supersede: Add tests.

* tests/test-supersede.c: New file.
* tests/test-supersede-open.h: New file.
* tests/test-supersede-fopen.h: New file.
* modules/supersede-tests: New file.

ChangeLog

@@ -1,5 +1,11 @@
 2020-07-05  Bruno Haible  <bruno@clisp.org>
 
+	supersede: Add tests.
+	* tests/test-supersede.c: New file.
+	* tests/test-supersede-open.h: New file.
+	* tests/test-supersede-fopen.h: New file.
+	* modules/supersede-tests: New file.
+
 	supersede: New module.
 	* lib/supersede.h: New file.
 	* lib/supersede.c: New file.

modules/supersede-tests

@@ -0,0 +1,21 @@
+Files:
+tests/test-supersede.c
+tests/test-supersede-open.h
+tests/test-supersede-fopen.h
+tests/macros.h
+
+Depends-on:
+mkdtemp
+filenamecat
+write
+read-file
+unlink
+rmdir
+symlink
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-supersede
+check_PROGRAMS += test-supersede
+test_supersede_LDADD = $(LDADD) $(LIB_ACL) $(LIB_CLOCK_GETTIME) $(LIB_GETRANDOM)

tests/test-supersede-fopen.h

@@ -0,0 +1,265 @@
+/* Tests for opening a file without destroying an old file with the same name.
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible, 2020.  */
+
+static void
+test_fopen_supersede (bool supersede_if_exists, bool supersede_if_does_not_exist)
+{
+  char xtemplate[] = "gnulibtestXXXXXX";
+  char *dir = mkdtemp (xtemplate);
+  char *filename = file_name_concat (dir, "test.mo", NULL);
+  struct stat statbuf;
+
+  /* Test the case that the file does not yet exist.  */
+  {
+    ASSERT (stat (filename, &statbuf) < 0);
+
+    struct supersede_final_action action;
+    FILE *fp =
+      fopen_supersede (filename, "wb",
+                       supersede_if_exists, supersede_if_does_not_exist,
+                       &action);
+    ASSERT (fp != NULL);
+    ASSERT (fwrite ("Hello world\n", 1, 12, fp) == 12 && fflush (fp) == 0);
+    if (supersede_if_does_not_exist)
+      ASSERT (stat (filename, &statbuf) < 0);
+    else
+      ASSERT (stat (filename, &statbuf) == 0);
+    ASSERT (fclose_supersede (fp, &action) == 0);
+
+    ASSERT (stat (filename, &statbuf) == 0);
+
+    size_t file_size;
+    char *file_contents = read_file (filename, RF_BINARY, &file_size);
+    ASSERT (file_size == 12);
+    ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+  }
+
+  /* Test the case that the file exists and is a regular file.  */
+  {
+    ASSERT (stat (filename, &statbuf) == 0);
+    dev_t orig_dev = statbuf.st_dev;
+    ino_t orig_ino = statbuf.st_ino;
+
+    struct supersede_final_action action;
+    FILE *fp =
+      fopen_supersede (filename, "wb",
+                       supersede_if_exists, supersede_if_does_not_exist,
+                       &action);
+    ASSERT (fp != NULL);
+    ASSERT (fwrite ("Foobar\n", 1, 7, fp) == 7 && fflush (fp) == 0);
+    ASSERT (stat (filename, &statbuf) == 0);
+    {
+      size_t file_size;
+      char *file_contents = read_file (filename, RF_BINARY, &file_size);
+      if (supersede_if_exists)
+        {
+          ASSERT (file_size == 12);
+          ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+        }
+      else
+        {
+          ASSERT (file_size == 7);
+          ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+        }
+    }
+    ASSERT (fclose_supersede (fp, &action) == 0);
+
+    ASSERT (stat (filename, &statbuf) == 0);
+
+    size_t file_size;
+    char *file_contents = read_file (filename, RF_BINARY, &file_size);
+    ASSERT (file_size == 7);
+    ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+
+    if (supersede_if_exists)
+      {
+        /* Verify that the file now has a different inode number, on the same
+           device.  */
+#if !(defined _WIN32 && !defined __CYGWIN__)
+        ASSERT (memcmp (&orig_dev, &statbuf.st_dev, sizeof (dev_t)) == 0);
+        ASSERT (memcmp (&orig_ino, &statbuf.st_ino, sizeof (ino_t)) != 0);
+#endif
+      }
+  }
+
+  /* Test the case that the file exists and is a character device.  */
+  {
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+
+    struct supersede_final_action action;
+    FILE *fp =
+      fopen_supersede (DEV_NULL, "wb",
+                       supersede_if_exists, supersede_if_does_not_exist,
+                       &action);
+    ASSERT (fp != NULL);
+    ASSERT (fwrite ("Foobar\n", 1, 7, fp) == 7 && fflush (fp) == 0);
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+    ASSERT (fclose_supersede (fp, &action) == 0);
