua_pop(L, 1); /* pop environment for default files */
return 1; return 1;
} }