mirror of https://github.com/octoleo/lsyncd.git
441 lines
9.2 KiB
C
441 lines
9.2 KiB
C
#include "config.h"
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#define LUA_USE_APICHECK 1
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#ifdef HAVE_SYS_INOTIFY_H
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# include <sys/inotify.h>
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#else
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# include "inotify-nosys.h"
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#endif
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <dirent.h>
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#include <errno.h>
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#include <limits.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <lua.h>
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#include <lualib.h>
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#include <lauxlib.h>
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/**
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* The inotify file descriptor.
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*/
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static int inotify_fd;
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/**
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* TODO allow configure.
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*/
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const uint32_t standard_event_mask =
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IN_ATTRIB | IN_CLOSE_WRITE | IN_CREATE |
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IN_DELETE | IN_DELETE_SELF | IN_MOVED_FROM |
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IN_MOVED_TO | IN_DONT_FOLLOW | IN_ONLYDIR;
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/**
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* Set to TERM or HUP in signal handler, when lsyncd should end or reset ASAP.
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*/
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volatile sig_atomic_t reset = 0;
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/**
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* "secured" calloc.
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*/
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void *
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s_calloc(size_t nmemb, size_t size)
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{
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void *r = calloc(nmemb, size);
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if (r == NULL) {
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printf("Out of memory!\n");
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exit(-1); // ERRNO
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}
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return r;
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}
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/**
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* "secured" malloc. the deamon shall kill itself
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* in case of out of memory.
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*/
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void *
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s_malloc(size_t size)
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{
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void *r = malloc(size);
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if (r == NULL) {
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printf("Out of memory!\n");
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exit(-1); // ERRNO
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}
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return r;
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}
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/*****************************************************************************
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* Library calls for lsyncd.lua
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*
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* These are as minimal as possible glues to the operating system needed for
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* lsyncd operation.
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*
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****************************************************************************/
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/**
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* Adds an inotify watch
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*
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* @param dir (Lua stack) path to directory
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* @return (Lua stack) numeric watch descriptor
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*/
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static int
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l_add_watch(lua_State *L)
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{
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const char *path = luaL_checkstring(L, 1);
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lua_Integer wd = inotify_add_watch(inotify_fd, path, standard_event_mask);
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lua_pushinteger(L, wd);
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return 1;
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}
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/**
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* Executes a subprocess. Does not wait for it to return.
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*
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* @param (Lua stack) Path to binary to call
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* @params (Lua stack) list of string as arguments
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* @return (Lua stack) the pid on success, 0 on failure.
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*/
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static int
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l_exec(lua_State *L)
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{
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const char *binary = luaL_checkstring(L, 1);
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int argc = lua_gettop(L) - 1;
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pid_t pid;
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int i;
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char const **argv = s_calloc(argc + 2, sizeof(char *));
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argv[0] = binary;
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for(i = 1; i <= argc; i++) {
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argv[i] = luaL_checkstring(L, i + 1);
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}
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argv[i] = NULL;
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pid = fork();
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if (pid == 0) {
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//if (!log->flag_nodaemon && log->logfile) {
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// if (!freopen(log->logfile, "a", stdout)) {
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// printlogf(log, ERROR, "cannot redirect stdout to [%s].", log->logfile);
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// }
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// if (!freopen(log->logfile, "a", stderr)) {
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// printlogf(log, ERROR, "cannot redirect stderr to [%s].", log->logfile);
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// }
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//}
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execv(binary, (char **)argv);
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// in a sane world execv does not return!
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printf("Failed executing [%s]!\n", binary);
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exit(-1); // ERRNO
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}
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free(argv);
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lua_pushnumber(L, pid);
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return 1;
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}
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/**
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* Converts a relative directory path to an absolute.
