setuid(2) — svr4 — mips UMIPS RISC/os 5.01



SETUID(2-SVR4)      RISC/os Reference Manual       SETUID(2-SVR4)



NAME
     setuid, setgid - set user and group IDs

SYNOPSIS
     #include <sys/types.h>
     #include <unistd.h>

     int setuid(uidt uid);

     int setgid(gidt gid);

DESCRIPTION
     The setuid system call sets the real user ID, effective user
     ID, and saved user ID of the calling process.  The setgid
     system call sets the real group ID, effective group ID, and
     saved group ID of the calling process.

     At login time, the real user ID, effective user ID, and
     saved user ID of the login process are set to the login ID
     of the user responsible for the creation of the process.
     The same is true for the real, effective, and saved group
     IDs; they are set to the group ID of the user responsible
     for the creation of the process.

     When a process calls exec(2) to execute a file (program),
     the user and/or group identifiers associated with the pro-
     cess can change.  If the file executed is a set-user-ID
     file, the effective and saved user IDs of the process are
     set to the owner of the file executed.  If the file executed
     is a set-group-ID file, the effective and saved group IDs of
     the process are set to the group of the file executed.  If
     the file executed is not a set-user-ID or set-group-ID file,
     the effective user ID, saved user ID, effective group ID,
     and saved group ID are not changed.

     The following subsections describe the behavior of setuid
     and setgid with respect to the three types of user and group
     IDs.

   setuid
     If the effective user ID of the process calling setuid is
     the superuser, the real, effective, and saved user IDs are
     set to the uid parameter.

     If the effective user ID of the calling process is not the
     superuser, but uid is either the real user ID or the saved
     user ID of the calling process, the effective user ID is set
     to uid.

   setgid
     If the effective user ID of the process calling setgid is
     the superuser, the real, effective, and saved group IDs are



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SETUID(2-SVR4)      RISC/os Reference Manual       SETUID(2-SVR4)



     set to the gid parameter.

     If the effective user ID of the calling process is not the
     superuser, but gid is either the real group ID or the saved
     group ID of the calling process, the effective group ID is
     set to gid.

     setuid and setgid fail if one or more of the following is
     true:

     EPERM     For setuid, if the effective user ID is not the
               superuser, and the uid parameter does not match
               either the real or saved user IDs.  For setgid, if
               the effective user ID is not the superuser, and
               the gid parameter does not match either the real
               or saved group IDs.

     EINVAL    The uid or gid is out of range.

DIAGNOSTICS
     Upon successful completion, a value of 0 is returned.  Oth-
     erwise, a value of -1 is returned and errno is set to indi-
     cate the error.

SEE ALSO
     intro(2), exec(2), getgroups(2), getuid(2), stat(5).





























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