From 2748750ba3a92ba27c7ef54668c9c71463284f22 Mon Sep 17 00:00:00 2001
From: marcel <marcel@FreeBSD.org>
Date: Thu, 13 Nov 2003 09:04:24 +0000
Subject: Do not ignore any possible errors that fseeko() may have. The fact is
 that fseeko() fails in very predictable and frequent ways on ia64. This is
 because the offset is actually an address in the process' address space,
 which on ia64 can be larger than long (for lseek) or off_t (for fseeko). The
 crux is the signedness. The register stack and memory stack are in region 4
 on ia64. This means that the sign bit is 1. The large positive virtual
 address is wrongly interpreted as a negative file offset.

There's no quick fix. Even if you get around the API by using a
SEEK_SET up to LONG_MAX and follow it up with a SEEK_CUR for the
remainder, the kernel simply cannot deal with it. and the second
seek will just fail.

Therefore, this change does not actually fix the root cause. It just
makes sure we're not spitting out all kinds of garbage or that the
get_struct() function in particular does not cause truss(1) to exit.
This, I might add, invariably happened way too soon for truss(1) to
be of any use on ia64...
---
 usr.bin/truss/syscalls.c | 46 ++++++++++++++++++++++++----------------------
 1 file changed, 24 insertions(+), 22 deletions(-)

(limited to 'usr.bin')

diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c
index 7d02183..c9e5e75 100644
--- a/usr.bin/truss/syscalls.c
+++ b/usr.bin/truss/syscalls.c
@@ -171,12 +171,14 @@ get_struct(int procfd, void *offset, void *buf, int len) {
 		err(1, "dup");
 	if ((p = fdopen(fd, "r")) == NULL)
 		err(1, "fdopen");
-	fseeko(p, (uintptr_t)offset, SEEK_SET);
-	for (pos = (char *)buf; len--; pos++) {
-		if ((c = fgetc(p)) == EOF)
-			return -1;
-		*pos = c;
-	}
+	if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
+		for (pos = (char *)buf; len--; pos++) {
+			if ((c = fgetc(p)) == EOF)
+				return (-1);
+			*pos = c;
+		}
+	} else
+		bzero(buf, len);
 	fclose(p);
 	return 0;
 }
@@ -201,27 +203,27 @@ get_string(int procfd, void *offset, int max) {
 	buf = malloc( size = (max ? max : 64 ) );
 	len = 0;
 	buf[0] = 0;
-	fseeko(p, (uintptr_t)offset, SEEK_SET);
-	while ((c = fgetc(p)) != EOF) {
-		buf[len++] = c;
-		if (c == 0 || len == max) {
-			buf[len] = 0;
-			break;
-		}
-		if (len == size) {
-			char *tmp;
-			tmp = realloc(buf, size+64);
-			if (tmp == NULL) {
+	if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
+		while ((c = fgetc(p)) != EOF) {
+			buf[len++] = c;
+			if (c == 0 || len == max) {
 				buf[len] = 0;
-				fclose(p);
-				return buf;
+				break;
+			}
+			if (len == size) {
+				char *tmp;
+				tmp = realloc(buf, size+64);
+				if (tmp == NULL) {
+					buf[len] = 0;
+					break;
+				}
+				size += 64;
+				buf = tmp;
 			}
-			size += 64;
-			buf = tmp;
 		}
 	}
 	fclose(p);
-	return buf;
+	return (buf);
 }
 
 
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