Initial implementation of our custom r_str_printf api

libr/include/r_util/r_str.h

@@ -314,6 +314,8 @@ R_API char *r_str_version(const char *program);
 R_API char *r_str_ss(const char* msg, const char *nl, int cs);
 
 R_API char *r_str_after(char *s, char c);
+R_API int r_str_printf(R_NONNULL char *buffer, size_t buffer_size, R_NONNULL const char *format, ...);
+  /// __attribute__ ((format (printf, 3, 4)));
 R_API int r_str_scanf(R_NONNULL const char *buffer, R_NONNULL const char *format, ...);
   /// __attribute__ ((format (scanf, 2, 3)));
 

libr/util/Makefile

@@ -15,7 +15,7 @@ OBJS+=udiff.o bdiff.o stack.o queue.o tree.o idpool.o assert.o bplist.o
 OBJS+=punycode.o pkcs7.o x509.o asn1.o asn1_str.o json_parser.o json_indent.o skiplist.o
 OBJS+=pj.o rbtree.o intervaltree.o qrcode.o vector.o str_constpool.o str_trim.o
 OBJS+=ascii_table.o protobuf.o graph_drawable.o axml.o sstext.o new_rbtree.o token.o
-OBJS+=rvc.o rvc_git.o rvc_rvc.o bscanf.o
+OBJS+=rvc.o rvc_git.o rvc_rvc.o bscanf.o rprintf.o
 
 ifeq (${HAVE_GPERF},1)
 OBJS+=d/ascii.o

libr/util/meson.build

@@ -42,6 +42,7 @@ r_util_sources = [
   'list.c',
   'log.c',
   'bscanf.c',
+  'rprintf.c',
   'mem.c',
   'name.c',
   'new_rbtree.c',

libr/util/rprintf.c

@@ -0,0 +1,145 @@
+// snprintf implementation for radare2 (safe+custom extensions)
+
+// %b for boolean (true|false)
+// %n is forbidden
+// modifier for padding
+// %P -> pad with zeroes
+// always null terminate
+
+#include <r_util.h>
+
+enum flag_itoa {
+	FILL_ZERO = 1,
+	PUT_PLUS = 2,
+	PUT_MINUS = 4,
+	BASE_2 = 8,
+	BASE_10 = 16,
+};
+
+static char *sitoa(char * buf, char *buf_end, unsigned int num, int width, enum flag_itoa flags) {
+	unsigned int base;
+	if (flags & BASE_2) {
+		base = 2;
+	} else if (flags & BASE_10) {
+		base = 10;
+	} else {
+		base = 16;
+	}
+	char tmp[32];
+	char *p = tmp;
+	do {
+		int rem = num % base;
+		*p++ = (rem <= 9) ? (rem + '0') : (rem + 'a' - 0xA);
+	} while ((num /= base));
+	width -= p - tmp;
+	char fill = (flags & FILL_ZERO)? '0' : ' ';
+	while (0 <= --width) {
+		*(buf++) = fill;
+	}
+	if (flags & PUT_MINUS) {
+		*(buf++) = '-';
+	} else if (flags & PUT_PLUS) {
+		*(buf++) = '+';
+	}
+	do {
+		*(buf++) = *(--p);
+	} while (tmp < p);
+	return buf;
+}
+
+static int my_vsnprintf(char * buf, size_t buf_size, const char *fmt, va_list va) {
+	char c;
+	const char *save = buf;
+	char *buf_end = buf + buf_size;
+	while ((c  = *fmt++)) {
+		int width = 0;
+		enum flag_itoa flags = 0;
+		if (c != '%') {
+			*(buf++) = c;
+			continue;
+		}
+redo_spec:
+		c  = *fmt++;
+		switch (c) {
+		case '%':
+			*(buf++) = c;
+			break;
+		case 'c':
+			 *(buf++) = va_arg (va, int);
+			 break;
+		case 'd':
+			 {
+			 int num = va_arg (va, int);
+			 if (num < 0) {
+				 num = -num;
+				 flags |= PUT_MINUS;
+			 }
+			 buf = sitoa (buf, buf_end, num, width, flags | BASE_10);
+			 }
+			 break;
+		case 'u':
+			 buf = sitoa (buf, buf_end, va_arg (va, unsigned int), width, flags | BASE_10);
+			 break;
+		case 'x':
+			 buf = sitoa (buf, buf_end, va_arg (va, unsigned int), width, flags);
+			 break;
+		case 'b':
+			 buf = sitoa (buf, buf_end, va_arg (va, unsigned int), width, flags | BASE_2);
+			 break;
+		case 's':;
+			 const char *p  = va_arg (va, const char *);
+			 if (p) {
+				 while (*p)
+					 *(buf++) = *(p++);
+			 }
+			 break;
+		case 'm':;
+			 const uint8_t *m  = va_arg (va, const uint8_t *);
+			 width = R_MIN (width, 64); // buffer limited to 256!
+			 if (m)
+				 for (;;) {
+					 buf = sitoa (buf, buf_end, *(m++), 2, FILL_ZERO);
+					 if (--width <= 0)
+						 break;
+					 *(buf++) = ':';
+				 }
+			 break;
+		case '0':
+			 if (!width) {
+				 flags |= FILL_ZERO;
+			 }
+			 // fall through
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+			 width = width * 10 + c - '0';
+			 goto redo_spec;
+		case '*':
+			 width = va_arg (va, unsigned int);
+			 goto redo_spec;
+		case '+':
+			 flags |= PUT_PLUS;
+			 goto redo_spec;
+		case '\0':
+		default:
+			 *(buf++) = '?';
+		}
+		width = 0;
+	}
+	*buf = '\0';
+	return buf - save;
+}
+
+R_API int r_str_printf(R_NONNULL char * buf, size_t buf_size, R_NONNULL const char * fmt, ...) {
+	va_list va;
+	va_start (va,fmt);
+	int ret = my_vsnprintf (buf, buf_size, fmt, va);
+	va_end (va);
+	return ret;
+}

test/unit/meson.build

@@ -56,6 +56,8 @@ if get_option('enable_tests')
     'stack',
     'str',
     'strbuf',
+    'scanf',
+    'printf',
     'table',
     'tree',
     'uleb128',

test/unit/test_printf.c

@@ -0,0 +1,20 @@
+#include <r_util.h>
+#include "minunit.h"
+
+bool test_r_str_printf(void) {
+	char res[32];
+	int count = r_str_printf (res, sizeof (res), "Hello %s", "World");
+	mu_assert_streq (res, "Hello World", "truncated string in custom scanf failed");
+	mu_assert_eq (count, 11, "return value");
+
+	mu_end;
+}
+
+bool all_tests(void) {
+	mu_run_test (test_r_str_printf);
+	return tests_passed != tests_run;
+}
+
+int main(int argc, char **argv) {
+	return all_tests ();
+}