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Diffstat (limited to 'man3/getgrnam.3')
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diff --git a/man3/getgrnam.3 b/man3/getgrnam.3 new file mode 100644 index 000000000..6e5bfe250 --- /dev/null +++ b/man3/getgrnam.3 @@ -0,0 +1,176 @@ +.\" 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 +.\" preserved on all copies. +.\" +.\" 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 +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date.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 2003-11-15 by aeb +.\" +.TH GETGRNAM 3 2003-11-15 "" "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 *" gbuf , +.br +.BI " char *" buf ", size_t " buflen ", struct group **" gbufp ); +.sp +.BI "int getgrgid_r(gid_t " gid ", struct group *" gbuf , +.br +.BI " char *" buf ", size_t " buflen ", struct group **" gbufp ); +.fi +.SH DESCRIPTION +The +.B getgrnam() +function returns a pointer to a structure containing +the group information from +.I /etc/group +for the entry that matches the group name +.IR name . +.PP +The +.B getgrgid() +function returns a pointer to a structure containing +the group information from +.I /etc/group +for the entry that matches the group gid +.IR gid . +.PP +The +.B getgrnam_r() +and +.B getgrgid_r() +functions find the same information, but store the retrieved group structure +in the space pointed to by +.IR gbuf . +This group 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 * gbufp . +.PP +The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows: +.sp +.RS +.nf +struct group { + char *gr_name; /* group name */ + char *gr_passwd; /* group password */ + gid_t gr_gid; /* group id */ + char **gr_mem; /* group members */ +}; +.fi +.RE +.PP +The maximum needed size for +.I buf +can be found using +.BR sysconf (3) +with the _SC_GETGR_R_SIZE_MAX parameter. +.SH "RETURN VALUE" +The \fBgetgrnam()\fP and \fBgetgrgid()\fP functions return a pointer +to the group information 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 getgrent() , +.BR getgrgid() , +or +.BR getgrnam() . +.LP +The \fBgetgrnam_r()\fP and \fBgetgrgid_r()\fP functions return +zero on success. In case of error, an error value is returned. +.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. +.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 +Insufficient memory. +.\" to allocate the group structure, or to allocate buffers +.TP +.B ERANGE +Insufficient buffer space supplied. +.SH FILES +.TP +.I /etc/group +group database file +.SH "CONFORMING TO" +SVID 3, BSD 4.3, 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, 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 shows 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 +.SH "SEE ALSO" +.BR endgrent (3), +.BR fgetgrent (3), +.BR getgrent (3), +.BR getpwnam (3), +.BR setgrent (3), +.BR group (5) |