We use an array of strings to represnt a JSONPath. Add a new %pJP format specifier that can be used to print them. This is useful for error messages when the lookup fails.
Signed-off-by: Ahmad Fatoum <[email protected]> --- lib/vsprintf.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ test/self/printf.c | 17 +++++++++++++++++ 2 files changed, 61 insertions(+) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 693f3c0cc0c8..cdb3906ea2ff 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -197,6 +197,27 @@ static char *string(char *buf, const char *end, const char *s, int field_width, return trailing_spaces(buf, end, len, &field_width, flags); } +static __maybe_unused char *string_array(char *buf, const char *end, char *const *s, + int field_width, int precision, int flags, + const char *separator) +{ + size_t i, len = strlen(separator); + + while (*s) { + buf = string(buf, end, *s, field_width, precision, flags); + if (!*++s) + break; + + for (i = 0; i < len; ++i) { + if (buf < end) + *buf = separator[i]; + ++buf; + } + } + + return buf; +} + static char *wstring(char *buf, const char *end, const wchar_t *s, int field_width, int precision, int flags) { @@ -368,6 +389,26 @@ char *hex_string(char *buf, const char *end, const u8 *addr, int field_width, return buf; } +static noinline_for_stack +char *jsonpath_string(char *buf, const char *end, char *const *path, int field_width, + int precision, int flags, const char *fmt) +{ + if ((unsigned long)path < PAGE_SIZE) + return string(buf, end, "<NULL>", field_width, precision, flags); + + if (buf < end) + *buf = '$'; + ++buf; + + if (*path) { + if (buf < end) + *buf = '.'; + ++buf; + } + + return string_array(buf, end, path, field_width, precision, flags, "."); +} + static noinline_for_stack char *address_val(char *buf, const char *end, const void *addr, int field_width, int precision, int flags, const char *fmt) @@ -458,6 +499,9 @@ static char *pointer(const char *fmt, char *buf, const char *end, const void *pt if (IS_ENABLED(CONFIG_PRINTF_HEXSTR)) return hex_string(buf, end, ptr, field_width, precision, flags, fmt); break; + case 'J': + if (fmt[1] == 'P' && IS_ENABLED(CONFIG_JSMN)) + return jsonpath_string(buf, end, ptr, field_width, precision, flags, fmt); } return raw_pointer(buf, end, ptr, field_width, precision, flags); diff --git a/test/self/printf.c b/test/self/printf.c index 7a74660868c2..eae40ed242c1 100644 --- a/test/self/printf.c +++ b/test/self/printf.c @@ -305,6 +305,22 @@ test_pointer(void) errptr(); } +static void __init +test_jsonpath(void) +{ + if (!IS_ENABLED(CONFIG_JSMN)) { + pr_info("skipping jsonpath tests: CONFIG_JSMN disabled in config\n"); + skipped_tests += 5; + return; + } + + test("<NULL>", "%pJP", NULL); + test("$", "%pJP", &(char *[]){ NULL }); + test("$.1", "%pJP", &(char *[]){ "1", NULL }); + test("$.1.23", "%pJP", &(char *[]){ "1", "23", NULL }); + test("$.1.23.456", "%pJP", &(char *[]){ "1", "23", "456", NULL }); +} + static void __init test_printf(void) { alloced_buffer = malloc(BUF_SIZE + 2*PAD_SIZE); @@ -317,6 +333,7 @@ static void __init test_printf(void) test_string(); test_pointer(); test_hexstr(); + test_jsonpath(); free(alloced_buffer); } -- 2.30.2
