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H A D | mkcompile_h | c8f3dea9 Fri Dec 06 07:03:02 CST 2019 Masahiro Yamada <masahiroy@kernel.org> mkcompile_h: use printf for LINUX_COMPILE_BY
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 such distros as 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, etc. 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 stdout 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 given.
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> c8f3dea9 Fri Dec 06 07:03:02 CST 2019 Masahiro Yamada <masahiroy@kernel.org> mkcompile_h: use printf for LINUX_COMPILE_BY 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 such distros as 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, etc. 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 stdout 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 given. 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>
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