diff options
Diffstat (limited to 'libgfortran/io/unix.c')
| -rw-r--r-- | libgfortran/io/unix.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/libgfortran/io/unix.c b/libgfortran/io/unix.c index d33c110..b3645f0 100644 --- a/libgfortran/io/unix.c +++ b/libgfortran/io/unix.c @@ -706,16 +706,28 @@ fd_truncate (unix_stream * s) /* Using ftruncate on a seekable special file (like /dev/null) is undefined, so we treat it as if the ftruncate succeeded. */ + if (!s->special_file + && ( #ifdef HAVE_FTRUNCATE - if (s->special_file || ftruncate (s->fd, s->logical_offset)) + ftruncate (s->fd, s->logical_offset) != 0 +#elif defined HAVE_CHSIZE + chsize (s->fd, s->logical_offset) != 0 #else -#ifdef HAVE_CHSIZE - if (s->special_file || chsize (s->fd, s->logical_offset)) -#endif + /* If we have neither, always fail and exit, noisily. */ + runtime_error ("required ftruncate or chsize support not present"), 1 #endif + )) { - s->physical_offset = s->file_length = 0; - return SUCCESS; + /* The truncation failed and we need to handle this gracefully. + The file length remains the same, but the file-descriptor + offset needs adjustment per the successful lseek above. + (Similarly, the contents of the buffer isn't valid anymore.) + A ftruncate call does not affect the physical (file-descriptor) + offset, according to the ftruncate manual, so neither should a + failed call. */ + s->physical_offset = s->logical_offset; + s->active = 0; + return FAILURE; } s->physical_offset = s->file_length = s->logical_offset; |