60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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grp/getgrgid.c
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Searchs the group database for a group with the given numeric group id in a
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thread-insecure manner.
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*******************************************************************************/
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#include <errno.h>
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#include <grp.h>
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#include <stdlib.h>
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struct group* getgrgid(gid_t gid)
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{
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static struct group result_object;
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static char* buf = NULL;
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static size_t buflen = 0;
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if ( !buf )
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{
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size_t new_buflen = 64;
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if ( !(buf = (char*) malloc(new_buflen)) )
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return NULL;
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buflen = new_buflen;
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}
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struct group* result;
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int errnum;
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retry:
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errnum = getgrgid_r(gid, &result_object, buf, buflen, &result);
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if ( errnum == ERANGE )
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{
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size_t new_buflen = 2 * buflen;
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char* new_buf = (char*) realloc(buf, new_buflen);
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if ( !new_buf )
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return NULL;
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buf = new_buf;
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buflen = new_buflen;
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goto retry;
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}
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if ( errnum < 0 )
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return errno = errnum, (struct group*) NULL;
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return result;
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}
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