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*
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* @param dir a relative path to directory
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* @return absolute path of directory
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*/
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static int
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l_real_dir(lua_State *L)
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{
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luaL_Buffer b;
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char *cbuf;
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const char *rdir = luaL_checkstring(L, 1);
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/* use c-library to get absolute path */
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cbuf = realpath(rdir, NULL);
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if (cbuf == NULL) {
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printf("failure getting absolute path of \"%s\"\n", rdir);
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return 0;
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}
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{
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/* makes sure its a directory */
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struct stat st;
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stat(cbuf, &st);
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if (!S_ISDIR(st.st_mode)) {
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printf("failure in real_dir \"%s\" is not a directory\n", rdir);
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free(cbuf);
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return 0;
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}
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}
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/* returns absolute path with a concated '/' */
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luaL_buffinit(L, &b);
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luaL_addstring(&b, cbuf);
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luaL_addchar(&b, '/');
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luaL_pushresult(&b);
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free(cbuf);
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return 1;
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}
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/**
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* Dumps the LUA stack. For debugging purposes.
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*/
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static int
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l_stackdump(lua_State* L)
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{
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int i;
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int top = lua_gettop(L);
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printf("total in stack %d\n",top);
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for (i = 1; i <= top; i++) {
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int t = lua_type(L, i);
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switch (t) {
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case LUA_TSTRING:
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printf("%d string: '%s'\n", i, lua_tostring(L, i));
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break;
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case LUA_TBOOLEAN:
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printf("%d boolean %s\n", i, lua_toboolean(L, i) ? "true" : "false");
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break;
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case LUA_TNUMBER:
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printf("%d number: %g\n", i, lua_tonumber(L, i));
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break;
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default: /* other values */
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printf("%d %s\n", i, lua_typename(L, t));
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break;
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}
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}
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printf("\n");
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return 0;
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}
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/**
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* Reads the directories sub directories.
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*
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* @param (Lua stack) absolute path to directory.
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* @return (Lua stack) a table of directory names.
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*/
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static int
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l_sub_dirs (lua_State *L)
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{
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const char * dirname = luaL_checkstring(L, 1);
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DIR *d;
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int idx = 1;
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d = opendir(dirname);
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if (d == NULL) {
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printf("cannot open dir %s.\n", dirname);
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return 0;
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}
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lua_newtable(L);
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while (!reset) {
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struct dirent *de = readdir(d);
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bool isdir;
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if (de == NULL) {
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/* finished */
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break;
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}
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if (de->d_type == DT_UNKNOWN) {
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/* must call stat on some systems :-/ */
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char *subdir = s_malloc(strlen(dirname) + strlen(de->d_name) + 2);
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struct stat st;
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strcpy(subdir, dirname);
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strcat(subdir, "/");
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strcat(subdir, de->d_name);
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stat(subdir, &st);
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isdir = S_ISDIR(st.st_mode);
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free(subdir);
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} else {
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/* we can trust readdir */
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isdir = de->d_type == DT_DIR;
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}
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if (!isdir || !strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
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/* ignore non directories and . and .. */
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continue;
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}
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/* add this to the Lua table */
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lua_pushnumber(L, idx++);
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lua_pushstring(L, de->d_name);
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lua_settable(L, -3);
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}
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return 1;
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}
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/**
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* Terminates lsyncd daemon.
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*
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* @param (Lua stack) exitcode for lsyncd.
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*
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* Does not return.
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*/
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int
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l_terminate(lua_State *L)
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{
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int exitcode = luaL_checkinteger(L, 1);
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exit(exitcode);
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return 0;
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}
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/*****************************************************************************
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* Lsyncd Core
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****************************************************************************/
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static const luaL_reg lsyncdlib[] = {
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{"add_watch", l_add_watch},
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{"exec", l_exec},
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{"real_dir", l_real_dir},
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{"stackdump", l_stackdump},
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{"sub_dirs", l_sub_dirs},
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{"terminate", l_terminate},
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{NULL, NULL}
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};
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/**
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* Waits after startup for all children.
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*
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* @param (Lua stack) a table of the children pids.
