Merge branch 'error-unused-results' into 'main'

Remove occurrences of unused-results warnings and mark them as errors

See merge request GNOME/glib!2798

gio/gio-tool-mount.c

@@ -112,7 +112,8 @@ prompt_for (const char *prompt, const char *default_value, gboolean echo)
 
 #endif
 
-  fgets(data, sizeof (data), stdin);
+  if (!fgets (data, sizeof (data), stdin))
+    g_error ("Failed to read from standard input");
 
 #ifdef HAVE_TERMIOS_H
   if (restore_flags)

glib/gbacktrace.c

@@ -45,6 +45,7 @@
 #include <time.h>
 
 #ifdef G_OS_UNIX
+#include <errno.h>
 #include <unistd.h>
 #include <sys/wait.h>
 #ifdef HAVE_SYS_SELECT_H
@@ -175,9 +176,14 @@ g_on_error_query (const gchar *prg_name)
   fflush (stdout);
 
   if (isatty(0) && isatty(1))
-    fgets (buf, 8, stdin);
+    {
+      if (fgets (buf, 8, stdin) == NULL)
+        _exit (0);
+    }
   else
-    strcpy (buf, "E\n");
+    {
+      strcpy (buf, "E\n");
+    }
 
   if ((buf[0] == 'E' || buf[0] == 'e')
       && buf[1] == '\n')
@@ -314,6 +320,59 @@ stack_trace_sigchld (int signum)
 
 #define BUFSIZE 1024
 
+static inline const char *
+get_strerror (char *buffer, gsize n)
+{
+#ifdef HAVE_STRERROR_R
+  return strerror_r (errno, buffer, n);
+#else
+  const char *error_str = strerror (errno);
+  if (!error_str)
+    return NULL;
+
+  strncpy (buffer, error_str, n);
+  return buffer;
+#endif
+}
+
+static gssize
+checked_write (int fd, gconstpointer buf, gsize n)
+{
+  gssize written = write (fd, buf, n);
+
+  if (written == -1)
+    {
+      char msg[BUFSIZE] = {0};
+      char error_str[BUFSIZE / 2] = {0};
+
+      get_strerror (error_str, sizeof (error_str) - 1);
+      snprintf (msg, sizeof (msg) - 1, "Unable to write to fd %d: %s", fd, error_str);
+      perror (msg);
+      _exit (0);
+    }
+
+  return written;
+}
+
+static int
+checked_dup (int fd)
+{
+  int new_fd = dup (fd);
+
+  if (new_fd == -1)
+    {
+      char msg[BUFSIZE] = {0};
+      char error_str[BUFSIZE / 2] = {0};
+
+      get_strerror (error_str, sizeof (error_str) - 1);
+      snprintf (msg, sizeof (msg) - 1, "Unable to duplicate fd %d: %s", fd, error_str);
+      perror (msg);
+      _exit (0);
+    }
+
+  return new_fd;
+}
+
 static void
 stack_trace (const char * const *args)
 {
@@ -351,9 +410,12 @@ stack_trace (const char * const *args)
 	    (void) fcntl (old_err, F_SETFD, getfd | FD_CLOEXEC);
 	}
 
-      close (0); dup (in_fd[0]);   /* set the stdin to the in pipe */
-      close (1); dup (out_fd[1]);  /* set the stdout to the out pipe */
-      close (2); dup (out_fd[1]);  /* set the stderr to the out pipe */
+      close (0);
+      checked_dup (in_fd[0]);   /* set the stdin to the in pipe */
+      close (1);
+      checked_dup (out_fd[1]);  /* set the stdout to the out pipe */
+      close (2);
+      checked_dup (out_fd[1]);  /* set the stderr to the out pipe */
 
       execvp (args[0], (char **) args);      /* exec gdb */
 
@@ -361,7 +423,8 @@ stack_trace (const char * const *args)
       if (old_err != -1)
         {
           close (2);
-          dup (old_err);
+          /* We can ignore the return value here as we're failing anyways */
+          (void) !dup (old_err);
         }
       perror ("exec " DEBUGGER " failed");
       _exit (0);
@@ -376,14 +439,14 @@ stack_trace (const char * const *args)
   FD_SET (out_fd[0], &fdset);
 
 #ifdef USE_LLDB
-  write (in_fd[1], "bt\n", 3);
-  write (in_fd[1], "p x = 0\n", 8);
-  write (in_fd[1], "process detach\n", 15);
-  write (in_fd[1], "quit\n", 5);
+  checked_write (in_fd[1], "bt\n", 3);
+  checked_write (in_fd[1], "p x = 0\n", 8);
+  checked_write (in_fd[1], "process detach\n", 15);
+  checked_write (in_fd[1], "quit\n", 5);
 #else
-  write (in_fd[1], "backtrace\n", 10);
-  write (in_fd[1], "p x = 0\n", 8);
-  write (in_fd[1], "quit\n", 5);
+  checked_write (in_fd[1], "backtrace\n", 10);
+  checked_write (in_fd[1], "p x = 0\n", 8);
+  checked_write (in_fd[1], "quit\n", 5);
 #endif
 
   idx = 0;

glib/tests/fileutils.c

@@ -1469,7 +1469,7 @@ test_file_test (void)
 
   fd = g_file_open_tmp (NULL, &name, &error);
   g_assert_no_error (error);
-  write (fd, "a", 1);
+  g_assert_cmpint (write (fd, "a", 1), ==, 1);
   g_assert_cmpint (g_fsync (fd), ==, 0);
   close (fd);
 
@@ -1477,7 +1477,7 @@ test_file_test (void)
   result = g_file_test (name, G_FILE_TEST_IS_SYMLINK);
   g_assert_false (result);
 
