diff options
| -rw-r--r-- | README | 9 | ||||
| -rw-r--r-- | include/vsprintf.h | 19 | ||||
| -rw-r--r-- | lib/vsprintf.c | 265 |
3 files changed, 241 insertions, 52 deletions
@@ -655,6 +655,15 @@ The following options need to be configured: to get the character out. Baud rates will need to default to something sensible. +- Safe printf() functions + Define CONFIG_SYS_VSNPRINTF to compile in safe versions of + the printf() functions. These are defined in + include/vsprintf.h and include snprintf(), vsnprintf() and + so on. Code size increase is approximately 300-500 bytes. + If this option is not given then these functions will + silently discard their buffer size argument - this means + you are not getting any overflow checking in this case. + - Boot Delay: CONFIG_BOOTDELAY - in seconds Delay before automatically booting the default image; set to -1 to disable autoboot. diff --git a/include/vsprintf.h b/include/vsprintf.h index 065144669..5195598f9 100644 --- a/include/vsprintf.h +++ b/include/vsprintf.h @@ -36,4 +36,23 @@ int sprintf(char *buf, const char *fmt, ...) int vsprintf(char *buf, const char *fmt, va_list args); char *simple_itoa(ulong i); +#ifdef CONFIG_SYS_VSNPRINTF +int snprintf(char *buf, size_t size, const char *fmt, ...) + __attribute__ ((format (__printf__, 3, 4))); +int scnprintf(char *buf, size_t size, const char *fmt, ...) + __attribute__ ((format (__printf__, 3, 4))); +int vsnprintf(char *buf, size_t size, const char *fmt, va_list args); +int vscnprintf(char *buf, size_t size, const char *fmt, va_list args); +#else +/* + * Use macros to silently drop the size parameter. Note that the 'cn' + * versions are the same as the 'n' versions since the functions assume + * there is always enough buffer space when !CONFIG_SYS_VSNPRINTF + */ +#define snprintf(buf, size, fmt, args...) sprintf(buf, fmt, ##args) +#define scnprintf(buf, size, fmt, args...) sprintf(buf, fmt, ##args) +#define vsnprintf(buf, size, fmt, args...) vsprintf(buf, fmt, ##args) +#define vscnprintf(buf, size, fmt, args...) vsprintf(buf, fmt, ##args) +#endif /* CONFIG_SYS_VSNPRINTF */ + #endif diff --git a/lib/vsprintf.c b/lib/vsprintf.c index e497a8686..7a145ea92 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -26,6 +26,9 @@ # define NUM_TYPE long long #define noinline __attribute__((noinline)) +/* some reluctance to put this into a new limits.h, so it is here */ +#define INT_MAX ((int)(~0U>>1)) + const char hex_asc[] = "0123456789abcdef"; #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4] @@ -291,7 +294,22 @@ static noinline char* put_dec(char *buf, unsigned NUM_TYPE num) #define SMALL 32 /* Must be 32 == 0x20 */ #define SPECIAL 64 /* 0x */ -static char *number(char *buf, unsigned NUM_TYPE num, int base, int size, int precision, int type) +#ifdef CONFIG_SYS_VSNPRINTF +/* + * Macro to add a new character to our output string, but only if it will + * fit. The macro moves to the next character position in the output string. + */ +#define ADDCH(str, ch) do { \ + if ((str) < end) \ + *(str) = (ch); \ + ++str; \ + } while (0) +#else +#define ADDCH(str, ch) (*(str)++ = (ch)) +#endif + +static char *number(char *buf, char *end, unsigned NUM_TYPE num, + int base, int size, int precision, int type) { /* we are called with base 8, 10 or 16, only, thus don't need "G..." */ static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */ @@ -353,37 +371,40 @@ static char *number(char *buf, unsigned NUM_TYPE num, int base, int size, int pr precision = i; /* leading space padding */ size -= precision; - if (!(type & (ZEROPAD+LEFT))) - while(--size >= 0) - *buf++ = ' '; + if (!