From 3f5e3f5d066dcffb80af48ae2cf35a01a85a8f10 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 6 Jul 2018 16:53:48 +0200 Subject: libio: Implement internal function __libc_readline_unlocked This is a variant of fgets which fails with ERANGE if the buffer is too small, and the buffer length is given as an argument of type size_t. This function will be useful for implementing NSS file reading operations. Compared to a direct implementation using the public API, it avoids an lseek system call in case the line terminator can be found in the internal read buffer. --- libio/tst-readline.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 236 insertions(+) create mode 100644 libio/tst-readline.c (limited to 'libio/tst-readline.c') diff --git a/libio/tst-readline.c b/libio/tst-readline.c new file mode 100644 index 0000000000..60c58c650a --- /dev/null +++ b/libio/tst-readline.c @@ -0,0 +1,236 @@ +/* Test the __libc_readline_unlocked function. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* Exercise __libc_readline_unlocked with various combinations of line + lengths, stdio buffer sizes, and line read buffer sizes. */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum + { + maximum_line_length = 7, + number_of_lines = 3, + }; + +/* -1: Do not set buffer size. 0: unbuffered. Otherwise, use this as + the size of the buffer. */ +static int buffer_size; + +/* These size of the buffer used for reading. Must be at least 2. */ +static int read_size; + +/* If a read files with ERANGE, increase the buffer size by this + amount. Must be positive. */ +static int read_size_increment; + +/* If non-zero, do not reset the read size after an ERANGE error. */ +static int read_size_preserve; + +/* If non-zero, no '\n' at the end of the file. */ +static int no_newline_at_eof; + +/* Length of the line, or -1 if the line is not present. */ +static int line_lengths[number_of_lines]; + +/* The name of the test file. */ +static char *test_file_path; + +/* The contents of the test file. */ +static char expected_contents[(maximum_line_length + 2) * number_of_lines + 1]; +static size_t expected_length; + +/* Returns a random byte which is not zero or the line terminator. */ +static char +random_char (void) +{ + static unsigned int rand_state = 1; + while (true) + { + char result = rand_r (&rand_state) >> 16; + if (result != 0 && result != '\n') + return result; + } +} + +/* Create the test file. */ +static void +prepare (int argc, char **argv) +{ + int fd = create_temp_file ("tst-readline-", &test_file_path); + TEST_VERIFY_EXIT (fd >= 0); + xclose (fd); +} + +/* Prepare the test file. Return false if the test parameters are + incongruent and the test should be skipped. */ +static bool +write_test_file (void) +{ + expected_length = 0; + char *p = expected_contents; + for (int lineno = 0; lineno < number_of_lines; ++lineno) + for (int i = 0; i < line_lengths[lineno]; ++i) + *p++ = random_char (); + expected_length = p - &expected_contents[0]; + if (no_newline_at_eof) + { + if (expected_length == 0) + return false; + --expected_length; + --p; + } + if (test_verbose > 0) + { + printf ("info: writing test file of %zu bytes:\n", expected_length); + for (int i = 0; i < number_of_lines; ++i) + printf (" line %d: %d\n", i, line_lengths[i]); + if (no_newline_at_eof) + puts (" (no newline at EOF)"); + } + TEST_VERIFY_EXIT (expected_length < sizeof (expected_contents)); + *p++ = '\0'; + support_write_file_string (test_file_path, expected_contents); + return true; +} + +/* Run a single test (a combination of a test file and read + parameters). */ +static void +run_test (void) +{ + TEST_VERIFY_EXIT (read_size_increment > 0); + if (test_verbose > 0) + { + printf ("info: running test: buffer_size=%d read_size=%d\n" + " read_size_increment=%d read_size_preserve=%d\n", + buffer_size, read_size, read_size_increment, read_size_preserve); + } + + struct xmemstream result; + xopen_memstream (&result); + + FILE *fp = xfopen (test_file_path, "rce"); + char *fp_buffer = NULL; + if (buffer_size == 0) + TEST_VERIFY_EXIT (setvbuf (fp, NULL, _IONBF, 0) == 0); + if (buffer_size > 0) + { + fp_buffer = xmalloc (buffer_size); + TEST_VERIFY_EXIT (setvbuf (fp, fp_buffer, _IOFBF, buffer_size) == 