diff mbox

[2/5] xfs_db: fix the 'source' command when passed as a -c option

Message ID 148494392855.5256.2805905613919243845.stgit@birch.djwong.org
State Superseded, archived
Headers show

Commit Message

Darrick J. Wong Jan. 20, 2017, 8:25 p.m. UTC
The 'source' command is supposed to read commands out of a file and
execute them.  This works great when done from an interactive command
line, but it doesn't work at all when invoked from the command line
because we never actually do anything with the opened file.

So don't load stdin into the input stack when we're only executing
command line options, and use that to decide if source_f is executing
from the command line so that we can actually run the input loop.  We'll
use this for the per-field fuzzing xfstests.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 db/init.c  |    2 +-
 db/input.c |   29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)



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Comments

Eric Sandeen Jan. 23, 2017, 10:29 p.m. UTC | #1
On 1/20/17 2:25 PM, Darrick J. Wong wrote:
> The 'source' command is supposed to read commands out of a file and
> execute them.  This works great when done from an interactive command
> line, but it doesn't work at all when invoked from the command line
> because we never actually do anything with the opened file.
> 
> So don't load stdin into the input stack when we're only executing
> command line options, and use that to decide if source_f is executing
> from the command line so that we can actually run the input loop.  We'll
> use this for the per-field fuzzing xfstests.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  db/init.c  |    2 +-
>  db/input.c |   29 +++++++++++++++++++++++++++--
>  2 files changed, 28 insertions(+), 3 deletions(-)
> 
> 
> diff --git a/db/init.c b/db/init.c
> index e60ac66..46af024 100644
> --- a/db/init.c
> +++ b/db/init.c
> @@ -254,7 +254,6 @@ main(
>  	char	**v;
>  	int	start_iocur_sp;
>  
> -	pushfile(stdin);
>  	init(argc, argv);
>  	start_iocur_sp = iocur_sp;
>  
> @@ -269,6 +268,7 @@ main(
>  		goto close_devices;
>  	}

Ok, so anything above this is commandline invocations.

Everything below is interactive...

> +	pushfile(stdin);
>  	while (!done) {
>  		if ((input = fetchline()) == NULL)
>  			break;
> diff --git a/db/input.c b/db/input.c
> index 8f65190..7b12c97 100644
> --- a/db/input.c
> +++ b/db/input.c
> @@ -145,6 +145,12 @@ get_prompt(void)
>  	return prompt;
>  }
>  
> +static bool
> +interactive_input(void)
> +{
> +	return inputstacksize == 1 && inputstack[0] == stdin;
> +}

how about just:

	return curinput == stdin?

> +
>  static char *
>  fetchline_internal(void)
>  {
> @@ -156,7 +162,9 @@ fetchline_internal(void)
>  
>  	rval = NULL;
>  	for (rlen = iscont = 0; ; ) {
> -		if (inputstacksize == 1) {
> +		if (curinput == NULL)
> +			return NULL;
> +		if (interactive_input()) {
>  			if (iscont)
>  				dbprintf("... ");
>  			else
> @@ -183,7 +191,8 @@ fetchline_internal(void)
>  		    (len = strlen(buf)) == 0) {
>  			popfile();
>  			if (curinput == NULL) {
> -				dbprintf("\n");
> +				if (interactive_input())
> +					dbprintf("\n");

I give up.  I see from testing that it is, but why is \n special here?

>  				return NULL;
>  			}
>  			iscont = 0;
> @@ -314,12 +323,28 @@ source_f(
>  	char	**argv)
>  {
>  	FILE	*f;
> +	int	c, done = 0;
> +	char	*input;
> +	char	**v;
>  
>  	f = fopen(argv[1], "r");
>  	if (f == NULL)
>  		dbprintf(_("can't open %s\n"), argv[0]);
>  	else
>  		pushfile(f);
> +
> +	/* If this isn't an interactive shell, run the commands now. */
> +	if (inputstacksize == 0 || inputstack[0] == stdin)

This confuses me a bit, partly from the comment.  We could be in
an interactive shell, but we've just issued a source command ...

If inputstacksize == 0, that means fopen failed and we didn't
do a pushfile, right?  Maybe best to just return in the failure
case above, and skip that test here?

And how can we ever be here w/ inputstack[0] == stdin?

