| Message ID | 11da03a97bde4e0332be6577a83e1476566d8e9f.1465245732.git.yann.morin.1998@free.fr |
|---|---|
| State | Accepted |
| Headers | show |
Hello, On Mon, 6 Jun 2016 22:43:38 +0200, Yann E. MORIN wrote: > +define PRINTF > + printf '$(subst $(sep),\n,\ > + $(subst $(PERCENT),$(PERCENT)$(PERCENT),\ > + $(subst $(QUOTE),$(QUOTE)\$(QUOTE)$(QUOTE),\ > + $(subst \,\\,$(1)))))\n' > +endef Do we expect this to be used outside of fs/common.mk? Since it's not the case today, I would suggest to move it there. Thomas
Thomas, All, On 2016-06-06 23:07 +0200, Thomas Petazzoni spake thusly: > On Mon, 6 Jun 2016 22:43:38 +0200, Yann E. MORIN wrote: > > > +define PRINTF > > + printf '$(subst $(sep),\n,\ > > + $(subst $(PERCENT),$(PERCENT)$(PERCENT),\ > > + $(subst $(QUOTE),$(QUOTE)\$(QUOTE)$(QUOTE),\ > > + $(subst \,\\,$(1)))))\n' > > +endef > > Do we expect this to be used outside of fs/common.mk? Since it's not > the case today, I would suggest to move it there. Indeed I don;t plan on using it outside of the fs infra for now (I have another series that will rely on it, but still in the fs infra). However, this is generic enough that it is not specific to the fs infra. Thus I believe it belong to pkg-utils. If you still prefer I move it to fs/common.mk, that's also OK for me. Regards, Yann E. MORIN.
On 06-06-16 23:25, Yann E. MORIN wrote: > Thomas, All, > > On 2016-06-06 23:07 +0200, Thomas Petazzoni spake thusly: >> On Mon, 6 Jun 2016 22:43:38 +0200, Yann E. MORIN wrote: >> >>> +define PRINTF >>> + printf '$(subst $(sep),\n,\ >>> + $(subst $(PERCENT),$(PERCENT)$(PERCENT),\ >>> + $(subst $(QUOTE),$(QUOTE)\$(QUOTE)$(QUOTE),\ >>> + $(subst \,\\,$(1)))))\n' >>> +endef >> >> Do we expect this to be used outside of fs/common.mk? Since it's not >> the case today, I would suggest to move it there. > > Indeed I don;t plan on using it outside of the fs infra for now (I have > another series that will rely on it, but still in the fs infra). > > However, this is generic enough that it is not specific to the fs infra. > Thus I believe it belong to pkg-utils. > > If you still prefer I move it to fs/common.mk, that's also OK for me. I think pkg-utils is the proper place. I imagine that there can be many other places where this can be useful. And even if it is only used in the fs infra, I would go and look for a function like that in pkg-utils.mk. Regards, Arnout
diff --git a/package/pkg-utils.mk b/package/pkg-utils.mk index f88313a..c61b3b6 100644 --- a/package/pkg-utils.mk +++ b/package/pkg-utils.mk @@ -104,6 +104,43 @@ define sep endef +PERCENT = % +QUOTE = ' +# ' # Meh... syntax-highlighting + +# This macro properly escapes a command string, then prints it with printf: +# +# - first, backslash '\' are self-escaped, so that they do not escape +# the following char and so that printf properly outputs a backslash; +# +# - next, single quotes are escaped by closing an existing one, adding +# an escaped one, and re-openning a new one (see below for the reason); +# +# - then '%' signs are self-escaped so that the printf does not interpret +# them as a format specifier, in case the variable contains an actual +# printf with a format; +# +# - finally, $(sep) is replaced with the literal '\n' so that make does +# not break on the so-expanded variable, but so that the printf does +# correctly output an LF. +# +# Note: this must be escaped in this order to avoid over-escaping the +# previously escaped elements. +# +# Once everything has been escaped, it is passed between single quotes +# (that's why the single-quotes are escaped they way they are, above, +# and why the dollar sign is not escaped) to printf(1). A trailing +# newline is apended, too. +# +# Note: leading or trailing spaces are *not* stripped. +# +define PRINTF + printf '$(subst $(sep),\n,\ + $(subst $(PERCENT),$(PERCENT)$(PERCENT),\ + $(subst $(QUOTE),$(QUOTE)\$(QUOTE)$(QUOTE),\ + $(subst \,\\,$(1)))))\n' +endef + # check-deprecated-variable -- throw an error on deprecated variables # example: # $(eval $(call check-deprecated-variable,FOO_MAKE_OPT,FOO_MAKE_OPTS))
In some cases we need to escape make variables and pass them to printf(1). This is the case in our fs infra, where we want to shoe-horn the commands to generate the filesystems in the fakeroot script, or the devices, permissions and users tables to their respective files. We currently do so by replacing $(sep) with the literal '\n' but that's not enough. This does not protect against strings with an embedded '%' or a backslash. Add a new macro that properly escapes a string and calls printf(1), so that we get the expected output. Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> --- package/pkg-utils.mk | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)