1 /* Invoke the system diff tool to compare two strings.
2 Copyright (C) 2016-2022 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 <https://www.gnu.org/licenses/>. */
18
19 #include <support/run_diff.h>
20
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <support/check.h>
25 #include <support/support.h>
26 #include <support/temp_file.h>
27 #include <support/xunistd.h>
28 #include <sys/wait.h>
29
30 static char *
write_to_temp_file(const char * prefix,const char * str)31 write_to_temp_file (const char *prefix, const char *str)
32 {
33 char *template = xasprintf ("run_diff-%s", prefix);
34 char *name = NULL;
35 int fd = create_temp_file (template, &name);
36 TEST_VERIFY_EXIT (fd >= 0);
37 free (template);
38 xwrite (fd, str, strlen (str));
39 xclose (fd);
40 return name;
41 }
42
43 void
support_run_diff(const char * left_label,const char * left,const char * right_label,const char * right)44 support_run_diff (const char *left_label, const char *left,
45 const char *right_label, const char *right)
46 {
47 /* Ensure that the diff command output is ordered properly with
48 standard output. */
49 TEST_VERIFY_EXIT (fflush (stdout) == 0);
50
51 char *left_path = write_to_temp_file ("left-diff", left);
52 char *right_path = write_to_temp_file ("right-diff", right);
53
54 pid_t pid = xfork ();
55 if (pid == 0)
56 {
57 execlp ("diff", "diff", "-u",
58 "--label", left_label, "--label", right_label,
59 "--", left_path, right_path,
60 NULL);
61 _exit (17);
62 }
63 else
64 {
65 int status;
66 xwaitpid (pid, &status, 0);
67 if (!WIFEXITED (status) || WEXITSTATUS (status) != 1)
68 printf ("warning: could not run diff, exit status: %d\n"
69 "*** %s ***\n%s\n"
70 "*** %s ***\n%s\n",
71 status, left_label, left, right_label, right);
72 }
73
74 free (right_path);
75 free (left_path);
76 }
77