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vcardtime.c, vcardvalue.c: don't use sscanf("%m$") formats
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@ksmurchison
ksmurchison committed Apr 23, 2024
1 parent 7fd1353 commit d838bc8
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Showing 2 changed files with 150 additions and 97 deletions.
222 changes: 134 additions & 88 deletions src/libicalvcard/vcardtime.c
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Original file line number Diff line number Diff line change
Expand Up @@ -139,60 +139,111 @@ int vcardtime_is_valid_time(const struct vcardtimetype t)

static int sprintf_date(const vcardtimetype t, char *buf, size_t size)
{
/* 3 zero-padded numeric arguments by position + NUL */
char fmt[19] = "";
/*
date = year [month day]
/ year "-" month
/ "--" month [day]
/ "--" "-" day
*/
const char *fmt;

if (t.year != -1) {
strcat(fmt, "%04d");
if (t.month == -1) {
fmt = "%04d";
}
else if (t.day == -1) {
fmt = "%04d-%02d";
}
else {
fmt = "%04d%02d%02d";
}

if (t.month != -1) {
strcat(fmt, (t.day != -1) ? "%02d%02d" : "-%02d");
return snprintf(buf, size, fmt, t.year, t.month, t.day);
}
else if (t.month != -1) {
if (t.day == -1) {
fmt = "--%02d";
}
else {
fmt = "--%02d%02d";
}

return snprintf(buf, size, fmt, t.month, t.day);
}
else {
strcat(fmt, "--");

strcat(fmt, (t.month != -1) ? "%2$02d" : "-");

if (t.day != -1) {
strcat(fmt, "%3$02d");
}
return snprintf(buf, size, "---%02d", t.day);
}

return snprintf(buf, size, fmt, t.year, t.month, t.day);
}

static int sprintf_time(const vcardtimetype t, int need_designator,
char *buf, size_t size)
{
/* "T" + sign + 5 zero-padded numeric arguments by position + NUL */
char fmt[33] = "";
/*
time = ["T"] hour [minute [second]] [zone]
/ ["T"] "-" minute [second]
/ ["T"] "-" "-" second
*/
const char *fmt;

if (need_designator) {
strcat(fmt, "T");
strncat(buf, "T", size);
buf++;
size--;
}

if (t.hour != -1) {
strcat(fmt, "%02d");
/* hour [minute [second]] [zone] */
int n;

if (t.minute != -1) {
strcat(fmt, (t.second != -1) ? "%02d%02d" : "%02d");
if (t.minute == -1) {
/* hour */
fmt = "%02d";
}
else if (t.second == -1) {
/* hour minute */
fmt = "%02d%02d";
}
else {
/* hour minute second */
fmt = "%02d%02d%02d";
}

n = snprintf(buf, size, fmt, t.hour, t.minute, t.second);

if (t.utcoffset != -1) {
strcat(fmt, (t.utcoffset == 0) ? "Z" : "%4$+03d%5$02d");
}
}
else {
strcat(fmt, (t.minute != -1) ? "-%2$02d" : "--");
/* zone = "Z" / ( sign hour minute ) */
buf += n;
size -= n;

if (t.second != -1) {
strcat(fmt, "%3$02d");
if (t.utcoffset == 0) {
strncpy(buf, "Z", size);
n++;
}
else {
n += snprintf(buf, size, "%+03d%02d",
t.utcoffset / 60, abs(t.utcoffset % 60));
}
}

return n;
}
else if (t.minute != -1) {
/* "-" minute [second] */
if (t.second == -1) {
/* "-" minute */
fmt = "-%02d";
}
else {
/* "-" minute second */
fmt = "-%02d%02d";
}

return snprintf(buf, size, fmt, t.hour, t.minute, t.second,
t.utcoffset / 60, abs(t.utcoffset % 60));
return snprintf(buf, size, fmt, t.minute, t.second);
}
else {
/* "-" "-" second */
return snprintf(buf, size, "--%02d", t.second);
}
}

char *vcardtime_as_vcard_string_r(const vcardtimetype t,
Expand Down Expand Up @@ -232,10 +283,15 @@ const char *vcardtime_as_vcard_string(const vcardtimetype t,

static const char *sscanf_date(const char *str, vcardtimetype *t)
{
char fmt[TIME_BUF_SIZE] = ""; /* 4 numeric arguments by position + NUL */
/*
date = year [month day]
/ year "-" month
/ "--" month [day]
/ "--" "-" day
*/
const char *month;
size_t ndig;
int nchar;
int nchar = 0;
char *newstr;

if (!str || !*str) {
Expand All @@ -246,181 +302,171 @@ static const char *sscanf_date(const char *str, vcardtimetype *t)
month = str + 2;

if (*month == '-') {
/* "--" "-" day */
ndig = num_digits(month+1);

if (ndig == 2) {
strcpy(fmt, "---%3$2u");
sscanf(str, "---%2u%n", &t->day, &nchar);
}
}
else {
/* "--" month [day] */
ndig = num_digits(month);

if (ndig == 4) {
/* month day */
strcpy(fmt, "--%2$2u%3$2u");
sscanf(str, "--%2u%2u%n", &t->month, &t->day, &nchar);
}
else if (ndig == 2) {
/* month */
strcpy(fmt, "--%2$2u");
sscanf(str, "--%2u%n", &t->month, &nchar);
}
}
}
else {
/* year [ ("-" month) / (month day)] */
ndig = num_digits(str);

