forked from rpms/glibc
407 lines
13 KiB
Diff
407 lines
13 KiB
Diff
commit bdee910e88006ae33dc83ac3d2c0708adb6627d0
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Wed Jul 15 13:41:31 2020 +0200
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nss: Add __nss_fgetent_r
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And helper functions __nss_readline, __nss_readline_seek,
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__nss_parse_line_result.
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This consolidates common code for handling overlong lines and
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parse files. Use the new functionality in internal_getent
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in nss/nss_files/files-XXX.c.
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Tested-by: Carlos O'Donell <carlos@redhat.com>
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Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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diff -rupN a/include/nss_files.h b/include/nss_files.h
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--- a/include/nss_files.h 2020-09-14 17:48:49.353699306 -0400
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+++ b/include/nss_files.h 2020-09-14 17:55:21.856488740 -0400
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@@ -25,6 +25,28 @@
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FILE *__nss_files_fopen (const char *path);
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libc_hidden_proto (__nss_files_fopen)
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+/* Read a line from FP, storing it BUF. Strip leading blanks and skip
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+ comments. Sets errno and returns error code on failure. Special
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+ failure: ERANGE means the buffer is too small. The function writes
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+ the original offset to *POFFSET (which can be negative in the case
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+ of non-seekable input). */
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+int __nss_readline (FILE *fp, char *buf, size_t len, off64_t *poffset);
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+libc_hidden_proto (__nss_readline)
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+
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+/* Seek FP to OFFSET. Sets errno and returns error code on failure.
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+ On success, sets errno to ERANGE and returns ERANGE (to indicate
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+ re-reading of the same input line to the caller). If OFFSET is
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+ negative, fail with ESPIPE without seeking. Intended to be used
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+ after parsing data read by __nss_readline failed with ERANGE. */
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+int __nss_readline_seek (FILE *fp, off64_t offset) attribute_hidden;
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+
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+/* Handles the result of a parse_line call (as defined by
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+ nss/nss_files/files-parse.c). Adjusts the file offset of FP as
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+ necessary. Returns 0 on success, and updates errno on failure (and
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+ returns that error code). */
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+int __nss_parse_line_result (FILE *fp, off64_t offset, int parse_line_result);
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+libc_hidden_proto (__nss_parse_line_result)
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+
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struct parser_data;
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/* Instances of the parse_line function from
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@@ -52,4 +74,11 @@ libnss_files_hidden_proto (_nss_files_pa
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libc_hidden_proto (_nss_files_parse_sgent)
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libc_hidden_proto (_nss_files_parse_spent)
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+/* Generic implementation of fget*ent_r. Reads lines from FP until
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+ EOF or a successful parse into *RESULT using PARSER. Returns 0 on
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+ success, ENOENT on EOF, ERANGE on too-small buffer. */
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+int __nss_fgetent_r (FILE *fp, void *result,
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+ char *buffer, size_t buffer_length,
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+ nss_files_parse_line parser) attribute_hidden;
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+
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#endif /* _NSS_FILES_H */
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diff -rupN a/nss/Makefile b/nss/Makefile
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--- a/nss/Makefile 2020-09-14 17:48:49.293697045 -0400
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+++ b/nss/Makefile 2020-09-14 17:55:21.860488891 -0400
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@@ -28,7 +28,9 @@ headers := nss.h
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routines = nsswitch getnssent getnssent_r digits_dots \
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valid_field valid_list_field rewrite_field \
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$(addsuffix -lookup,$(databases)) \
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- compat-lookup nss_hash nss_files_fopen
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+ compat-lookup nss_hash nss_files_fopen \
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+ nss_readline nss_parse_line_result \
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+ nss_fgetent_r
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# These are the databases that go through nss dispatch.
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# Caution: if you add a database here, you must add its real name
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diff -rupN a/nss/Versions b/nss/Versions
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--- a/nss/Versions 2020-09-14 17:48:49.294697083 -0400
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+++ b/nss/Versions 2020-09-14 17:55:21.867489155 -0400
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@@ -21,7 +21,7 @@ libc {
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__nss_passwd_lookup2; __nss_group_lookup2; __nss_hosts_lookup2;
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__nss_services_lookup2; __nss_next2; __nss_lookup;
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__nss_hash; __nss_database_lookup2;
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- __nss_files_fopen;
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+ __nss_files_fopen; __nss_readline; __nss_parse_line_result;
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}
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}
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diff -rupN a/nss/nss_fgetent_r.c b/nss/nss_fgetent_r.c
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--- a/nss/nss_fgetent_r.c 1969-12-31 19:00:00.000000000 -0500
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+++ b/nss/nss_fgetent_r.c 2020-09-14 17:55:21.870489268 -0400
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@@ -0,0 +1,55 @@
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+/* Generic implementation of fget*ent_r.
