mirrors/emacs
1
Fork 0
mirror of git://git.sv.gnu.org/emacs.git synced 2025-12-27 15:52:00 -08:00
Code Issues Projects Releases Wiki Activity

* src/lread.c (infile): Set/reset it like a dynamically scoped variable

Browse source 
I've seen segfaults where `infile` is nil when we get to
readbyte_from_file, presumably because Fload set it to NULL (via
close_infile_unwind) just before returning to its caller which was
probably itself within another read/load and for some reason
readevalloop didn't get to re-set `infile` like it used to do at every
iteration.  I was not able to really track down the bug, but the way
`infile` was set/reset seemed fragile and managing it like a standard
dynamically-scoped var seems both safer (and more efficient since we
don't need readevalloop to constantly re-set it).

(readchar): Assert that `infile` is set if using a function the depends on it.
(readbyte_from_file): Assert that `infile` is set.
(close_infile_unwind): Reset `infile` to its previous value rather than
to NULL.
(Fload): Remember the previous value of `infile` before chaning it.
(readevalloop): Don't set `infile` any more.
This commit is contained in:
Stefan Monnier 2019-07-31 11:19:39 -04:00
parent 495d0667fc
commit bedcc2d87b
1 changed files with 11 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

17
src/lread.c
View file

@ -287,6 +287,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
if (EQ (readcharfun, Qget_file_char))
{
eassert (infile);
readbyte = readbyte_from_file;
goto read_multibyte;
}
@ -320,6 +321,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
string, and the cdr part is a value of readcharfun given to
read_vector. */
readbyte = readbyte_from_string;
eassert (infile);
if (EQ (XCDR (readcharfun), Qget_emacs_mule_file_char))
emacs_mule_encoding = 1;
goto read_multibyte;
@ -328,6 +330,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
if (EQ (readcharfun, Qget_emacs_mule_file_char))
{
readbyte = readbyte_from_file;
eassert (infile);
emacs_mule_encoding = 1;
goto read_multibyte;
}
@ -506,6 +509,7 @@ readbyte_from_stdio (void)
static int
readbyte_from_file (int c, Lisp_Object readcharfun)
{
eassert (infile);
if (c >= 0)
{
eassert (infile->lookahead < sizeof infile->buf);
@ -1078,10 +1082,11 @@ suffix_p (Lisp_Object string, const char *suffix)
static void
close_infile_unwind (void *arg)
{
FILE *stream = arg;
eassert (infile == NULL || infile->stream == stream);
infile = NULL;
fclose (stream);
struct infile *prev_infile = arg;
fprintf (stderr, "Closing infile: back to %x!\n", prev_infile);
eassert (infile);
fclose (infile->stream);
infile = prev_infile;
}
DEFUN ("load", Fload, Sload, 1, 5, 0,
@ -1413,7 +1418,7 @@ Return t if the file exists and loads successfully. */)
{
if (! stream)
report_file_error ("Opening stdio stream", file);
set_unwind_protect_ptr (fd_index, close_infile_unwind, stream);
set_unwind_protect_ptr (fd_index, close_infile_unwind, infile);
}
if (! NILP (Vpurify_flag))
@ -2019,7 +2024,7 @@ readevalloop (Lisp_Object readcharfun,
if (b && first_sexp)
whole_buffer = (BUF_PT (b) == BUF_BEG (b) && BUF_ZV (b) == BUF_Z (b));
infile = infile0;
eassert (!infile0 || infile == infile0);
read_next:
c = READCHAR;
if (c == ';')