+int lc_setgid(lua_State* L)
+{
+ int gid = -1;
+ if(lua_gettop(L) < 1)
+ return 0;
+ if(!lua_isnumber(L, 1) && lua_tostring(L, 1))
+ {
+ /* Passed GID is actually a string, so look up the GID */
+ struct group *g;
+ g = getgrnam(lua_tostring(L, 1));
+ if(!g)
+ {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "no-such-group");
+ return 2;
+ }
+ gid = g->gr_gid;
+ }
+ else
+ {
+ gid = lua_tonumber(L, 1);
+ }
+
+ if(gid>-1)
+ {
+ /* Ok, attempt setgid */
+ errno = 0;
+ if(setgid(gid))
+ {
+ /* Fail */
+ lua_pushboolean(L, 0);
+ switch(errno)
+ {
+ case EINVAL:
+ lua_pushstring(L, "invalid-gid");
+ break;
+ case EPERM:
+ lua_pushstring(L, "permission-denied");
+ break;
+ default:
+ lua_pushstring(L, "unknown-error");
+ }
+ return 2;
+ }
+ else
+ {
+ /* Success! */
+ lua_pushboolean(L, 1);
+ return 1;
+ }
+ }
+
+ /* Seems we couldn't find a valid GID to switch to */
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "invalid-gid");
+ return 2;
+}
+
+int lc_initgroups(lua_State* L)
+{
+ int ret;
+ gid_t gid;
+ struct passwd *p;
+
+ if(!lua_isstring(L, 1))
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, "invalid-username");
+ return 2;
+ }
+ p = getpwnam(lua_tostring(L, 1));
+ if(!p)
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, "no-such-user");
+ return 2;
+ }
+ if(lua_gettop(L) < 2)
+ lua_pushnil(L);
+ switch(lua_type(L, 2))
+ {
+ case LUA_TNIL:
+ gid = p->pw_gid;
+ break;
+ case LUA_TNUMBER:
+ gid = lua_tointeger(L, 2);
+ break;
+ default:
+ lua_pushnil(L);
+ lua_pushstring(L, "invalid-gid");
+ return 2;
+ }
+ ret = initgroups(lua_tostring(L, 1), gid);
+ if(ret)
+ {
+ switch(errno)
+ {
+ case ENOMEM:
+ lua_pushnil(L);
+ lua_pushstring(L, "no-memory");
+ break;
+ case EPERM:
+ lua_pushnil(L);
+ lua_pushstring(L, "permission-denied");
+ break;
+ default:
+ lua_pushnil(L);
+ lua_pushstring(L, "unknown-error");
+ }
+ }
+ else
+ {
+ lua_pushboolean(L, 1);
+ lua_pushnil(L);
+ }
+ return 2;
+}
+
+int lc_umask(lua_State* L)
+{
+ char old_mode_string[7];
+ mode_t old_mode = umask(strtoul(luaL_checkstring(L, 1), NULL, 8));
+
+ snprintf(old_mode_string, sizeof(old_mode_string), "%03o", old_mode);
+ old_mode_string[sizeof(old_mode_string)-1] = 0;
+ lua_pushstring(L, old_mode_string);
+
+ return 1;
+}
+
+int lc_mkdir(lua_State* L)
+{
+ int ret = mkdir(luaL_checkstring(L, 1), S_IRUSR | S_IWUSR | S_IXUSR
+ | S_IRGRP | S_IWGRP | S_IXGRP
+ | S_IROTH | S_IXOTH); /* mode 775 */
+
+ lua_pushboolean(L, ret==0);
+ if(ret)
+ {
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+ return 1;
+}
+
+/* Like POSIX's setrlimit()/getrlimit() API functions.
+ *
+ * Syntax:
+ * pposix.setrlimit( resource, soft limit, hard limit)
+ *
+ * Any negative limit will be replace with the current limit by an additional call of getrlimit().
+ *
+ * Example usage:
+ * pposix.setrlimit("NOFILE", 1000, 2000)
+ */
+int string2resource(const char *s) {
+ if (!strcmp(s, "CORE")) return RLIMIT_CORE;
+ if (!strcmp(s, "CPU")) return RLIMIT_CPU;
+ if (!strcmp(s, "DATA")) return RLIMIT_DATA;
+ if (!strcmp(s, "FSIZE")) return RLIMIT_FSIZE;
+ if (!strcmp(s, "NOFILE")) return RLIMIT_NOFILE;
+ if (!strcmp(s, "STACK")) return RLIMIT_STACK;
+#if !(defined(sun) || defined(__sun))
+ if (!strcmp(s, "MEMLOCK")) return RLIMIT_MEMLOCK;
+ if (!strcmp(s, "NPROC")) return RLIMIT_NPROC;
+ if (!strcmp(s, "RSS")) return RLIMIT_RSS;
+#endif
+ return -1;
+}
+
+int lc_setrlimit(lua_State *L) {
+ int arguments = lua_gettop(L);
+ int softlimit = -1;
+ int hardlimit = -1;
+ const char *resource = NULL;
+ int rid = -1;
+ if(arguments < 1 || arguments > 3) {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "incorrect-arguments");
+ }
+
+ resource = luaL_checkstring(L, 1);
+ softlimit = luaL_checkinteger(L, 2);
+ hardlimit = luaL_checkinteger(L, 3);
+
+ rid = string2resource(resource);
+ if (rid != -1) {
+ struct rlimit lim;
+ struct rlimit lim_current;
+
+ if (softlimit < 0 || hardlimit < 0) {
+ if (getrlimit(rid, &lim_current)) {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "getrlimit-failed");
+ return 2;
+ }
+ }
+
+ if (softlimit < 0) lim.rlim_cur = lim_current.rlim_cur;
+ else lim.rlim_cur = softlimit;
+ if (hardlimit < 0) lim.rlim_max = lim_current.rlim_max;
+ else lim.rlim_max = hardlimit;
+
+ if (setrlimit(rid, &lim)) {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "setrlimit-failed");
