shell script run when I am root but I get a permission denied when it is invoked from a Makefile (still as root)

≡放荡痞女 提交于 2019-12-13 06:53:41

问题


I need to run a Make script that invokes a shell script.

I can run the shell script directly as root but when running make on the makefile (still as root) make is denied permission to run the same shell script?

The offending line in the Makefile is that one:

PLATFORM=$(shell $(ROOT)/systype.sh)

I could go in and hardcode the value of every PLATFORM variable of every Makefile scrip on the system but that would be pointless fix, I'd like to understand why there is that Permission Denied error:

make[1]: execvp: ../systype.sh: Permission denied

PS: The content of the shell script is not the issue even if the shell script only contain ls or echo linux the Permission is Denied to the Make utility to run the shell script.

PS: I am not a make expert by an mean so if the explanation is related to Make please be as specific as you can.


回答1:


In your comments above you say when you "run it manually" you use . scriptname.sh, is that correct? You use . followed by scriptname.sh?

That does not run the script, that sources the script. Your statement that scriptname.sh will execute with and without the x permission since it is a shell script is wrong. You can source the script if you have read permissions. But you cannot execute the script unless you have execute permissions.

"Sourcing" means that a new shell is not started: instead your current shell (where you type that command) reads the contents of the script and runs them just as if you'd typed them in by hand, in the current shell. At the end all the side-effects (directory changes, variable assignments, etc.) that were performed in that script are still available in your current script.

"Executing" means that the script is treated like a program, but the program is a new shell that's started, which then reads the contents of the script and executes it. Once the script ends the shell exits and all side-effects are lost.

The $(shell ...) function in make will not source your script (unless you also use . there, which you did not). It will try to run your script. The error you show implies that either systype.sh did not have the execution bit set, or else that it had an invalid #! line. There's no other explanation I can think of.

If sourcing the file really does what you want then why not just use the same method in $(shell ...) that you use in your own personal use:

PLATFORM=$(shell . $(ROOT)/systype.sh)

If changing the user permission didn't work, are you sure that whatever user owns the script is the same user you're using to invoke make? You say you're "running as root"; is the script owned by root? Or is it owned by you and you're running sudo make or similar?

I don't know why you don't just use:

chmod +x systype.sh

and call it a day.




回答2:


Adding execution permission to the file Group rather that the file User fixed the issue.

PS: I wonder why? It seems the Make utility run shell scripts not with the same user that started Make...



来源:https://stackoverflow.com/questions/28332397/shell-script-run-when-i-am-root-but-i-get-a-permission-denied-when-it-is-invoked

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