feat: add streq, printErr and printPadded

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dualfroz committed 2026-09-08 21:45:40 +02:00
1 parent 09239a27e8
commit 607eaff366
2 files changed
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#include "ulib.h"
/*
* Only ever spawned by cwdtest.c, with no argv at all -- unlike every other
* *test / *target pair in this kernel (which rendezvous over a shared pipe
* handle passed as an argv string), this pair's whole point is that the
* KERNEL itself hands this process its starting directory at creation time
* (sched.c's threadCreate/threadCreateUser, via the new initialCwd helper
* that mirrors initialPgid's own "inherit from whoever is currently
* running" shape for Thread.pgid), never anything cwdtest.c has to pass
* explicitly.
*
* Proves inheritance first, then proves the inherited value is a real,
* independent COPY rather than shared state: this process's own later
* chdir() must not reach back into cwdtest.c's Thread.cwd (cwdtest.c's own
* post-wait getcwd() check is the other half of that proof).
*/
static int streq(const char* a, const char* b)
{
while (*a && *a == *b) {
a++;
b++;
}
return *a == *b;
}
int main(void)
{
print("cwdtarget: start, pid=");
printDec(userGetpid());
print("\n");
char cwdBuf[64];
long len = userGetcwd(cwdBuf, sizeof(cwdBuf));
if (len < 0 || !streq(cwdBuf, "/tmp/cwda")) {
print("cwdtarget: FAIL inherited cwd, got: ");
print(len < 0 ? "(error)" : cwdBuf);
print("\n");
return 1;
}
print("cwdtarget: inherited-cwd-ok\n");
if (userChdir("/tmp/cwdb") != 0) {
print("cwdtarget: FAIL chdir /tmp/cwdb\n");
return 1;
}
len = userGetcwd(cwdBuf, sizeof(cwdBuf));
if (len < 0 || !streq(cwdBuf, "/tmp/cwdb")) {
print("cwdtarget: FAIL getcwd after own chdir, got: ");
print(len < 0 ? "(error)" : cwdBuf);
print("\n");
return 1;
}
/* Relative path again -- must land at /tmp/cwdb/note, a COMPLETELY
different file than cwdtest.c's own /tmp/cwda/note despite the
identical relative name "note", since each process resolves it
against its own Thread.cwd. */
int fd = (int)userOpen("note", oCreate | oWriteOnly | oTrunc);
if (fd < 0) {
print("cwdtarget: FAIL create relative note in cwdb\n");
return 1;
}
const char* payload = "cwdb-payload";
unsigned long payloadLen = stringLength(payload);
if (userWrite(fd, payload, payloadLen) != (long)payloadLen) {
print("cwdtarget: FAIL write relative note in cwdb\n");
return 1;
}
userClose(fd);
print("cwdtarget: relative-write-cwdb-ok\n");
return 0;
}
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#include "ulib.h"
/*
* Real ring-3 "date": the first live demo of rtc.c/sysTime's wall-clock
* time, spawned directly by kmain.c at boot exactly like nicetest.c above
* it -- fully synchronous, no injected keystroke or pipe rendezvous, so
* unlike most of this kernel's live demos this one has no scheduling-
* timing race to flake on at all.
*
* Deliberately duplicates (not shares) Howard Hinnant's civil-calendar
* algorithm rtc.c already uses: this file writes its OWN forward
* (civil -> epoch) and inverse (epoch -> civil) implementations from
* scratch, independent of the kernel side. Decoding the epoch userTime()
* returns and then re-encoding it back with this independent forward
* function must reproduce the exact same number, which proves this
* program's own encode/decode pair is a true bijection over the date it
* actually ran on -- a real, self-verifying round trip, not a print
* nobody checks.
*/
static void printErr(const char* text)
{
userWrite(2, text, stringLength(text));
}
/* Zero-padded unsigned decimal, `width` digits minimum (e.g. printPadded(7, 2)
-> "07"). Never negative here -- every field this file ever passes in is
already a non-negative calendar component. */
static void printPadded(long value, int width)
{
char digits[16];
int len = 0;
long remaining = value;
if (remaining == 0)
digits[len++] = '0';
while (remaining > 0) {
digits[len++] = (char)('0' + (remaining % 10));
remaining /= 10;
}
while (len < width)
digits[len++] = '0';
for (int i = len - 1; i >= 0; i--)
userWrite(1, &digits[i], 1);
}
/* Howard Hinnant's days_from_civil -- forward direction, civil date to a
day count relative to 1970-01-01. See rtc.c for the same algorithm used
kernel-side; this copy is independent, not shared, on purpose (see file
header comment). */
static long daysFromCivil(long y, long m, long d)
{
y -= (m <= 2) ? 1 : 0;
long era = (y >= 0 ? y : y - 399) / 400;
long yoe = y - era * 400;
long doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
long doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
return era * 146097 + doe - 719468;
}
/* Howard Hinnant's civil_from_days -- the inverse direction, a day count
back to a civil date. */
static void civilFromDays(long z, long* outYear, long* outMonth, long* outDay)
{
z += 719468;
long era = (z >= 0 ? z : z - 146096) / 146097;
long doe = z - era * 146097;
long yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
long yy = yoe + era * 400;
long doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
long mp = (5 * doy + 2) / 153;
long dd = doy - (153 * mp + 2) / 5 + 1;
long mm = mp + (mp < 10 ? 3 : -9);
*outYear = yy + (mm <= 2 ? 1 : 0);
*outMonth = mm;
*outDay = dd;
}
int main(void)
{
long epoch = userTime();
if (epoch <= 0) {
printErr("date: FAIL sysTime returned a non-positive epoch\n");
return 1;
}
long days = epoch / 86400;
long secondsOfDay = epoch % 86400;
long hour = secondsOfDay / 3600;
long minute = (secondsOfDay % 3600) / 60;
long second = secondsOfDay % 60;
long year;
long month;
long day;
civilFromDays(days, &year, &month, &day);
if (year < 2020 || year > 2099) {
printErr("date: FAIL implausible year decoded\n");
return 1;
}
printPadded(year, 4);
userWrite(1, "-", 1);
printPadded(month, 2);
userWrite(1, "-", 1);
printPadded(day, 2);
userWrite(1, " ", 1);
printPadded(hour, 2);
userWrite(1, ":", 1);
printPadded(minute, 2);
userWrite(1, ":", 1);
printPadded(second, 2);
userWrite(1, "\n", 1);
printErr("date: printed-ok\n");
long roundTrip = daysFromCivil(year, month, day) * 86400 + hour * 3600 + minute * 60 + second;
if (roundTrip != epoch) {
printErr("date: FAIL roundtrip mismatch\n");
return 1;
}
printErr("date: roundtrip-ok\n");
return 0;
}