kqueue/kqdir.c

   1 /* compile with:
   2    gcc kqdir.c -o kqdir -Wall -W -Wextra -ansi -pedantic */
   3
   4 #include <dirent.h>
   5 #include <fcntl.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>    /* for strerror () */
   9 #include <unistd.h>
  10 #include <sys/event.h>
  11
  12 #define MAX_ENTRIES 256
  13
  14 /* function prototypes */
  15 void diep(const char *s);
  16
  17 int main(int argc, char *argv[])
  18 {
  19     struct kevent evlist[MAX_ENTRIES];    /* events we want to monitor */
  20     struct kevent chlist[MAX_ENTRIES];    /* events that were triggered */
  21     struct dirent *pdent;
  22     DIR *pdir;
  23     char fullpath[256];
  24     int fdlist[MAX_ENTRIES], cnt, i, kq, nev;
  25
  26     /* check argument count */
  27     if (argc != 2) {
  28         fprintf(stderr, "Usage: %s directory\n", argv[0]);
  29         exit(EXIT_FAILURE);
  30     }
  31
  32     /* create a new kernel event queue */
  33     if ((kq = kqueue()) == -1)
  34         diep("kqueue");
  35
  36     /* open directory named by argv[1], associate a directory stream
  37        with it and return a pointer to it
  38      */
  39     if ((pdir = opendir(argv[1])) == NULL)
  40         diep("opendir");
  41
  42     /* skip . and .. entries */
  43     cnt = 0;
  44     while((pdent = readdir(pdir)) != NULL && cnt++ < 2)
  45         ;
  46
  47     /* get all directory entries and for each one of them,
  48        initialise a kevent structure
  49     */
  50     cnt = 0;
  51     while((pdent = readdir(pdir)) != NULL) {
  52         /* check whether we have exceeded the max number of
  53            entries that we can monitor
  54          */
  55         if (cnt > MAX_ENTRIES - 1) {
  56             fprintf(stderr, "Max number of entries exceeded\n");
  57             goto CLEANUP_AND_EXIT;
  58         }
  59
  60         /* check path length
  61            don't forget +1 for the '\0'
  62          */
  63         if (strlen(argv[1] + strlen(pdent->d_name) + 2) > 256) {
  64             fprintf(stderr,"Max path length exceeded\n");
  65             goto CLEANUP_AND_EXIT;
  66         }
  67         strcpy(fullpath, argv[1]);
  68         strcat(fullpath, "/");
  69         strcat(fullpath, pdent->d_name);
  70
  71         /* open directory entry */
  72         if ((fdlist[cnt] = open(fullpath, O_RDONLY)) == -1) {
  73             perror("open");
  74             goto CLEANUP_AND_EXIT;
  75         }
  76
  77         /* initialise kevent structure */
  78         EV_SET(&chlist[cnt], fdlist[cnt], EVFILT_VNODE,
  79                EV_ADD | EV_ENABLE | EV_ONESHOT,
  80                NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_ATTRIB,
  81                0, 0);
  82
  83         cnt++;
  84     }
  85
  86     /* loop forever */
  87     for (;;) {
  88         nev = kevent(kq, chlist, cnt, evlist, cnt, NULL);
  89         if (nev == -1)
  90             perror("kevent");
  91
  92         else if (nev > 0) {
  93             for (i = 0; i < nev; i++) {
  94                 if (evlist[i].flags & EV_ERROR) {
  95                     fprintf(stderr, "EV_ERROR: %s\n", strerror(evlist[i].data));
  96                     goto CLEANUP_AND_EXIT;
  97                 }
  98
  99                 if (evlist[i].fflags & NOTE_DELETE)
 100                     printf("fd: %d Deleted\n", evlist[i].ident);
 101
 102                 else if (evlist[i].fflags & NOTE_EXTEND
 103                          || evlist[i].fflags & NOTE_WRITE)
 104                     printf("fd: %d Modified\n", evlist[i].ident);
 105
 106                 else if (evlist[i].fflags & NOTE_ATTRIB)
 107                     printf("fd: %d Attributes modified\n", evlist[i].ident);
 108             }
 109         }
 110     }
 111
 112     /* close open file descriptors, directory stream and kqueue */
 113 CLEANUP_AND_EXIT:;
 114     for (i = 0; i < cnt; i++)
 115         close(fdlist[i]);
 116     closedir(pdir);
 117     close(kq);
 118
 119     return EXIT_SUCCESS;
 120 }
 121
 122 void diep(const char *s)
 123 {
 124     perror(s);
 125     exit(EXIT_FAILURE);
 126 }
 127