asrcmd(3x)asrcmd(3x)NAME
asrcmd, asrcmdv - execute a command on a remote machine
SYNOPSIS
#include <arraysvcs.h>
int asrcmd(asserver_t Server, char *User, char *CmdLine, int *fd2p);
int asrcmdv(asserver_t Server, char *User, char **CmdV, int *fd2p);
DESCRIPTION
The asrcmd and asrcmdv functions are used to execute an arbitrary command
on a remote machine. They are similar in some respects to rcmd(3N)
except that the connection and user authentication is provided by Array
Services, so the user does not necessarily have to have root privileges.
Both asrcmd and asrcmdv pass the command to the remote user's default
shell for execution using the standard shell command line option "-c".
For example, if the requested command is ls -l and the remote user's
shell is /bin/tcsh, then the following command would be invoked on the
remote machine:
/bin/tcsh -c "ls -l"
The only difference between asrcmd and asrcmdv is in the way that the
remote command is specified.
The Server argument is an array server token created with
asopenserver(3X) that specifies the remote machine that is to execute the
command. If NULL is specified instead, the command will be executed on
the same machine as the one running the default array services daemon,
though this is not generally very useful. See array(1) for more
information on how the default array services daemon is selected.
The User argument specifies the login name of the user on the remote
machine that should execute the command. Specifying NULL will cause the
command to be executed using the same user login name as the one
executing asrcmd/asrcmdv.
The CmdLine argument to asrcmd is a single string containing the entire
command to be executed, such as it might be typed on the command line.
The CmdV argument to asrcmdv is an argv-style array of string pointers
containing the list of arguments that make up the command to be executed.
The array should be terminated with a NULL pointer. Note that the list
of arguments will be concatenated into a single string (with a single
space between each) before it is passed to the remote user's default
shell for execution. It may therefore be necessary to include
appropriate shell quote characters if individual arguments contain
embedded space or tab characters.
If the remote command is successfully initiated, a socket in the internet
domain of type SOCK_STREAM is returned to the caller and given to the
remote command as stdin and stdout. If fd2p is non-zero, then an
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asrcmd(3x)asrcmd(3x)
auxillary channel to a control process will be set up, and a descriptor
for it will be placed in *fd2p. The control process will return output
from the command's stderr, and will also accept bytes on this channel as
being UNIX signal numbers, to be forwarded to the process group of the
command. If fd2p is 0, then the stderr of the remote command will be
made the same as the stdout and no provision is made for sending
arbitrary signals to the remote process.
NOTESasrcmd and asrcmdv are found in the library "libarray.so", and will be
loaded if the option "-larray" is used with cc(1) or ld(1).
SEE ALSOarray(1), ascommand(3X), aserrorcode(3X), asopenserver(3X), rcmd(3N).
DIAGNOSTICS
If successful, asrcmd and asrcmdv both return a socket descriptor
attached to the remote command's stdin and stdout. If the remote command
cannot be started, -1 is returned and aserrorcode is set appropriately.
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