rexec_af(3)

1rexec(3)                   Library Functions Manual                   rexec(3)
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NAME

6       rexec, rexec_af - return stream to a remote command
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LIBRARY

9       Standard C library (libc, -lc)
10

SYNOPSIS

12       #include <netdb.h>
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14       [[deprecated]]
15       int rexec(char **restrict ahost, int inport,
16                 const char *restrict user, const char *restrict passwd,
17                 const char *restrict cmd, int *restrict fd2p);
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19       [[deprecated]]
20       int rexec_af(char **restrict ahost, int inport,
21                 const char *restrict user, const char *restrict passwd,
22                 const char *restrict cmd, int *restrict fd2p,
23                 sa_family_t af);
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25       rexec(), rexec_af():
26           Since glibc 2.19:
27               _DEFAULT_SOURCE
28           In glibc up to and including 2.19:
29               _BSD_SOURCE
30

DESCRIPTION

32       This interface is obsoleted by rcmd(3).
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34       The  rexec()  function looks up the host *ahost using gethostbyname(3),
35       returning -1 if the host does not exist.  Otherwise, *ahost is  set  to
36       the  standard  name  of  the host.  If a username and password are both
37       specified, then these are used to authenticate  to  the  foreign  host;
38       otherwise  the  environment and then the .netrc file in user's home di‐
39       rectory are searched for appropriate information.  If all  this  fails,
40       the user is prompted for the information.
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42       The  port  inport specifies which well-known DARPA Internet port to use
43       for the connection; the call getservbyname("exec", "tcp") (see  getser‐
44       vent(3))  will return a pointer to a structure that contains the neces‐
45       sary port.  The protocol for connection is described in detail in  rex‐
46       ecd(8).
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48       If  the  connection  succeeds,  a socket in the Internet domain of type
49       SOCK_STREAM is returned to the caller, and given to the remote  command
50       as  stdin and stdout.  If fd2p is nonzero, then an auxiliary channel to
51       a control process will be setup, and a file descriptor for it  will  be
52       placed  in  *fd2p.   The  control process will return diagnostic output
53       from the command (unit 2) on this channel, and will also  accept  bytes
54       on  this  channel  as being UNIX signal numbers, to be forwarded to the
55       process group of the command.  The diagnostic information returned does
56       not  include  remote authorization failure, as the secondary connection
57       is set up after authorization has been verified.  If fd2p  is  0,  then
58       the  stderr (unit 2 of the remote command) will be made the same as the
59       stdout and no provision is made for sending arbitrary  signals  to  the
60       remote  process, although you may be able to get its attention by using
61       out-of-band data.
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63   rexec_af()
64       The rexec() function works  over  IPv4  (AF_INET).   By  contrast,  the
65       rexec_af()  function  provides  an  extra argument, af, that allows the
66       caller to select the protocol.   This  argument  can  be  specified  as
67       AF_INET,  AF_INET6, or AF_UNSPEC (to allow the implementation to select
68       the protocol).
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ATTRIBUTES

71       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
72       tributes(7).
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74       ┌──────────────────────────────────────────┬───────────────┬───────────┐
75       │Interface                                 │ Attribute     │ Value     │
76       ├──────────────────────────────────────────┼───────────────┼───────────┤
77       │rexec(), rexec_af()                       │ Thread safety │ MT-Unsafe │
78       └──────────────────────────────────────────┴───────────────┴───────────┘
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STANDARDS

81       None.
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HISTORY

84       rexec()
85              4.2BSD, BSD, Solaris.
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87       rexec_af()
88              glibc 2.2.
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BUGS

91       The rexec() function sends the unencrypted password across the network.
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93       The  underlying service is considered a big security hole and therefore
94       not enabled on many sites; see rexecd(8) for explanations.
95