FreeCalypso > hg > freecalypso-tools
view target-utils/simagent/stringarg.c @ 965:2969032bdfac
fcup-smsend[mult]: fix buglet in K&R C NULL pointer passing
The only 100% safe way to pass a NULL pointer as a function argument
in K&R C is to cast 0 to a pointer type; failing to do so may cause
mysterious bugs (invalid stack frames or garbage in argument registers)
on 64-bit machines. This issue has already been fixed in most of
FC host tools, but I just found some missed spots: passing of NULL UDH
to PDU encoding functions in fcup-smsend[mult] in the case of single
(not concatenated) SMS.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Fri, 01 Sep 2023 07:33:51 +0000 |
parents | 0cffc53991f9 |
children |
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/* * This module contains the function that parses our hex string arguments. */ #include <ctype.h> #include "types.h" static decode_hex_digit(c) { if (isdigit(c)) return c - '0'; else if (islower(c)) return c - 'a' + 10; else return c - 'A' + 10; } decode_hex_string_arg(arg, buf, maxlen) char *arg; u8 *buf; unsigned maxlen; { unsigned count; for (count = 0; ; ) { while (isspace(*arg)) arg++; if (!*arg) break; if (!isxdigit(arg[0]) || !isxdigit(arg[1])) { printf("ERROR: invalid hex string input\n"); return(-1); } if (count >= maxlen) { printf("ERROR: hex string input is too long\n"); return(-1); } buf[count++] = (decode_hex_digit(arg[0]) << 4) | decode_hex_digit(arg[1]); arg += 2; } return count; }