Re: [PATCH] ash: support BASH_XTRACEFD when built Bash compatibly

[Denys Vlasenko]

Applied in this form:

preverrout_fd = 2;
+   if (BASH_XTRACEFD && xflag) {
+   /* NB: bash closes fd == $BASH_XTRACEFD when it is changed.
+* we do not emulate this. We only use its value.
+*/
+   const char *xtracefd = lookupvar("BASH_XTRACEFD");
+   if (xtracefd && is_number(xtracefd))
+   preverrout_fd = atoi(xtracefd);
+
+   }
status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);

On Fri, Aug 4, 2017 at 12:58 PM, Johannes Schindelin
 wrote:
> There is a very useful feature in Bash where you can redirect the trace
> enabled by `set -x` to a file descriptor *different* than 2. This comes
> in particularly handy when validating the error output of commands, say,
> in Git's test suite, while tracing at the same time.
>
> It is such a useful feature, and very easily implemented.
>
> Signed-off-by: Johannes Schindelin 
> ---
>  shell/ash.c | 7 +++
>  1 file changed, 7 insertions(+)
>
> diff --git a/shell/ash.c b/shell/ash.c
> index 8c9f4adc6..1d1596fec 100644
> --- a/shell/ash.c
> +++ b/shell/ash.c
> @@ -182,6 +182,8 @@
>  #define IF_BASH_PATTERN_SUBST   IF_ASH_BASH_COMPAT
>  #defineBASH_SUBSTR  ENABLE_ASH_BASH_COMPAT
>  #define IF_BASH_SUBSTR  IF_ASH_BASH_COMPAT
> +#defineBASH_XTRACEFDENABLE_ASH_BASH_COMPAT
> +#define IF_BASH_XTRACEFDIF_ASH_BASH_COMPAT
>  /* [[ EXPR ]] */
>  #defineBASH_TEST2   (ENABLE_ASH_BASH_COMPAT * ENABLE_ASH_TEST)
>  #defineBASH_SOURCE  ENABLE_ASH_BASH_COMPAT
> @@ -9740,6 +9742,7 @@ evalcommand(union node *cmd, int flags)
> int status;
> char **nargv;
> smallint cmd_is_exec;
> +   IF_BASH_XTRACEFD(const char *xtracefd;)
>
> /* First expand the arguments. */
> TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
> @@ -9791,6 +9794,10 @@ evalcommand(union node *cmd, int flags)
>
> expredir(cmd->ncmd.redirect);
> redir_stop = pushredir(cmd->ncmd.redirect);
> +#ifdef BASH_XTRACEFD
> +   xtracefd = lookupvar("BASH_XTRACEFD");
> +   if (!xtracefd || (preverrout_fd = atoi(xtracefd)) < 0)
> +#endif
> preverrout_fd = 2;
> status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);
>
>
> base-commit: 4dc86699b57ff35c287ca396d562ec206776694a
> --
> 2.13.3.windows.1.1055.g9b9ea5f2d78
>
> Published-As: 
> https://github.com/dscho/busybox-w32/releases/tag/busybox-xtracefd-v1
> Fetch-It-Via: git fetch https://github.com/dscho/busybox-w32 
> busybox-xtracefd-v1
> ___
> busybox mailing list
> busybox@busybox.net
> http://lists.busybox.net/mailman/listinfo/busybox
___
busybox mailing list
busybox@busybox.net
http://lists.busybox.net/mailman/listinfo/busybox

[PATCH] ash: support BASH_XTRACEFD when built Bash compatibly

[Johannes Schindelin]

There is a very useful feature in Bash where you can redirect the trace
enabled by `set -x` to a file descriptor *different* than 2. This comes
in particularly handy when validating the error output of commands, say,
in Git's test suite, while tracing at the same time.

It is such a useful feature, and very easily implemented.

Signed-off-by: Johannes Schindelin 
---
 shell/ash.c | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/shell/ash.c b/shell/ash.c
index 8c9f4adc6..1d1596fec 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -182,6 +182,8 @@
 #define IF_BASH_PATTERN_SUBST   IF_ASH_BASH_COMPAT
 #defineBASH_SUBSTR  ENABLE_ASH_BASH_COMPAT
 #define IF_BASH_SUBSTR  IF_ASH_BASH_COMPAT
+#defineBASH_XTRACEFDENABLE_ASH_BASH_COMPAT
+#define IF_BASH_XTRACEFDIF_ASH_BASH_COMPAT
 /* [[ EXPR ]] */
 #defineBASH_TEST2   (ENABLE_ASH_BASH_COMPAT * ENABLE_ASH_TEST)
 #defineBASH_SOURCE  ENABLE_ASH_BASH_COMPAT
@@ -9740,6 +9742,7 @@ evalcommand(union node *cmd, int flags)
int status;
char **nargv;
smallint cmd_is_exec;
+   IF_BASH_XTRACEFD(const char *xtracefd;)
 
/* First expand the arguments. */
TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
@@ -9791,6 +9794,10 @@ evalcommand(union node *cmd, int flags)
 
expredir(cmd->ncmd.redirect);
redir_stop = pushredir(cmd->ncmd.redirect);
+#ifdef BASH_XTRACEFD
+   xtracefd = lookupvar("BASH_XTRACEFD");
+   if (!xtracefd || (preverrout_fd = atoi(xtracefd)) < 0)
+#endif
preverrout_fd = 2;
status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);
 

base-commit: 4dc86699b57ff35c287ca396d562ec206776694a
-- 
2.13.3.windows.1.1055.g9b9ea5f2d78

Published-As: 
https://github.com/dscho/busybox-w32/releases/tag/busybox-xtracefd-v1
Fetch-It-Via: git fetch https://github.com/dscho/busybox-w32 busybox-xtracefd-v1
___
busybox mailing list
busybox@busybox.net
http://lists.busybox.net/mailman/listinfo/busybox