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Implement scansets support in RStr.scanf ##util
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@radare @trufae
radare authored and trufae committed Feb 7, 2024
1 parent 64aa644 commit c75ad89
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Showing 2 changed files with 123 additions and 20 deletions.
128 changes: 108 additions & 20 deletions libr/util/bscanf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,64 @@
#define _BSCANF_CHECK_BUFFER() _BSCANF_CHECK('\0' != *buffer);
#define _BSCANF_CHECK_STRTONUM() _BSCANF_CHECK(buf_ptr != end_ptr);

static bool scanset_check(const char *scanset, char ch) {
bool negated = false;
if (*scanset == '^') {
scanset++;
negated = true;
}
const char *ss = scanset;
while (*ss) {
bool found = false;
if (ss[1] == '-') {
const char min = ss[0];
const char max = ss[2];
if (ch >= min && ch <= max) {
found = true;
}
ss += 2;
} else {
found = (*ss == ch);
ss++;
}
if (negated) {
if (found) {
return false;
}
} else {
if (!found) {
return false;
}
}
}
if (negated) {
return true;
}
return false;
}

static const char *scanset_parse(const char *fmt_ptr, char *scanset, size_t scanset_size) {
char *scanset_last = scanset + sizeof (scanset);
char *scanset_cur = scanset;
*scanset_cur = 0;
fmt_ptr++;
while (*fmt_ptr) {
if (scanset_cur >= scanset_last) {
R_LOG_ERROR ("Too large scanset found");
return NULL;
}
if (*fmt_ptr == ']') {
fmt_ptr ++;
break;
}
*scanset_cur = *fmt_ptr;
scanset_cur++;
*scanset_cur = 0;
fmt_ptr++;
}
return fmt_ptr;
}

R_API int r_str_scanf(const char *buffer, const char *format, ...) {
R_RETURN_VAL_IF_FAIL (buffer && format, -1);
/* Our return value. On a conversion error, we return this immediately. */
Expand Down Expand Up @@ -49,7 +107,7 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {

while (*fmt_ptr) {
/* We ignore spaces before specifiers. */
if (isspace(*fmt_ptr)) {
if (isspace (*fmt_ptr)) {
/* Any whitespace in the format consumes all of the whitespace in the buffer. */
_BSCANF_CONSUME_WSPACE();
fmt_ptr++;
Expand Down Expand Up @@ -114,12 +172,12 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {
}

/* All other specifiers move the buffer pointer, so check that it's not NUL. */
_BSCANF_CHECK_BUFFER();
_BSCANF_CHECK_BUFFER ();

if ('%' == *fmt_ptr) {
/* '%': match literal %. */
_BSCANF_CONSUME_WSPACE();
_BSCANF_MATCH();
_BSCANF_CONSUME_WSPACE ();
_BSCANF_MATCH ();
buf_ptr++;
} else if ('c' == *fmt_ptr || 's' == *fmt_ptr) {
/* 'c'/'s': match a character sequence/string. */
Expand All @@ -128,14 +186,18 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {

/* 'c' conversion specifiers DO NOT consume whitespace. */
if ('c' != *fmt_ptr) {
_BSCANF_CONSUME_WSPACE();
_BSCANF_CONSUME_WSPACE ();
}

if (is_suppressed) {
/* Consume the character (string) and ignore it in this case. */
for (; max_width > 0; max_width--) {
while (true) {
buf_ptr++;
if (*buf_ptr == '\0' || (isspace(*buf_ptr) && 's' == *fmt_ptr)) {
if (*buf_ptr == '\0') {
break;
}
if ((isspace (*buf_ptr) && 's' == *fmt_ptr)) {
buf_ptr++;
break;
}
}
Expand Down Expand Up @@ -212,17 +274,45 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {
}

