lsyncd/core/mci.c
2018-05-06 22:46:00 +02:00

793 lines
14 KiB
C

/*
| mci.c from Lsyncd -- the Live (Mirror) Syncing Demon
|
| The (generic) C part of the inteface between mantle and core.
|
| Note that some mci functions are provided directly
| in their respective core subsystems
|
| License: GPLv2 (see COPYING) or any later version
| Authors: Axel Kittenberger <axkibe@gmail.com>
*/
#include "feature.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <signal.h> // FIXME abstract this away
#include <syslog.h> // FIXME abstract this away
#include <string.h>
#include <unistd.h>
#define LUA_USE_APICHECK 1
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include "log.h"
#include "mci.h"
#include "mem.h"
#include "observe.h"
#include "pipe.h"
#include "signal.h"
#include "time.h"
#include "userobs.h"
#include "util.h"
#ifdef WITH_INOTIFY
# include "inotify.h"
#endif
#define CORE_LIBNAME "core"
#define INOTIFY_LIBNAME "inotify"
/*
| The Lua part of Lsyncd
*/
extern const char mantle_out[];
extern size_t mantle_size;
/*
| The Lua coded default sync implementations
*/
extern const char default_out[];
extern size_t default_size;
/*
| True only on first time.
| FIXME do away.
*/
extern bool first_time;
/*
| Makes sure there is one file system monitor.
*/
#ifndef WITH_INOTIFY
# error "needing at least one notification system. please rerun cmake"
#endif
/*
| All monitors supported by this Lsyncd.
*/
extern char *monitors[];
/*
| Variable which address is used as
| the cores index in the lua registry to
| index the mantle-core-interface
|
| Its value is used to determined if the
| mantle has registered itself already.
*/
static int mci = 0;
/*
| Dummy variable which address is used as
| the cores index n the lua registry to
| the lua runners error handler.
*/
int callError;
/*
| Executes a subprocess. Does not wait for it to return.
|
| Params on Lua stack:
|
| 1: Path to binary to call
| 2: List of string as arguments
| or "<" in which case the next argument is a string
| that will be piped on stdin.
| The arguments will follow that one.
|
| Returns (Lua stack) the pid on success, 0 on failure.
*/
static int
l_exec( lua_State * L )
{
// the binary to call
const char *binary = luaL_checkstring( L, 1 );
// number of arguments
int argc = lua_gettop( L ) - 1;
// the pid spawned
pid_t pid;
// the arguments position in the lua arguments
int li = 1;
// the pipe to text
char const * pipe_text = NULL;
// the pipes length
size_t pipe_len = 0;
// the arguments
char const ** argv;
// pipe file descriptors
int pipefd[ 2 ];
int i;
// expands tables
// and removes nils
for( i = 1; i <= lua_gettop( L ); i++ )
{
if( lua_isnil( L, i ) )
{
lua_remove( L, i );
i--;
argc--;
continue;
}
if( lua_istable( L, i ) )
{
int tlen;
int it;
lua_checkstack( L, lua_gettop( L ) + lua_rawlen( L, i ) + 1 );
// moves table to top of stack
lua_pushvalue( L, i );
lua_remove( L, i );
argc--;
tlen = lua_rawlen( L, -1 );
for( it = 1; it <= tlen; it++ )
{
lua_pushinteger( L, it );
lua_gettable( L, -2 );
lua_insert( L, i );
i++;
argc++;
}
i--;
lua_pop( L, 1 );
}
}
// writes a log message (if needed).
