lkml.org 
[lkml]   [2019]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v7 07/10] vsprintf: Consolidate handling of unknown pointer specifiers
Date
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 it introduces a warning about that test_hashed() function
is unused. It is going to be used again by a later patch.

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
lib/test_printf.c | 3 +--
lib/vsprintf.c | 28 +++++++++++++++++-----------
2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 659b6cc0d483..250ee864b8b8 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -462,8 +462,7 @@ 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 9817d171f608..f471a658422f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1435,6 +1435,8 @@ 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);
@@ -1457,7 +1459,8 @@ 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
@@ -1585,7 +1588,7 @@ 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);
@@ -1689,7 +1692,7 @@ 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);
}
}

@@ -1697,7 +1700,10 @@ 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]) {
@@ -1706,7 +1712,7 @@ 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
}
}
@@ -1739,7 +1745,8 @@ 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;
@@ -1760,8 +1767,7 @@ 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);
@@ -1817,7 +1823,7 @@ 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);
@@ -1896,7 +1902,7 @@ 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':
--
2.16.4
\
 
 \ /
  Last update: 2019-04-17 13:55    [W:0.278 / U:0.596 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site