readdir_r is now deprecated.[1][2] The readdir_r() function was invented as a reentrant version of readdir(3). It reads the next directory entry from the directory stream dirp, and returns it in the caller-allocated buffer pointed to by entry. For details of the dirent structure, see readdir(3). A pointer to the returned buffer is placed in *result; if the end of the directory stream was encountered, then NULL is instead returned in *result. It is recommended that applications use readdir(3) instead of readdir_r(). Furthermore, since version 2.24, glibc deprecates readdir_r(). The reasons are as follows: * On systems where NAME_MAX is undefined, calling readdir_r() may be unsafe because the interface does not allow the caller to specify the length of the buffer used for the returned directory entry. * On some systems, readdir_r() can't read directory entries with very long names. When the glibc implementation encounters such a name, readdir_r() fails with the error ENAMETOOLONG after the final directory entry has been read. On some other systems, readdir_r() may return a success status, but the returned d_name field may not be null terminated or may be truncated. * In the current POSIX.1 specification (POSIX.1-2008), readdir(3) is not required to be thread-safe. However, in modern implementations (including the glibc implementation), concurrent calls to readdir(3) that specify different directory streams are thread-safe. Therefore, the use of readdir_r() is generally unnecessary in multithreaded programs. In cases where multiple threads must read from the same directory stream, using readdir(3) with external synchronization is still preferable to the use of readdir_r(), for the reasons given in the points above. * It is expected that a future version of POSIX.1 will make readdir_r() obsolete, and require that readdir(3) be thread-safe when concurrently employed on different directory streams. [1]: http://man7.org/linux/man-pages/man3/readdir_r.3.html [2]: https://lwn.net/Articles/696475/ --- luxio.c | 73 ++++++++++++++++++----------------------------------------------- 1 file changed, 20 insertions(+), 53 deletions(-) diff --git a/luxio.c b/luxio.c index 4b7b707..7501af3 100644 --- a/luxio.c +++ b/luxio.c @@ -82,13 +82,6 @@ static int safe_pathconf(const char *path, int conf) return (pc < LUXIO_MIN_PATHSIZE) ? LUXIO_MIN_PATHSIZE : pc; } -static int safe_fpathconf(int fd, int conf) -{ - int pc = fpathconf(fd, conf); - - return (pc < LUXIO_MIN_PATHSIZE) ? LUXIO_MIN_PATHSIZE : pc; -} - #undef LUXIO_MIN_PATHSIZE /* External interface to Lua *************************************************/ @@ -731,7 +724,6 @@ otherwise everything is just too painful. typedef struct { DIR *dirp; - struct dirent *buf, *ent; } luxio_readdir_state; static int @@ -740,7 +732,6 @@ luxio_readdir_gc(lua_State *L) luxio_readdir_state *s = luaL_checkudata(L, 1, LUXIO_READDIR_METATABLE); closedir(s->dirp); - free(s->buf); return 0; } @@ -786,7 +777,6 @@ luxio_opendir(lua_State *L) /* 5.1.2 */ { const char *path = luaL_checkstring(L, 1); DIR *d = opendir(path); - size_t bufz; luxio_readdir_state *s; if (d == NULL) { @@ -796,16 +786,7 @@ luxio_opendir(lua_State *L) /* 5.1.2 */ } s = lua_newuserdata(L, sizeof(*s)); - s->dirp = d; - /* + 256 because it'd always be +1 if it weren't for the horrors - * of Solaris. If we were using autoconf, we could use Ben - * Hutchings' function mentioned in his article "readdir_r considered - * harmful". - */ - bufz = sizeof(struct dirent) + safe_pathconf(path, _PC_NAME_MAX) + 256; - s->buf = malloc(bufz); - luxio__bless_readdir(L); return 1; @@ -822,7 +803,6 @@ luxio_fdopendir(lua_State *L) /* POSIX.1-2008 */ { int fd = luaL_checkinteger(L, 1); DIR *d = fdopendir(fd); - size_t bufz; luxio_readdir_state *s; if (d == NULL) { @@ -834,14 +814,6 @@ luxio_fdopendir(lua_State *L) /* POSIX.1-2008 */ s = lua_newuserdata(L, sizeof(*s)); s->dirp = d; - /* + 256 because it'd always be +1 if it weren't for the horrors - * of Solaris. If we were using autoconf, we could use Ben - * Hutchings' function mentioned in his article "readdir_r considered - * harmful". - */ - bufz = sizeof(struct dirent) + safe_fpathconf(fd, _PC_NAME_MAX) + 256; - s->buf = malloc(bufz); - luxio__bless_readdir(L); return 1; @@ -861,9 +833,6 @@ luxio_closedir(lua_State *L) /* 5.1.2 */ s->dirp = NULL; } - free(s->buf); - s->buf = NULL; - return 0; } @@ -885,34 +854,32 @@ static int luxio_readdir(lua_State *L) /* 5.1.2 */ { luxio_readdir_state *s = luaL_checkudata(L, 1, LUXIO_READDIR_METATABLE); - int err; - - err = readdir_r(s->dirp, s->buf, &s->ent); - if (err == 0 && s->ent != NULL) { - lua_pushinteger(L, 0); - lua_createtable(L, 0, 3); - lua_pushinteger(L, s->ent->d_ino); - lua_setfield(L, -2, "d_ino"); - lua_pushstring(L, s->ent->d_name); - lua_setfield(L, -2, "d_name"); -#ifdef HAVE_D_TYPE - lua_pushinteger(L, s->ent->d_type); - lua_setfield(L, -2, "d_type"); -#endif - return 2; - } + errno = 0; + struct dirent *ent = readdir(s->dirp); - if (s->ent == NULL) { - /* end of directory */ - lua_pushnil(L); + if (ent == NULL) { + if (errno != 0) { + lua_pushinteger(L, errno); + } else { + /* end of directory */ + lua_pushnil(L); + } return 1; } - lua_pushinteger(L, err); - - return 1; + lua_pushinteger(L, 0); + lua_createtable(L, 0, 3); + lua_pushinteger(L, ent->d_ino); + lua_setfield(L, -2, "d_ino"); + lua_pushstring(L, ent->d_name); + lua_setfield(L, -2, "d_name"); +#ifdef HAVE_D_TYPE + lua_pushinteger(L, ent->d_type); + lua_setfield(L, -2, "d_type"); +#endif + return 2; } /*** Reset directory stream -- 2.12.2.510.ge1104a5.dirty