} else if ('[' == *fmt_ptr) {
/* TODO: '[': match a non-empty sequence of characters from a set. */
_BSCANF_CHECK(0);

char scanset[32] = {0};
// https://cplusplus.com/reference/cstdio/scanf/
/* '[': match a non-empty sequence of characters from a scanset. */
fmt_ptr = scanset_parse (fmt_ptr, scanset, sizeof (scanset));
if (!fmt_ptr) {
// error invalid scanset
goto beach;
}
// process scanset and fill the string
/* String conversion requires a width. */
_BSCANF_CHECK_STRING();
_BSCANF_CHECK_STRING ();
/* '[' conversion specifiers DO NOT consume whitespace. */
char_ptr = va_arg (args, char*);
_BSCANF_CHECK_NULL (char_ptr);
*char_ptr = 0; // null byte the first char before failing
if (max_width < 1) {
R_LOG_DEBUG ("Missing length specifier for string");
} else {
for (; *buf_ptr && max_width > 0; max_width--) {
if (!scanset_check (scanset, *buf_ptr)) {
break;
}
*char_ptr = *buf_ptr;
char_ptr++;
buf_ptr++;
}
if (max_width == 0) {
R_LOG_DEBUG ("Truncated string in scanf");
}
/* Strings must be null-terminated. */
*char_ptr = '\0';
num_args_set++;
}
// reset max width value
max_width = 0;

} else if ('i' == *fmt_ptr || 'd' == *fmt_ptr) {
/* 'i'/'d': match a integer/decimal integer. */

_BSCANF_CONSUME_WSPACE();
_BSCANF_CONSUME_WSPACE ();
base = ('d' == *fmt_ptr) * 10;

if (is_suppressed) {
Expand All @@ -234,19 +324,19 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {
*long_ptr = (long) strtol (buf_ptr, &end_ptr, base);
} else if ('L' == length_mod) {
ut64_ptr = va_arg (args, ut64*);
_BSCANF_CHECK_NULL(long_ptr);
_BSCANF_CHECK_NULL (long_ptr);
*ut64_ptr = (ut64) strtoll (buf_ptr, &end_ptr, base);
} else if ('h' == length_mod) {
short_ptr = va_arg (args, short*);
_BSCANF_CHECK_NULL (short_ptr);
*short_ptr = (short) (strtol (buf_ptr, &end_ptr, base));
} else {
int_ptr = va_arg (args, int*);
_BSCANF_CHECK_NULL(int_ptr);
_BSCANF_CHECK_NULL (int_ptr);
*int_ptr = (int) (strtol (buf_ptr, &end_ptr, base));
}

_BSCANF_CHECK_STRTONUM();
_BSCANF_CHECK_STRTONUM ();
buf_ptr = end_ptr;
num_args_set++;

Expand Down Expand Up @@ -275,8 +365,7 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {
num_args_set++;

} else if ('p' == *fmt_ptr) {

_BSCANF_CONSUME_WSPACE();
_BSCANF_CONSUME_WSPACE ();
base = 16;

if (is_suppressed) {
Expand All @@ -294,8 +383,7 @@ R_API int r_str_scanf(const char *buffer, const char *format, ...) {
num_args_set++;
} else if ('u' == *fmt_ptr || 'o' == *fmt_ptr || 'x' == *fmt_ptr || 'X' == *fmt_ptr) {
/* 'u'/'o'/'x': match a unsigned decimal/octal/hexadecimal integer */

_BSCANF_CONSUME_WSPACE();
_BSCANF_CONSUME_WSPACE ();
base = ('u' == *fmt_ptr) * 10 + ('o' == *fmt_ptr) * 8 +
('x' == *fmt_ptr || 'X' == *fmt_ptr) * 16;

Expand Down
15 changes: 15 additions & 0 deletions test/unit/test_scanf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ bool test_r_str_scanf(void) {
res = r_str_scanf ("0x120000023b2d8000", "0x%Lx", &bignum);
mu_assert_eq (0x120000023b2d8000, bignum, "portable ut64 scanf failed");
mu_assert_eq (res, 1, "return value for scanf failed");

mu_end;
}

Expand All @@ -36,9 +37,23 @@ bool test_r_str_scanf_pointer(void) {
mu_end;
}

bool test_r_str_scanf_scanset(void) {
char msg0[32];
char msg1[32];
char *s = r_str_newf ("Hello World ITS OVER\nAGAIN");
int res = r_str_scanf (s, "%.s %*s %.[^\n]", sizeof (msg0), &msg0, sizeof (msg1), &msg1);
free (s);
mu_assert_streq (msg0, "Hello", "first word");
mu_assert_streq (msg1, "ITS OVER", "the rest until newline");
mu_assert_eq (res, 2, "return value for scanf failed");

mu_end;
}

bool all_tests(void) {
mu_run_test (test_r_str_scanf);
mu_run_test (test_r_str_scanf_pointer);
mu_run_test (test_r_str_scanf_scanset);
return tests_passed != tests_run;
}

Expand Down

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