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/* vim:syntax=c 
 */ 
/* -*- c -*- 
|| This file is part of Pike. For copyright information see COPYRIGHT. 
|| Pike is distributed under GPL, LGPL and MPL. See the file COPYING 
|| for more information. 
*/ 
 
/* Module for the linux inotify api. 
 * 
 * Ref: inotify(7) 
 * 
 */ 
 
#ifdef HAVE_CONFIG_H 
# include "config.h" 
#endif 
 
#include "global.h" 
#include "interpret.h" 
#include "module.h" 
#include "program.h" 
#include "stralloc.h" 
#include "svalue.h" 
#include "object.h" 
#include "pike_types.h" 
#include "builtin_functions.h" 
#include "fdlib.h" 
#include "pike_threadlib.h" 
 
#include "modules/files/file.h" 
 
#ifdef HAVE_SYS_INOTIFY_H 
 
#include <sys/inotify.h> 
#include <errno.h> 
#include <unistd.h> 
 
DECLARATIONS 
 
/*! @module System */ 
 
/*! @module Inotify 
 *! This module implements an API to linux inotify. It is available on all 
 *! kernels from version 2.6.13 onwards. Inotify offers fast and scalable file 
 *! notifications. 
 */ 
 
/*! @decl constant IN_ALL_EVENTS 
 *! This is a derived constant that is not part of the standard inotify API. It 
 *! is the union of all other constants. 
 *! 
 *! @decl constant IN_ACCESS 
 *! @decl constant IN_ATTRIB 
 *! @decl constant IN_CLOSE 
 *! @decl constant IN_CLOSE_WRITE 
 *! @decl constant IN_CLOSE_NOWRITE 
 *! @decl constant IN_CREATE 
 *! @decl constant IN_DELETE 
 *! @decl constant IN_DELETE_SELF 
 *! @decl constant IN_MODIFY 
 *! @decl constant IN_MOVE_SELF 
 *! @decl constant IN_MOVED_FROM 
 *! @decl constant IN_MOVED_TO 
 *! @decl constant IN_OPEN 
 *! @decl constant IN_MOVE 
 *! @decl constant IN_CLOSE 
 *! @decl constant IN_DONT_FOLLOW 
 *! @decl constant IN_MASK_ADD 
 *! @decl constant IN_ONESHOT 
 *! @decl constant IN_ONLYDIR 
 *! @decl constant IN_IGNORED 
 *! @decl constant IN_ISDIR 
 *! @decl constant IN_Q_OVERFLOW 
 *! @decl constant IN_UNMOUNT 
 *!     Please have a look at the inotify(7) manpage for information about 
 *!     these constants. 
 *! @note 
 *!     Some constants may not be available when the module has been 
 *!     compiled on a machine with linux kernel before 2.6.15. See the 
 *!     manpage for more details. 
 */ 
 
/*! @decl array(string|int) parse_event(string data) 
 *! Parses one inotify_event struct from @expr{data@}. 
 *! @returns 
 *!     Returns an array consisting of 
 *!     @array 
 *!         @elem int 0 
 *!             The watch descriptor returned by @[_Instance()->add_watch()] 
 *!             when the watch for this file was added. 
 *!         @elem int 1 
 *!             An integer that describes the event that occured. See 
 *!             the inotify manpage for a list of possible events and 
 *!             their numerical identifiers. 
 *!         @elem int 2 
 *!             An integer cookie that can be used to group together 
 *!             different events that were triggered by moving a file 
 *!             from one location to another. 
 *!         @elem string 3 
 *!             The name of the file. This will only be present if the 
 *!             event happened to a file in a directory that was 
 *!             watched, e.g. with @[System.Inotify.IN_CREATE]. 
 *!             Otherwise this will be 0. 
 *!         @elem int 4 
 *!             The length of the data that has been parsed. If the @[data] 
 *!             string contains more than one inotify event, this parse 
 *!             function needs to be called again with the remainder as 
 *!             an argument. 
 *!     @endarray 
 */ 
PIKEFUN array(string|int) parse_event(string data) { 
    struct inotify_event * event; 
    size_t len; 
 
