Move notify.c into portability.c (collate the #ifdefs), move global variables

into a structure passed as arguments, add x prefix to functions that can fail,
add overflow test.

4 files changed, 107 insertions, 93 deletions

diff --git a/lib/notify.c b/lib/notify.c
deleted file mode 100644
index a7993e2a..00000000
--- a/lib/notify.c
+++ /dev/null
@@ -1,87 +0,0 @@
-#include "toys.h"
-
-static char **paths;
-static int *fds;
-static int count;
-
-#ifdef __APPLE__
-
-#include <sys/event.h>
-
-static int kq = -1;
-
-void notify_init(int max)
-{
-  if ((kq = kqueue()) == -1) perror_exit("kqueue");
-  paths = xmalloc(max * sizeof(char *));
-  fds = xmalloc(max * sizeof(int));
-}
-
-int notify_add(int fd, char *path)
-{
-  struct kevent event;
-
-  EV_SET(&event, fd, EVFILT_VNODE, EV_ADD|EV_CLEAR, NOTE_WRITE, 0, NULL);
-  if (kevent(kq, &event, 1, NULL, 0, NULL) == -1 || event.flags & EV_ERROR)
-    return -1;
-  paths[count] = path;
-  fds[count++] = fd;
-  return 0;
-}
-
-int notify_wait(char **path)
-{
-  struct kevent event;
-  int i;
-
-  for (;;) {
-    if (kevent(kq, NULL, 0, &event, 1, NULL) != -1) {
-      // We get the fd for free, but still have to search for the path.
-      for (i=0; i<count; i++) if (fds[i]==event.ident) {
-        *path = paths[i];
-        return event.ident;
-      }
-    }
-  }
-}
-
-#else
-
-#include <sys/inotify.h>
-
-static int ffd = -1;
-static int *ids;
-
-void notify_init(int max)
-{
-  if ((ffd = inotify_init()) < 0) perror_exit("inotify_init");
-  fds = xmalloc(max * sizeof(int));
-  ids = xmalloc(max * sizeof(int));
-  paths = xmalloc(max * sizeof(char *));
-}
-
-int notify_add(int fd, char *path)
-{
-  ids[count] = inotify_add_watch(ffd, path, IN_MODIFY);
-  if (ids[count] == -1) return -1;
-  paths[count] = path;
-  fds[count++] = fd;
-  return 0;
-}
-
-int notify_wait(char **path)
-{
-  struct inotify_event ev;
-  int i;
-
-  for (;;) {
-    if (sizeof(ev)!=read(ffd, &ev, sizeof(ev))) perror_exit("inotify");
-
-    for (i=0; i<count; i++) if (ev.wd==ids[i]) {
-      *path = paths[i];
-      return fds[i];
-    }
-  }
-}
-
-#endif
diff --git a/lib/portability.c b/lib/portability.c
index c75e8ba5..726e42a9 100644
--- a/lib/portability.c
+++ b/lib/portability.c
@@ -153,3 +153,97 @@ struct mtab_list *xgetmountlist(char *path)
 }
 
