| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
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| .\" 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| .\" manual page may be incorrect or out-of-date.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 |
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| .\" 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 2003-11-15 by aeb |
| .\" |
| .TH GETGRNAM 3 2016-03-15 "" "Linux Programmer's Manual" |
| .SH NAME |
| getgrnam, getgrnam_r, getgrgid, getgrgid_r \- get group file entry |
| .SH SYNOPSIS |
| .nf |
| .B #include <sys/types.h> |
| .B #include <grp.h> |
| .sp |
| .BI "struct group *getgrnam(const char *" name ); |
| .sp |
| .BI "struct group *getgrgid(gid_t " gid ); |
| .sp |
| .BI "int getgrnam_r(const char *" name ", struct group *" grp , |
| .br |
| .BI " char *" buf ", size_t " buflen ", struct group **" result ); |
| .sp |
| .BI "int getgrgid_r(gid_t " gid ", struct group *" grp , |
| .br |
| .BI " char *" buf ", size_t " buflen ", struct group **" result ); |
| .fi |
| .sp |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .ad l |
| .in |
| .sp |
| .BR getgrnam_r (), |
| .BR getgrgid_r (): |
| .RS 4 |
| _POSIX_C_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .ad b |
| .SH DESCRIPTION |
| The |
| .BR getgrnam () |
| function returns a pointer to a structure containing |
| the broken-out fields of the record in the group database |
| (e.g., the local group file |
| .IR /etc/group , |
| NIS, and LDAP) |
| that matches the group name |
| .IR name . |
| .PP |
| The |
| .BR getgrgid () |
| function returns a pointer to a structure containing |
| the broken-out fields of the record in the group database |
| that matches the group ID |
| .IR gid . |
| .PP |
| The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows: |
| .sp |
| .in +4n |
| .nf |
| struct group { |
| char *gr_name; /* group name */ |
| char *gr_passwd; /* group password */ |
| gid_t gr_gid; /* group ID */ |
| char **gr_mem; /* NULL-terminated array of pointers |
| to names of group members */ |
| }; |
| .fi |
| .in |
| .PP |
| For more information about the fields of this structure, see |
| .BR group (5). |
| .PP |
| The |
| .BR getgrnam_r () |
| and |
| .BR getgrgid_r () |
| functions obtain the same information as |
| .BR getgrnam () |
| and |
| .BR getgrgid (), |
| but store the retrieved |
| .I group |
| structure |
| in the space pointed to by |
| .IR grp . |
| The string fields pointed to by the members of the |
| .I group |
| structure 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 |
| .IR *result . |
| .PP |
| The call |
| |
| sysconf(_SC_GETGR_R_SIZE_MAX) |
| |
| returns either \-1, without changing |
| .IR errno , |
| or an initial suggested size for |
| .IR buf . |
| (If this size is too small, |
| the call fails with |
| .BR ERANGE , |
| in which case the caller can retry with a larger buffer.) |
| .SH RETURN VALUE |
| The |
| .BR getgrnam () |
| and |
| .BR getgrgid () |
| functions return a pointer to a |
| .I group |
| 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 a static area, and may be overwritten |
| by subsequent calls to |
| .BR getgrent (3), |
| .BR getgrgid (), |
| or |
| .BR getgrnam (). |
| (Do not pass the returned pointer to |
| .BR free (3).) |
| .LP |
| On success, |
| .BR getgrnam_r () |
| and |
| .BR getgrgid_r () |
| return zero, and set |
| .IR *result |
| to |
| .IR grp . |
| If no matching group record was found, |
| these functions return 0 and store NULL in |
| .IR *result . |
| In case of error, an error number is returned, and NULL is stored in |
| .IR *result . |
| .SH ERRORS |
| .TP |
| .BR 0 " or " ENOENT " or " ESRCH " or " EBADF " or " EPERM " or ... " |
| The given |
| .I name |
| or |
| .I gid |
| was not found. |
| .TP |
| .B EINTR |
| A signal was caught; see |
| .BR signal (7). |
| .TP |
| .B EIO |
| I/O error. |
| .TP |
| .B EMFILE |
| The per-process limit on the number of open file descriptors has been reached. |
| .TP |
| .B ENFILE |
| The system-wide limit on the total number of open files has been reached. |
| .TP |
| .B ENOMEM |
| .\" not in POSIX |
| Insufficient memory to allocate |
| .I group |
| structure. |
| .\" to allocate the group structure, or to allocate buffers |
| .TP |
| .B ERANGE |
| Insufficient buffer space supplied. |
| .SH FILES |
| .TP |
| .I /etc/group |
| local group database file |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lb lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR getgrnam () |
| T} Thread safety MT-Unsafe race:grnam locale |
| T{ |
| .BR getgrgid () |
| T} Thread safety MT-Unsafe race:grgid locale |
| T{ |
| .BR getgrnam_r (), |
| .br |
| .BR getgrgid_r () |
| T} Thread safety MT-Safe locale |
| .TE |
| .SH CONFORMING TO |
| POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. |
| .SH NOTES |
| The formulation given above under "RETURN VALUE" is from POSIX.1. |
| .\" POSIX.1-2001, POSIX.1-2008 |
| It does not call "not found" an error, 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 up to version 2.6, Irix 6.5 - give ENOENT |
| .\" glibc since version 2.7 - give 0 |
| .\" 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 |
| .SH SEE ALSO |
| .BR endgrent (3), |
| .BR fgetgrent (3), |
| .BR getgrent (3), |
| .BR getpwnam (3), |
| .BR setgrent (3), |
| .BR group (5) |