| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
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| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
| .\" professionally. |
| .\" |
| .\" Formatted or processed versions of this manual, if unaccompanied by |
| .\" the source, must acknowledge the copyright and authors of this work. |
| .\" |
| .\" References consulted: |
| .\" Linux libc source code |
| .\" Lewine's "POSIX Programmer's Guide" (O'Reilly & Associates, 1991) |
| .\" 386BSD man pages |
| .\" |
| .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) |
| .\" Modified 1996-05-27 by Martin Schulze (joey@linux.de) |
| .\" Modified 2003-11-15 by aeb |
| .\" |
| .TH GETPWNAM 3 1996-05-27 "GNU" "Linux Programmer's Manual" |
| .SH NAME |
| getpwnam, getpwnam_r, getpwuid, getpwuid_r \- get password file entry |
| .SH SYNOPSIS |
| .nf |
| .B #include <sys/types.h> |
| .B #include <pwd.h> |
| .sp |
| .BI "struct passwd *getpwnam(const char *" name ); |
| .sp |
| .BI "struct passwd *getpwuid(uid_t " uid ); |
| .sp |
| .BI "int getpwnam_r(const char *" name ", struct passwd *" pwbuf , |
| .br |
| .BI " char *" buf ", size_t " buflen ", struct passwd **" pwbufp ); |
| .sp |
| .BI "int getpwuid_r(uid_t " uid ", struct passwd *" pwbuf , |
| .br |
| .BI " char *" buf ", size_t " buflen ", struct passwd **" pwbufp ); |
| .fi |
| .SH DESCRIPTION |
| The |
| .BR getpwnam () |
| function returns a pointer to a structure containing |
| the broken-out fields of the record in the password database |
| (e.g., the local password file |
| .IR /etc/passwd , |
| NIS, and LDAP) |
| that matches the user name |
| .IR name . |
| .PP |
| The |
| .BR getpwuid () |
| function returns a pointer to a structure containing |
| the broken-out fields of the record in the password database |
| that matches the user ID |
| .IR uid . |
| .PP |
| The |
| .BR getpwnam_r () |
| and |
| .BR getpwuid_r () |
| functions obtain the same information, but store the retrieved |
| .I passwd |
| structure in the space pointed to by |
| .IR pwbuf . |
| This |
| .I passwd |
| structure contains pointers to strings, and these strings |
| are stored in the buffer |
| .I buf |
| of size |
| .IR buflen . |
| A pointer to the result (in case of success) or NULL (in case no entry |
| was found or an error occurred) is stored in |
| .RI * pwbufp . |
| .PP |
| The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows: |
| .sp |
| .RS 0.25i |
| .nf |
| struct passwd { |
| char *pw_name; /* user name */ |
| char *pw_passwd; /* user password */ |
| uid_t pw_uid; /* user ID */ |
| gid_t pw_gid; /* group ID */ |
| char *pw_gecos; /* real name */ |
| char *pw_dir; /* home directory */ |
| char *pw_shell; /* shell program */ |
| }; |
| .fi |
| .RE |
| .PP |
| The maximum needed size for |
| .I buf |
| can be found using |
| .BR sysconf (3) |
| with the _SC_GETPW_R_SIZE_MAX parameter. |
| .SH "RETURN VALUE" |
| The \fBgetpwnam\fP() and \fBgetpwuid\fP() functions return a pointer to a |
| .I passwd |
| structure, or NULL if the matching entry is not found or |
| an error occurs. |
| If an error occurs, |
| .I errno |
| is set appropriately. |
| If one wants to check |
| .I errno |
| after the call, it should be set to zero before the call. |
| .LP |
| The return value may point to static area, and may be overwritten |
| by subsequent calls to |
| .BR getpwent (), |
| .BR getpwnam (), |
| or |
| .BR getpwuid (). |
| .LP |
| The \fBgetpwnam_r\fP() and \fBgetpwuid_r\fP() functions return |
| zero on success. In case of error, an error number is returned. |
| .SH ERRORS |
| .TP |
| .BR 0 " or " ENOENT " or " ESRCH " or " EBADF " or " EPERM " or ... " |
| The given |
| .I name |
| or |
| .I uid |
| was not found. |
| .TP |
| .B EINTR |
| A signal was caught. |
| .TP |
| .B EIO |
| I/O error. |
| .TP |
| .B EMFILE |
| The maximum number (OPEN_MAX) of files was open already in the calling process. |
| .TP |
| .B ENFILE |
| The maximum number of files was open already in the system. |
| .TP |
| .B ENOMEM |
| .\" not in POSIX |
| Insufficient memory to allocate passwd structure. |
| .\" This structure is static, allocated 0 or 1 times. No memory leak. (libc45) |
| .TP |
| .B ERANGE |
| Insufficient buffer space supplied. |
| .SH FILES |
| .TP |
| .I /etc/passwd |
| local password database file |
| .fi |
| .SH "CONFORMING TO" |
| SVID 3, 4.3BSD, POSIX 1003.1-2003 |
| .SH NOTES |
| The formulation given above under "RETURN VALUE" is from POSIX 1003.1-2001. |
| It does not call "not found" an error, and hence does not specify what value |
| .I errno |
| might have in this situation. But that makes it impossible to recognize |
| errors. One might argue that according to POSIX |
| .I errno |
| should be left unchanged if an entry is not found. Experiments on various |
| Unix-like systems show that lots of different values occur in this |
| situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others. |
| .\" more precisely: |
| .\" AIX 5.1 - gives ESRCH |
| .\" OSF1 4.0g - gives EWOULDBLOCK |
| .\" libc, glibc, Irix 6.5 - give ENOENT |
| .\" FreeBSD 4.8, OpenBSD 3.2, NetBSD 1.6 - give EPERM |
| .\" SunOS 5.8 - gives EBADF |
| .\" Tru64 5.1b, HP-UX-11i, SunOS 5.7 - give 0 |
| |
| The |
| .I pw_dir |
| field contains the name of the initial working directory of the user. |
| Login programs use the value of this field to initialize |
| the HOME environment variable for the login shell. |
| An application that wants to determine its user's home directory |
| should inspect the value of HOME (rather than the value |
| .IR getpwuid(getuid())->pw_dir ) |
| since this allows the user to modify their notion of |
| "the home directory" during a login session. |
| To determine the (initial) home directory of another user, |
| it is necessary to use |
| .I getpwnam("username")->pw_dir |
| or similar. |
| .SH "SEE ALSO" |
| .BR endpwent (3), |
| .BR fgetpwent (3), |
| .BR getgrnam (3), |
| .BR getpw (3), |
| .BR getpwent (3), |
| .BR putpwent (3), |
| .BR setpwent (3), |
| .BR passwd (5) |