system（）：为什么我在EMACS中使用R时没有像在bash终端中那样使用相同的权限？

Question

update: the error only occurs when logged into R from within emacs

what works:

When I ssh into a remote server and run

$ ./foo.rb

from the bash shell, it works. Furthermore, if I launch R and execute $ R

system('./foo.rb')

I am in a group with permission to read/write/execute the file. File permissions are -rwxrwx---

what doesn't work:

Launch emacs and start an R session:

• Mx R

• ssh-myserver: .

  system('./foo.rb')

I get the following error:

ruby: Permission denied -- foo.rb (LoadError)

why is this? Is there a way to work around this?

I can not find any information from ?system or ?system2

---

Here is the output from sessionInfo()

> sessionInfo()
R version 2.12.2 (2011-02-25)
Platform: x86_64-redhat-linux-gnu (64-bit)

locale:
[1] C

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
 [1] PECAn_0.1.1      xtable_1.5-6     gridExtra_0.7    RMySQL_0.7-5    
 [5] DBI_0.2-5        ggplot2_0.8.9    proto_0.3-8      reshape_0.8.3   
 [9] plyr_1.6         rjags_2.2.0-2    coda_0.13-5      lattice_0.19-17 
[13] randtoolbox_1.09 rngWELL_0.9      MASS_7.3-11      XML_3.2-0       

loaded via a namespace (and not attached):
[1] digest_0.4.2
Warning message:
'DESCRIPTION' file has 'Encoding' field and re-encoding is not possible 

---

output of 'id' and 'env' from ssh and emacs, per comment by @sarnold (changed user names, group names, and ip addresses)

1. server

1.1 'id'

 uid=1668(dleb) gid=1668(dleb) groups=117(ebusers),159(lab_admin),166(lab),1340(pal_web),1668(dleb)

1.2 'env'

LC_PAPER=en_US.UTF-8
LC_ADDRESS=en_US.UTF-8
LC_MONETARY=en_US.UTF-8
SHELL=/usr/local/bin/system-specific
KDE_NO_IPV6=1
SSH_CLIENT=888.888.888.88 51857 22
NCARG_FONTCAPS=/usr/lib64/ncarg/fontcaps
LC_NUMERIC=en_US.UTF-8
USER=dleb
LS_COLORS=
LC_TELEPHONE=en_US.UTF-8
KDEDIR=/usr
NCARG_GRAPHCAPS=/usr/lib64/ncarg/graphcaps
MAIL=/var/mail/dleb
PATH=/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/opt/dell/srvadmin/bin
LC_IDENTIFICATION=en_US.UTF-8
LC_COLLATE=en_US.UTF-8
R_LIBS=/home/a-m/dleb/lib/R
PWD=/home/dleb
NCARG_ROOT=/usr
KDE_IS_PRELINKED=1
LANG=en_US.UTF-8
NCARG_DATABASE=/usr/lib64/ncarg/database
MODULEPATH=/usr/share/Modules/modulefiles:/etc/modulefiles
LOADEDMODULES=
LC_MEASUREMENT=en_US.UTF-8
NCARG_LIB=/usr/lib64/ncarg
SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
NCARG_NCARG=/usr/share/ncarg
SHLVL=1
HOME=/home/a-m/dleb
LOGNAME=dleb
CVS_RSH=ssh
SSH_CONNECTION=888.888.888.88 51857 999.999.999.99 22
LC_CTYPE=en_US.UTF-8
MODULESHOME=/usr/share/Modules
LESSOPEN=|/usr/bin/lesspipe.sh %s
DISPLAY=localhost:15.0
LC_TIME=en_US.UTF-8
G_BROKEN_FILENAMES=1
LC_NAME=en_US.UTF-8
_=/bin/env

emacs/ess R session

2.1 system('id')

uid=1668(dleb) gid=1668(dleb) groups=117(ebusers),159(lab_admin),166(lab),1340(pal_web),1668(dleb)

2.2 system('env')

