Add set/get/endfsent() support for musl libc

This patch adds support for the following /etc/fstab API's on systems
that do not have them, e.g. musl libc on Alpine Linux.

- setfsent()
- getfsent(), and
- endfsent()

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

configure.ac

@@ -24,7 +24,8 @@ AC_PROG_INSTALL
 
 # Configuration.
 AC_HEADER_STDC
-AC_CHECK_FUNCS(strstr getopt)
+AC_CHECK_HEADERS(fstaby.h)
+AC_CHECK_FUNCS(strstr getopt getfsenty)
 
 # Check for uint[8,16,32]_t
 AC_TYPE_UINT8_T

finit.c

@@ -27,7 +27,9 @@
 #include <ctype.h>
 #include <glob.h>
 #include <dirent.h>
+#ifdef HAVE_FSTAB_H
 #include <fstab.h>
+#endif
 #include <mntent.h>
 #include <sys/mount.h>
 #include <sys/stat.h>		/* umask(), mkdir() */

helpers.c

@@ -254,6 +254,45 @@ void set_hostname(char **hostname)
 		sethostname(*hostname, strlen(*hostname));
 }
 
+#ifndef HAVE_GETFSENT
+static lfile_t *fstab = NULL;
+
+int setfsent(void)
+{
+	if (fstab)
+		lfclose(fstab);
+
+	fstab = lfopen("/etc/fstab", " \t\n");
+	if (!fstab)
+		return 0;
+
+	return 1;
+}
+
+struct fstab *getfsent(void)
+{
+	static struct fstab fs;
+
+	fs.fs_spec    = lftok(fstab);
+	fs.fs_file    = lftok(fstab);
+	fs.fs_vfstype = lftok(fstab);
+	fs.fs_mntops  = lftok(fstab);
+	fs.fs_type    = (const char *)lftok(fstab);
+	fs.fs_freq    = atoi(lftok(fstab) ?: 0);
+	fs.fs_passno  = atoi(lftok(fstab) ?: 0);
+
+	return &fs;
+}
+
+void endfsent(void)
+{
+	if (fstab)
+		lfclose(fstab);
+
+	fstab = NULL;
+}
+#endif	/* HAVE_GETFSENT */
+
 /**
  * Local Variables:
  *  indent-tabs-mode: t

helpers.h

@@ -86,6 +86,22 @@ int     run_interactive (char *cmd, char *fmt, ...);
 pid_t   run_getty       (char *tty, char *speed, char *term, int console);
 int     run_parts       (char *dir, char *cmd);
 
+#ifndef HAVE_GETFSENT
+struct fstab {
+	char       *fs_spec;       /* block device name */
+	char       *fs_file;       /* mount point */
+	char       *fs_vfstype;    /* file-system type */
+	char       *fs_mntops;     /* mount options */
+	const char *fs_type;       /* rw/rq/ro/sw/xx option */
+	int         fs_freq;       /* dump frequency, in days */
+	int         fs_passno;     /* pass number on parallel dump */
+};
+
+int           setfsent(void);
+void          endfsent(void);
+struct fstab *getfsent(void);
+#endif	/* HAVE_GETFSENT */
+
 #endif /* FINIT_HELPERS_H_ */
 
 /**