diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/tail.c | 63 |
1 files changed, 44 insertions, 19 deletions
diff --git a/src/tail.c b/src/tail.c index 75e9d53e3..68cc819d6 100644 --- a/src/tail.c +++ b/src/tail.c @@ -1300,9 +1300,10 @@ check_fspec (struct File_spec *fspec, int wd, int *prev_wd) error (EXIT_FAILURE, errno, _("write error")); } -/* Tail N_FILES files forever, or until killed. - Check modifications using the inotify events system. */ -static void +/* Attempt to tail N_FILES files forever, or until killed. + Check modifications using the inotify events system. + Return false on error, or true to revert to polling. */ +static bool tail_forever_inotify (int wd, struct File_spec *f, size_t n_files, double sleep_interval) { @@ -1311,7 +1312,9 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files, /* Map an inotify watch descriptor to the name of the file it's watching. */ Hash_table *wd_to_name; - bool found_watchable = false; + bool found_watchable_file = false; + bool found_unwatchable_dir = false; + bool no_inotify_resources = false; bool writer_is_dead = false; int prev_wd; size_t evlen = 0; @@ -1355,9 +1358,15 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files, if (f[i].parent_wd < 0) { - error (0, errno, _("cannot watch parent directory of %s"), - quote (f[i].name)); - continue; + if (errno != ENOSPC) /* suppress confusing error. */ + error (0, errno, _("cannot watch parent directory of %s"), + quote (f[i].name)); + else + error (0, 0, _("inotify resources exhausted")); + found_unwatchable_dir = true; + /* We revert to polling below. Note invalid uses + of the inotify API will still be diagnosed. */ + break; } } @@ -1365,7 +1374,12 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files, if (f[i].wd < 0) { - if (errno != f[i].errnum) + if (errno == ENOSPC) + { + no_inotify_resources = true; + error (0, 0, _("inotify resources exhausted")); + } + else if (errno != f[i].errnum) error (0, errno, _("cannot watch %s"), quote (f[i].name)); continue; } @@ -1373,12 +1387,22 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files, if (hash_insert (wd_to_name, &(f[i])) == NULL) xalloc_die (); - found_watchable = true; + found_watchable_file = true; } } - if (follow_mode == Follow_descriptor && !found_watchable) - return; + /* Linux kernel 2.6.24 at least has a bug where eventually, ENOSPC is always + returned by inotify_add_watch. In any case we should revert to polling + when there are no inotify resources. Also a specified directory may not + be currently present or accessible, so revert to polling. */ + if (no_inotify_resources || found_unwatchable_dir) + { + /* FIXME: release hash and inotify resources allocated above. */ + errno = 0; + return true; + } + if (follow_mode == Follow_descriptor && !found_watchable_file) + return false; prev_wd = f[n_files - 1].wd; @@ -2140,16 +2164,18 @@ main (int argc, char **argv) When follow_mode == Follow_name we would ideally like to detect that. Note if there is a change to the original file then we'll recheck it and follow the new file, or ignore it if the - file has changed to being remote. */ + file has changed to being remote. + + FIXME: when using inotify, and a directory for a watched file + is recreated, then we don't recheck any new file when + follow_mode == Follow_name */ if (tailable_stdin (F, n_files) || any_remote_file (F, n_files)) disable_inotify = true; if (!disable_inotify) { int wd = inotify_init (); - if (wd < 0) - error (0, errno, _("inotify cannot be used, reverting to polling")); - else + if (0 <= wd) { /* Flush any output from tail_file, now, since tail_forever_inotify flushes only after writing, @@ -2157,11 +2183,10 @@ main (int argc, char **argv) if (fflush (stdout) != 0) error (EXIT_FAILURE, errno, _("write error")); - tail_forever_inotify (wd, F, n_files, sleep_interval); - - /* The only way the above returns is upon failure. */ - exit (EXIT_FAILURE); + if (!tail_forever_inotify (wd, F, n_files, sleep_interval)) + exit (EXIT_FAILURE); } + error (0, errno, _("inotify cannot be used, reverting to polling")); } #endif tail_forever (F, n_files, sleep_interval); |