if( check_logcat( "Exec" ) <= settings.log_level )
{
lua_checkstack( L, lua_gettop( L ) + argc * 3 + 2 );
lua_pushvalue( L, 1 );
for( i = 1; i <= argc; i++ )
{
lua_pushstring( L, " [" );
lua_pushvalue( L, i + 1 );
lua_pushstring( L, "]" );
}
lua_concat( L, 3 * argc + 1 );
// replaces midfile 0 chars by linefeed
size_t len = 0;
const char * cs = lua_tolstring( L, -1, &len );
char * s = s_calloc( len + 1, sizeof( char ) );
for( i = 0; i < len; i++ )
{
s[ i ] = cs[ i ] ? cs[ i ] : '\n';
}
logstring0( LOG_DEBUG, "Exec", s );
free( s );
lua_pop( L, 1 );
}
if( argc >= 2 && !strcmp( luaL_checkstring( L, 2 ), "<" ) )
{
// pipes something into stdin
if( !lua_isstring( L, 3 ) )
{
logstring( "Error", "in spawn(), expected a string after pipe '<'" );
exit( -1 );
}
pipe_text = lua_tolstring( L, 3, &pipe_len );
if( strlen( pipe_text ) > 0 )
{
pipe_create( pipefd );
}
else
{
pipe_text = NULL;
}
argc -= 2;
li += 2;
}
// prepares the arguments
argv = s_calloc( argc + 2, sizeof( char * ) );
argv[ 0 ] = binary;
for( i = 1; i <= argc; i++ )
{
argv[i] = luaL_checkstring( L, i + li );
}
argv[ i ] = NULL;
// the fork!
pid = fork( );
if( pid == 0 )
{
// replaces stdin for pipes
if( pipe_text ) dup2( pipefd[ 0 ], STDIN_FILENO );
// if lsyncd runs as a daemon and has a logfile it will redirect
// stdout/stderr of child processes to the logfile.
if( settings.log_file )
{
if( !freopen( settings.log_file, "a", stdout ) )
{
printlogf( L, "Error", "cannot redirect stdout to '%s'.", settings.log_file );
}
if( !freopen( settings.log_file, "a", stderr ) )
{
printlogf( L, "Error", "cannot redirect stderr to '%s'.", settings.log_file );
}
}
execv( binary, ( char ** ) argv );
// in a sane world execv does not return!
printlogf( L, "Error", "Failed executing [ %s ]!", binary );
exit( -1 );
}
if( pipe_text )
{
// closes read-end of pipe, this is for child process only
close( pipefd[ 0 ] );
pipe_write( pipefd, pipe_text, pipe_len );
}
free( argv );
lua_pushnumber( L, pid );
return 1;
}
/*
| Registers the mantle core interface with the core.
|
| Params on Lua stack:
| 1: The luacode mantle.
|
| Returns on Lua stack:
| nothing
*/
static int
l_mci( lua_State *L )
{
if( mci )
{
logstring( "Error", "Luacode interface already registered!" );
exit( -1 );
}
mci = 1;
lua_pushlightuserdata( L, (void *) &mci );
// switches the passed mantle interface as parameter and the key &mci
lua_insert( L, 1 );
// saves the table of the mci in the lua registry
lua_settable( L, LUA_REGISTRYINDEX );
// saves the error function extras
lua_pushlightuserdata( L, (void *) &callError );
lua_pushlightuserdata( L, (void *) &mci );
lua_gettable( L, LUA_REGISTRYINDEX );
lua_pushstring( L, "callError" );
lua_gettable( L, -2 );
lua_remove( L, -2 );
lua_settable( L, LUA_REGISTRYINDEX );
if( lua_gettop( L ) )
{
logstring( "Error", "internal, stack is dirty." );
l_stackdump( L );
exit( -1 );
}
}
/*
| Converts a relative directory path to an absolute.
|
| Params on Lua stack:
| 1: a relative path to directory
|
| Returns on Lua stack:
| The absolute path of directory
*/
static int
l_realdir( lua_State *L )
{
luaL_Buffer b;
const char *rdir = luaL_checkstring(L, 1);
char *adir = get_realpath( rdir );
if( !adir )
{
printlogf(
L, "Error",
"failure getting absolute path of [%s]",
rdir
);
return 0;
}
{
// makes sure its a directory
struct stat st;
if( stat( adir, &st ) )
{
printlogf(
L, "Error",
"cannot get absolute path of dir '%s': %s",
rdir,
strerror( errno )
);
free( adir );
return 0;
}
if( !S_ISDIR( st.st_mode ) )
{
printlogf(
L, "Error",
"cannot get absolute path of dir '%s': is not a directory",
rdir
);
free( adir );
return 0;
}
}
// returns absolute path with a concated '/'
luaL_buffinit( L, &b );
luaL_addstring( &b, adir );
luaL_addchar( &b, '/' );
luaL_pushresult( &b );
free( adir );
return 1;
}
/*
| Dumps the Lua stack.
| For debugging purposes.
