[PATCH v6 7/9] vsprintf: Consolidate handling of unknown pointer specifiers
From: Petr Mladek
Date: Fri Feb 08 2019 - 10:24:50 EST
There are few printk formats that make sense only with two or more
specifiers. Also some specifiers make sense only when a kernel feature
is enabled.
The handling of unknown specifiers is inconsistent and not helpful.
Using WARN() looks like an overkill for this type of error. pr_warn()
is not good either. It would by handled via printk_safe buffer and
it might be hard to match it with the problematic string.
A reasonable compromise seems to be writing the unknown format specifier
into the original string with a question mark, for example (%pC?).
It should be self-explaining enough. Note that it is in brackets
to follow the (null) style.
Note that the changes in test_printf.c revert many changes made
by the commit 4d42c44727a062e233 ("lib/vsprintf: Print time and
date in human readable format via %pt\n"). The format %pt does
not longer produce a hashed pointer.
Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
---
lib/test_printf.c | 39 ++++-----------------------------------
lib/vsprintf.c | 28 +++++++++++++++++-----------
2 files changed, 21 insertions(+), 46 deletions(-)
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 659b6cc0d483..159bb78b3992 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -250,11 +250,12 @@ plain_format(void)
#endif /* BITS_PER_LONG == 64 */
static int __init
-plain_hash_to_buffer(const void *p, char *buf, size_t len)
+plain_hash(void)
{
+ char buf[PLAIN_BUF_SIZE];
int nchars;
- nchars = snprintf(buf, len, "%p", p);
+ nchars = snprintf(buf, sizeof(buf), "%p", PTR);
if (nchars != PTR_WIDTH)
return -1;
@@ -265,20 +266,6 @@ plain_hash_to_buffer(const void *p, char *buf, size_t len)
return 0;
}
- return 0;
-}
-
-
-static int __init
-plain_hash(void)
-{
- char buf[PLAIN_BUF_SIZE];
- int ret;
-
- ret = plain_hash_to_buffer(PTR, buf, PLAIN_BUF_SIZE);
- if (ret)
- return ret;
-
if (strncmp(buf, PTR_STR, PTR_WIDTH) == 0)
return -1;
@@ -309,23 +296,6 @@ plain(void)
}
static void __init
-test_hashed(const char *fmt, const void *p)
-{
- char buf[PLAIN_BUF_SIZE];
- int ret;
-
- /*
- * No need to increase failed test counter since this is assumed
- * to be called after plain().
- */
- ret = plain_hash_to_buffer(p, buf, PLAIN_BUF_SIZE);
- if (ret)
- return;
-
- test(buf, fmt, p);
-}
-
-static void __init
symbol_ptr(void)
{
}
@@ -462,8 +432,7 @@ struct_rtc_time(void)
.tm_year = 118,
};
- test_hashed("%pt", &tm);
-
+ test("(%ptR?)", "%pt", &tm);
test("2018-11-26T05:35:43", "%ptR", &tm);
test("0118-10-26T05:35:43", "%ptRr", &tm);
test("05:35:43|2018-11-26", "%ptRt|%ptRd", &tm, &tm);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index ab59db1c1146..d8509f6adda6 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1434,6 +1434,8 @@ static noinline_for_stack
char *ip_addr_string(char *buf, char *end, const void *ptr,
struct printf_spec spec, const char *fmt)
{
+ char *err_fmt_msg;
+
switch (fmt[1]) {
case '6':
return ip6_addr_string(buf, end, ptr, spec, fmt);
@@ -1456,7 +1458,8 @@ char *ip_addr_string(char *buf, char *end, const void *ptr,
}}
}
- return ptr_to_id(buf, end, ptr, spec);
+ err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
+ return string_nocheck(buf, end, err_fmt_msg, spec);
}
static noinline_for_stack
@@ -1584,7 +1587,7 @@ char *netdev_bits(char *buf, char *end, const void *addr,
size = sizeof(netdev_features_t);
break;
default:
- return ptr_to_id(buf, end, addr, spec);
+ return string_nocheck(buf, end, "(%pN?)", spec);
}
return special_hex_number(buf, end, num, size);
@@ -1688,7 +1691,7 @@ char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
case 'R':
return rtc_str(buf, end, (const struct rtc_time *)ptr, fmt);
default:
- return ptr_to_id(buf, end, ptr, spec);
+ return string_nocheck(buf, end, "(%ptR?)", spec);
}
}
@@ -1696,7 +1699,10 @@ static noinline_for_stack
char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
const char *fmt)
{
- if (!IS_ENABLED(CONFIG_HAVE_CLK) || !clk)
+ if (!IS_ENABLED(CONFIG_HAVE_CLK))
+ return string_nocheck(buf, end, "(%pC?)", spec);
+
+ if (!clk)
return string(buf, end, NULL, spec);
switch (fmt[1]) {
@@ -1705,7 +1711,7 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
#ifdef CONFIG_COMMON_CLK
return string(buf, end, __clk_get_name(clk), spec);
#else
- return ptr_to_id(buf, end, clk, spec);
+ return string_nocheck(buf, end, "(%pC?)", spec);
#endif
}
}
@@ -1738,7 +1744,8 @@ char *format_flags(char *buf, char *end, unsigned long flags,
}
static noinline_for_stack
-char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
+char *flags_string(char *buf, char *end, void *flags_ptr,
+ struct printf_spec spec, const char *fmt)
{
unsigned long flags;
const struct trace_print_flags *names;
@@ -1759,8 +1766,7 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
names = gfpflag_names;
break;
default:
- WARN_ONCE(1, "Unsupported flags modifier: %c\n", fmt[1]);
- return buf;
+ return string_nocheck(buf, end, "(%pG?)", spec);
}
return format_flags(buf, end, flags, names);
@@ -1816,7 +1822,7 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
str_spec.field_width = -1;
if (!IS_ENABLED(CONFIG_OF))
- return string_nocheck(buf, end, "(!OF)", spec);
+ return string_nocheck(buf, end, "(%pOF?)", spec);
if ((unsigned long)dn < PAGE_SIZE)
return string_nocheck(buf, end, "(null)", spec);
@@ -1895,7 +1901,7 @@ static char *kobject_string(char *buf, char *end, void *ptr,
return device_node_string(buf, end, ptr, spec, fmt + 1);
}
- return ptr_to_id(buf, end, ptr, spec);
+ return string_nocheck(buf, end, "(%pO?)", spec);
}
/*
@@ -2091,7 +2097,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
#endif
case 'G':
- return flags_string(buf, end, ptr, fmt);
+ return flags_string(buf, end, ptr, spec, fmt);
case 'O':
return kobject_string(buf, end, ptr, spec, fmt);
case 'x':
--
2.13.7