I'm wondering if this isn't cleaner and still correct:

        f = fopen(argv[1], "r");
        if (f == NULL) {
                dbprintf(_("can't open %s\n"), argv[0]);
                return 0;
        }

        /* Run the sourced commands now */
        pushfile(f);
        while (!done) {
                if ((input = fetchline_internal()) == NULL)

> +		return 0;
> +	while (!done) {
> +		if ((input = fetchline_internal()) == NULL)
> +			break;
> +		v = breakline(input, &c);
> +		if (c)
> +			done = command(c, v);
> +		doneline(input, v);
> +	}
> +
>  	return 0;
>  }
>  
> 
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Darrick J. Wong Jan. 23, 2017, 11:39 p.m. UTC | #2
On Mon, Jan 23, 2017 at 04:29:00PM -0600, Eric Sandeen wrote:
> On 1/20/17 2:25 PM, Darrick J. Wong wrote:
> > The 'source' command is supposed to read commands out of a file and
> > execute them.  This works great when done from an interactive command
> > line, but it doesn't work at all when invoked from the command line
> > because we never actually do anything with the opened file.
> > 
> > So don't load stdin into the input stack when we're only executing
> > command line options, and use that to decide if source_f is executing
> > from the command line so that we can actually run the input loop.  We'll
> > use this for the per-field fuzzing xfstests.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  db/init.c  |    2 +-
> >  db/input.c |   29 +++++++++++++++++++++++++++--
> >  2 files changed, 28 insertions(+), 3 deletions(-)
> > 
> > 
> > diff --git a/db/init.c b/db/init.c
> > index e60ac66..46af024 100644
> > --- a/db/init.c
> > +++ b/db/init.c
> > @@ -254,7 +254,6 @@ main(
> >  	char	**v;
> >  	int	start_iocur_sp;
> >  
> > -	pushfile(stdin);
> >  	init(argc, argv);
> >  	start_iocur_sp = iocur_sp;
> >  
> > @@ -269,6 +268,7 @@ main(
> >  		goto close_devices;
> >  	}
> 
> Ok, so anything above this is commandline invocations.
> 
> Everything below is interactive...
> 
> > +	pushfile(stdin);
> >  	while (!done) {
> >  		if ((input = fetchline()) == NULL)
> >  			break;
> > diff --git a/db/input.c b/db/input.c
> > index 8f65190..7b12c97 100644
> > --- a/db/input.c
> > +++ b/db/input.c
> > @@ -145,6 +145,12 @@ get_prompt(void)
> >  	return prompt;
> >  }
> >  
> > +static bool
> > +interactive_input(void)
> > +{
> > +	return inputstacksize == 1 && inputstack[0] == stdin;
> > +}
> 
> how about just:
> 
> 	return curinput == stdin?

Sure.

> > +
> >  static char *
> >  fetchline_internal(void)
> >  {
> > @@ -156,7 +162,9 @@ fetchline_internal(void)
> >  
> >  	rval = NULL;
> >  	for (rlen = iscont = 0; ; ) {
> > -		if (inputstacksize == 1) {
> > +		if (curinput == NULL)
> > +			return NULL;
> > +		if (interactive_input()) {
> >  			if (iscont)
> >  				dbprintf("... ");
> >  			else
> > @@ -183,7 +191,8 @@ fetchline_internal(void)
> >  		    (len = strlen(buf)) == 0) {
> >  			popfile();
> >  			if (curinput == NULL) {
> > -				dbprintf("\n");
> > +				if (interactive_input())
> > +					dbprintf("\n");
> 
> I give up.  I see from testing that it is, but why is \n special here?

When we have an interactive session, no libreadline, and the user hits
^D, this makes it so that we print a newline before the prompt returns
so that we don't end up with:

xfs_db> bash-2.05$

However, now that we've moved pushfile(stdin), it's possible that a
non-interactive session (which is what you get with "-c 'source moo'")
will pop all the fds off the stack, causing the newline to print.

A better fix for all this is to:

if (curinput == stdin)
	dbprintf("\n");
popfile();
iscont = 0...

Another odd quirk I noticed is that when an invocation of
fetchline_internal reaches feof/ferror on a file descriptor, it'll pop
the input stack and try to continue with the next lower level.  Since
each source_f starts its own interpreter loop we could just jump out
when we run out of input data and let the /caller/ continue with the fd
that it pushed onto the stack.

