libio/tst-readline.c

   1 /* Test the __libc_readline_unlocked function.
   2    Copyright (C) 2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /* Exercise __libc_readline_unlocked with various combinations of line
  20    lengths, stdio buffer sizes, and line read buffer sizes.  */
  21
  22 #include <errno.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <support/check.h>
  27 #include <support/support.h>
  28 #include <support/temp_file.h>
  29 #include <support/test-driver.h>
  30 #include <support/xmemstream.h>
  31 #include <support/xstdio.h>
  32 #include <support/xunistd.h>
  33
  34 enum
  35   {
  36     maximum_line_length = 7,
  37     number_of_lines = 3,
  38   };
  39
  40 /* -1: Do not set buffer size.  0: unbuffered.  Otherwise, use this as
  41    the size of the buffer.  */
  42 static int buffer_size;
  43
  44 /* These size of the buffer used for reading.  Must be at least 2.  */
  45 static int read_size;
  46
  47 /* If a read files with ERANGE, increase the buffer size by this
  48    amount.  Must be positive.  */
  49 static int read_size_increment;
  50
  51 /* If non-zero, do not reset the read size after an ERANGE error.  */
  52 static int read_size_preserve;
  53
  54 /* If non-zero, no '\n' at the end of the file.  */
  55 static int no_newline_at_eof;
  56
  57 /* Length of the line, or -1 if the line is not present.  */
  58 static int line_lengths[number_of_lines];
  59
  60 /* The name of the test file.  */
  61 static char *test_file_path;
  62
  63 /* The contents of the test file.  */
  64 static char expected_contents[(maximum_line_length + 2) * number_of_lines + 1];
  65 static size_t expected_length;
  66
  67 /* Returns a random byte which is not zero or the line terminator.  */
  68 static char
  69 random_char (void)
  70 {
  71   static unsigned int rand_state = 1;
  72   while (true)
  73     {
  74       char result = rand_r (&rand_state) >> 16;
  75       if (result != 0 && result != '\n')
  76         return result;
  77     }
  78 }
  79
  80 /* Create the test file.  */
  81 static void
  82 prepare (int argc, char **argv)
  83 {
  84   int fd = create_temp_file ("tst-readline-", &test_file_path);
  85   TEST_VERIFY_EXIT (fd >= 0);
  86   xclose (fd);
  87 }
  88
  89 /* Prepare the test file.  Return false if the test parameters are
  90    incongruent and the test should be skipped.  */
  91 static bool
  92 write_test_file (void)
  93 {
  94   expected_length = 0;
  95   char *p = expected_contents;
  96   for (int lineno = 0; lineno < number_of_lines; ++lineno)
  97     for (int i = 0; i < line_lengths[lineno]; ++i)
  98       *p++ = random_char ();
  99   expected_length = p - &expected_contents[0];
 100   if (no_newline_at_eof)
 101     {
 102       if (expected_length == 0)
 103         return false;
 104       --expected_length;
 105       --p;
 106     }
 107   if (test_verbose > 0)
 108     {
 109       printf ("info: writing test file of %zu bytes:\n", expected_length);
 110       for (int i = 0; i < number_of_lines; ++i)
 111         printf (" line %d: %d\n", i, line_lengths[i]);
 112       if (no_newline_at_eof)
 113         puts ("  (no newline at EOF)");
 114     }
 115   TEST_VERIFY_EXIT (expected_length < sizeof (expected_contents));
 116   *p++ = '\0';
 117   support_write_file_string (test_file_path, expected_contents);
 118   return true;
 119 }
 120
 121 /* Run a single test (a combination of a test file and read
 122    parameters).  */
 123 static void
 124 run_test (void)
 125 {
 126   TEST_VERIFY_EXIT (read_size_increment > 0);
 127   if (test_verbose > 0)
 128     {
 129       printf ("info: running test: buffer_size=%d read_size=%d\n"
 130               "  read_size_increment=%d read_size_preserve=%d\n",
