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Stop the shim silently going deaf mid-command #3

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6 changes: 6 additions & 0 deletions cmd/undo/run.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import (
"os/exec"
"path/filepath"
"strings"
"syscall"

"github.com/edaywalid/undo/internal/session"
)
Expand Down Expand Up @@ -105,6 +106,11 @@ func cmdRun(argv []string) {
if runErr != nil {
if ee, ok := runErr.(*exec.ExitError); ok {
code = ee.ExitCode()
// killed by a signal: ExitCode is -1, which os.Exit turns
// into 255. Report it the way a shell does.
if ws, ok := ee.Sys().(syscall.WaitStatus); ok && ws.Signaled() {
code = 128 + int(ws.Signal())
}
} else {
s.Remove()
fatal(runErr)
Expand Down
25 changes: 21 additions & 4 deletions shim/undo_shim.c
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Original file line number Diff line number Diff line change
Expand Up @@ -344,6 +344,20 @@ static int ignored(const char *abs)
#define DEDUP_CAP 16384
static char *dedup_tab[DEDUP_CAP];
static int dedup_count;
static char dedup_dir[PATH_MAX];

/* The table covers one command. A shell preloaded with the shim
* (UNDO_CAPTURE_SHELL=1) outlives every session it runs, so a path saved
* for an earlier command must not suppress its backup in the next one. */
static void dedup_reset(const char *dir)
{
for (int i = 0; i < DEDUP_CAP; i++) {
free(dedup_tab[i]);
dedup_tab[i] = NULL;
}
dedup_count = 0;
snprintf(dedup_dir, sizeof dedup_dir, "%s", dir);
}

static unsigned long path_hash(const char *s)
{
Expand All @@ -359,6 +373,11 @@ static unsigned long path_hash(const char *s)
* records it and returns 0. */
static int mod_seen(const char *abs)
{
const char *dir = session_dir();
if (!dir)
return 0;
if (strcmp(dedup_dir, dir) != 0)
dedup_reset(dir);
if (dedup_count * 4 >= DEDUP_CAP * 3)
return 0; /* table nearly full: stop deduping, keep saving */
unsigned long i = path_hash(abs) & (DEDUP_CAP - 1);
Expand Down Expand Up @@ -547,11 +566,9 @@ int rmdir(const char *path)
int ok;
handle_rmdir_pre(AT_FDCWD, path, abs, mode, &ok);
int rc = real_rmdir(path);
if (rc == 0 && ok) {
in_shim = 1;
if (rc == 0 && ok)
jwrite("rmdir", abs, mode, NULL);
in_shim = 0;
}
in_shim = 0;
return rc;
}

Expand Down
35 changes: 34 additions & 1 deletion test/e2e.sh
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Expand Up @@ -187,7 +187,40 @@ sd="$UNDO_DATA_DIR/sessions/$last"
"$UNDO" -y >/dev/null
[[ $(cat "$PLAY/churn.txt") == original ]] || fail "dedup broke restore, got $(cat "$PLAY/churn.txt")"

echo "== case 19: undo doctor passes its live self-test"
echo "== case 19: a failed rmdir does not stop the rest of the command being recorded"
mkdir -p "$PLAY/full/x" "$PLAY/gone"
run_armed "rmdir $PLAY/full $PLAY/gone || true"
[[ -d $PLAY/full && ! -d $PLAY/gone ]] || fail "rmdir did not run as expected"
"$UNDO" -y >/dev/null
[[ -d $PLAY/gone ]] || fail "second rmdir was not journaled after the first failed"

# One long-lived process writing the same file under two sessions in a
# row: what UNDO_CAPTURE_SHELL=1 does, where the shim is loaded into the
# shell itself rather than into a fresh child per command.
if command -v python3 >/dev/null 2>&1; then
echo "== case 20: one process spanning two sessions backs up in both"
f=$PLAY/shared.txt
echo v0 >"$f"
s1=$UNDO_DATA_DIR/sessions/$(date +%s%N | cut -c1-16); mkdir -p "$s1/data"
echo "write v1" >"$s1/cmd"; sleep 0.01
s2=$UNDO_DATA_DIR/sessions/$(date +%s%N | cut -c1-16); mkdir -p "$s2/data"
echo "write v2" >"$s2/cmd"
LD_PRELOAD="$LIB" python3 -c "
import os, sys
for sess, body in ((sys.argv[1], 'v1'), (sys.argv[2], 'v2')):
os.environ['UNDO_SESSION'] = sess
with open(sys.argv[3], 'w') as fh:
fh.write(body + '\n')
" "$s1" "$s2" "$f"
[[ $(cat "$f") == v2 ]] || fail "writes did not run"
grep -q "shared.txt" "$s2/journal" 2>/dev/null || fail "second session recorded nothing"
"$UNDO" -y >/dev/null
[[ $(cat "$f") == v1 ]] || fail "second session did not restore v1, got $(cat "$f")"
else
echo "== case 20: skipped (no python3)"
fi

echo "== case 21: undo doctor passes its live self-test"
out=$("$UNDO" doctor 2>&1) || fail "doctor exited non-zero: $out"
grep -q "\[ok \] capture" <<<"$out" || fail "doctor capture check did not pass"
grep -q "\[ok \] restore" <<<"$out" || fail "doctor restore check did not pass"
Expand Down