+
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+  }
+
+  /* Test the case that the file is a symbolic link to an existing regular
+     file.  */
+  {
+    const char *linkname = "link1";
+    unlink (linkname);
+    if (symlink (filename, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) == 0);
+        dev_t orig_dev = statbuf.st_dev;
+        ino_t orig_ino = statbuf.st_ino;
+
+        struct supersede_final_action action;
+        FILE *fp =
+          fopen_supersede (linkname, "wb",
+                           supersede_if_exists, supersede_if_does_not_exist,
+                           &action);
+        ASSERT (fp != NULL);
+        ASSERT (fwrite ("New\n", 1, 4, fp) == 4 && fflush (fp) == 0);
+        ASSERT (stat (linkname, &statbuf) == 0);
+        {
+          size_t file_size;
+          char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+          if (supersede_if_exists)
+            {
+              ASSERT (file_size == 7);
+              ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+            }
+          else
+            {
+              ASSERT (file_size == 4);
+              ASSERT (memcmp (file_contents, "New\n", 4) == 0);
+            }
+        }
+        ASSERT (fclose_supersede (fp, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        size_t file_size;
+        char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+        ASSERT (file_size == 4);
+        ASSERT (memcmp (file_contents, "New\n", 4) == 0);
+
+        if (supersede_if_exists)
+          {
+            /* Verify that the file now has a different inode number, on the
+               same device.  */
+#if !(defined _WIN32 && !defined __CYGWIN__)
+            ASSERT (memcmp (&orig_dev, &statbuf.st_dev, sizeof (dev_t)) == 0);
+            ASSERT (memcmp (&orig_ino, &statbuf.st_ino, sizeof (ino_t)) != 0);
+#endif
+          }
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Test the case that the file is a symbolic link to an existing character
+     device.  */
+  {
+    const char *linkname = "link2";
+    unlink (linkname);
+    if (symlink (DEV_NULL, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        struct supersede_final_action action;
+        FILE *fp =
+          fopen_supersede (linkname, "wb",
+                           supersede_if_exists, supersede_if_does_not_exist,
+                           &action);
+        ASSERT (fp != NULL);
+        ASSERT (fwrite ("New\n", 1, 4, fp) == 4 && fflush (fp) == 0);
+        ASSERT (stat (linkname, &statbuf) == 0);
+        ASSERT (fclose_supersede (fp, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+
+  /* Test the case that the file is a symbolic link to a nonexistent file in an
+     existing directory.  */
+  {
+    const char *linkname = "link3";
+    unlink (linkname);
+    if (symlink (filename, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        struct supersede_final_action action;
+        FILE *fp =
+          fopen_supersede (linkname, "wb",
+                           supersede_if_exists, supersede_if_does_not_exist,
+                           &action);
+        ASSERT (fp != NULL);
+        ASSERT (fwrite ("Hello world\n", 1, 12, fp) == 12 && fflush (fp) == 0);
+        if (supersede_if_does_not_exist)
+          ASSERT (stat (linkname, &statbuf) < 0);
+        else
+          ASSERT (stat (linkname, &statbuf) == 0);
+        ASSERT (fclose_supersede (fp, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        size_t file_size;
+        char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+        ASSERT (file_size == 12);
+        ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Test the case that the file is a symbolic link to a nonexistent file in a
+     nonexistent directory.  */
+  {
+    const char *linkname = "link4";
+    unlink (linkname);
+    if (symlink ("/nonexistent/gnulibtest8237/24715863701440", linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        struct supersede_final_action action;
+        FILE *fp =
+          fopen_supersede (linkname, "wb",
+                           supersede_if_exists, supersede_if_does_not_exist,
+                           &action);
+        ASSERT (fp == NULL);
+        ASSERT (errno == ENOENT);
+
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+  rmdir (dir);
+}