    if (data->size_shift) 
        Pike_error("Inotify events should not be wide.\n"); 
 
    if ((size_t)data->len < sizeof(struct inotify_event)) 
        Pike_error("Malformed data.\n"); 
 
    event = (struct inotify_event *)data->str; 
    pop_n_elems(args); 
 
    if (event->len > data->len - sizeof(struct inotify_event)) 
        Pike_error("Data missing.\n"); 
 
    push_int((int)event->wd); 
    push_int((int)event->mask); 
    push_int((int)event->cookie); 
 
    if (event->len && (len = strlen(event->name))) 
        push_string(make_shared_binary_string(event->name, len)); 
    else 
        push_int(0); 
 
    push_int((int)(event->len + sizeof(struct inotify_event))); 
 
    f_aggregate(5); 
} 
 
/*! @class _Instance 
 *!     Simple wrapper class that gives direct access to the @tt{inotify(7)@} 
 *!     interface. On create an inotify instance is initiated by calling 
 *!     @tt{inotify_init(2)@}. Every object of this class has its own inotify 
 *!     file descriptor. Use this class only if you want direct access to 
 *!     the file descriptor to read from it manually. For a more user 
 *!     friendly inferface use @[System.Inotify.Instance]. 
 *! 
 *! @seealso 
 *!     @[System.Inotify.Instance] 
 */ 
PIKECLASS _Instance { 
    CVAR int fd; 
    CVAR struct object * fd_object; 
 
    /*! @decl int add_watch(string file, int mask) 
     *! Add a watch for a certain file or directory and specific events. 
     *! Adding more than one watch for one file will overwrite the 
     *! previous watch unless @[System.Inotify.IN_MASK_ADD] is contained 
     *! in the mask. 
     *! @param path 
     *!     Path of the file or directory. 
     *! @param mask 
     *!     Integer mask specifying the event type. This can be a 
     *!     combination of different event types using bitwise OR. 
     *!     See the inotify manpage for possible values and their 
     *!     description. The values defined by the inotify header 
     *!     file are exported by @[System.Inotify] as constants 
     *!     using the same names (e.g. @[System.Inotify.IN_CREATE]). 
     *! @returns 
     *!     Returns a watch descriptor. 
     *! @note 
     *!     Subdirectories are not watched. If you want to watch 
     *!     subdirectories as well, you need to add watches for 
     *!     them individually. 
     *! 
     *! @seealso 
     *!     @[rm_watch()], @[parse_event()] 
     */ 
    PIKEFUN int add_watch(string file, int mask) { 
        INT32 err; 
 
        if (file->size_shift) 
            Pike_error("Widestring filenames are not allowed.\n"); 
 
        err = inotify_add_watch(THIS->fd, file->str, (INT32)mask); 
 
        if (err == -1) 
            Pike_error("inotify_add_watch failed: %s\n", 
                       strerror(errno)); 
        else 
            RETURN err; 
    } 
 
 
    /*! @decl object get_fd() 
     *! @returns 
     *!     Returns the file descriptor associated with this inotify instance. 
     *! @note 
     *!     Use @[fd()] instead. 
     */ 
    PIKEFUN int get_fd() { 
        push_int(THIS->fd); 
    } 
 
    /*! @decl object fd() 
     *! @returns 
     *!     Returns a instance of @[Stdio.Fd] corresponding to the inotify instance. This can passed to 
     *!     @[Stdio.File()->assign()]. 
     */ 
    PIKEFUN object fd() { 
        ref_push_object(THIS->fd_object); 
    } 
 
