futility: slight tweak to the logging implementation

Just reporting that the parent process is "/bin/bash" doesn't
help much. Let's also report the cmdline args given to the parent
and the cwd. This will help us identify which shell script is
calling futility with the wrong args.

BUG=chromium:231547
BRANCH=ToT
TEST=make runtests

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Change-Id: I800995ff269ab8d8c56cad8827d8de48a53cd150
Reviewed-on: https://chromium-review.googlesource.com/216715
Reviewed-on: https://chromium-review.googlesource.com/227869
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Commit-Queue: Daisuke Nojiri <dnojiri@chromium.org>

2 files changed, 61 insertions, 25 deletions

diff --git a/futility/futility.c b/futility/futility.c
index f18edb50..1a132202 100644
--- a/futility/futility.c
+++ b/futility/futility.c
@@ -99,7 +99,7 @@ static void deprecated(const char *depname)
 static int log_fd = -1;
 
 /* Write the string and a newline. Silently give up on errors */
-static void log_str(char *str)
+static void log_str(char *prefix, char *str)
 {
 	int len, done, n;
 
@@ -109,6 +109,15 @@ static void log_str(char *str)
 	if (!str)
 		str = "(NULL)";
 
+	if (prefix && *prefix) {
+		len = strlen(prefix);
+		for (done = 0; done < len; done += n) {
+			n = write(log_fd, prefix + done, len - done);
+			if (n < 0)
+				return;
+		}
+	}
+
 	len = strlen(str);
 	if (len == 0) {
 		str = "(EMPTY)";
@@ -176,35 +185,58 @@ static void log_open(void)
 		log_close();
 }
 
-#define CALLER_PREFIX "CALLER:"
 static void log_args(int argc, char *argv[])
 {
 	int i;
 	ssize_t r;
 	pid_t parent;
 	char buf[80];
-	char str_caller[PATH_MAX + sizeof(CALLER_PREFIX)] = CALLER_PREFIX;
-	char *truename = str_caller + sizeof(CALLER_PREFIX) - 1;
-	/* Note: truename starts on the \0 from CALLER_PREFIX, so we can write
-	 * PATH_MAX chars into truename and still append a \0 at the end. */
+	FILE *fp;
+	char caller_buf[PATH_MAX];
 
 	log_open();
 
 	/* delimiter */
-	log_str("##### HEY #####");
+	log_str(NULL, "##### HEY #####");
 
 	/* Can we tell who called us? */
 	parent = getppid();
 	snprintf(buf, sizeof(buf), "/proc/%d/exe", parent);
-	r = readlink(buf, truename, PATH_MAX);
+	r = readlink(buf, caller_buf, sizeof(caller_buf) - 1);
 	if (r >= 0) {
-		truename[r] = '\0';
-		log_str(str_caller);
+		caller_buf[r] = '\0';
+		log_str("CALLER:", caller_buf);
+	}
+
+	/* From where? */
+	snprintf(buf, sizeof(buf), "/proc/%d/cwd", parent);
+	r = readlink(buf, caller_buf, sizeof(caller_buf) - 1);
+	if (r >= 0) {
+		caller_buf[r] = '\0';
+		log_str("DIR:", caller_buf);
+	}
+
+	/* And maybe the args? */
+	snprintf(buf, sizeof(buf), "/proc/%d/cmdline", parent);
+	fp = fopen(buf, "r");
+	if (fp) {
+		memset(caller_buf, 0, sizeof(caller_buf));
+		r = fread(caller_buf, 1, sizeof(caller_buf) - 1, fp);
+		if (r > 0) {
+			char *s = caller_buf;
+			for (i = 0; i < r && *s; ) {
+				log_str("CMDLINE:", s);
+				while (i < r && *s)
+					i++, s++;
+				i++, s++;
+			}
+		}
+		fclose(fp);
 	}
 
 	/* Now log the stuff about ourselves */
 	for (i = 0; i < argc; i++)
-		log_str(argv[i]);
+		log_str(NULL, argv[i]);
 
 	log_close();
 }
diff --git a/tests/futility/test_main.sh b/tests/futility/test_main.sh
index cae42051..17a54675 100755
--- a/tests/futility/test_main.sh
+++ b/tests/futility/test_main.sh
@@ -17,24 +17,28 @@ cd "$OUTDIR"
 grep Usage "$TMP"
 
 # Make sure logging does something.
-# Note: This will zap any existing log file. Too bad.
 LOG="/tmp/futility.log"
-rm -f "$LOG"
-touch "$LOG"
+[ -f ${LOG} ] && mv ${LOG} ${LOG}.backup
+touch ${LOG}
 "$FUTILITY" help
-grep "$FUTILITY" "$LOG"
-rm "$LOG"
+grep "$FUTILITY" ${LOG}
+rm -f ${LOG}
+[ -f ${LOG}.backup ] && mv ${LOG}.backup ${LOG}
 
 # Make sure deprecated functions fail via symlink
-ln -sf "$FUTILITY" dev_sign_file
-if ./dev_sign_file 2>${TMP}.outmsg ; then false; fi
-grep deprecated ${TMP}.outmsg
-# They may still fail when invoked through futility (this one does),
-# but with a different error message.
-"$FUTILITY" dev_sign_file 1>${TMP}.outmsg2 2>&1 || true
-if grep deprecated ${TMP}.outmsg2; then false; fi
-
+DEPRECATED="dev_sign_file"
+
+for i in $DEPRECATED; do
+  ln -sf "$FUTILITY" $i
+  if ./$i 2>${TMP}.outmsg ; then false; fi
+  grep deprecated ${TMP}.outmsg
+  # They may still fail when invoked through futility
+  # but with a different error message.
+  "$FUTILITY" $i 1>${TMP}.outmsg2 2>&1 || true
+  if grep deprecated ${TMP}.outmsg2; then false; fi
+  rm -f $i
+done
 
 # cleanup
-rm -f ${TMP}* ./dev_sign_file
+rm -f ${TMP}*
 exit 0