The <pwd.h> and <grp.h> family of functions are supposed to return nothing with no error set if there is no matching entry.
57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/*
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* Copyright (c) 2013, 2021 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* pwd/getpwnam.c
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* Searchs the passwd database for a user with the given username 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 <pwd.h>
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#include <stdlib.h>
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struct passwd* getpwnam(const char* username)
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{
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int old_errno = errno;
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static struct passwd 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 passwd* result;
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int errnum;
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retry:
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errnum = getpwnam_r(username, &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 passwd*) NULL;
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errno = old_errno;
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return result;
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}
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