s390/boot: Add field width and padding handling to boot_printk()

Enhance boot_printk() to support field width and padding across all
argument types for better formatting.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/boot/printk.c b/arch/s390/boot/printk.c
index 7379fdc9831f8d4aa9192bd6af60b9daf5f41a11..2f5d699768afc76c50ff2d49949f7ba401e689e1 100644 (file)
--- a/arch/s390/boot/printk.c
+++ b/arch/s390/boot/printk.c
@@ -13,13 +13,37 @@
 
 const char hex_asc[] = "0123456789abcdef";
 
+#define MAX_NUMLEN 17
 static char *as_hex(char *dst, unsigned long val, int pad)
 {
-       char *p, *end = p = dst + max(pad, (int)__fls(val | 1) / 4 + 1);
+       char *p = dst + max(pad, (int)__fls(val | 1) / 4 + 1);
 
-       for (*p-- = 0; p >= dst; val >>= 4)
+       for (*p-- = '\0'; p >= dst; val >>= 4)
                *p-- = hex_asc[val & 0x0f];
-       return end;
+       return dst;
+}
+
+static ssize_t strpad(char *dst, size_t dst_size, const char *src,
+                     int _pad, bool zero_pad)
+{
+       ssize_t len = strlen(src), pad = _pad;
+       char *p = dst;
+
+       if (max(len, abs(pad)) >= dst_size)
+               return -E2BIG;
+
+       if (pad > len) {
+               memset(p, zero_pad ? '0' : ' ', pad - len);
+               p += pad - len;
+       }
+       memcpy(p, src, len);
+       p += len;
+       if (pad < 0 && -pad > len) {
+               memset(p, ' ', -pad - len);
+               p += -pad - len;
+       }
+       *p = '\0';
+       return p - dst;
 }
 
 static char *symstart(char *p)
@@ -58,22 +82,22 @@ static noinline char *findsym(unsigned long ip, unsigned short *off, unsigned sh
        return NULL;
 }
 
-static noinline char *strsym(void *ip)
+#define MAX_SYMLEN 64
+static noinline char *strsym(char *buf, void *ip)
 {
-       static char buf[64];
        unsigned short off;
        unsigned short len;
        char *p;
 
        p = findsym((unsigned long)ip, &off, &len);
        if (p) {
-               strncpy(buf, p, sizeof(buf));
+               strncpy(buf, p, MAX_SYMLEN);
                /* reserve 15 bytes for offset/len in symbol+0x1234/0x1234 */
-               p = buf + strnlen(buf, sizeof(buf) - 15);
+               p = buf + strnlen(buf, MAX_SYMLEN - 15);
                strcpy(p, "+0x");
-               p = as_hex(p + 3, off, 0);
-               strcpy(p, "/0x");
-               as_hex(p + 3, len, 0);
+               as_hex(p + 3, off, 0);
+               strcat(p, "/0x");
+               as_hex(p + strlen(p), len, 0);
        } else {
                as_hex(buf, (unsigned long)ip, 16);
        }
@@ -91,10 +115,13 @@ void boot_printk(const char *fmt, ...)
 {
        char buf[1024] = { 0 };
        char *end = buf + sizeof(buf) - 1; /* make sure buf is 0 terminated */
-       unsigned long pad;
-       char *p = buf;
+       bool zero_pad;
+       char *strval, *p = buf;
+       char valbuf[MAX(MAX_SYMLEN, MAX_NUMLEN)];
        va_list args;
        char lenmod;
+       ssize_t len;
+       int pad;
 
        va_start(args, fmt);
        for (; p < end && *fmt; fmt++) {
@@ -106,7 +133,8 @@ void boot_printk(const char *fmt, ...)
                        *p++ = '%';
                        continue;
                }
-               pad = isdigit(*fmt) ? simple_strtol(fmt, (char **)&fmt, 10) : 0;
+               zero_pad = (*fmt == '0');
+               pad = simple_strtol(fmt, (char **)&fmt, 10);
                lenmod = (*fmt == 'h' || *fmt == 'l' || *fmt == 'z') ? *fmt++ : 0;
                if (lenmod == 'h' && *fmt == 'h') {
                        lenmod = 'H';
@@ -116,21 +144,25 @@ void boot_printk(const char *fmt, ...)
                case 's':
                        if (lenmod)
                                goto out;
-                       p = buf + strlcat(buf, va_arg(args, char *), sizeof(buf));
+                       strval = va_arg(args, char *);
+                       zero_pad = false;
                        break;
                case 'p':
                        if (*++fmt != 'S' || lenmod)
                                goto out;
-                       p = buf + strlcat(buf, strsym(va_arg(args, void *)), sizeof(buf));
+                       strval = strsym(valbuf, va_arg(args, void *));
+                       zero_pad = false;
                        break;
                case 'x':
-                       if (end - p <= max(sizeof(long) * 2, pad))
-                               goto out;
-                       p = as_hex(p, va_arg_len_type(args, lenmod, unsigned), pad);
+                       strval = as_hex(valbuf, va_arg_len_type(args, lenmod, unsigned), 0);
                        break;
                default:
                        goto out;
                }
+               len = strpad(p, end - p, strval, pad, zero_pad);
+               if (len == -E2BIG)
+                       break;
+               p += len;
        }
 out:
        va_end(args);