fseeko(file_size, SEEK_SET) -> fseek(0L, SEEK_END)
1) File may grows between operations, so fseeko to file_size may miss
2) 0L, SEEK_END is the same code using in tail in all other places
1) really check for size overflow by checking negative value.
2) since mmap() not support files over INT_MAX size, add check for it
until either mmap() will be fixed or tail will be rewritted to handle
large files alternatively.
3) replace fseek(... file_size, SEEK_SET) with fseek(... 0L, SEEK_END)
to avoid off_t -> long cast
4) Use exit() if file is too big instead of warning and wrong logic
afterwards.
filesystem not being kq-aware), then fall back to using sleep. This
allows tail to work with NFS filesystems again without chewing up CPU time.
When given the -F flag, resort to sleep/stat after the file was moved
or deleted. This allows a window where the file being tailed does not
exist at all, which is typically the case during log rotation. Switch
back to using kq (if possible) after the file is reopened.
stat() the file being followed and do a close/reopen if the file has been
renamed and/or rotated. This is damn useful for leaving running on files
in /var/log when newsyslog(8) rotates them.
- Use MAP_FAILED instead of the constant -1 to indicate
failure (required by POSIX).
- Removed flag arguments of '0' (required by POSIX).
- Fixed code which expected an error return of 0.
- Fixed code which thought any address with the high bit set
was an error.
- Check for failure where no checks were present.
Discussed with: bde
- timeval in select loop was depending on not having the remaining time
returned from select(), causing a busy spin on an implementation that
does implement it.
- the err() usage was pretty bogus, some of the error messages had
strerror attached manually and then reattached by err().