if (ndig == 8) {
/* year month day */
strcpy(fmt, "%1$4u%2$2u%3$2u");
sscanf(str, "%4u%2u%2u%n", &t->year, &t->month, &t->day, &nchar);
}
else if (ndig == 4) {
month = str + 4;

if (!*month) {
/* year */
strcpy(fmt, "%1$4u");
sscanf(str, "%4u%n", &t->year, &nchar);
}
else if (*month == '-') {
/* year "-" month [ "-" day ] */
ndig = num_digits(++month);

if (ndig == 2) {
strcpy(fmt, "%1$4u-%2$2u");

if (month[2] == '-') {
strcat(fmt, "-%3$2u");
sscanf(str, "%4u-%2u-%2u%n",
&t->year, &t->month, &t->day, &nchar);
}
else {
sscanf(str, "%4u-%2u%n",
&t->year, &t->month, &nchar);
}
}
}
}
}

if (!*fmt) {
if (!nchar) {
/* invalid time */
return NULL;
}

strcat(fmt, "%4$n");
sscanf(str, fmt, &t->year, &t->month, &t->day, &nchar);

newstr = (char *)str + nchar;
return newstr;
}

static const char *sscanf_zone(const char *str, vcardtimetype *t)
{
char fmt[16] = ""; /* 3 numeric arguments by position + NUL */
int offset_h = 0, offset_m = 0, nchar;
/*
zone = "Z"
/ ( "+" / "-" ) hour [minute]
*/
unsigned offset_h = 0, offset_m = 0;
char sign[2] = "";
size_t ndig;
char *newstr;
int nchar = 0;

if (!str || !*str) {
/* empty string */
return NULL;
}
else if (*str == 'Z') {
/* zone = utc-designator */
strcpy(fmt, "Z");
nchar = 1;
}
else if (strchr("+-", *str)) {
/* zone = utc-offset = sign hour [minute] */
ndig = num_digits(str+1);

if (ndig == 4) {
/* sign hour minute */
strcpy(fmt, "%1$3d%2$2u");
sscanf(str, "%1[+-]%2u%2u%n", sign, &offset_h, &offset_m, &nchar);
}
else if (ndig == 2) {
/* sign hour */
strcpy(fmt, "%1$3d");
sscanf(str, "%1[+-]%2u%n", sign, &offset_h, &nchar);
}
}

if (!*fmt) {
if (!nchar) {
/* invalid zone */
return NULL;
}

strcat(fmt, "%3$n");
sscanf(str, fmt, &offset_h, &offset_m, &nchar);

t->utcoffset = 60 * offset_h + ((offset_h < 0) ? -offset_m : offset_m);
t->utcoffset = 60 * offset_h + offset_m;
if (*sign == '-') t->utcoffset = -t->utcoffset;

newstr = (char *)str + nchar;
return newstr;
}

static const char *sscanf_time(const char *str, vcardtimetype *t)
{
char fmt[27] = ""; /* "%1$2u:%2$2u:%3$2u.%4$u%5$n" + NUL */
/*
time = hour [ ":" minute ":" second [ "." secfrac ] ]
/ hour [ minute [second]] [zone]
/ "-" minute [second]
/ "-" "-" second
*/
unsigned secfrac;
size_t ndig;
int nchar;
int nchar = 0;

if (!str || !*str) {
/* empty string */
return NULL;
}
else if (*str == '-') {
if (str[1] == '-') {
/* "-" "-" second */
ndig = num_digits(str+2);

if (ndig == 2) {
strcpy(fmt, "--%3$2u");
sscanf(str, "--%2u%n", &t->second, &nchar);
}
}
else {
/* "-" minute [second] */
ndig = num_digits(str+1);

if (ndig == 4) {
/* minute second */
strcpy(fmt, "-%2$2u%3$2u");
sscanf(str, "-%2u%2u%n", &t->minute, &t->second, &nchar);
}
else if (ndig == 2) {
/* minute */
strcpy(fmt, "-%2$2u");
sscanf(str, "-%2u%n", &t->minute, &nchar);
t->second = 0;
}
}
}
else {
/* hour [minute [second]] [zone] */
ndig = num_digits(str);

if (ndig == 6) {
/* hour minute second */
strcpy(fmt, "%1$2u%2$2u%3$2u");
sscanf(str, "%2u%2u%2u%n", &t->hour, &t->minute, &t->second, &nchar);
}
else if (ndig == 4) {
/* hour minute */
strcpy(fmt, "%1$2u%2$2u");
sscanf(str, "%2u%2u%n", &t->hour, &t->minute, &nchar);
t->second = 0;
}
else if (ndig == 2) {
/* hour [ ":" minute ":" second [ "." secfrac ] ] */
strcpy(fmt, "%1$2u");

if (str[2] == ':') {
strcat(fmt, ":%2$2u:%3$2u");

if (str[8] == '.') {
strcat(fmt, ".%4$u");
sscanf(str, "%2u:%2u:%2u.%u%n",
&t->hour, &t->minute, &t->second, &secfrac, &nchar);
}
else {
sscanf(str, "%2u:%2u:%2u%n",
&t->hour, &t->minute, &t->second, &nchar);
}
}
else {
sscanf(str, "%2u%n", &t->hour, &nchar);
}
}
}

if (!*fmt) {
if (!nchar) {
/* invalid time */
return NULL;
}

strcat(fmt, "%5$n");
sscanf(str, fmt, &t->hour, &t->minute, &t->second, &secfrac, &nchar);
str += nchar;

if (t->hour != -1 && *str) {
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