+ return 2;
+ }
+ } else {
+ /* Unsupported resoucrce. Sorry I'm pretty limited by POSIX standard. */
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "invalid-resource");
+ return 2;
+ }
+ lua_pushboolean(L, 1);
+ return 1;
+}
+
+int lc_getrlimit(lua_State *L) {
+ int arguments = lua_gettop(L);
+ const char *resource = NULL;
+ int rid = -1;
+ struct rlimit lim;
+
+ if (arguments != 1) {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "invalid-arguments");
+ return 2;
+ }
+
+ resource = luaL_checkstring(L, 1);
+ rid = string2resource(resource);
+ if (rid != -1) {
+ if (getrlimit(rid, &lim)) {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "getrlimit-failed.");
+ return 2;
+ }
+ } else {
+ /* Unsupported resoucrce. Sorry I'm pretty limited by POSIX standard. */
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "invalid-resource");
+ return 2;
+ }
+ lua_pushboolean(L, 1);
+ lua_pushnumber(L, lim.rlim_cur);
+ lua_pushnumber(L, lim.rlim_max);
+ return 3;
+}
+
+int lc_abort(lua_State* L)
+{
+ abort();
+ return 0;
+}
+
+int lc_uname(lua_State* L)
+{
+ struct utsname uname_info;
+ if(uname(&uname_info) != 0)
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+ lua_newtable(L);
+ lua_pushstring(L, uname_info.sysname);
+ lua_setfield(L, -2, "sysname");
+ lua_pushstring(L, uname_info.nodename);
+ lua_setfield(L, -2, "nodename");
+ lua_pushstring(L, uname_info.release);
+ lua_setfield(L, -2, "release");
+ lua_pushstring(L, uname_info.version);
+ lua_setfield(L, -2, "version");
+ lua_pushstring(L, uname_info.machine);
+ lua_setfield(L, -2, "machine");
+ return 1;
+}
+
+int lc_setenv(lua_State* L)
+{
+ const char *var = luaL_checkstring(L, 1);
+ const char *value;
+
+ /* If the second argument is nil or nothing, unset the var */
+ if(lua_isnoneornil(L, 2))
+ {
+ if(unsetenv(var) != 0)
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+ lua_pushboolean(L, 1);
+ return 1;
+ }
+
+ value = luaL_checkstring(L, 2);
+
+ if(setenv(var, value, 1) != 0)
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+
+ lua_pushboolean(L, 1);
+ return 1;
+}
+
+#ifdef WITH_MALLINFO
+int lc_meminfo(lua_State* L)
+{
+ struct mallinfo info = mallinfo();
+ lua_newtable(L);
+ /* This is the total size of memory allocated with sbrk by malloc, in bytes. */
+ lua_pushinteger(L, info.arena);
+ lua_setfield(L, -2, "allocated");
+ /* This is the total size of memory allocated with mmap, in bytes. */
+ lua_pushinteger(L, info.hblkhd);
+ lua_setfield(L, -2, "allocated_mmap");
+ /* This is the total size of memory occupied by chunks handed out by malloc. */
+ lua_pushinteger(L, info.uordblks);
+ lua_setfield(L, -2, "used");
+ /* This is the total size of memory occupied by free (not in use) chunks. */
+ lua_pushinteger(L, info.fordblks);
+ lua_setfield(L, -2, "unused");
+ /* This is the size of the top-most releasable chunk that normally borders the
+ end of the heap (i.e., the high end of the virtual address space's data segment). */
+ lua_pushinteger(L, info.keepcost);
+ lua_setfield(L, -2, "returnable");
+ return 1;
+}
+#endif
+
+/* File handle extraction blatantly stolen from
+ * https://github.com/rrthomas/luaposix/blob/master/lposix.c#L631
+ * */
+
+#if _XOPEN_SOURCE >= 600 || _POSIX_C_SOURCE >= 200112L || defined(_GNU_SOURCE)
+int lc_fallocate(lua_State* L)
+{
+ off_t offset, len;
+ FILE *f = *(FILE**) luaL_checkudata(L, 1, LUA_FILEHANDLE);
+
+ offset = luaL_checkinteger(L, 2);
+ len = luaL_checkinteger(L, 3);
+
+#if defined(_GNU_SOURCE)
+ if(fallocate(fileno(f), FALLOC_FL_KEEP_SIZE, offset, len) == 0)
+ {
+ lua_pushboolean(L, 1);
+ return 1;
+ }
+
+ if(errno != ENOSYS && errno != EOPNOTSUPP)
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+#else
+#warning Only using posix_fallocate() fallback.
+#warning Linux fallocate() is strongly recommended if available: recompile with -D_GNU_SOURCE
+#warning Note that posix_fallocate() will still be used on filesystems that dont support fallocate()
+#endif
+
+ if(posix_fallocate(fileno(f), offset, len) == 0)
+ {
+ lua_pushboolean(L, 1);
+ return 1;
+ }
+ else
+ {
+ lua_pushnil(L);
+ lua_pushstring(L, strerror(errno));
+ /* posix_fallocate() can leave a bunch of NULs at the end, so we cut that
+ * this assumes that offset == length of the file */
+ ftruncate(fileno(f), offset);
+ return 2;
+ }
+}
+#endif
+