    /*! @decl int rm_watch(int wd) 
     *! Remove a watch. 
     *! @param wd 
     *!     The watch descriptor that was returned by @[add_watch()]. 
     */ 
    PIKEFUN void rm_watch(int wd) { 
        INT32 err; 
 
        err = inotify_rm_watch(THIS->fd, wd); 
 
        if (err == 0) { 
            return; 
        } 
 
        if (errno == EINVAL) { 
            Pike_error("Wrong argument to rm_watch().\n"); 
        } else if (errno == EBADF) { 
            Pike_error("Oups. I feel funny inside.\n"); 
        } 
    } 
 
    INIT { 
        struct object * o; 
        THIS->fd = inotify_init(); 
        THIS->fd_object = NULL; 
 
        if (THIS->fd == -1) switch (errno) { 
        case EMFILE: 
            Pike_error("User limit on inotify instances reached.\n"); 
        case ENFILE: 
            Pike_error("User limit on file descriptors reached.\n"); 
        case ENOMEM: 
            Pike_error("No free kernel memory available.\n"); 
        } 
 
        o = file_make_object_from_fd(THIS->fd, FILE_READ, fd_CAN_NONBLOCK); 
        /* We will close the inotify fd on EXIT */ 
        ((struct my_file *)(o->storage + o->prog->inherits->storage_offset))->flags |= FILE_NO_CLOSE_ON_DESTRUCT; 
        THIS->fd_object = o; 
    } 
 
    EXIT { 
        if (THIS->fd_object) { 
            free_object(THIS->fd_object); 
            THIS->fd_object = NULL; 
        } 
        if (THIS->fd != -1) { 
            int fd = THIS->fd; 
            /* 
             * currently (linux 3.4.9) closing an inotify fd takes in the order of 100 ms 
             */ 
            THREADS_ALLOW(); 
            close(fd); 
            THREADS_DISALLOW(); 
        } 
    } 
} 
 
/*! @endclass 
 */ 
 
#define ADD_ICONST(name) do {                   \ 
    add_integer_constant(#name, name, 0);       \ 
} while(0); 
 
#else /* !HAVE_SYS_INOTIFY_H */ 
 
#define ADD_ICONST(name) 
 
#endif /* HAVE_SYS_INOTIFY_H */ 
 
PIKE_MODULE_INIT { 
    ADD_ICONST(IN_ACCESS); 
    ADD_ICONST(IN_ALL_EVENTS); 
    ADD_ICONST(IN_ATTRIB); 
    ADD_ICONST(IN_CLOSE_WRITE); 
    ADD_ICONST(IN_CLOSE_NOWRITE); 
    ADD_ICONST(IN_CREATE); 
    ADD_ICONST(IN_DELETE); 
    ADD_ICONST(IN_DELETE_SELF); 
    ADD_ICONST(IN_MODIFY); 
    ADD_ICONST(IN_MOVE_SELF); 
    ADD_ICONST(IN_MOVED_FROM); 
    ADD_ICONST(IN_MOVED_TO); 
    ADD_ICONST(IN_OPEN); 
 
    ADD_ICONST(IN_MOVE); 
    ADD_ICONST(IN_CLOSE); 
 
/* some of these came with 2.6.15 linux and 2.5 glibc */ 
#ifdef IN_DONT_FOLLOW 
    ADD_ICONST(IN_DONT_FOLLOW); 
#endif 
#ifdef IN_MASK_ADD 
    ADD_ICONST(IN_MASK_ADD); 
#endif 
    ADD_ICONST(IN_ONESHOT); 
#ifdef IN_ONLYDIR 
    ADD_ICONST(IN_ONLYDIR); 
#endif 
 
    ADD_ICONST(IN_IGNORED); 
    ADD_ICONST(IN_ISDIR); 
    ADD_ICONST(IN_Q_OVERFLOW); 
    ADD_ICONST(IN_UNMOUNT); 
 
    INIT 
} 
 
PIKE_MODULE_EXIT { 
    EXIT 
} 
 
/*! @endmodule 
 */ 
/*! @endmodule 
 */