diff options
| -rw-r--r-- | Documentation/printk-formats.txt | 32 | ||||
| -rw-r--r-- | lib/vsprintf.c | 71 |
2 files changed, 103 insertions, 0 deletions
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt index b4498218c474..5a615c14f75d 100644 --- a/Documentation/printk-formats.txt +++ b/Documentation/printk-formats.txt @@ -70,6 +70,38 @@ DMA addresses types dma_addr_t: For printing a dma_addr_t type which can vary based on build options, regardless of the width of the CPU data path. Passed by reference. +Raw buffer as an escaped string: + + %*pE[achnops] + + For printing raw buffer as an escaped string. For the following buffer + + 1b 62 20 5c 43 07 22 90 0d 5d + + few examples show how the conversion would be done (the result string + without surrounding quotes): + + %*pE "\eb \C\a"\220\r]" + %*pEhp "\x1bb \C\x07"\x90\x0d]" + %*pEa "\e\142\040\\\103\a\042\220\r\135" + + The conversion rules are applied according to an optional combination + of flags (see string_escape_mem() kernel documentation 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. + + ESCAPE_ANY_NP is the sane choice for many cases, in particularly for + printing SSIDs. + + If field width is omitted the 1 byte only will be escaped. + Raw buffer as a hex string: %*ph 00 01 02 ... 3f %*phC 00:01:02: ... :3f 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 |