exec_cmd: RUNTIME_PREFIX on OpenBSD systems

Enable Git to resolve its own binary location using getexecpath().

Signed-off-by: Brad Smith <brad@comstyle.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: brad0

Makefile

@@ -378,6 +378,9 @@ include shared.mak
 # Perl scripts to use a modified entry point header allowing them to resolve
 # support files at runtime.
 #
+# When using RUNTIME_PREFIX, define HAVE_GETEXECPATH if your platform supports
+# the getexecpath() function.
+#
 # When using RUNTIME_PREFIX, define HAVE_BSD_KERN_PROC_SYSCTL if your platform
 # supports the KERN_PROC BSD sysctl function.
 #
@@ -2356,6 +2359,10 @@ endif
 
 ifdef RUNTIME_PREFIX
 
+        ifdef HAVE_GETEXECPATH
+		BASIC_CFLAGS += -DHAVE_GETEXECPATH
+        endif
+
         ifdef HAVE_BSD_KERN_PROC_SYSCTL
 		BASIC_CFLAGS += -DHAVE_BSD_KERN_PROC_SYSCTL
         endif

config.mak.uname

@@ -343,6 +343,9 @@ ifeq ($(uname_S),OpenBSD)
 	CSPRNG_METHOD = arc4random
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
 	FILENO_IS_A_MACRO = UnfortunatelyYes
+	ifeq ($(shell test "`expr "$(uname_R)" : '\([0-9][0-9]*\)\.'`" -ge 8 && echo 1),1)
+		HAVE_GETEXECPATH = YesPlease
+	endif
 endif
 ifeq ($(uname_S),MirBSD)
 	NO_STRCASESTR = YesPlease

exec-cmd.c

@@ -129,6 +129,26 @@ static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
 }
 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */
 
+#ifdef HAVE_GETEXECPATH
+/*
+ * Resolves the executable path using getexecpath(3).
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_getexecpath(struct strbuf *buf)
+{
+	char path[PATH_MAX];
+	if (getexecpath(path, sizeof(path)) == 0) {
+		trace_printf(
+			"trace: resolved executable path from getexecpath: %s\n",
+			path);
+		strbuf_addstr(buf, path);
+		return 0;
+	}
+	return -1;
+}
+#endif /* HAVE_GETEXECPATH */
+
 #ifdef HAVE_NS_GET_EXECUTABLE_PATH
 /*
  * Resolves the executable path by querying Darwin application stack.
@@ -209,6 +229,10 @@ static int git_get_exec_path(struct strbuf *buf, const char *argv0)
 	 * after the first successful method.
 	 */
 	if (
+#ifdef HAVE_GETEXECPATH
+		git_get_exec_path_getexecpath(buf) &&
+#endif /* HAVE_GETEXECPATH */
+
 #ifdef HAVE_BSD_KERN_PROC_SYSCTL
 		git_get_exec_path_bsd_sysctl(buf) &&
 #endif /* HAVE_BSD_KERN_PROC_SYSCTL */