libsa: add string precision support to vprintf

We already had a hack to ignore the precision, but the ACPI driver
requires an actual implementation--it prints garbage at the end of
some strings otherwise.  This patch adds support for precision for
strings only, limiting printing to the given number of characters.
For all other specifiers, precision is still unsupported.

Change-Id: I1d41fc70a0d0494db695c22ba609262a50b86e08

diff --git a/sys/lib/libsa/subr_prf.c b/sys/lib/libsa/subr_prf.c
index 93f101728985d7a49123693e76c5761f022ec2dc..d6fc0defc2bb60d877f98a14194be57b83058377 100644 (file)
--- a/sys/lib/libsa/subr_prf.c
+++ b/sys/lib/libsa/subr_prf.c
@@ -191,6 +191,9 @@ kdoprnt(void (*put)(int), const char *fmt, va_list ap)
 #ifdef LIBSA_PRINTF_WIDTH_SUPPORT
        int width;
        char *q;
+#if defined(__minix)
+       int max;
+#endif /* defined(__minix) */
 #endif
 
        for (;;) {
@@ -202,18 +205,20 @@ kdoprnt(void (*put)(int), const char *fmt, va_list ap)
                lflag = 0;
 #ifdef LIBSA_PRINTF_WIDTH_SUPPORT
                width = 0;
+#if defined(__minix)
+               max = -1;
+#endif /* defined(__minix) */
 #endif
 reswitch:
                switch (ch = *fmt++) {
 #ifdef LIBSA_PRINTF_WIDTH_SUPPORT
 #if defined(__minix)
-               /* LSC: FIXME: this is a simple hack which ignores the thing for now. */
                case '.':
-                       /* eat up digits */
-                       while( ((('1' >= *fmt) && ( *fmt <= '9'))
-                                || (*fmt == '*')) )
-                                fmt++;
-                       fmt++;
+                       if (*fmt == '*') {
+                               max = va_arg(ap, int);
+                               fmt++;
+                       } else for (max = 0; *fmt >= '0' && *fmt <= '9'; fmt++)
+                               max = max * 10 + *fmt - '0';
                        goto reswitch;
 #endif /* defined(__minix) */
                case '#':
@@ -274,10 +279,19 @@ reswitch:
 #ifdef LIBSA_PRINTF_WIDTH_SUPPORT
                        for (q = p; *q != '\0'; ++q)
                                continue;
+#if defined(__minix)
+                       if (max >= 0 && q - p > max)
+                               q = &p[max];
+#endif /* defined(__minix) */
                        width -= q - p;
 #endif
                        RPAD();
+#if defined(LIBSA_PRINTF_WIDTH_SUPPORT) && defined(__minix)
+                       while ((max < 0 || max-- > 0) &&
+                           (ch = (unsigned char)*p++))
+#else /* !defined(LIBSA_PRINTF_WIDTH_SUPPORT) || !defined(__minix) */
                        while ((ch = (unsigned char)*p++))
+#endif /* !defined(LIBSA_PRINTF_WIDTH_SUPPORT) || !defined(__minix) */
                                put(ch);
                        LPAD();
                        break;