1 files changed, 93 insertions, 35 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 6021757a4496..1dc2d1d18fa8 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -22,6 +22,8 @@
 #include <linux/string.h>
 #include <linux/ctype.h>
 #include <linux/kernel.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
 
 #include <asm/page.h>           /* for PAGE_SIZE */
 #include <asm/div64.h>
@@ -482,6 +484,89 @@ static char *number(char *buf, char *end, unsigned long long num, int base, int
         return buf;
 }
 
+static char *string(char *buf, char *end, char *s, int field_width, int precision, int flags)
+{
+        int len, i;
+
+        if ((unsigned long)s < PAGE_SIZE)
+                s = "<NULL>";
+
+        len = strnlen(s, precision);
+
+        if (!(flags & LEFT)) {
+                while (len < field_width--) {
+                        if (buf < end)
+                                *buf = ' ';
+                        ++buf;
+                }
+        }
+        for (i = 0; i < len; ++i) {
+                if (buf < end)
+                        *buf = *s;
+                ++buf; ++s;
+        }
+        while (len < field_width--) {
+                if (buf < end)
+                        *buf = ' ';
+                ++buf;
+        }
+        return buf;
+}
+
+static inline void *dereference_function_descriptor(void *ptr)
+{
+#if defined(CONFIG_IA64) || defined(CONFIG_PPC64)
+        void *p;
+        if (!probe_kernel_address(ptr, p))
+                ptr = p;
+#endif
+        return ptr;
+}
+
+static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags)
+{
+        unsigned long value = (unsigned long) ptr;
+#ifdef CONFIG_KALLSYMS
+        char sym[KSYM_SYMBOL_LEN];
+        sprint_symbol(sym, value);
+        return string(buf, end, sym, field_width, precision, flags);
+#else
+        field_width = 2*sizeof(void *);
+        flags |= SPECIAL | SMALL | ZEROPAD;
+        return number(buf, end, value, 16, field_width, precision, flags);
+#endif
+}
+
+/*
+ * Show a '%p' thing.  A kernel extension is that the '%p' is followed
+ * by an extra set of alphanumeric characters that are extended format
+ * specifiers.
+ *
+ * Right now we just handle 'F' (for symbolic Function descriptor pointers)
+ * and 'S' (for Symbolic direct pointers), but this can easily be
+ * extended in the future (network address types etc).
+ *
+ * The difference between 'S' and 'F' is that on ia64 and ppc64 function
+ * pointers are really function descriptors, which contain a pointer the
+ * real address. 
+ */
+static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
+{
+        switch (*fmt) {
+        case 'F':
+                ptr = dereference_function_descriptor(ptr);
+                /* Fallthrough */
+        case 'S':
+                return symbol_string(buf, end, ptr, field_width, precision, flags);
+        }
+        flags |= SMALL;
+        if (field_width == -1) {
+                field_width = 2*sizeof(void *);
+                flags |= ZEROPAD;
+        }
+        return number(buf, end, (unsigned long) ptr, 16, field_width, precision, flags);
+}
+
 /**
  * vsnprintf - Format a string and place it in a buffer
  * @buf: The buffer to place the result into
@@ -502,11 +587,9 @@ static char *number(char *buf, char *end, unsigned long long num, int base, int
  */
 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 {
-        int len;
         unsigned long long num;
-        int i, base;
+        int base;
         char *str, *end, c;
-        const char *s;
 
         int flags;              /* flags to number() */
 
@@ -622,43 +705,18 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
                                 continue;
 
                         case 's':
-                                s = va_arg(args, char *);
-                                if ((unsigned long)s < PAGE_SIZE)
-                                        s = "<NULL>";
-
-                                len = strnlen(s, precision);
-
-                                if (!(flags & LEFT)) {
-                                        while (len < field_width--) {
-                                                if (str < end)
-                                                        *str = ' ';
-                                                ++str;
-                                        }
-                                }
-                                for (i = 0; i < len; ++i) {
-                                        if (str < end)
-                                                *str = *s;
-                                        ++str; ++s;
-                                }
-                                while (len < field_width--) {
-                                        if (str < end)
-                                                *str = ' ';
-                                        ++str;
-                                }
+                                str = string(str, end, va_arg(args, char *), field_width, precision, flags);
                                 continue;
 
                         case 'p':
-                                flags |= SMALL;
-                                if (field_width == -1) {
-                                        field_width = 2*sizeof(void *);
-                                        flags |= ZEROPAD;
-                                }
-                                str = number(str, end,
-                                                (unsigned long) va_arg(args, void *),
-                                                16, field_width, precision, flags);
+                                str = pointer(fmt+1, str, end,
+                                                va_arg(args, void *),
+                                                field_width, precision, flags);
+                                /* Skip all alphanumeric pointer suffixes */
+                                while (isalnum(fmt[1]))
+                                        fmt++;
                                 continue;
 
-
                         case 'n':
                                 /* FIXME:
                                 * What does C99 say about the overflow case here? */