etags: fix #line parsing (\\", long lines)

* lib-src/etags.c (readline): Don’t mishandle lines like
‘#line 1 "a//"’, which has an escaped backslash before ‘"’.
Don’t mishandle lines so long that sscanf overflows %n.
This commit is contained in:
Paul Eggert 2024-04-30 01:20:12 -07:00
parent de59c02c68
commit 7e2309c6fc

View file

@ -7375,26 +7375,26 @@ readline (linebuffer *lbp, FILE *stream)
/* Check whether this is a #line directive. */
if (result > 12 && strneq (lbp->buffer, "#line ", 6))
{
intmax_t lno;
int start = 0;
char *lno_start = lbp->buffer + 6;
char *lno_end;
intmax_t lno = strtoimax (lno_start, &lno_end, 10);
char *quoted_filename
= lno_start < lno_end ? skip_spaces (lno_end) : NULL;
if (sscanf (lbp->buffer, "#line %"SCNdMAX" \"%n", &lno, &start) >= 1
&& start > 0) /* double quote character found */
if (quoted_filename && *quoted_filename == '"')
{
char *endp = lbp->buffer + start;
char *endp = quoted_filename;
while (*++endp && *endp != '"')
endp += *endp == '\\' && endp[1];
while ((endp = strchr (endp, '"')) != NULL
&& endp[-1] == '\\')
endp++;
if (endp != NULL)
if (*endp)
/* Ok, this is a real #line directive. Let's deal with it. */
{
char *taggedabsname; /* absolute name of original file */
char *taggedfname; /* name of original file as given */
char *name; /* temp var */
char *name = quoted_filename + 1;
discard_until_line_directive = false; /* found it */
name = lbp->buffer + start;
*endp = '\0';
canonicalize_filename (name);
taggedabsname = absolute_filename (name, tagfiledir);