从PHP中运行Rscript：无法加载共享库

Question

I am trying to run R code from within PHP. I am using RHEL 7.4.

However, because Apache runs as a different user than installed the R packages, it cannot load packages:

My PHP code has this line:

echo shell_exec("(Rscript -e 'library(lme4, lib.loc = \"/var/www/R/lib\")')2>&1");

which produces this error in the browser:

Error: package or namespace load failed for 'lme4' in dyn.load(file, DLLpath = DLLpath, ...):
 unable to load shared object '/var/www/R/lib/Rcpp/libs/Rcpp.so':
  /var/www/R/lib/Rcpp/libs/Rcpp.so: failed to map segment from shared object: Permission denied
Execution halted

The file /var/www/R/lib/Rcpp/libs/Rcpp.so has permissions 775, so I don't think the permissions are actually the problem.

How can I tell Apache / PHP where to look for the shared libraries?

The server is not public-facing, so I would take any solution from properly accessing the shared library, to giving user apache sudo access with NOPASSWD to run as my user (or something similarly reckless, since that didn't actually work...).

Thank you!

Answer 1

This appears due in part to an SELinux setting in Red Hat. I'm not entirely sure whether this is Red Hat-centric, or specific to the configuration at my university (who installed Red Hat in the first place).

Originally:

$ getenforce
Enforcing

Fix:

$ sudo setenforce 0
$ getenforce
Permissive

Persistent fix: modify /etc/selinux/config to have the line

SELINUX=Permissive

Credit to this StackOverflow thread.