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*/
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void
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wait_startup(lua_State *L)
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{
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/* the number of pids in table */
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int pidn;
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/* the pid table */
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int *pids;
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/* the number of children to be waited for */
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int remaining = 0;
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int i;
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/* checks if Lua script returned a table */
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if (lua_type(L, 1) == LUA_TNIL) {
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printf("Lua function startup did not return a pidtable!\n");
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exit(-1); // ERRNO
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}
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/* determines size of the pid-table */
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pidn = lua_objlen (L, -1);
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if (pidn == 0) {
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/* nothing to do on zero pids */
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return;
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}
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/* reads the pid table from Lua stack */
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pids = s_calloc(pidn, sizeof(int));
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for(i = 0; i < pidn; i++) {
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lua_rawgeti(L, -1, i + 1);
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pids[i] = luaL_checkinteger(L, -1);
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lua_pop(L, 1);
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/* ignores zero pids */
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if (pids[i]) {
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remaining++;
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}
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}
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/* waits for the children */
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while(remaining) {
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/* argument for waitpid, and exitcode of child */
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int status, exitcode;
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/* new process id in case of retry */
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int newp;
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/* process id of terminated child process */
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int wp = waitpid(0, &status, 0);
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/* if nothing really finished ignore */
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if (wp == 0 || !WIFEXITED(status)) {
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continue;
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}
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exitcode = WEXITSTATUS(status);
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/* checks if the pid is one waited for */
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for(i = 0; i < pidn; i++) {
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if (pids[i] == wp) {
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break;
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}
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}
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if (i >= pidn) {
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/* not a pid waited for */
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continue;
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}
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/* calls the lua script to determine what to do on child failure */
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lua_getglobal(L, "startup_returned");
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lua_pushinteger(L, wp);
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lua_pushinteger(L, exitcode);
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lua_call(L, 2, 1);
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newp = luaL_checkinteger(L, -1);
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lua_pop(L, 1);
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/* replace the new pid in the pidtable,
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or zero it on no new pid */
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for(i = 0; i < pidn; i++) {
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if (pids[i] == wp) {
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pids[i] = newp;
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if (newp == 0) {
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remaining--;
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}
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}
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}
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}
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free(pids);
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}
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/**
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* Main
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*/
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int
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main(int argc, char *argv[])
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{
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/* the Lua interpreter */
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lua_State* L;
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/* load Lua */
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L = lua_open();
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luaL_openlibs(L);
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luaL_register(L, "lsyncd", lsyncdlib);
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lua_setglobal(L, "lysncd");
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if (luaL_loadfile(L, "lsyncd.lua")) {
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printf("error loading lsyncd.lua: %s\n", lua_tostring(L, -1));
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return -1; // ERRNO
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}
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if (lua_pcall(L, 0, LUA_MULTRET, 0)) {
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printf("error running lsyncd.lua: %s\n", lua_tostring(L, -1));
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return -1; // ERRNO
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}
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if (luaL_loadfile(L, "lsyncd-conf.lua")) {
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printf("error loading lsyncd-conf.lua: %s\n", lua_tostring(L, -1));
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return -1; // ERRNO
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}
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if (lua_pcall(L, 0, LUA_MULTRET, 0)) {
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printf("error running lsyncd-conf.lua: %s\n", lua_tostring(L, -1));
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return -1; // ERRNO
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}
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/* open inotify */
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inotify_fd = inotify_init();
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if (inotify_fd == -1) {
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printf("Cannot create inotify instance! (%d:%s)\n", errno, strerror(errno));
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return -1; // ERRNO
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}
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/* initialize */
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/* lua code will set configuration and add watches */
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lua_getglobal(L, "lsyncd_initialize");
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lua_call(L, 0, 0);
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/* startup */
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/* lua code will perform startup calls like recursive rsync */
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lua_getglobal(L, "startup");
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lua_call(L, 0, 1);
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wait_startup(L);
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/* cleanup */
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close(inotify_fd);
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lua_close(L);
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return 0;
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}
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