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+ Copyright (C) 2020 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <errno.h>
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+#include <nss_files.h>
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+
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+int
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+__nss_fgetent_r (FILE *fp, void *result, char *buffer, size_t buffer_length,
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+ nss_files_parse_line parser)
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+{
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+ int ret;
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+
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+ _IO_flockfile (fp);
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+
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+ while (true)
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+ {
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+ off64_t original_offset;
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+ ret = __nss_readline (fp, buffer, buffer_length, &original_offset);
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+ if (ret == 0)
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+ {
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+ /* Parse the line into *RESULT. */
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+ ret = parser (buffer, result,
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+ (struct parser_data *) buffer, buffer_length, &errno);
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+
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+ /* Translate the result code from the parser into an errno
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+ value. Also seeks back to the start of the line if
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+ necessary. */
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+ ret = __nss_parse_line_result (fp, original_offset, ret);
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+
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+ if (ret == EINVAL)
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+ /* Skip over malformed lines. */
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+ continue;
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+ }
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+ break;
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+ }
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+
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+ _IO_funlockfile (fp);
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+
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+ return ret;
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+}
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diff -rupN a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c
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--- a/nss/nss_files/files-XXX.c 2020-09-14 17:48:49.296697158 -0400
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+++ b/nss/nss_files/files-XXX.c 2020-09-14 17:55:21.878489569 -0400
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@@ -135,10 +135,9 @@ internal_getent (FILE *stream, struct ST
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char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO
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EXTRA_ARGS_DECL)
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{
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- char *p;
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struct parser_data *data = (void *) buffer;
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size_t linebuflen = buffer + buflen - data->linebuffer;
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- int parse_result;
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+ int saved_errno = errno; /* Do not clobber errno on success. */
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if (buflen < sizeof *data + 2)
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{
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@@ -149,66 +148,42 @@ internal_getent (FILE *stream, struct ST
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while (true)
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{
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- ssize_t r = __libc_readline_unlocked
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- (stream, data->linebuffer, linebuflen);
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- if (r < 0)
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- {
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- *errnop = errno;
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- H_ERRNO_SET (NETDB_INTERNAL);
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- if (*errnop == ERANGE)
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- /* Request larger buffer. */
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- return NSS_STATUS_TRYAGAIN;
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- else
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- /* Other read failure. */
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- return NSS_STATUS_UNAVAIL;
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- }
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- else if (r == 0)
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+ off64_t original_offset;
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+ int ret = __nss_readline (stream, data->linebuffer, linebuflen,
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+ &original_offset);
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+ if (ret == ENOENT)
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{
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/* End of file. */
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H_ERRNO_SET (HOST_NOT_FOUND);
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+ __set_errno (saved_errno);
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return NSS_STATUS_NOTFOUND;
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}
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-
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- /* Everything OK. Now skip leading blanks. */
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- p = data->linebuffer;
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- while (isspace (*p))
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- ++p;
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-
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- /* Ignore empty and comment lines. */
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- if (*p == '\0' || *p == '#')
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- continue;
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-
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- /* Parse the line. */
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- *errnop = EINVAL;
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- parse_result = parse_line (p, result, data, buflen, errnop EXTRA_ARGS);
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-
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- if (parse_result == -1)
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+ else if (ret == 0)
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{
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- if (*errnop == ERANGE)
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+ ret = __nss_parse_line_result (stream, original_offset,
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+ parse_line (data->linebuffer,
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+ result, data, buflen,
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+ errnop EXTRA_ARGS));
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+ if (ret == 0)
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{
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- /* Return to the original file position at the beginning
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- of the line, so that the next call can read it again
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- if necessary. */
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- if (__fseeko64 (stream, -r, SEEK_CUR) != 0)
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- {
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- if (errno == ERANGE)
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- *errnop = EINVAL;
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- else
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- *errnop = errno;
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- H_ERRNO_SET (NETDB_INTERNAL);
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- return NSS_STATUS_UNAVAIL;
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- }
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+ /* Line has been parsed successfully. */
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+ __set_errno (saved_errno);
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+ return NSS_STATUS_SUCCESS;
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}
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- H_ERRNO_SET (NETDB_INTERNAL);
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- return NSS_STATUS_TRYAGAIN;
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+ else if (ret == EINVAL)
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+ /* If it is invalid, loop to get the next line of the file
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+ to parse. */
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+ continue;
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}
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- /* Return the data if parsed successfully. */
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- if (parse_result != 0)
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- return NSS_STATUS_SUCCESS;
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-
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- /* If it is invalid, loop to get the next line of the file to
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- parse. */
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+ *errnop = ret;
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+ H_ERRNO_SET (NETDB_INTERNAL);
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+ if (ret == ERANGE)
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+ /* Request larger buffer. */
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+ return NSS_STATUS_TRYAGAIN;
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+ else
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+ /* Other read failure. */
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+ return NSS_STATUS_UNAVAIL;
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}
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}
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diff -rupN a/nss/nss_parse_line_result.c b/nss/nss_parse_line_result.c
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--- a/nss/nss_parse_line_result.c 1969-12-31 19:00:00.000000000 -0500
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+++ b/nss/nss_parse_line_result.c 2020-09-14 17:55:21.880489645 -0400
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@@ -0,0 +1,46 @@
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+/* Implementation of __nss_parse_line_result.
