From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sun, 2 Jul 2017 00:31:50 +0000 (+0000)
Subject: Use program_invocation_name instead of a local progname variable
X-Git-Tag: v4.18~9
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=340b00aaa7330c74be7c5c2bc9533c613579bd50;p=strace

Use program_invocation_name instead of a local progname variable

Emulate program_invocation_name only if it is not provided by libc.

* configure.ac: Check for program_invocation_name variable.
* strace.c (progname): Remove.
[!HAVE_PROGRAM_INVOCATION_NAME] (program_invocation_name): New variable.
(verror_msg, error_msg_and_help): Use it instead of progname.
(init): Initialize program_invocation_name instead of progname.
---

diff --git a/configure.ac b/configure.ac
index bc7b637d..eb7b0e78 100644
--- a/configure.ac
+++ b/configure.ac
@@ -709,6 +709,16 @@ if test "x$st_cv_have___builtin_popcount" = xyes; then
 		  [Define to 1 if the system provides __builtin_popcount function])
 fi
 
+AC_CACHE_CHECK([for program_invocation_name], [st_cv_have_program_invocation_name],
+	       [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <errno.h>]],
+						[[return !*program_invocation_name]])],
+			       [st_cv_have_program_invocation_name=yes],
+			       [st_cv_have_program_invocation_name=no])])
+if test "x$st_cv_have_program_invocation_name" = xyes; then
+	AC_DEFINE([HAVE_PROGRAM_INVOCATION_NAME], [1],
+		  [Define to 1 if the system provides program_invocation_name variable])
+fi
+
 AC_CHECK_LIB([dl], [dladdr], [dl_LIBS='-ldl'], [dl_LIBS=])
 if test "x$ac_cv_lib_dl_dladdr" = xyes; then
 	AC_DEFINE([HAVE_DLADDR], [1], [Define to 1 if the system provides dladdr])
diff --git a/strace.c b/strace.c
index 2bb4ec15..5ece0247 100644
--- a/strace.c
+++ b/strace.c
@@ -151,7 +151,10 @@ static struct tcb *current_tcp;
 
 static struct tcb **tcbtab;
 static unsigned int nprocs, tcbtabsize;
-static const char *progname;
+
+#ifndef HAVE_PROGRAM_INVOCATION_NAME
+char *program_invocation_name;
+#endif
 
 unsigned os_release; /* generated from uname()'s u.release */
 
@@ -298,13 +301,15 @@ static void verror_msg(int err_no, const char *fmt, va_list p)
 	msg = NULL;
 	if (vasprintf(&msg, fmt, p) >= 0) {
 		if (err_no)
-			fprintf(stderr, "%s: %s: %s\n", progname, msg, strerror(err_no));
+			fprintf(stderr, "%s: %s: %s\n",
+				program_invocation_name, msg, strerror(err_no));
 		else
-			fprintf(stderr, "%s: %s\n", progname, msg);
+			fprintf(stderr, "%s: %s\n",
+				program_invocation_name, msg);
 		free(msg);
 	} else {
 		/* malloc in vasprintf failed, try it without malloc */
-		fprintf(stderr, "%s: ", progname);
+		fprintf(stderr, "%s: ", program_invocation_name);
 		vfprintf(stderr, fmt, p);
 		if (err_no)
 			fprintf(stderr, ": %s\n", strerror(err_no));
@@ -339,7 +344,8 @@ void error_msg_and_help(const char *fmt, ...)
 		va_start(p, fmt);
 		verror_msg(0, fmt, p);
 	}
-	fprintf(stderr, "Try '%s -h' for more information.\n", progname);
+	fprintf(stderr, "Try '%s -h' for more information.\n",
+		program_invocation_name);
 	die();
 }
 
@@ -1617,7 +1623,11 @@ init(int argc, char *argv[])
 	int c, i;
 	int optF = 0;
 
-	progname = argv[0] ? argv[0] : "strace";
+	if (!program_invocation_name || !*program_invocation_name) {
+		static char name[] = "strace";
+		program_invocation_name =
+			(argv[0] && *argv[0]) ? argv[0] : name;
+	}
 
 	strace_tracer_pid = getpid();