On Thu, May 28, 2015 at 11:52:22PM +0100, Nicholas Marriott wrote:
> Hi
> 
> Can you make a patch against -current? Your source tree seems pretty out
> of date.

arg, my bads.

> Yes please check the return values from fcntl and fstat.

I added check for fstat, but not for fcntl.

The problem with fcntl is when '-' is "/dev/zero" (for example), fcntl
return error "Operation not supported by device".

$ file - < /dev/zero
-: cannot stat '-' (Operation not supported by device)

There are two problems:
  - inconsistency with "file /dev/zero" as it works well
  - invalid error message (cannot stat), whereas it is "cannot fcntl"

What do you think ? Should I trait fcntl(O_NONBLOCK) as error ?



I have also integrated the comment from sthen@ in order to have file
working like before:
  - mention "/dev/stdin" instead of "-" in report
  - don't need to pass -s when "-" is used


I have changed the file.1 patch too.


> > file(1) in 5.5:
> > ---------------
> > 
> > $ echo foobar | file - 
> > /dev/stdin: ASCII text
> > 
> > $ echo foobar | file -s /dev/stdin
> > /dev/stdin: ASCII text
> > 
> > 
> > 
> > file(1) in -current:
> > --------------------
> > 
> > $ echo foobar | file -        
> > -: cannot stat '-' (No such file or directory)
> > 
> > $ echo foobar | file -s /dev/stdin
> > /dev/stdin: data
> > 
> > 
> > 
> > after patching:
> > ---------------
> > 

$ echo foobar | file -
/dev/stdin: ASCII text

$ file - < file.c
/dev/stdin: ASCII C program text

$ file ./-                              # process the file named '-'
./-: cannot stat './-' (No such file or directory)

Thanks.
-- 
Sébastien Marie


Index: file.1
===================================================================
RCS file: /cvs/src/usr.bin/file/file.1,v
retrieving revision 1.41
diff -u -p -r1.41 file.1
--- file.1      27 Apr 2015 11:12:49 -0000      1.41
+++ file.1      29 May 2015 10:30:53 -0000
@@ -74,6 +74,14 @@ or
 .Em data
 meaning anything else.
 .Pp
+If 
+.Ar file
+is a single dash
+.Pq Sq -
+,
+.Nm
+reads from the standard input.
+.Pp
 The options are as follows:
 .Bl -tag -width indent
 .It Fl b
Index: file.c
===================================================================
RCS file: /cvs/src/usr.bin/file/file.c,v
retrieving revision 1.39
diff -u -p -r1.39 file.c
--- file.c      28 May 2015 19:26:37 -0000      1.39
+++ file.c      29 May 2015 10:30:53 -0000
@@ -208,9 +208,20 @@ main(int argc, char **argv)
                memset(&msg, 0, sizeof msg);
                msg.idx = idx;
 
-               if (lstat(argv[idx], &msg.sb) == -1) {
+               if (strcmp(argv[idx], "-") == 0) {
+                       if (fstat(STDIN_FILENO, &msg.sb) == -1) {
+                               fd = -1;
+                               msg.error = errno;
+
+                       } else {
+                               fd = STDIN_FILENO;
+                               (void)fcntl(fd, O_NONBLOCK);
+                       }
+                       
+               } else if (lstat(argv[idx], &msg.sb) == -1) {
                        fd = -1;
                        msg.error = errno;
+
                } else {
                        fd = open(argv[idx], O_RDONLY|O_NONBLOCK);
                        if (fd == -1 && (errno == ENFILE || errno == EMFILE))
@@ -435,6 +447,10 @@ try_stat(struct input_file *inf)
                    strerror(inf->msg->error));
                return (1);
        }
+
+       if (strcmp(inf->path, "-") == 0)
+               return (0);
+
        if (sflag) {
                switch (inf->msg->sb.st_mode & S_IFMT) {
                case S_IFBLK:
@@ -611,7 +627,10 @@ test_file(struct input_file *inf, size_t
        if (bflag)
                printf("%s\n", inf->result);
        else {
-               xasprintf(&label, "%s:", inf->path);
+               if (strcmp(inf->path, "-") == 0)
+                       xasprintf(&label, "/dev/stdin:");
+               else
+                       xasprintf(&label, "%s:", inf->path);
                printf("%-*s %s\n", (int)width, label, inf->result);
                free(label);
        }

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