> 
> >  				return NULL;
> >  			}
> >  			iscont = 0;
> > @@ -314,12 +323,28 @@ source_f(
> >  	char	**argv)
> >  {
> >  	FILE	*f;
> > +	int	c, done = 0;
> > +	char	*input;
> > +	char	**v;
> >  
> >  	f = fopen(argv[1], "r");
> >  	if (f == NULL)
> >  		dbprintf(_("can't open %s\n"), argv[0]);
> >  	else
> >  		pushfile(f);
> > +
> > +	/* If this isn't an interactive shell, run the commands now. */
> > +	if (inputstacksize == 0 || inputstack[0] == stdin)
> 
> This confuses me a bit, partly from the comment.  We could be in
> an interactive shell, but we've just issued a source command ...
> 
> If inputstacksize == 0, that means fopen failed and we didn't
> do a pushfile, right?  Maybe best to just return in the failure
> case above, and skip that test here?
> 
> And how can we ever be here w/ inputstack[0] == stdin?
> 
> I'm wondering if this isn't cleaner and still correct:
> 
>         f = fopen(argv[1], "r");
>         if (f == NULL) {
>                 dbprintf(_("can't open %s\n"), argv[0]);
>                 return 0;
>         }
> 
>         /* Run the sourced commands now */
>         pushfile(f);
>         while (!done) {
>                 if ((input = fetchline_internal()) == NULL)

Yes, that does seem cleaner.

--D

> 
> > +		return 0;
> > +	while (!done) {
> > +		if ((input = fetchline_internal()) == NULL)
> > +			break;
> > +		v = breakline(input, &c);
> > +		if (c)
> > +			done = command(c, v);
> > +		doneline(input, v);
> > +	}
> > +
> >  	return 0;
> >  }
> >  
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
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diff mbox

Patch

diff --git a/db/init.c b/db/init.c
index e60ac66..46af024 100644
--- a/db/init.c
+++ b/db/init.c
@@ -254,7 +254,6 @@  main(
 	char	**v;
 	int	start_iocur_sp;
 
-	pushfile(stdin);
 	init(argc, argv);
 	start_iocur_sp = iocur_sp;
 
@@ -269,6 +268,7 @@  main(
 		goto close_devices;
 	}
 
+	pushfile(stdin);
 	while (!done) {
 		if ((input = fetchline()) == NULL)
 			break;
diff --git a/db/input.c b/db/input.c
index 8f65190..7b12c97 100644
--- a/db/input.c
+++ b/db/input.c
@@ -145,6 +145,12 @@  get_prompt(void)
 	return prompt;
 }
 
+static bool
+interactive_input(void)
+{
+	return inputstacksize == 1 && inputstack[0] == stdin;
+}
+
 static char *
 fetchline_internal(void)
 {
@@ -156,7 +162,9 @@  fetchline_internal(void)
 
 	rval = NULL;
 	for (rlen = iscont = 0; ; ) {
-		if (inputstacksize == 1) {
+		if (curinput == NULL)
+			return NULL;
+		if (interactive_input()) {
 			if (iscont)
 				dbprintf("... ");
 			else
@@ -183,7 +191,8 @@  fetchline_internal(void)
 		    (len = strlen(buf)) == 0) {
 			popfile();
 			if (curinput == NULL) {
-				dbprintf("\n");
+				if (interactive_input())
+					dbprintf("\n");
 				return NULL;
 			}
 			iscont = 0;
@@ -314,12 +323,28 @@  source_f(
 	char	**argv)
 {
 	FILE	*f;
+	int	c, done = 0;
+	char	*input;
+	char	**v;
 
 	f = fopen(argv[1], "r");
 	if (f == NULL)
 		dbprintf(_("can't open %s\n"), argv[0]);
 	else
 		pushfile(f);
+
+	/* If this isn't an interactive shell, run the commands now. */
+	if (inputstacksize == 0 || inputstack[0] == stdin)
+		return 0;
+	while (!done) {
+		if ((input = fetchline_internal()) == NULL)
+			break;
+		v = breakline(input, &c);
+		if (c)
+			done = command(c, v);
+		doneline(input, v);
+	}
+
 	return 0;
 }