 131               buffer_size, read_size, read_size_increment, read_size_preserve);
 132     }
 133
 134   struct xmemstream result;
 135   xopen_memstream (&result);
 136
 137   FILE *fp = xfopen (test_file_path, "rce");
 138   char *fp_buffer = NULL;
 139   if (buffer_size == 0)
 140     TEST_VERIFY_EXIT (setvbuf (fp, NULL, _IONBF, 0) == 0);
 141   if (buffer_size > 0)
 142     {
 143       fp_buffer = xmalloc (buffer_size);
 144       TEST_VERIFY_EXIT (setvbuf (fp, fp_buffer, _IOFBF, buffer_size) == 0);
 145     }
 146
 147   char *line_buffer = xmalloc (read_size);
 148   size_t line_buffer_size = read_size;
 149
 150   while (true)
 151     {
 152       ssize_t ret = __libc_readline_unlocked
 153         (fp, line_buffer, line_buffer_size);
 154       if (ret < 0)
 155         {
 156           TEST_VERIFY (ret == -1);
 157           if (errno != ERANGE)
 158             FAIL_EXIT1 ("__libc_readline_unlocked: %m");
 159           line_buffer_size += read_size_increment;
 160           free (line_buffer);
 161           line_buffer = xmalloc (line_buffer_size);
 162           /* Try reading this line again.  */
 163         }
 164       else if (ret == 0)
 165         break;
 166       else
 167         {
 168           /* A line has been read.  Save it.  */
 169           TEST_VERIFY (ret == strlen (line_buffer));
 170           const char *pnl = strchr (line_buffer, '\n');
 171           /* If there is a \n, it must be at the end.  */
 172           TEST_VERIFY (pnl == NULL || pnl == line_buffer + ret - 1);
 173           fputs (line_buffer, result.out);
 174
 175           /* Restore the original read size if required.  */
 176           if (line_buffer_size > read_size && !read_size_preserve)
 177             {
 178               line_buffer_size = read_size;
 179               free (line_buffer);
 180               line_buffer = xmalloc (line_buffer_size);
 181             }
 182         }
 183     }
 184
 185   xfclose (fp);
 186   free (fp_buffer);
 187   free (line_buffer);
 188
 189   xfclose_memstream (&result);
 190   TEST_VERIFY (result.length == expected_length);
 191   TEST_VERIFY (strcmp (result.buffer, expected_contents) == 0);
 192   if (test_verbose > 0)
 193     {
 194       printf ("info: expected (%zu): [[%s]]\n",
 195               expected_length, expected_contents);
 196       printf ("info:   actual (%zu): [[%s]]\n", result.length, result.buffer);
 197     }
 198   free (result.buffer);
 199 }
 200
 201 /* Test one test file with multiple read parameters.  */
 202 static void
 203 test_one_file (void)
 204 {
 205   for (buffer_size = -1; buffer_size <= maximum_line_length + 1; ++buffer_size)
 206     for (read_size = 2; read_size <= maximum_line_length + 2; ++read_size)
 207       for (read_size_increment = 1; read_size_increment <= 4;
 208            ++read_size_increment)
 209         for (read_size_preserve = 0; read_size_preserve < 2;
 210              ++read_size_preserve)
 211           run_test ();
 212 }
 213
 214
 215 static int
 216 do_test (void)
 217 {
 218   /* Set up the test file contents.  */
 219   for (line_lengths[0] = -1; line_lengths[0] <= maximum_line_length;
 220        ++line_lengths[0])
 221     for (line_lengths[1] = -1; line_lengths[1] <= maximum_line_length;
 222          ++line_lengths[1])
 223       for (line_lengths[2] = -1; line_lengths[2] <= maximum_line_length;
 224            ++line_lengths[2])
 225         for (no_newline_at_eof = 0; no_newline_at_eof < 2; ++no_newline_at_eof)
 226           {
 227             if (!write_test_file ())
 228               continue;
 229             test_one_file ();
 230           }
 231   free (test_file_path);
 232   return 0;
 233 }
 234
 235 #define PREPARE prepare
 236 #include <support/test-driver.c>