On 02/14/2017 05:08 PM, Paul Eggert wrote:
> On 02/13/2017 12:20 PM, Eric Blake wrote:
>> undossify_input causes more problems than it
>> solves. We should trust fopen("r") to do the right thing, rather than
>> reinventing it ourselves.
>
> Yes, that makes sense. Attached is a proposed patch to implement this.
> It assumes the patch you already submitted for Bug#25707.
>
> This patch keeps the -U option, for MS-Windows users who want to
> override fopen "-r"'s choice of binary vs text I/O. Perhaps that's too
> conservative? It would be easy to turn -U into a no-op too.
For reference, here's the patch I applied to Cygwin when building
grep-3.0; it didn't go as far as your patch in killing -u (so I like
your patch better), but had the same net effect of keeping -U as a way
to force binary behavior, while using fcntl() to learn (after-the-fact)
whether our force-to-binary was a no-op, and only doing undossify stuff
if we turned a text-mode into binary-mode:
--- origsrc/grep-3.0/src/dosbuf.c 2017-01-01 05:34:33.000000000 -0600
+++ src/grep-3.0/src/dosbuf.c 2017-02-14 09:50:08.701835000 -0600
@@ -48,6 +48,7 @@ static struct dos_map *dos_pos_map;
static int dos_pos_map_size = 0;
static int dos_pos_map_used = 0;
static int inp_map_idx = 0, out_map_idx = 1;
+static int mode_forced;
/* Set default DOS file type to binary. */
static void
@@ -95,7 +96,7 @@ guess_type (char *buf, size_t buflen)
static size_t
undossify_input (char *buf, size_t buflen)
{
- if (! O_BINARY)
+ if (! O_BINARY || ! mode_forced)
return buflen;
size_t bytes_left = 0;
@@ -186,7 +187,7 @@ undossify_input (char *buf, size_t bufle
static off_t
dossified_pos (off_t byteno)
{
- if (! O_BINARY)
+ if (! O_BINARY || ! mode_forced)
return byteno;
off_t pos_lo;
--- origsrc/grep-3.0/src/grep.c 2017-02-08 19:37:33.000000000 -0600
+++ src/grep-3.0/src/grep.c 2017-02-14 09:58:11.134855800 -0600
@@ -1860,10 +1860,17 @@ grepdesc (int desc, bool command_line)
goto closeout;
}
- /* Set input to binary mode. Pipes are simulated with files
- on DOS, so this includes the case of "foo | grep bar". */
+ /* Force input to binary mode, while remembering if it was originally
+ text. Options -u and -U only matter on text mounts. */
+ mode_forced = 0;
if (O_BINARY && !isatty (desc))
- set_binary_mode (desc, O_BINARY);
+ {
+ if (fcntl (desc, F_GETFL) & O_TEXT)
+ {
+ set_binary_mode (desc, O_BINARY);
+ mode_forced = 1;
+ }
+ }
count = grep (desc, &st, &ineof);
if (count_matches)
@@ -2586,7 +2593,7 @@ main (int argc, char **argv)
break;
case 'f':
- fp = STREQ (optarg, "-") ? stdin : fopen (optarg, O_TEXT ? "rt"
: "r");
+ fp = STREQ (optarg, "-") ? stdin : fopen (optarg, "r");
if (!fp)
die (EXIT_TROUBLE, errno, "%s", optarg);
oldcc = keycc;
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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