Add support for building elogind against musl libc

* Check whether printf.h is available and define/undef HAVE_PRINTF_H
  accordingly.
* Added src/shared/parse-printf-format.[hc] by Emil Renner Berthing
  <systemd@esmil.dk> that provides parse_printf_format() if printf.h
  is unavailable
* Added src/basic/musl_missing.h by Juergen Buchmueller
  <pullmoll@t-online.de> that implements glibc functions missing in
  musl libc as macros.
* Extended src/basic/musl_missing.h and added
  src/basic/musl_missing.c providing
  - program_invocation_name
  - program_invocation_short_name and
  - elogind_set_program_name() to set the two where appropriate.
* Added calls to elogind_set_program_name() to all main() functions
  where needed.
* A few other fixes to work nicely with musl libc.

1 files changed, 94 insertions, 0 deletions

diff --git a/src/basic/musl_missing.h b/src/basic/musl_missing.h
new file mode 100644
index 000000000..f54319d1b
--- /dev/null
+++ b/src/basic/musl_missing.h
@@ -0,0 +1,94 @@
+#pragma once
+#ifndef ELOGIND_BASIC_MUSL_MISSING_H_INCLUDED
+#define ELOGIND_BASIC_MUSL_MISSING_H_INCLUDED
+
+
+/****************************************************************
+ * musl_missing.h - work around glibc extensions for musl libc.
+ *
+ * Implements glibc functions missing in musl libc as macros.
+ * Is to be included where these functions are used.
+ * Also defines some glibc only constants as either 0 or
+ * as found in the corresponding glibc header file.
+ *
+ * Juergen Buchmueller <pullmoll@t-online.de> for Void Linux
+ * Public Domain; no warranties whatsoever. Thank you Mr. P.
+ *
+ ****************************************************************/
+
+
+void elogind_set_program_name(const char* pcall);
+
+#if !defined(__GLIBC__)
+#include "config.h"
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define strerror_r(e, m, k) (strerror_r(e, m, k) < 0 ? strdup("strerror_r() failed") : m);
+
+#ifndef _ERRNO_H
+extern char *program_invocation_name;
+extern char *program_invocation_short_name;
+#endif // errno.h included beforehand
+
+/*
+ * Possibly TODO according to http://man7.org/linux/man-pages/man3/getenv.3.html
+ * + test if the process's effective user ID does not match its real user ID or
+ *   the process's effective group ID does not match its real group ID;
+ *   typically this is the result of executing a set-user-ID or set-
+ *   group-ID program. Is calling issetugid() sufficient here?
+ * + test if the effective capability bit was set on the executable file
+ * + test if the process has a nonempty permitted capability set
+ */
+#if !defined(HAVE_SECURE_GETENV) && !defined(HAVE___SECURE_GETENV)
+#  define secure_getenv(name) \
+        (issetugid() ? NULL : getenv(name))
+#  define HAVE_SECURE_GETENV 1
+#endif // HAVE_[__]SECURE_GETENV
+
+/* Poor man's basename */
+#define basename(path) \
+        (strrchr(path, '/') ? strrchr(path, '/')+1 : path)
+
+/* strndupa may already be defined in another compatibility header */
+#if !defined(strndupa)
+#define strndupa(src, n) \
+        (__extension__ ({const char *in = (src);   \
+                size_t len = strnlen(in, (n)) + 1; \
+                char *out = (char *) alloca(len);  \
+                out[len-1] = '\0';                 \
+                (char *) memcpy(out, in, len-1);}) \
+        )
+#endif
+
+/* See http://man7.org/linux/man-pages/man3/canonicalize_file_name.3.html */
+#define canonicalize_file_name(path) \
+        realpath(path, NULL)
+
+typedef int (*__compar_fn_t)(const void *, const void *);
+
+/* GLOB_BRACE is another glibc extension - ignore it for musl libc */
+#define GLOB_BRACE 0
+
+/* getnameinfo(3) glibc extensions are undefined in musl libc */
+#define NI_IDN 0
+#define NI_IDN_USE_STD3_ASCII_RULES 0
+
+/* Taken from glibc's net/if_arp.h */
+#if !defined(ARPHRD_IEEE802154_PHY)
+#define ARPHRD_IEEE802154_PHY 805        /* IEEE 802.15.4 PHY header.  */
+#endif
+
+/* Shorthand for type of comparison functions. */
+#ifndef __COMPAR_FN_T
+# define __COMPAR_FN_T
+typedef int (*__compar_fn_t) (const void *, const void *);
+typedef __compar_fn_t comparison_fn_t;
+#endif
+
+
+#endif // !defined(__GLIBC__)
+
+#endif // ELOGIND_BASIC_MUSL_MISSING_H_INCLUDED
+