setuid(2) [osf1 man page]
setuid(2) System Calls Manual setuid(2) NAME
setuid - Sets the user ID SYNOPSIS
#include <unistd.h> int setuid ( uid_t user_id ); Application developers may want to specify an #include statement for <sys/types.h> before the one for <unistd.h> if programs are being developed for multiple platforms. The additional #include statement is not required on Tru64 UNIX systems or by ISO or X/Open standards, but may be required on other vendors' systems that conform to these standards. STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: setuid(): XSH5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Specifies the new user ID. DESCRIPTION
The setuid() function sets the real user ID, effective user ID, and the saved set user ID to the user_id parameter. To change the real user ID, the effective user ID, and the saved set user ID, the calling process must have superuser privilege. If the process does not have appropriate privilege, but the user_id parameter is equal to the real user ID or the saved set user ID, the setuid() function sets the effective user ID to the user_id parameter. The real user ID and saved set user ID remain unchanged. RETURN VALUES
Upon successful completion, the setuid() function returns a value of 0 (zero). Otherwise, the function returns a value of -1 and sets errno to indicate the error. ERRORS
The setuid() function sets errno to the specified values for the following conditions: [Tru64 UNIX] The process is attempting an operation that would exceeds a system limit, such as the number of tasks or threads allowed for a user ID. The value of the user_id parameter is invalid. The process does not have superuser privileges, and the user_id parameter does not match the real user ID or the saved set user ID. RELATED INFORMATION
Functions: exec(2), getuid(2), setgid(2), setreuid(2) Standards: standards(5) delim off setuid(2)
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setuid(2) System Calls setuid(2) NAME
setuid, setegid, seteuid, setgid - set user and group IDs SYNOPSIS
#include <sys/types.h> #include <unistd.h> int setuid(uid_t uid); int setgid(gid_t gid); int seteuid(uid_t euid); int setegid(gid_t egid); DESCRIPTION
The setuid() function sets the real user ID, effective user ID, and saved user ID of the calling process. The setgid() function sets the real group ID, effective group ID, and saved group ID of the calling process. The setegid() and seteuid() functions set the effective group and user IDs respectively for the calling process. See intro(2) for more information on real, effective, and saved user and group IDs. 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 one of the exec(2) family of functions to execute a file (program), the user and/or group identifiers associated with the process 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. If the {PRIV_PROC_SETID} privilege is asserted in the effective set of the process calling setuid(), the real, effective, and saved user IDs are set to the uid argument. If the uid argument is 0 and none of the saved, effective or real UID is 0, additional restrictions apply. See privileges(5). If the {PRIV_PROC_SETID} privilege is not asserted in the effective set, 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. If the {PRIV_PROC_SETID} privilege is asserted in the effective set of the process calling setgid(), the real, effective, and saved group IDs are set to the gid argument. If the {PRIV_PROC_SETID} privilege is not asserted in the effective set, 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. RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The setuid() and setgid() functions will fail if: EINVAL The value of uid or gid is out of range. EPERM For setuid() and seteuid(), the {PRIV_PROC_SETID} privilege is not asserted in the effective set of the calling process and the uid argument does not match either the real or saved user IDs, or an attempt is made to change to UID 0 and none of the existing UIDs is 0, in which case additional privileges are required. For setgid() and setegid(), the {PRIV_PROC_SETID} privilege is not asserted in the effective set and the gid argument does not match either the real or saved group IDs. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
intro(2), exec(2), getgroups(2), getuid(2), stat.h(3HEAD), attributes(5), privileges(5), standards(5) SunOS 5.10 20 Jan 2003 setuid(2)