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

1 files changed, 43 insertions, 11 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();
 }