Portability: use POSIX strerror() where it's available; fake it with

  sys_errlist[] where not.

4 files changed, 21 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index a818806..abf4b12 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -624,3 +624,6 @@ Changes since rc-1.5b2
   rc_exit().  This bug is easily tickled on systems (like Linux) which
   allow you to open(2) but not read(2) directories: `. /tmp'.  In all
   previous versions of rc, this caused the shell to exit.
+
+  Portability: use POSIX strerror() where it's available; fake it with
+  sys_errlist[] where not.
diff --git a/configure.ac b/configure.ac
index 87cb15e..e901c06 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,7 +38,7 @@ AC_TYPE_SIZE_T
 AC_TYPE_UID_T
 AC_CHECK_TYPE(ssize_t, long)
 
-AC_CHECK_FUNCS(getgroups setpgrp setrlimit)
+AC_CHECK_FUNCS(getgroups setpgrp setrlimit strerror)
 RC_FUNC_GETGROUPS
 
 RC_FUNC_SIGSETJMP
diff --git a/proto.h b/proto.h
index 0f24fb5..7d2fe2a 100644
--- a/proto.h
+++ b/proto.h
@@ -59,6 +59,15 @@ extern void qsort(void *, size_t, size_t, int (*)(const void *, const void *));
 
 #endif /* STDC_HEADERS */
 
+#if HAVE_STRERROR
+/* Smells like POSIX. */
+#else
+/* Assume BSD-style sys_errlist[]. */
+extern int sys_nerr;
+extern char *sys_errlist[];
+#define strerror(x) ((0 <= (x)) && (errno < (x)) ? sys_errlist[x] : (char *)0)
+#endif
+
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
diff --git a/utils.c b/utils.c
index ded0c03..00be28b 100644
--- a/utils.c
+++ b/utils.c
@@ -19,14 +19,15 @@ extern void pr_error(char *s, int offset) {
 /* our perror */
 
 extern void uerror(char *s) {
-	extern int sys_nerr;
-	extern char *sys_errlist[];
-	if (errno > sys_nerr)
-		return;
-	if (s != NULL)
-		fprint(2, "%s: %s\n", s, sys_errlist[errno]);
+	char *err;
+
+	err = strerror(errno);
+	if (!err) err = "unknown error";
+
+	if (s)
+		fprint(2, "%s: %s\n", s, err);
 	else
-		fprint(2, "%s\n", sys_errlist[errno]);
+		fprint(2, "%s\n", err);
 }
 
 /* Die horribly. This should never get called. Please let me know if it does. */