 #endif
+
+#ifdef __APPLE__
+
+#include <sys/event.h>
+
+struct xnotify *xnotify_init(int max)
+{
+  struct xnotify *not = xzalloc(sizeof(struct xnotify));
+
+  not->max = max;
+  if ((not->kq = kqueue()) == -1) perror_exit("kqueue");
+  not->paths = xmalloc(max * sizeof(char *));
+  not->fds = xmalloc(max * sizeof(int));
+
+  return not;
+}
+
+int xnotify_add(struct xnotify *not, int fd, char *path)
+{
+  struct kevent event;
+
+  if (not->count == not->max) error_exit("xnotify_add overflow");
+  EV_SET(&event, fd, EVFILT_VNODE, EV_ADD|EV_CLEAR, NOTE_WRITE, 0, NULL);
+  if (kevent(not->kq, &event, 1, NULL, 0, NULL) == -1 || event.flags & EV_ERROR)
+    return -1;
+  not->paths[not->count] = path;
+  not->fds[not->count++] = fd;
+
+  return 0;
+}
+
+int xnotify_wait(struct xnotify *not, char **path)
+{
+  struct kevent event;
+  int i;
+
+  for (;;) {
+    if (kevent(not->kq, NULL, 0, &event, 1, NULL) != -1) {
+      // We get the fd for free, but still have to search for the path.
+      for (i = 0; i<not->count; i++) if (not->fds[i]==event.ident) {
+        *path = paths[i];
+
+        return event.ident;
+      }
+    }
+  }
+}
+
+#else
+
+#include <sys/inotify.h>
+
+struct xnotify *xnotify_init(int max)
+{
+  struct xnotify *not = xzalloc(sizeof(struct xnotify));
+
+  not->max = max;
+  if ((not->kq = inotify_init()) < 0) perror_exit("inotify_init");
+  not->paths = xmalloc(max * sizeof(char *));
+  not->fds = xmalloc(max * 2 * sizeof(int));
+
+  return not;
+}
+
+int xnotify_add(struct xnotify *not, int fd, char *path)
+{
+  int i = 2*not->count;
+
+  if (not->max == not->count) error_exit("xnotify_add overflow");
+  if ((not->fds[i] = inotify_add_watch(not->kq, path, IN_MODIFY))==-1)
+    return -1;
+  not->fds[i+1] = fd;
+  not->paths[not->count++] = path;
+
+  return 0;
+}
+
+int xnotify_wait(struct xnotify *not, char **path)
+{
+  struct inotify_event ev;
+  int i;
+
+  for (;;) {
+    if (sizeof(ev)!=read(not->kq, &ev, sizeof(ev))) perror_exit("inotify");
+
+    for (i = 0; i<not->count; i++) if (ev.wd==not->fds[2*i]) {
+      *path = not->paths[i];
+
+      return not->fds[2*i+1];
+    }
+  }
+}
+
+#endif
diff --git a/lib/portability.h b/lib/portability.h
index f4a2b327..f5f8352a 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -309,6 +309,12 @@ static inline void confstr(int a, char *b, int c) {strcpy(b, a ? "POSIXLY_CORREC
 #endif
 
 // Paper over the differences between BSD kqueue and Linux inotify for tail.
-void notify_init(int max);
-int notify_add(int fd, char *path);
-int notify_wait(char **path);
+
+struct xnotify {
+  char **paths;
+  int max, *fds, count, kq;
+};
+
+struct xnotify *xnotify_init(int max);
+int xnotify_add(struct xnotify *not, int fd, char *path);
+int xnotify_wait(struct xnotify *not, char **path);
diff --git a/toys/posix/tail.c b/toys/posix/tail.c
index 49a7f69b..d49a70c2 100644
--- a/toys/posix/tail.c
+++ b/toys/posix/tail.c
@@ -36,6 +36,7 @@ GLOBALS(
   long n, c;
 
   int file_no, last_fd;
+  struct xnotify *not;
 )
 
 struct line_list {
@@ -139,7 +140,7 @@ static void do_tail(int fd, char *name)
     char *s = name;
 
     if (!fd) sprintf(s = toybuf, "/proc/self/fd/%d", fd);
-    if (notify_add(fd, s) == -1) perror_exit("-f on '%s' failed", s);
+    if (xnotify_add(TT.not, fd, s)) perror_exit("-f on '%s' failed", s);
   }
 
   if (TT.file_no++) xputc('\n');
@@ -233,13 +234,13 @@ void tail_main(void)
     }
   }
 
-  if (FLAG(f)) notify_init(toys.optc);
+  if (FLAG(f)) TT.not = xnotify_init(toys.optc);
   loopfiles_rw(args, O_RDONLY|WARN_ONLY|(O_CLOEXEC*!FLAG(f)), 0, do_tail);
 
   if (FLAG(f) && TT.file_no) {
     for (;;) {
       char *path;
-      int fd = notify_wait(&path), len;
+      int fd = xnotify_wait(TT.not, &path), len;
 
       // Read new data.
       while ((len = read(fd, toybuf, sizeof(toybuf)))>0) {