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author | 2014-10-13 15:55:18 -0700 | |
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committer | 2014-10-14 02:18:26 +0200 | |
commit | 71dca95d5cf5ece6c1bee8e625e23c16025952c7 (patch) | |
tree | 098b1a20867ef6d1b38f549f162c160610b3cbff /lib/vsprintf.c | |
parent | lib / string_helpers: introduce string_escape_mem() (diff) | |
download | linux-71dca95d5cf5ece6c1bee8e625e23c16025952c7.tar.gz linux-71dca95d5cf5ece6c1bee8e625e23c16025952c7.tar.bz2 linux-71dca95d5cf5ece6c1bee8e625e23c16025952c7.zip |
lib/vsprintf: add %*pE[achnops] format specifier
This allows user to print a given buffer as an escaped string. The
rules are applied according to an optional mix of flags provided by
additional format letters.
For example, if the given buffer is:
1b 62 20 5c 43 07 22 90 0d 5d
The result strings would be:
%*pE "\eb \C\a"\220\r]"
%*pEhp "\x1bb \C\x07"\x90\x0d]"
%*pEa "\e\142\040\\\103\a\042\220\r\135"
Please, read Documentation/printk-formats.txt and lib/string_helpers.c
kernel documentation to get further information.
[akpm@linux-foundation.org: tidy up comment layout, per Joe]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Joe Perches <joe@perches.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/vsprintf.c')
-rw-r--r-- | lib/vsprintf.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index ba3cd0a35640..ec337f64f52d 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -33,6 +33,7 @@ #include <asm/page.h> /* for PAGE_SIZE */ #include <asm/sections.h> /* for dereference_function_descriptor() */ +#include <linux/string_helpers.h> #include "kstrtox.h" /** @@ -1101,6 +1102,62 @@ char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa, } static noinline_for_stack +char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec, + const char *fmt) +{ + bool found = true; + int count = 1; + unsigned int flags = 0; + int len; + + if (spec.field_width == 0) + return buf; /* nothing to print */ + + if (ZERO_OR_NULL_PTR(addr)) + return string(buf, end, NULL, spec); /* NULL pointer */ + + + do { + switch (fmt[count++]) { + case 'a': + flags |= ESCAPE_ANY; + break; + case 'c': + flags |= ESCAPE_SPECIAL; + break; + case 'h': + flags |= ESCAPE_HEX; + break; + case 'n': + flags |= ESCAPE_NULL; + break; + case 'o': + flags |= ESCAPE_OCTAL; + break; + case 'p': + flags |= ESCAPE_NP; + break; + case 's': + flags |= ESCAPE_SPACE; + break; + default: + found = false; + break; + } + } while (found); + + if (!flags) + flags = ESCAPE_ANY_NP; + + len = spec.field_width < 0 ? 1 : spec.field_width; + + /* Ignore the error. We print as many characters as we can */ + string_escape_mem(addr, len, &buf, end - buf, flags, NULL); + + return buf; +} + +static noinline_for_stack char *uuid_string(char *buf, char *end, const u8 *addr, struct printf_spec spec, const char *fmt) { @@ -1221,6 +1278,17 @@ int kptr_restrict __read_mostly; * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order * - 'I[6S]c' for IPv6 addresses printed as specified by * http://tools.ietf.org/html/rfc5952 + * - 'E[achnops]' For an escaped buffer, where rules are defined by combination + * of the following flags (see string_escape_mem() for the + * details): + * a - ESCAPE_ANY + * c - ESCAPE_SPECIAL + * h - ESCAPE_HEX + * n - ESCAPE_NULL + * o - ESCAPE_OCTAL + * p - ESCAPE_NP + * s - ESCAPE_SPACE + * By default ESCAPE_ANY_NP is used. * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form * "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" * Options for %pU are: @@ -1321,6 +1389,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, }} } break; + case 'E': + return escaped_string(buf, end, ptr, spec, fmt); case 'U': return uuid_string(buf, end, ptr, spec, fmt); case 'V': @@ -1633,6 +1703,7 @@ qualifier: * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper * case. + * %*pE[achnops] print an escaped buffer * %*ph[CDN] a variable-length hex string with a separator (supports up to 64 * bytes of the input) * %n is ignored |