0); + } + + char *line_buffer = xmalloc (read_size); + size_t line_buffer_size = read_size; + + while (true) + { + ssize_t ret = __libc_readline_unlocked + (fp, line_buffer, line_buffer_size); + if (ret < 0) + { + TEST_VERIFY (ret == -1); + if (errno != ERANGE) + FAIL_EXIT1 ("__libc_readline_unlocked: %m"); + line_buffer_size += read_size_increment; + free (line_buffer); + line_buffer = xmalloc (line_buffer_size); + /* Try reading this line again. */ + } + else if (ret == 0) + break; + else + { + /* A line has been read. Save it. */ + TEST_VERIFY (ret == strlen (line_buffer)); + const char *pnl = strchr (line_buffer, '\n'); + /* If there is a \n, it must be at the end. */ + TEST_VERIFY (pnl == NULL || pnl == line_buffer + ret - 1); + fputs (line_buffer, result.out); + + /* Restore the original read size if required. */ + if (line_buffer_size > read_size && !read_size_preserve) + { + line_buffer_size = read_size; + free (line_buffer); + line_buffer = xmalloc (line_buffer_size); + } + } + } + + xfclose (fp); + free (fp_buffer); + free (line_buffer); + + xfclose_memstream (&result); + TEST_VERIFY (result.length == expected_length); + TEST_VERIFY (strcmp (result.buffer, expected_contents) == 0); + if (test_verbose > 0) + { + printf ("info: expected (%zu): [[%s]]\n", + expected_length, expected_contents); + printf ("info: actual (%zu): [[%s]]\n", result.length, result.buffer); + } + free (result.buffer); +} + +/* Test one test file with multiple read parameters. */ +static void +test_one_file (void) +{ + for (buffer_size = -1; buffer_size <= maximum_line_length + 1; ++buffer_size) + for (read_size = 2; read_size <= maximum_line_length + 2; ++read_size) + for (read_size_increment = 1; read_size_increment <= 4; + ++read_size_increment) + for (read_size_preserve = 0; read_size_preserve < 2; + ++read_size_preserve) + run_test (); +} + + +static int +do_test (void) +{ + /* Set up the test file contents. */ + for (line_lengths[0] = -1; line_lengths[0] <= maximum_line_length; + ++line_lengths[0]) + for (line_lengths[1] = -1; line_lengths[1] <= maximum_line_length; + ++line_lengths[1]) + for (line_lengths[2] = -1; line_lengths[2] <= maximum_line_length; + ++line_lengths[2]) + for (no_newline_at_eof = 0; no_newline_at_eof < 2; ++no_newline_at_eof) + { + if (!write_test_file ()) + continue; + test_one_file (); + } + free (test_file_path); + return 0; +} + +#define PREPARE prepare +#include -- cgit v1.2.3 From 4fa34da6793c442255fc003cf659c85b197ab29a Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 10 Jul 2018 11:03:08 +0200 Subject: Fix copyright years in recent commits --- ChangeLog | 6 ++++++ libio/readline.c | 2 +- libio/tst-readline.c | 2 +- nss/tst-nss-files-hosts-getent.c | 2 +- 4 files changed, 9 insertions(+), 3 deletions(-) (limited to 'libio/tst-readline.c') diff --git a/ChangeLog b/ChangeLog index 7a052c344a..8068171e2b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2018-07-10 Florian Weimer + + * libio/readline.c: Fix copyright year. + * libio/tst-readline.c Likewise. + * nss/tst-nss-files-hosts-getent.c: Likewise. + 2018-07-06 Florian Weimer [BZ #18991] diff --git a/libio/readline.c b/libio/readline.c index 3638459176..3372ba2999 100644 --- a/libio/readline.c +++ b/libio/readline.c @@ -1,5 +1,5 @@ /* fgets with ERANGE error reporting and size_t buffer length. - Copyright (C) 2017 Free Software Foundation, Inc. + Copyright (C) 2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or diff --git a/libio/tst-readline.c b/libio/tst-readline.c index 60c58c650a..9322ef68da 100644 --- a/libio/tst-readline.c +++ b/libio/tst-readline.c @@ -1,5 +1,5 @@ /* Test the __libc_readline_unlocked function. - Copyright (C) 2017 Free Software Foundation, Inc. + Copyright (C) 2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or diff --git a/nss/tst-nss-files-hosts-getent.c b/nss/tst-nss-files-hosts-getent.c index d7514e8e38..3f5baced32 100644 --- a/nss/tst-nss-files-hosts-getent.c +++ b/nss/tst-nss-files-hosts-getent.c @@ -1,5 +1,5 @@ /* Enumerate /etc/hosts with a long line (bug 18991). - Copyright (C) 2017 Free Software Foundation, Inc. + Copyright (C) 2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or -- cgit v1.2.3