LN_S=ln -s
R_TEXI2DVICMD=/usr/bin/texi2dvi
LC_PAPER=en_US.UTF-8
SED=/bin/sed
LC_ADDRESS=en_US.UTF-8
R_PDFVIEWER=/usr/bin/xdg-open
LC_MONETARY=en_US.UTF-8
HOSTNAME=ebi-forecast
R_INCLUDE_DIR=/usr/include/R
R_PRINTCMD=lpr
SHELL=/usr/local/bin/system-specific
TERM=dumb
AWK=gawk
HISTSIZE=1
R_RD4DVI=ae
SSH_CLIENT=888.888.888.88 51159 22
KDE_NO_IPV6=1
R_RD4PDF=times,hyper
R_PAPERSIZE=a4
NCARG_FONTCAPS=/usr/lib64/ncarg/fontcaps
PERL=/usr/bin/perl
LC_NUMERIC=en_US.UTF-8
SSH_TTY=/dev/pts/14
LC_ALL=C
EMACS=t
USER=dleb
LC_TELEPHONE=en_US.UTF-8
LS_COLORS=
LD_LIBRARY_PATH=/usr/lib64/R/lib:/usr/local/lib64:/usr/lib/jvm/jre/lib/amd64/server:/usr/lib/jvm/jre/lib/amd64:/usr/lib/jvm/java/lib/amd64:/usr/java/packages/lib/amd64:/lib:/usr/lib
TAR=/bin/gtar
ENV=
R_ZIPCMD=/usr/bin/zip
KDEDIR=/usr
PAGER=/usr/bin/less
NCARG_GRAPHCAPS=/usr/lib64/ncarg/graphcaps
R_GZIPCMD=/usr/bin/gzip
PATH=/bin:/usr/bin:/usr/sbin:/usr/local/bin
LC_COLLATE=en_US.UTF-8
LC_IDENTIFICATION=en_US.UTF-8
EGREP=/bin/grep -E
PWD=/home/a-m/dleb/pecan
INPUTRC=/etc/inputrc
R_LIBS=/home/a-m/dleb/lib/R
NCARG_ROOT=/usr
R_SHARE_DIR=/usr/share/R
WHICH=/usr/bin/which
EDITOR=vi
LANG=en_US.UTF-8
KDE_IS_PRELINKED=1
R_LIBS_SITE=/usr/local/lib/R/site-library:/usr/local/lib/R/library:/usr/lib64/R/library:/usr/share/R/library
M    ODULEPATH=/usr/share/Modules/modulefiles:/etc/modulefiles
NCARG_DATABASE=/usr/lib64/ncarg/database
LC_MEASUREMENT=en_US.UTF-8
LOADEDMODULES=
PS3=
R_BROWSER=/usr/bin/xdg-open
SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
NCARG_LIB=/usr/lib64/ncarg
HOME=/home/a-m/dleb
SHLVL=1
NCARG_NCARG=/usr/share/ncarg
R_ARCH=
TR=/usr/bin/tr
MAKE=make
R_UNZIPCMD=/usr/bin/unzip
LOGNAME=dleb
CVS_RSH=ssh
LC_CTYPE=en_US.UTF-8
SSH_CONNECTION=888.888.888.88 51159 999.999.999.99 22
R_BZIPCMD=/usr/bin/bzip2
MODULESHOME=/usr/share/Modules
LESSOPEN=|/usr/bin/lesspipe.sh %s
PROMPT_COMMAND=
R_HOME=/usr/lib64/R
DISPLAY=localhost:22.0
R_PLATFORM=x86_64-redhat-linux-gnu
INSIDE_EMACS=23.2.1,tramp:2.1.18-23.2
R_LIBS_USER=~/R/x86_64-redhat-linux-gnu-library/2.12
LC_TIME=en_US.UTF-8
R_DOC_DIR=/usr/share/doc/R-2.12.2
R_SESSION_TMPDIR=/tmp/RtmpqA6bpJ
HISTFILE=/home/a-m/dleb/.tramp_history
G_BROKEN_FILENAMES=1
LC_NAME=en_US.UTF-8
_=/bin/env

Answer 1

Assuming you started up R as the same user, you do. You error is not coming from a permissions problem for foo.rb , however, or else your shell would be giving the error. (ie sh: ./test.rb: Permission denied ; see example below). Here, ruby itself is giving the error. Without knowing exactly what is in your foo.rb , I would suggest digging in there to see what it is trying to load/source, and checking the permissions on those.

#!/usr/bin/env ruby

puts 'Hello world'

Now in R....

> system('ls -l test.rb')
-rw-r--r--  1 jcolby  staff  40 Oct 21 08:23 test.rb
> system('./test.rb')
sh: ./test.rb: Permission denied
> system('chmod a+x test.rb')
> system('./test.rb')
Hello world

Answer 2

I presume the M ODULEPATH in the Emacs-derived output is simply a copy and paste typo.

The differences between the two env outputs is much greater than I expected; I've selected the ones that look slightly suspicious to me:

$ diff -u works fails
--- works   2011-10-24 15:04:02.000000000 -0700
+++ fails   2011-10-24 15:12:36.000000000 -0700
...
+LD_LIBRARY_PATH=/usr/lib64/R/lib:/usr/local/lib64:/usr/lib/jvm/jre/lib/amd64/server:/usr/lib/jvm/jre/lib/amd64:/usr/lib/jvm/java/lib/amd64:/usr/java/packages/lib/amd64:/lib:/usr/lib
...
-PATH=/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/opt/dell/srvadmin/bin
-PWD=/home/dleb
...
+PATH=/bin:/usr/bin:/usr/sbin:/usr/local/bin
...
+PWD=/home/a-m/dleb/pecan
...

In the emacs-derived session, your LD_LIBRARY_PATH environment variable may be changing specifics of which dynamically linked libraries are being used when executing ruby . If you ssh in to your server and execute your foo.rb with the changed LD_LIBRARY_PATH , does it work or fail?

LD_LIBRARY_PATH=/usr/lib64/R/lib:/usr/local/lib64:/usr/lib/jvm/jre/lib/amd64/server:/usr/lib/jvm/jre/lib/amd64:/usr/lib/jvm/java/lib/amd64:/usr/java/packages/lib/amd64:/lib:/usr/lib ./foo.rb

The PATH environment variable between the two sessions is different; perhaps you have permission to execute /usr/local/bin/ruby (or the libraries in /usr/local/lib/ruby/ ) but not /usr/bin/ruby (or the libraries in /usr/lib/ruby/ ). Does your script use #!env ruby or does it use #!/usr/bin/ruby (or some other fixed path)?

Your pwd in one instance is /home/dleb , the other /home/am/dleb/pecan -- but HOME is set to /home/am/dleb on both systems. Is /home/dleb a symbolic link or does it actually exist separate from /home/am/dleb ? (This really is grasping at straws -- I don't think this is it, but this problem is baffling.)

One last thing to consider: is your server confined with a tool such as AppArmor , SELinux , TOMOYO , or SMACK ? Any of these mandatory access control tools can prevent an application from writing in specific locations, perhaps they aren't yet configured for your site. Check dmesg(1) output to see if there are any rejection messages, most or all these tools log to dmesg(1) if auditd(8) isn't running.