tests/test-supersede-open.h

@@ -0,0 +1,262 @@
+/* Tests for opening a file without destroying an old file with the same name.
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible, 2020.  */
+
+static void
+test_open_supersede (bool supersede_if_exists, bool supersede_if_does_not_exist)
+{
+  char xtemplate[] = "gnulibtestXXXXXX";
+  char *dir = mkdtemp (xtemplate);
+  char *filename = file_name_concat (dir, "test.mo", NULL);
+  struct stat statbuf;
+
+  /* Test the case that the file does not yet exist.  */
+  {
+    ASSERT (stat (filename, &statbuf) < 0);
+
+    struct supersede_final_action action;
+    int fd = open_supersede (filename, O_RDWR | O_TRUNC, 0666,
+                             supersede_if_exists, supersede_if_does_not_exist,
+                             &action);
+    ASSERT (fd >= 0);
+    ASSERT (write (fd, "Hello world\n", 12) == 12);
+    if (supersede_if_does_not_exist)
+      ASSERT (stat (filename, &statbuf) < 0);
+    else
+      ASSERT (stat (filename, &statbuf) == 0);
+    ASSERT (close_supersede (fd, &action) == 0);
+
+    ASSERT (stat (filename, &statbuf) == 0);
+
+    size_t file_size;
+    char *file_contents = read_file (filename, RF_BINARY, &file_size);
+    ASSERT (file_size == 12);
+    ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+  }
+
+  /* Test the case that the file exists and is a regular file.  */
+  {
+    ASSERT (stat (filename, &statbuf) == 0);
+    dev_t orig_dev = statbuf.st_dev;
+    ino_t orig_ino = statbuf.st_ino;
+
+    struct supersede_final_action action;
+    int fd = open_supersede (filename, O_RDWR | O_TRUNC, 0666,
+                             supersede_if_exists, supersede_if_does_not_exist,
+                             &action);
+    ASSERT (fd >= 0);
+    ASSERT (write (fd, "Foobar\n", 7) == 7);
+    ASSERT (stat (filename, &statbuf) == 0);
+    {
+      size_t file_size;
+      char *file_contents = read_file (filename, RF_BINARY, &file_size);
+      if (supersede_if_exists)
+        {
+          ASSERT (file_size == 12);
+          ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+        }
+      else
+        {
+          ASSERT (file_size == 7);
+          ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+        }
+    }
+    ASSERT (close_supersede (fd, &action) == 0);
+
+    ASSERT (stat (filename, &statbuf) == 0);
+
+    size_t file_size;
+    char *file_contents = read_file (filename, RF_BINARY, &file_size);
+    ASSERT (file_size == 7);
+    ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+
+    if (supersede_if_exists)
+      {
+        /* Verify that the file now has a different inode number, on the same
+           device.  */
+#if !(defined _WIN32 && !defined __CYGWIN__)
+        ASSERT (memcmp (&orig_dev, &statbuf.st_dev, sizeof (dev_t)) == 0);
+        ASSERT (memcmp (&orig_ino, &statbuf.st_ino, sizeof (ino_t)) != 0);
+#endif
+      }
+  }
+
+  /* Test the case that the file exists and is a character device.  */
+  {
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+
+    struct supersede_final_action action;
+    int fd = open_supersede (DEV_NULL, O_RDWR | O_TRUNC, 0666,
+                             supersede_if_exists, supersede_if_does_not_exist,
+                             &action);
+    ASSERT (fd >= 0);
+    ASSERT (write (fd, "Foobar\n", 7) == 7);
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+    ASSERT (close_supersede (fd, &action) == 0);
+
+    ASSERT (stat (DEV_NULL, &statbuf) == 0);
+  }
+
+  /* Test the case that the file is a symbolic link to an existing regular
+     file.  */
+  {
+    const char *linkname = "link1";
+    unlink (linkname);
+    if (symlink (filename, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) == 0);
+        dev_t orig_dev = statbuf.st_dev;
+        ino_t orig_ino = statbuf.st_ino;
+
+        struct supersede_final_action action;
+        int fd =
+          open_supersede (linkname, O_RDWR | O_TRUNC, 0666,
+                          supersede_if_exists, supersede_if_does_not_exist,
+                          &action);
+        ASSERT (fd >= 0);
+        ASSERT (write (fd, "New\n", 4) == 4);
+        ASSERT (stat (linkname, &statbuf) == 0);
+        {
+          size_t file_size;
+          char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+          if (supersede_if_exists)
+            {
+              ASSERT (file_size == 7);
+              ASSERT (memcmp (file_contents, "Foobar\n", 7) == 0);
+            }
