1 files changed, 48 insertions, 5 deletions
diff --git a/libc/stdio/stdio.c b/libc/stdio/stdio.c
index 1462874f0..c84731675 100644
--- a/libc/stdio/stdio.c
+++ b/libc/stdio/stdio.c
@@ -3105,14 +3105,22 @@ void perror(register const char *s)
 #ifdef __STDIO_PRINTF_M_SPEC
 	fprintf(_stderr, "%s%s%m\n", s, sep); /* Use the gnu %m feature. */
 #else
-	/* TODO: use strerror_r instead? */
-	fprintf(_stderr, "%s%s%s\n", s, sep, strerror(errno));
+	{
+		char buf[64];
+		fprintf(_stderr, "%s%s%s\n", s, sep,
+				_stdio_strerror_r(errno, buf, sizeof(buf)));
+	}
 #endif
 #else
 	/* Note: Assumes stderr not closed or buffered. */
-	__STDIO_THREADLOCK(stderr);
-	_stdio_fdout(STDERR_FILENO, s, sep, strerror(errno));
-	__STDIO_THREADUNLOCK(stderr);
+	{
+		char buf[64];
+
+		__STDIO_THREADLOCK(stderr);
+		_stdio_fdout(STDERR_FILENO, s, sep,
+					 _stdio_strerror_r(errno, buf, sizeof(buf)));
+		__STDIO_THREADUNLOCK(stderr);
+	}
 #endif
 }
 
@@ -3209,3 +3217,38 @@ char *_uintmaxtostr(char * __restrict bufend, uintmax_t uval,
 #undef INTERNAL_DIV_MOD
 
 #endif
+/**********************************************************************/
+#ifdef L__stdio_strerror_r
+
+/* This is an internal routine, and assumes buf and buflen are set
+ * appropriately.
+ * 
+ * WARNING!!! While it is similar to the glibc strerror_r function,
+ * it is not the same.  It is expected that "unknown" error strings
+ * will fit in the buffer passed.  Also, the return value may not
+ * be == buf, as unknown strings are "right-justified" in the buf
+ * due to the way _int10stostr works. */
+
+static const char unknown[] = "Unknown error";
+
+char *_stdio_strerror_r(int err, char *buf, size_t buflen)
+{
+	int errsave;
+
+	assert(buflen >= __UIM_BUFLEN_INT + sizeof(unknown));
+
+	errsave = errno;			/* Backup the errno. */
+
+	if (strerror_r(err, buf, buflen)) {	/* Failed! */
+		__set_errno(errsave);	/* Restore old errno. */
+
+		buf = _int10tostr(buf+buflen-1, err) - sizeof(unknown);
+		strcpy(buf, unknown);
+		buf[sizeof(unknown)-1] = ' '; /* Overwrite the nul. */
+	}
+
+	return buf;
+}
+
+#endif
+/**********************************************************************/