package: dropbear: make PATH configurable

Make the default PATH dropbear is using configurable.

If not specified, it will continue to default to dropbear's DEFAULT_PATH.

Signed-off-by Markus Mayer <[email protected]>

---
 package/dropbear/Config.in   | 6 ++++++
 package/dropbear/dropbear.mk | 8 ++++++++
 2 files changed, 14 insertions(+)

package/dropbear/Config.in +0 -0

index 6700778161..0cc68d737d 100644

package/dropbear/dropbear.mk +1 -0

index 01a1a07b76..9da340670a 100644
@@ -51,6 +51,14 @@ define DROPBEAR_DISABLE_STANDALONE
 	$(SED) 's:\(#define NON_INETD_MODE\):/*\1 */:' $(@D)/options.h
 endef
 
+ifneq ($(BR2_PACKAGE_DROPBEAR_PATH),"")

Make the default PATH dropbear is using configurable.

If not specified, it will continue to default to dropbear's DEFAULT_PATH.

Signed-off-by Markus Mayer <[email protected]>

---

Changes since v1:
- Made regex safer
+ allow multiple spaces after #define
+ make sure there are spaces or tabs after DEFAULT_PATH

 package/dropbear/Config.in   | 6 ++++++
 package/dropbear/dropbear.mk | 8 ++++++++
 2 files changed, 14 insertions(+)

package/dropbear/Config.in +6 -0

index 6700778161ba..0cc68d737d2c 100644
@@ -55,4 +55,10 @@ config BR2_PACKAGE_DROPBEAR_LASTLOG
 	  Enable logging of dropbear access to lastlog. Notice that
 	  Buildroot does not generate lastlog by default.
 
+config BR2_PACKAGE_DROPBEAR_PATH
+	string "dropbear default path"
+	help
+	  Use the path specified here as dropbear's default path.
+	  If not specified, dropbear will use "/usr/bin:/bin".
+
 endif

package/dropbear/dropbear.mk +8 -0

index 01a1a07b7696..9da340670a70 100644
@@ -51,6 +51,14 @@ define DROPBEAR_DISABLE_STANDALONE
 	$(SED) 's:\(#define NON_INETD_MODE\):/*\1 */:' $(@D)/options.h
 endef
 
+ifneq ($(BR2_PACKAGE_DROPBEAR_PATH),"")
+define DROPBEAR_CUSTOM_PATH
+	$(SED) 's|^\(#define \+DEFAULT_PATH\)[	 ]\+.*|\1 $(BR2_PACKAGE_DROPBEAR_PATH)|' $(@D)/options.h
+endef
+
+DROPBEAR_POST_EXTRACT_HOOKS += DROPBEAR_CUSTOM_PATH
+endif
+
 define DROPBEAR_INSTALL_INIT_SYSTEMD
 	$(INSTALL) -D -m 644 package/dropbear/dropbear.service \
 		$(TARGET_DIR)/usr/lib/systemd/system/dropbear.service

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Quoted 6 lines

On 2018-03-09 14:41 -0800, Markus Mayer spake thusly:

Quoted 1 line

Make the default PATH dropbear is using configurable.

But pushing the thing even further, we think a generic solution is even better:
- in the "System configuration" sub-menu, add a new option that basically is "Default PATH" and defaults to /bin:/sbin:/usr/bin:/usr/sbin

Would it make sense to use the order /bin:/usr/bin:/sbin:/usr/sbin? Conceptually, that would make it pick up non-admin and non-system tools first. In reality, it likely wouldn't make a difference, because there won't be programs of the same name in a "bin" path and in an "sbin" path. But if there are, for whatever reason, it's nicer if it picks the one that will do "less damage" by default, unless explicitly told otherwise.
Anyway, it's just a thought.

Quoted 1 line

Care to have a look?

I like it. :-)

Quoted 11 lines

Quoted 8 lines

Would it make sense to use the order /bin:/usr/bin:/sbin:/usr/sbin? Conceptually, that would make it pick up non-admin and non-system tools first. In reality, it likely wouldn't make a difference, because there won't be programs of the same name in a "bin" path and in an "sbin" path. But if there are, for whatever reason, it's nicer if it picks the one that will do "less damage" by default, unless explicitly told otherwise.
Anyway, it's just a thought.

Currently, system/skeleton/etc/profile contains /bin:/sbin:/usr/bin:/usr/sbin so I'd suggest we keep that as the default for this new option.

Okay, I'll leave it as is.

Quoted 3 lines

Cool thanks! Don't forget to Cc me on the resulting series, so I'm sure not to miss it. (which does not mean you'll get a fast review, mind you! :-/)

Looks like the main challenge will be to change etc/profile. Right now, it is being copied (rsynched) as is. That won't be possible anymore. It'll have to replace a place holder with the actual PATH as set in the new config option.

$ head system/skeleton/etc/profile
export PATH=/bin:/sbin:/usr/bin:/usr/sbin

if [ "$PS1" ]; then

    if [ "`id -u`" -eq 0 ]; then
        export PS1='# '
    else
        export PS1='$ '
    fi

fi

Do you know of any examples in the Buildroot code where the "build" process has to modify a script and insert the value of a Buildroot config option? If this is already being done elsewhere, I'd like to use the same approach here if possible.

From: "Yann Morin" <[email protected]>
To: "Markus Mayer" <[email protected]>
Cc: "buildroot" <[email protected]>
Sent: Domingo, 16 de dezembro de 2018 13:26:03
Subject: Re: [Buildroot] [PATCH v2] package: dropbear: make PATH configurable

Markus, All,

On 2018-03-09 14:41 -0800, Markus Mayer spake thusly:

Quoted 1 line

Make the default PATH dropbear is using configurable.

We've discussed this with Thomas, and as Carlos noticed, we woudl need a similar solution for openssh.

But pushing the thing even further, we think a generic solution is even better:

- in the "System configuration" sub-menu, add a new option that basically is "Default PATH" and defaults to /bin:/sbin:/usr/bin:/usr/sbin

- use that to set PATH in /etc/profile (from the skeleton-init-common package)

Notice that /bin and /sbin are redundant with their /usr counterparts for BR2_ROOTFS_MERGED_USR=y.

In one of my current projects there is a /etc/profile.d/path.sh file in a rootfs overlay containing
#!/bin/sh
PATH="$(test -L /bin || echo /bin:)$(test -L /sbin || echo /sbin:)/usr/bin:/usr/sbin"