| Message ID | 20191206130302.11473-2-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST} | expand |
On Fri, Dec 6, 2019 at 10:03 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > Commit 858805b336be ("kbuild: add $(BASH) to run scripts with > bash-extension") shed light on portability issues. Here is another one. > > Since commit f07726048d59 ("Fix handling of backlash character in > LINUX_COMPILE_BY name"), we must escape a backslash contained in > LINUX_COMPILE_BY. This is not working on distros like Ubuntu. > > As the POSIX spec [1] says, if any of the operands contain a backslash > ( '\' ) character, the results are implementation-defined. > > The actual shell of /bin/sh could be bash, dash depending on distros, > and the behavior of builtin echo command is different among them. > > The bash builtin echo, unless -e is given, copies the arguments to > output without expanding escape sequences (BSD-like behavior). > > The dash builtin echo, in contrast, adopts System V behavior, which > does expand escape sequences without any option. > > Even non-builtin /bin/echo behaves differently depending on the system. > Due to these variations, echo is considered as a non-portable command. > Using printf is the common solution to avoid the portability issue. > > [1] https://pubs.opengroup.org/onlinepubs/009695399/utilities/echo.html > > Fixes: 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension") > Reported-by: XXing Wei <xxing.wei@unisoc.com> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- Applied to linux-kbuid. > > scripts/mkcompile_h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h > index 3097fec1756a..3a5a4b210c86 100755 > --- a/scripts/mkcompile_h > +++ b/scripts/mkcompile_h > @@ -69,7 +69,7 @@ UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)" > > echo \#define UTS_VERSION \"$UTS_VERSION\" > > - echo \#define LINUX_COMPILE_BY \"$LINUX_COMPILE_BY\" > + printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY" > echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\" > > echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//'`\" > -- > 2.17.1 >
diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h index 3097fec1756a..3a5a4b210c86 100755 --- a/scripts/mkcompile_h +++ b/scripts/mkcompile_h @@ -69,7 +69,7 @@ UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)" echo \#define UTS_VERSION \"$UTS_VERSION\" - echo \#define LINUX_COMPILE_BY \"$LINUX_COMPILE_BY\" + printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY" echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\" echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//'`\"
Commit 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension") shed light on portability issues. Here is another one. Since commit f07726048d59 ("Fix handling of backlash character in LINUX_COMPILE_BY name"), we must escape a backslash contained in LINUX_COMPILE_BY. This is not working on distros like Ubuntu. As the POSIX spec [1] says, if any of the operands contain a backslash ( '\' ) character, the results are implementation-defined. The actual shell of /bin/sh could be bash, dash depending on distros, and the behavior of builtin echo command is different among them. The bash builtin echo, unless -e is given, copies the arguments to output without expanding escape sequences (BSD-like behavior). The dash builtin echo, in contrast, adopts System V behavior, which does expand escape sequences without any option. Even non-builtin /bin/echo behaves differently depending on the system. Due to these variations, echo is considered as a non-portable command. Using printf is the common solution to avoid the portability issue. [1] https://pubs.opengroup.org/onlinepubs/009695399/utilities/echo.html Fixes: 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension") Reported-by: XXing Wei <xxing.wei@unisoc.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/mkcompile_h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)