compat/fsmonitor/fsm-settings-darwin.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "repository.h"
   4 #include "fsmonitor-settings.h"
   5 #include "fsmonitor.h"
   6 #include <sys/param.h>
   7 #include <sys/mount.h>
   8
   9 /*
  10  * Remote working directories are problematic for FSMonitor.
  11  *
  12  * The underlying file system on the server machine and/or the remote
  13  * mount type (NFS, SAMBA, etc.) dictates whether notification events
  14  * are available at all to remote client machines.
  15  *
  16  * Kernel differences between the server and client machines also
  17  * dictate the how (buffering, frequency, de-dup) the events are
  18  * delivered to client machine processes.
  19  *
  20  * A client machine (such as a laptop) may choose to suspend/resume
  21  * and it is unclear (without lots of testing) whether the watcher can
  22  * resync after a resume.  We might be able to treat this as a normal
  23  * "events were dropped by the kernel" event and do our normal "flush
  24  * and resync" --or-- we might need to close the existing (zombie?)
  25  * notification fd and create a new one.
  26  *
  27  * In theory, the above issues need to be addressed whether we are
  28  * using the Hook or IPC API.
  29  *
  30  * For the builtin FSMonitor, we create the Unix domain socket for the
  31  * IPC in the .git directory.  If the working directory is remote,
  32  * then the socket will be created on the remote file system.  This
  33  * can fail if the remote file system does not support UDS file types
  34  * (e.g. smbfs to a Windows server) or if the remote kernel does not
  35  * allow a non-local process to bind() the socket.  (These problems
  36  * could be fixed by moving the UDS out of the .git directory and to a
  37  * well-known local directory on the client machine, but care should
  38  * be taken to ensure that $HOME is actually local and not a managed
  39  * file share.)
  40  *
  41  * So (for now at least), mark remote working directories as
  42  * incompatible.
  43  */
  44 static enum fsmonitor_reason check_remote(struct repository *r)
  45 {
  46         struct statfs fs;
  47
  48         if (statfs(r->worktree, &fs) == -1) {
  49                 int saved_errno = errno;
  50                 trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
  51                                  r->worktree, strerror(saved_errno));
  52                 errno = saved_errno;
  53                 return FSMONITOR_REASON_ERROR;
  54         }
  55
  56         trace_printf_key(&trace_fsmonitor,
  57                          "statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
  58                          r->worktree, fs.f_type, fs.f_flags, fs.f_fstypename);
  59
  60         if (!(fs.f_flags & MNT_LOCAL))
  61                 return FSMONITOR_REASON_REMOTE;
  62
  63         return FSMONITOR_REASON_OK;
  64 }
  65
  66 enum fsmonitor_reason fsm_os__incompatible(struct repository *r)
  67 {
  68         enum fsmonitor_reason reason;
  69
  70         reason = check_remote(r);
  71         if (reason != FSMONITOR_REASON_OK)
  72                 return reason;
  73
  74         return FSMONITOR_REASON_OK;
  75 }