-  symlink (name, "symlink");
+  g_assert_no_errno (symlink (name, "symlink"));
   result = g_file_test ("symlink", G_FILE_TEST_IS_SYMLINK);
   g_assert_true (result);
   unlink ("symlink");
@@ -1500,7 +1500,7 @@ test_set_contents (void)
 
   fd = g_file_open_tmp (NULL, &name, &error);
   g_assert_no_error (error);
-  write (fd, "a", 1);
+  g_assert_cmpint (write (fd, "a", 1), ==, 1);
   g_assert_cmpint (g_fsync (fd), ==, 0);
   close (fd);
 
@@ -1593,7 +1593,7 @@ test_set_contents_full (void)
 
                 fd = g_file_open_tmp (NULL, &file_name, &error);
                 g_assert_no_error (error);
-                write (fd, "a", 1);
+                g_assert_cmpint (write (fd, "a", 1), ==, 1);
                 g_assert_no_errno (g_fsync (fd));
                 close (fd);
 
@@ -1726,7 +1726,7 @@ test_set_contents_full_read_only_file (void)
    * existing file permissions. */
   fd = g_file_open_tmp (NULL, &file_name, &error);
   g_assert_no_error (error);
-  write (fd, "a", 1);
+  g_assert_cmpint (write (fd, "a", 1), ==, 1);
   g_assert_no_errno (g_fsync (fd));
   close (fd);
   g_assert_no_errno (g_chmod (file_name, 0400)); /* S_IREAD */
@@ -1800,7 +1800,7 @@ test_set_contents_full_read_only_directory (void)
       file_name = g_build_filename (dir_name, "file", NULL);
       fd = g_open (file_name, O_CREAT | O_RDWR, 0644);
       g_assert_cmpint (fd, >=, 0);
-      write (fd, "a", 1);
+      g_assert_cmpint (write (fd, "a", 1), ==, 1);
       g_assert_no_errno (g_fsync (fd));
       close (fd);
 
@@ -1895,8 +1895,8 @@ test_read_link (void)
   g_assert_nonnull (file);
   fclose (file);
 
-  g_assert_cmpint (symlink (filename, link1), ==, 0);
-  g_assert_cmpint (symlink (link1, link2), ==, 0);
+  g_assert_no_errno (symlink (filename, link1));
+  g_assert_no_errno (symlink (link1, link2));
 
   error = NULL;
   data = g_file_read_link (link1, &error);

glib/tests/io-channel-basic.c

@@ -320,7 +320,7 @@ spawn_process (int children_nb)
       /* Spawn new Unix process */
       cmdline = g_strdup_printf ("%s --child %d:%d &",
                                  exec_name, pipe_to_sub[0], pipe_from_sub[1]);
-      system (cmdline);
+      g_assert_no_errno (system (cmdline));
 #endif
       g_free (cmdline);
 
@@ -375,9 +375,9 @@ run_process (int argc, char *argv[])
         buf[j] = ' ' + ((buflen + j) % 95);
       g_debug ("io-channel-basic: child writing %d+%d bytes to %d",
                (int) (sizeof (i) + sizeof (buflen)), buflen, writefd);
-      write (writefd, &i, sizeof (i));
-      write (writefd, &buflen, sizeof (buflen));
-      write (writefd, buf, buflen);
+      g_assert_cmpint (write (writefd, &i, sizeof (i)), ==, sizeof (i));
+      g_assert_cmpint (write (writefd, &buflen, sizeof (buflen)), ==, sizeof (buflen));
+      g_assert_cmpint (write (writefd, buf, buflen), ==, buflen);
 
 #ifdef G_OS_WIN32
       if (i % 10 == 0)

glib/tests/mainloop.c

@@ -1467,8 +1467,8 @@ test_source_unix_fd_api (void)
   gint fds_a[2];
   gint fds_b[2];
 
-  pipe (fds_a);
-  pipe (fds_b);
+  g_assert_cmpint (pipe (fds_a), ==, 0);
+  g_assert_cmpint (pipe (fds_b), ==, 0);
 
   source_a = g_source_new (&no_funcs, sizeof (FlagSource));
   source_b = g_source_new (&no_funcs, sizeof (FlagSource));

glib/tests/spawn-multithreaded.c

@@ -157,9 +157,9 @@ test_spawn_childs (void)
   main_loop = g_main_loop_new (NULL, FALSE);
 
 #ifdef G_OS_WIN32
-  system ("cd .");
+  g_assert_no_errno (system ("cd ."));
 #else
-  system ("true");
+  g_assert_no_errno (system ("true"));
 #endif
 
   n_alive = 2;
@@ -200,9 +200,9 @@ test_spawn_childs_threads (void)
   main_loop = g_main_loop_new (NULL, FALSE);
 
 #ifdef G_OS_WIN32
-  system ("cd .");
+  g_assert_no_errno (system ("cd ."));
 #else
-  system ("true");
+  g_assert_no_errno (system ("true"));
 #endif
 
   n_alive = 2;

glib/tests/unix.c

@@ -40,7 +40,7 @@ test_pipe (void)
   g_assert (res);
   g_assert_no_error (error);
 
-  write (pipefd[1], "hello", sizeof ("hello"));
+  g_assert_cmpint (write (pipefd[1], "hello", sizeof ("hello")), ==, sizeof ("hello"));
   memset (buf, 0, sizeof (buf));
   bytes_read = read (pipefd[0], buf, sizeof(buf) - 1);
   g_assert_cmpint (bytes_read, >, 0);

meson.build

@@ -473,6 +473,7 @@ if cc.get_id() == 'gcc' or cc.get_id() == 'clang'
     '-Werror=init-self',
     '-Werror=missing-include-dirs',
     '-Werror=pointer-arith',
+    '-Werror=unused-result',
   ]
 
   warning_c_args = warning_common_args + [