(type & (ZEROPAD + LEFT))) { + while (--size >= 0) + ADDCH(buf, ' '); + } /* sign */ if (sign) - *buf++ = sign; + ADDCH(buf, sign); /* "0x" / "0" prefix */ if (need_pfx) { - *buf++ = '0'; + ADDCH(buf, '0'); if (base == 16) - *buf++ = ('X' | locase); + ADDCH(buf, 'X' | locase); } /* zero or space padding */ if (!(type & LEFT)) { char c = (type & ZEROPAD) ? '0' : ' '; + while (--size >= 0) - *buf++ = c; + ADDCH(buf, c); } /* hmm even more zero padding? */ while (i <= --precision) - *buf++ = '0'; + ADDCH(buf, '0'); /* actual digits of result */ while (--i >= 0) - *buf++ = tmp[i]; + ADDCH(buf, tmp[i]); /* trailing space padding */ while (--size >= 0) - *buf++ = ' '; + ADDCH(buf, ' '); return buf; } -static char *string(char *buf, char *s, int field_width, int precision, int flags) +static char *string(char *buf, char *end, char *s, int field_width, + int precision, int flags) { int len, i; @@ -394,16 +415,16 @@ static char *string(char *buf, char *s, int field_width, int precision, int flag if (!(flags & LEFT)) while (len < field_width--) - *buf++ = ' '; + ADDCH(buf, ' '); for (i = 0; i < len; ++i) - *buf++ = *s++; + ADDCH(buf, *s++); while (len < field_width--) - *buf++ = ' '; + ADDCH(buf, ' '); return buf; } #ifdef CONFIG_CMD_NET -static char *mac_address_string(char *buf, u8 *addr, int field_width, +static char *mac_address_string(char *buf, char *end, u8 *addr, int field_width, int precision, int flags) { char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */ @@ -417,10 +438,11 @@ static char *mac_address_string(char *buf, u8 *addr, int field_width, } *p = '\0'; - return string(buf, mac_addr, field_width, precision, flags & ~SPECIAL); + return string(buf, end, mac_addr, field_width, precision, + flags & ~SPECIAL); } -static char *ip6_addr_string(char *buf, u8 *addr, int field_width, +static char *ip6_addr_string(char *buf, char *end, u8 *addr, int field_width, int precision, int flags) { char ip6_addr[8 * 5]; /* (8 * 4 hex digits), 7 colons and trailing zero */ @@ -435,10 +457,11 @@ static char *ip6_addr_string(char *buf, u8 *addr, int field_width, } *p = '\0'; - return string(buf, ip6_addr, field_width, precision, flags & ~SPECIAL); + return string(buf, end, ip6_addr, field_width, precision, + flags & ~SPECIAL); } -static char *ip4_addr_string(char *buf, u8 *addr, int field_width, +static char *ip4_addr_string(char *buf, char *end, u8 *addr, int field_width, int precision, int flags) { char ip4_addr[4 * 4]; /* (4 * 3 decimal digits), 3 dots and trailing zero */ @@ -456,7 +479,8 @@ static char *ip4_addr_string(char *buf, u8 *addr, int field_width, } *p = '\0'; - return string(buf, ip4_addr, field_width, precision, flags & ~SPECIAL); + return string(buf, end, ip4_addr, field_width, precision, + flags & ~SPECIAL); } #endif @@ -478,10 +502,12 @@ static char *ip4_addr_string(char *buf, u8 *addr, int field_width, * function pointers are really function descriptors, which contain a * pointer to the real address. */ -static char *pointer(const char *fmt, char *buf, void *ptr, int field_width, int precision, int flags) +static char *pointer(const char *fmt, char *buf, char *end, void *ptr, + int field_width, int precision, int flags) { if (!ptr) - return string(buf, "(null)", field_width, precision, flags); + return string(buf, end, "(null)", field_width, precision, + flags); #ifdef CONFIG_CMD_NET switch (*fmt) { @@ -489,15 +515,18 @@ static char *pointer(const char *fmt, char *buf, void *ptr, int field_width, int flags |= SPECIAL; /* Fallthrough */ case 'M': - return mac_address_string(buf, ptr, field_width, precision, flags); + return mac_address_string(buf, end, ptr, field_width, + precision, flags); case 'i': flags |= SPECIAL; /* Fallthrough */ case 'I': if (fmt[1] == '6') - return ip6_addr_string(buf, ptr, field_width, precision, flags); + return