*/
int
l_stackdump( lua_State * L )
{
int i;
int top = lua_gettop( L );
printlogf( L, "Debug", "total on stack %d", top );
for( i = 1; i <= top; i++ )
{
int t = lua_type( L, i );
switch( t )
{
case LUA_TSTRING:
printlogf(
L, "Debug",
"%d string: '%s'", i, lua_tostring( L, i )
);
break;
case LUA_TBOOLEAN:
printlogf( L, "Debug",
"%d boolean %s", i, lua_toboolean( L, i ) ? "true" : "false"
);
break;
case LUA_TNUMBER:
printlogf( L, "Debug", "%d number: %g", i, lua_tonumber( L, i ) );
break;
default:
printlogf( L, "Debug", "%d %s", i, lua_typename( L, t ) );
break;
}
}
return 0;
}
/*
| Reads the directories entries.
|
| Params on Lua stack:
| 1: absolute path to directory
|
| Returns on Lua stack:
| a table of directory names.
| names are keys
| values are boolean true on dirs.
*/
static int
l_readdir( lua_State *L )
{
const char * dirname = luaL_checkstring( L, 1 );
DIR *d = opendir( dirname );
if( d == NULL )
{
printlogf( L, "Error", "cannot open dir [%s].", dirname );
return 0;
}
lua_newtable( L );
while( !hup && !term )
{
struct dirent *de = readdir( d );
bool isdir;
// finished?
if( de == NULL ) break;
// ignores . and ..
if( !strcmp( de->d_name, "." ) || !strcmp( de->d_name, ".." ) ) continue;
if( de->d_type == DT_UNKNOWN )
{
// must call stat on some systems :-/
// ( e.g. ReiserFS )
char *entry = s_malloc( strlen( dirname ) + strlen( de->d_name ) + 2 );
struct stat st;
strcpy( entry, dirname );
strcat( entry, "/" );
strcat( entry, de->d_name );
lstat( entry, &st );
isdir = S_ISDIR( st.st_mode );
free( entry );
}
else
{
// otherwise readdir can be trusted
isdir = de->d_type == DT_DIR;
}
// adds this entry to the Lua table
lua_pushstring( L, de->d_name );
lua_pushboolean( L, isdir );
lua_settable( L, -3 );
}
closedir( d );
return 1;
}
/*
| Immediately terminates Lsyncd.
|
| Params on Lua stack:
| 1: exitcode of Lsyncd.
|
| Does not return.
|
*/
int
l_terminate( lua_State *L )
{
int exitcode = luaL_checkinteger( L, 1 );
exit( exitcode );
return 0;
}
/*
| Configures core parameters.
|
| Params on Lua stack:
| 1: a string, configure option
| 2: depends on Param 1
*/
static int
l_configure( lua_State *L )
{
const char * command = luaL_checkstring( L, 1 );
if( !strcmp( command, "running" ) )
{
// set by mantle after first initialize
// from this on log to configurated log end instead of
// stdout/stderr
first_time = false;
if( !settings.log_file )
{
settings.log_syslog = true;
const char * log_ident = settings.log_ident ? settings.log_ident : "lsyncd";
openlog( log_ident, 0, settings.log_facility );
}
logstring( "Normal", "--- Startup ---" );
}
else if( !strcmp( command, "logfile" ) )
{
const char * file = luaL_checkstring( L, 2 );
if( settings.log_file )
{
free( settings.log_file );
}
settings.log_file = s_strdup( file );
}
else if( !strcmp( command, "logfacility" ) )
{
if( lua_isstring( L, 2 ) )
{
const char * fname = luaL_checkstring( L, 2 );
settings.log_facility = log_getFacility( L, fname );
}
else if (lua_isnumber(L, 2))
{
settings.log_facility = luaL_checknumber( L, 2 );
}
else
{
printlogf( L, "Error", "Logging facility must be a number or string" );
exit( -1 );
}
}
else if( !strcmp( command, "logident" ) )
{
const char * ident = luaL_checkstring( L, 2 );
if( settings.log_ident ) free( settings.log_ident );
settings.log_ident = s_strdup( ident );
}
else
{
printlogf(
L, "Error",
"Internal error, unknown parameter in l_configure( %s )",
command
);
exit( -1 );
}
return 0;
}
/*
| The Lsnycd's core library.