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+ Copyright (C) 2020 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <nss_files.h>
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+
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+#include <assert.h>
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+#include <errno.h>
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+
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+int
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+__nss_parse_line_result (FILE *fp, off64_t offset, int parse_line_result)
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+{
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+ assert (parse_line_result >= -1 && parse_line_result <= 1);
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+
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+ switch (__builtin_expect (parse_line_result, 1))
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+ {
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+ case 1:
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+ /* Sucess. */
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+ return 0;
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+ case 0:
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+ /* Parse error. */
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+ __set_errno (EINVAL);
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+ return EINVAL;
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+ case -1:
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+ /* Out of buffer space. */
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+ return __nss_readline_seek (fp, offset);
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+
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+ default:
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+ __builtin_unreachable ();
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+ }
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+}
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+libc_hidden_def (__nss_parse_line_result)
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diff -rupN a/nss/nss_readline.c b/nss/nss_readline.c
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--- a/nss/nss_readline.c 1969-12-31 19:00:00.000000000 -0500
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+++ b/nss/nss_readline.c 2020-09-14 17:55:21.883489758 -0400
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@@ -0,0 +1,99 @@
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+/* Read a line from an nss_files database file.
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+ Copyright (C) 2020 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <nss_files.h>
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+
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+#include <ctype.h>
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+#include <errno.h>
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+#include <string.h>
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+
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+int
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+__nss_readline (FILE *fp, char *buf, size_t len, off64_t *poffset)
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+{
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+ /* We need space for at least one character, the line terminator,
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+ and the NUL byte. */
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+ if (len < 3)
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+ {
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+ *poffset = -1;
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+ __set_errno (ERANGE);
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+ return ERANGE;
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+ }
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+
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+ while (true)
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+ {
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+ /* Keep original offset for retries. */
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+ *poffset = __ftello64 (fp);
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+
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+ buf[len - 1] = '\xff'; /* Marker to recognize truncation. */
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+ if (fgets_unlocked (buf, len, fp) == NULL)
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+ {
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+ if (feof_unlocked (fp))
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+ {
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+ __set_errno (ENOENT);
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+ return ENOENT;
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+ }
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+ else
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+ {
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+ /* Any other error. Do not return ERANGE in this case
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+ because the caller would retry. */
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+ if (errno == ERANGE)
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+ __set_errno (EINVAL);
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+ return errno;
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+ }
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+ }
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+ else if (buf[len - 1] != '\xff')
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+ /* The buffer is too small. Arrange for re-reading the same
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+ line on the next call. */
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+ return __nss_readline_seek (fp, *poffset);
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+
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+ /* fgets_unlocked succeeded. */
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+
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+ /* Remove leading whitespace. */
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+ char *p = buf;
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+ while (isspace (*p))
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+ ++p;
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+ if (*p == '\0' || *p == '#')
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+ /* Skip empty lines and comments. */
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+ continue;
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+ if (p != buf)
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+ memmove (buf, p, strlen (p));
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+
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+ /* Return line to the caller. */
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+ return 0;
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+ }
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+}
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+libc_hidden_def (__nss_readline)
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+
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+int
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+__nss_readline_seek (FILE *fp, off64_t offset)
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+{
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+ if (offset < 0 /* __ftello64 failed. */
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+ || __fseeko64 (fp, offset, SEEK_SET) < 0)
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+ {
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+ /* Without seeking support, it is not possible to
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+ re-read the same line, so this is a hard failure. */
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+ fseterr_unlocked (fp);
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+ __set_errno (ESPIPE);
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+ return ESPIPE;
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+ }
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+ else
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+ {
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+ __set_errno (ERANGE);
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+ return ERANGE;
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+ }
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+}
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