+          else
+            {
+              ASSERT (file_size == 4);
+              ASSERT (memcmp (file_contents, "New\n", 4) == 0);
+            }
+        }
+        ASSERT (close_supersede (fd, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        size_t file_size;
+        char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+        ASSERT (file_size == 4);
+        ASSERT (memcmp (file_contents, "New\n", 4) == 0);
+
+        if (supersede_if_exists)
+          {
+            /* Verify that the file now has a different inode number, on the
+               same device.  */
+#if !(defined _WIN32 && !defined __CYGWIN__)
+            ASSERT (memcmp (&orig_dev, &statbuf.st_dev, sizeof (dev_t)) == 0);
+            ASSERT (memcmp (&orig_ino, &statbuf.st_ino, sizeof (ino_t)) != 0);
+#endif
+          }
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Test the case that the file is a symbolic link to an existing character
+     device.  */
+  {
+    const char *linkname = "link2";
+    unlink (linkname);
+    if (symlink (DEV_NULL, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        struct supersede_final_action action;
+        int fd =
+          open_supersede (linkname, O_RDWR | O_TRUNC, 0666,
+                          supersede_if_exists, supersede_if_does_not_exist,
+                          &action);
+        ASSERT (fd >= 0);
+        ASSERT (write (fd, "New\n", 4) == 4);
+        ASSERT (stat (linkname, &statbuf) == 0);
+        ASSERT (close_supersede (fd, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+
+  /* Test the case that the file is a symbolic link to a nonexistent file in an
+     existing directory.  */
+  {
+    const char *linkname = "link3";
+    unlink (linkname);
+    if (symlink (filename, linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        struct supersede_final_action action;
+        int fd =
+          open_supersede (linkname, O_RDWR | O_TRUNC, 0666,
+                          supersede_if_exists, supersede_if_does_not_exist,
+                          &action);
+        ASSERT (fd >= 0);
+        ASSERT (write (fd, "Hello world\n", 12) == 12);
+        if (supersede_if_does_not_exist)
+          ASSERT (stat (linkname, &statbuf) < 0);
+        else
+          ASSERT (stat (linkname, &statbuf) == 0);
+        ASSERT (close_supersede (fd, &action) == 0);
+
+        ASSERT (stat (linkname, &statbuf) == 0);
+
+        size_t file_size;
+        char *file_contents = read_file (linkname, RF_BINARY, &file_size);
+        ASSERT (file_size == 12);
+        ASSERT (memcmp (file_contents, "Hello world\n", 12) == 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Test the case that the file is a symbolic link to a nonexistent file in a
+     nonexistent directory.  */
+  {
+    const char *linkname = "link4";
+    unlink (linkname);
+    if (symlink ("/nonexistent/gnulibtest8237/24715863701440", linkname) >= 0)
+      {
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        struct supersede_final_action action;
+        int fd =
+          open_supersede (linkname, O_RDWR | O_TRUNC, 0666,
+                          supersede_if_exists, supersede_if_does_not_exist,
+                          &action);
+        ASSERT (fd < 0);
+        ASSERT (errno == ENOENT);
+
+        ASSERT (stat (linkname, &statbuf) < 0);
+
+        /* Clean up.  */
+        unlink (linkname);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+  rmdir (dir);
+}

tests/test-supersede.c

@@ -0,0 +1,63 @@
+/* Tests for opening a file without destroying an old file with the same name.
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible, 2020.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "supersede.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "filenamecat.h"
+#include "read-file.h"
+#include "macros.h"
+
+/* The name of the "always silent" device.  */
+#if defined _WIN32 && ! defined __CYGWIN__
+/* Native Windows API.  */
+# define DEV_NULL "NUL"
+#else
+/* Unix API.  */
+# define DEV_NULL "/dev/null"
+#endif
+
+#include "test-supersede-open.h"
+#include "test-supersede-fopen.h"
+
+int
+main (void)
+{
+  test_open_supersede (false, false);
+  test_open_supersede (false, true);
+  test_open_supersede (true, false);
+  test_open_supersede (true, true);
+
+  test_fopen_supersede (false, false);
+  test_fopen_supersede (false, true);
+  test_fopen_supersede (true, false);
+  test_fopen_supersede (true, true);
+
+  return 0;
+}