CODEWITHSUNDEEP
clinuxbash
vesontio
vesontio

Reputation: 381

system() keeps returning 127

I am developing a shared-library L which is used by an other system service S. In my program I need to call a small program P, which uses Oracle shared libraries.

The small program P is packaged and installed correctly, and the environment variables, such as PATH,LD_LIBRARY_PATH and ORACLE_HOME are set correctly. I can run P on command line without any problem.

But when service S call my library L which runs the small program P via system(), it gives me a return code 127. I've googled, people says it's a command not found error, probably a PATH issue, so I've tried with absolute path like the following

int status = system("/usr/bin/myprog --args");
if (status < 0) { ... }
ret = WEXITSTATUS(status);

ret still equals 127.

Any idea please ? Thank you.

Update It turns out that the service S is launched via command daemon, in its init.d script, I have found the following line:

daemon /usr/bin/myserv

if I export explicitly all my environment variables (PATH, ORACLE_HOME and LD_LIBRARY_PATH), it works. I don't know if daemon eliminates my environment variables.

Upvotes: 1

Views: 2237

Answers (2)

user3629249
user3629249

Reputation: 16550

this excerpt from the man page for system()

-----------------------------------------------------------------
The value returned is -1 on  error  (e.g.,  fork(2)  failed),  and  the
   return  status  of the command otherwise.  
This latter return status is
   in the format specified in wait(2).  
Thus, the exit code of the command
   will  be  WEXITSTATUS(status).   
In case /bin/sh could not be executed,
   the exit status will be that of a command that does exit(127)."
-----------------------------------------------------------------

indicates the 127 means that /bin/sh could not be executed.

Upvotes: 1

vesontio
vesontio

Reputation: 381

Well, I have found the answer:How to make unix service see environment variables?,the environment variables are removed in init.d script.

Upvotes: 0

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