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authorElliott Hughes <enh@google.com>2019-05-23 16:28:19 -0700
committerRob Landley <rob@landley.net>2019-05-25 18:59:30 -0500
commitc82d3108947c93c9e27553a44f319171776e92a3 (patch)
treec85d419eba73989ced08e21d934dce7ba18792d0 /lib
parentcf624717b45049b3d394aeeda85a3ee9b89388af (diff)
downloadtoybox-c82d3108947c93c9e27553a44f319171776e92a3.tar.gz
tail: support -f on BSD too.
Factor out the inotify code and add a kqueue equivalent. Specifically tested on macOS 10.14, but I assume this works for other BSDs too, given that I worked from the FreeBSD man page...
Diffstat (limited to 'lib')
-rw-r--r--lib/notify.c87
-rw-r--r--lib/portability.h5
2 files changed, 92 insertions, 0 deletions
diff --git a/lib/notify.c b/lib/notify.c
new file mode 100644
index 00000000..a7993e2a
--- /dev/null
+++ b/lib/notify.c
@@ -0,0 +1,87 @@
+#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.h b/lib/portability.h
index ccb1b1c5..f4a2b327 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -307,3 +307,8 @@ int xgetrandom(void *buf, unsigned len, unsigned flags);
#include <string.h>
static inline void confstr(int a, char *b, int c) {strcpy(b, a ? "POSIXLY_CORRECT=1" : "/bin:/usr/bin");}
#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);