*/
static const luaL_Reg corelib[ ] =
{
{ "configure", l_configure },
{ "exec", l_exec },
{ "log", l_log },
{ "mci", l_mci },
{ "now", l_now },
{ "nonobserve_fd", l_nonobserve_fd },
{ "observe_fd", l_observe_fd },
{ "onsignal", l_onsignal },
{ "readdir", l_readdir },
{ "realdir", l_realdir },
{ "stackdump", l_stackdump },
{ "terminate", l_terminate },
{ NULL, NULL }
};
/*
| Registers the Lsyncd's core library.
*/
void
register_core( lua_State *L )
{
lua_newtable( L );
luaL_setfuncs( L, corelib, 0 );
lua_setglobal( L, CORE_LIBNAME );
register_jiffies( L );
#ifdef WITH_INOTIFY
lua_getglobal( L, CORE_LIBNAME );
register_inotify( L );
lua_setfield( L, -2, INOTIFY_LIBNAME );
lua_pop( L, 1 );
#endif
if( lua_gettop( L ) )
{
logstring( "Error", "internal, stack not empty in lsyncd_register( )" );
exit( -1 );
}
}
/*
| Pushes a function from the mantle on the stack.
| As well as the callError handler.
| FIXME rename
*/
void
load_mci(
lua_State * L,
const char * name
)
{
printlogf( L, "Call", "%s( )", name );
// pushes the error handler
lua_pushlightuserdata( L, (void *) &callError );
lua_gettable( L, LUA_REGISTRYINDEX );
// pushes the function
lua_pushlightuserdata( L, (void *) &mci );
lua_gettable( L, LUA_REGISTRYINDEX );
lua_pushstring( L, name );
lua_gettable( L, -2 );
lua_remove( L, -2 );
}
/*
| Loads the mantle.
*/
void
mci_load_mantle(
lua_State * L
)
{
// loads the lsyncd mantle
if( luaL_loadbuffer( L, mantle_out, mantle_size, "mantle" ) )
{
printlogf( L, "Error", "loading mantle: %s", lua_tostring( L, -1 ) );
exit( -1 );
}
// prepares the luacode executing the script
if( lua_pcall( L, 0, 0, 0 ) )
{
printlogf( L, "Error", "preparing mantle: %s", lua_tostring( L, -1 ) );
exit( -1 );
}
{
// asserts the Lsyncd's version matches
// double checks the if mantle version is the same as core version
const char *lversion;
lua_getglobal( L, "lsyncd_version" );
lversion = luaL_checkstring( L, -1 );
if( strcmp( lversion, PACKAGE_VERSION ) )
{
printlogf(
L, "Error",
"Version mismatch luacode is '%s', but core is '%s'",
lversion, PACKAGE_VERSION
);
exit( -1 );
}
lua_pop( L, 1 );
}
}
/*
| Loads the default implementations.
*/
void
mci_load_default(
lua_State * L
)
{
// loads the default sync implementations
if( luaL_loadbuffer( L, default_out, default_size, "default" ) )
{
printlogf( L, "Error",
"loading default sync implementations: %s", lua_tostring( L, -1 ) );
exit( -1 );
}
// loads the user enivornment
// the default sync implementations are actually not priviledged in any way
lua_getglobal( L, "userENV" );
lua_setupvalue( L, -2, 1 );
// prepares the default sync implementations
if( lua_pcall( L, 0, 0, 0 ) )
{
printlogf( L, "Error",
"preparing default sync implementations: %s", lua_tostring( L, -1 ) );
exit( -1 );
}
}