ip6_addr_string(buf, end, ptr, field_width, + precision, flags); if (fmt[1] == '4') - return ip4_addr_string(buf, ptr, field_width, precision, flags); + return ip4_addr_string(buf, end, ptr, field_width, + precision, flags); flags &= ~SPECIAL; break; } @@ -507,27 +536,31 @@ static char *pointer(const char *fmt, char *buf, void *ptr, int field_width, int field_width = 2*sizeof(void *); flags |= ZEROPAD; } - return number(buf, (unsigned long) ptr, 16, field_width, precision, flags); + return number(buf, end, (unsigned long)ptr, 16, field_width, + precision, flags); } /** - * vsprintf - Format a string and place it in a buffer - * @buf: The buffer to place the result into - * @fmt: The format string to use - * @args: Arguments for the format string + * Format a string and place it in a buffer (base function) + * + * @param buf The buffer to place the result into + * @param size The size of the buffer, including the trailing null space + * @param fmt The format string to use + * @param args Arguments for the format string + * @return The number characters which would be generated for the given + * input, excluding the trailing '\0', as per ISO C99. Note that fewer + * characters may be written if this number of characters is >= size. * - * This function follows C99 vsprintf, but has some extensions: + * This function follows C99 vsnprintf, but has some extensions: * %pS output the name of a text symbol * %pF output the name of a function pointer * %pR output the address range in a struct resource * - * The function returns the number of characters written - * into @buf. - * * Call this function if you are already dealing with a va_list. - * You probably want sprintf() instead. + * You probably want snprintf() instead. */ -int vsprintf(char *buf, const char *fmt, va_list args) +static int vsnprintf_internal(char *buf, size_t size, const char *fmt, + va_list args) { unsigned NUM_TYPE num; int base; @@ -542,12 +575,20 @@ int vsprintf(char *buf, const char *fmt, va_list args) /* 'z' support added 23/7/1999 S.H. */ /* 'z' changed to 'Z' --davidm 1/25/99 */ /* 't' added for ptrdiff_t */ + char *end = buf + size; +#ifdef CONFIG_SYS_VSNPRINTF + /* Make sure end is always >= buf - do we want this in U-Boot? */ + if (end < buf) { + end = ((void *)-1); + size = end - buf; + } +#endif str = buf; for (; *fmt ; ++fmt) { if (*fmt != '%') { - *str++ = *fmt; + ADDCH(str, *fmt); continue; } @@ -609,20 +650,22 @@ int vsprintf(char *buf, const char *fmt, va_list args) switch (*fmt) { case 'c': - if (!(flags & LEFT)) + if (!(flags & LEFT)) { while (--field_width > 0) - *str++ = ' '; - *str++ = (unsigned char) va_arg(args, int); + ADDCH(str, ' '); + } + ADDCH(str, (unsigned char) va_arg(args, int)); while (--field_width > 0) - *str++ = ' '; + ADDCH(str, ' '); continue; case 's': - str = string(str, va_arg(args, char *), field_width, precision, flags); + str = string(str, end, va_arg(args, char *), + field_width, precision, flags); continue; case 'p': - str = pointer(fmt+1, str, + str = pointer(fmt+1, str, end, va_arg(args, void *), field_width, precision, flags); /* Skip all alphanumeric pointer suffixes */ @@ -641,7 +684,7 @@ int vsprintf(char *buf, const char *fmt, va_list args) continue; case '%': - *str++ = '%'; + ADDCH(str, '%'); continue; /* integer number formats - set up the flags and "break" */ @@ -662,9 +705,9 @@ int vsprintf(char *buf, const char *fmt, va_list args) break; default: - *str++ = '%'; + ADDCH(str, '%'); if (*fmt) - *str++ = *fmt; + ADDCH(str, *fmt); else --fmt; continue; @@ -688,17 +731,135 @@ int vsprintf(char *buf, const char *fmt, va_list args) if (flags & SIGN) num = (signed int) num; } - str = number(str, num, base, field_width, precision, flags); + str = number(str, end, num, base, field_width, precision, + flags); } + +#ifdef CONFIG_SYS_VSNPRINTF + if (size > 0) { + ADDCH(str, '\0'); + if (str > end) + end[-1] = '\0'; + } +#else *str = '\0'; +#endif + /* the trailing null byte doesn't count towards the total */ return str-buf; } +#ifdef CONFIG_SYS_VSNPRINTF +int vsnprintf(char *buf, size_t size, const char *fmt, + va_list args) +{ + return vsnprintf_internal(buf, size, fmt, args); +} + +/** + * Format a string and place it in a buffer (va_list version) + * + * @param buf The buffer to place the result into + * @param size The size of the buffer, including the trailing null space + * @param fmt The format string to use + * @param args Arguments for the format string + * @return the number of characters which have been written into + * the @buf not including the trailing '\0'. If @size is == 0 the function + * returns 0. + * + * If you're not already dealing with a va_list consider using scnprintf(). + * + * See the vsprintf() documentation for format string extensions over C99. + */ +int vscnprintf(char *buf, size_t size, const char *fmt, va_list args) +{ + int i; + + i = vsnprintf(buf, size, fmt, args); + + if (likely(i < size)) + return i; + if (size != 0) + return size - 1; + return 0; +} + /** - * sprintf - Format a string and place it in a buffer - * @buf: The buffer to place the result into - * @fmt: The format string to use - * @...: Arguments for the format string + * Format a string and place it in a buffer + * + * @param buf The buffer to place the result into + * @param size The size of the buffer, including the trailing null space + * @param fmt The format string to use + * @param ... Arguments for the format string + * @return the number of characters which would be + * generated for the given input, excluding the trailing null, + * as per ISO C99. If the return is greater than or equal to + * @size, the resulting string is truncated. + * + * See the vsprintf() documentation for format string extensions over C99. + */ +int snprintf(char *buf, size_t size, const char *fmt, ...) +{ + va_list args; + int i; + + va_start(args, fmt); + i = vsnprintf(buf, size, fmt, args); + va_end(args); + + return i; +} + +/** + * Format a string and place it in a buffer + * + * @param buf The buffer to place the result into + * @param size The size of the buffer, including the trailing null space + * @param fmt The format string to use + * @param ... Arguments for the format string + * + * The return value is the number of characters written into @buf not including + * the trailing '\0'. If @size is == 0 the function returns 0. + * + * See the vsprintf() documentation for format string extensions over C99. + */ + +int scnprintf(char *buf, size_t size, const char *fmt, ...) +{ + va_list args; + int i; + + va_start(args, fmt); + i = vscnprintf(buf, size, fmt, args); + va_end(args); + + return i; +} +#endif /* CONFIG_SYS_VSNPRINT */ + +/** + * Format a string and place it in a buffer (va_list version) + * + * @param buf The buffer to place the result into + * @param fmt The format string to use + * @param args Arguments for the format string + * + * The function returns the number of characters written + * into @buf. Use vsnprintf() or vscnprintf() in order to avoid + * buffer overflows. + * + * If you're not already dealing with a va_list consider using sprintf(). + */ +int vsprintf(char *buf, const char *fmt, va_list args) +{ + return vsnprintf_internal(buf, INT_MAX, fmt, args); +} + +/** + * Format a string and place it in a buffer + * + * @param buf The buffer to place the result into + * @param fmt The format string to use + * @param ... Arguments for the format string * * The function returns the number of characters written * into @buf. |