X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=filemon.c;h=a293fe85e7d3e0bfd1a4ab9b04ec0a299f142c1d;hb=229c6d070b1ddb2cebb0a3f12bc71713795cd627;hp=0c8a1d0ca409b8bad0abfb340c35ab0ee50ebfee;hpb=70dd320284cd9f3f3f09871809c35f6396bfeb15;p=innduct.git

diff --git a/filemon.c b/filemon.c
index 0c8a1d0..a293fe8 100644
--- a/filemon.c
+++ b/filemon.c
@@ -33,58 +33,61 @@
 
 #include <sys/inotify.h>
 
-static int filemon_inotify_fd;
-static int filemon_inotify_wdmax;
-static InputFile **filemon_inotify_wd2ipf;
+DEFLIST(Filemon_Perfile);
 
 struct Filemon_Perfile {
+  ISNODE(Filemon_Perfile);
+  InputFile *ipf;
   int wd;
 };
 
-static void filemon_method_startfile(InputFile *ipf, Filemon_Perfile *pf) {
-  int wd= inotify_add_watch(filemon_inotify_fd, ipf->path, IN_MODIFY);
-  if (wd < 0) sysdie("inotify_add_watch %s", ipf->path);
-
-  if (wd >= filemon_inotify_wdmax) {
-    int newmax= wd+2;
-    filemon_inotify_wd2ipf= xrealloc(filemon_inotify_wd2ipf,
-				 sizeof(*filemon_inotify_wd2ipf) * newmax);
-    memset(filemon_inotify_wd2ipf + filemon_inotify_wdmax, 0,
-	   sizeof(*filemon_inotify_wd2ipf) * (newmax - filemon_inotify_wdmax));
-    filemon_inotify_wdmax= newmax;
-  }
+static int filemon_inotify_fd;
+static Filemon_PerfileList filemon_inotify_watches;
 
-  assert(!filemon_inotify_wd2ipf[wd]);
-  filemon_inotify_wd2ipf[wd]= ipf;
+static void filemon_method_startfile(InputFile *ipf, Filemon_Perfile *pf) {
+  pf->ipf= ipf;
 
-  dbg("filemon inotify startfile %p wd=%d wdmax=%d",
-      ipf, wd, filemon_inotify_wdmax);
+  pf->wd= inotify_add_watch(filemon_inotify_fd, ipf->path, IN_MODIFY);
+  if (pf->wd < 0) sysdie("filemon inotify: inotify_add_watch %s", ipf->path);
 
-  pf->wd= wd;
+  LIST_ADDHEAD(filemon_inotify_watches, pf);
+  dbg("filemon inotify: startfile %p wd=%d pf=%p", ipf, pf->wd, pf);
 }
 
 static void filemon_method_stopfile(InputFile *ipf, Filemon_Perfile *pf) {
-  int wd= pf->wd;
-  dbg("filemon inotify stopfile %p wd=%d", ipf, wd);
-  int r= inotify_rm_watch(filemon_inotify_fd, wd);
-  if (r) syscrash("inotify_rm_watch");
-  filemon_inotify_wd2ipf[wd]= 0;
+  dbg("filemon inotify: stopfile %p wd=%d pf=%p", ipf, pf->wd, pf);
+  int r= inotify_rm_watch(filemon_inotify_fd, pf->wd);
+  if (r) syscrash("filemon inotify: inotify_rm_watch");
+  LIST_REMOVE(filemon_inotify_watches, pf);
 }
 
 static void *filemon_inotify_readable(oop_source *lp, int fd,
 				      oop_event e, void *u) {
   struct inotify_event iev;
+  InputFile *ipf;
   for (;;) {
     int r= read(filemon_inotify_fd, &iev, sizeof(iev));
     if (r==-1) {
       if (isewouldblock(errno)) break;
-      syscrash("read from inotify master");
-    } else if (r==sizeof(iev)) {
-      assert(iev.wd >= 0 && iev.wd < filemon_inotify_wdmax);
-    } else {
-      crash("inotify read %d bytes wanted struct of %d", r, (int)sizeof(iev));
+      syscrash("filemon inotify: read from inotify master");
+    } else if (r!=sizeof(iev)) {
+      crash("filemon inotify: read %d bytes when wanted struct of %d",
+	    r, (int)sizeof(iev));
     }
-    InputFile *ipf= filemon_inotify_wd2ipf[iev.wd];
+    Filemon_Perfile *pf;
+    FOR_LIST_NODE(pf, filemon_inotify_watches)
+      if (pf->wd == iev.wd) goto found;
+    /* Linux seems to remember events and can produce them even after
+     * you've removed the watch.  This means that we can't spot bugs
+     * where we lose track of our watches and have to just regard
+     * unexpected random watch events as normal.  It's not a
+     * correctness problem as the watch is just a prod to read a file,
+     * which is harmless if it does not need to be read. */
+    dbg("filemon inotify: read event with unknown wd=%d", iev.wd);
+    continue;
+    
+  found:
+    ipf= pf->ipf;
     /*dbg("filemon inotify readable read %p wd=%d", ipf, iev.wd);*/
     tailing_make_readable(ipf);
   }
@@ -92,27 +95,27 @@ static void *filemon_inotify_readable(oop_source *lp, int fd,
 }
 
 int filemon_method_init(void) {
+  LIST_INIT(filemon_inotify_watches);
   filemon_inotify_fd= inotify_init();
   if (filemon_inotify_fd<0) {
-    syswarn("filemon/inotify: inotify_init failed");
+    syswarn("filemon inotify: inotify_init failed");
     return 0;
   }
   xsetnonblock(filemon_inotify_fd, 1);
   loop->on_fd(loop, filemon_inotify_fd, OOP_READ, filemon_inotify_readable, 0);
 
-  dbg("filemon inotify init filemon_inotify_fd=%d", filemon_inotify_fd);
+  dbg("filemon inotify: init filemon_inotify_fd=%d", filemon_inotify_fd);
   return 1;
 }
 
 void filemon_method_dump_info(FILE *f) {
-  int i;
   fprintf(f,"inotify");
   DUMPV("%d",,filemon_inotify_fd);
-  DUMPV("%d",,filemon_inotify_wdmax);
+  DUMPV("%d",filemon_inotify_watches.,count);
   fprintf(f,"\n");
-  for (i=0; i<filemon_inotify_wdmax; i++)
-    if (filemon_inotify_wd2ipf[i])
-      fprintf(f," wd2ipf[%d]=%p\n", i, filemon_inotify_wd2ipf[i]);
+  Filemon_Perfile *pf;
+  FOR_LIST_NODE(pf, filemon_inotify_watches)
+    fprintf(f," watching %p wd=%d pf=%p\n", pf->ipf, pf->wd, pf);
 }
 
 #endif /* HAVE_INOTIFY && !HAVE_FILEMON */
@@ -124,7 +127,7 @@ void filemon_method_dump_info(FILE *f) {
 struct Filemon_Perfile { int dummy; };
 
 int filemon_method_init(void) {
-  warn("filemon/dummy: no filemon method compiled in");
+  warn("filemon dummy: no filemon method compiled in");
   return 0;
 }
 static void filemon_method_startfile(InputFile *ipf, Filemon_Perfile *pf) { }
@@ -148,4 +151,3 @@ void filemon_stop(InputFile *ipf) {
   free(ipf->filemon);
   ipf->filemon= 0;
 }
-