Changeset 59f388a in mainline

Timestamp:

2017-04-04T20:56:47Z (8 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

51774cd

Parents:

8fe46a0

Message:

Fail legacy interfaces if the position is too large for them to represent

HelenOS interfaces support unsigned 64-bit file sizes and offsets. This
is in contrast with C99-ish and POSIX-ish interfaces in libc and libposix.
The legacy API emulation internally uses the native unsigned 64-bit file
sizes and positions and so it may happen that a returned file size or
offset are bigger than the legacy interface can represent. We choose
to report failure in such a case in order to avoid returning wrong
results.

Location:

uspace/lib

Files:

• c/generic/io/io.c (modified) (1 diff)
• posix/source/sys/stat.c (modified) (4 diffs)
• posix/source/unistd.c (modified) (1 diff)

uspace/lib/c/generic/io/io.c

@@ -834 +834 @@
 off64_t ftell(FILE *stream)
 {
+        /* The native position is too large for the C99-ish interface. */
+        if (stream->pos - stream->ungetc_chars > INT64_MAX)
+                return EOF;
+
         if (stream->error)
                 return EOF;

uspace/lib/posix/source/sys/stat.c

@@ -49 +49 @@
  * @param dest POSIX stat struct.
  * @param src HelenOS stat struct.
+ *
+ * @return 0 on success, -1 on error.
  */
-static void stat_to_posix(struct posix_stat *dest, struct stat *src)
+static int stat_to_posix(struct posix_stat *dest, struct stat *src)
 {
         memset(dest, 0, sizeof(struct posix_stat));
@@ -68 +70 @@
         dest->st_nlink = src->lnkcnt;
         dest->st_size = src->size;
+
+        if (src->size > INT64_MAX) {
+                errno = ERANGE;
+                return -1;
+        }
+
+        return 0;
 }
 
@@ -83 +92 @@
         if (rc < 0)
                 return -1;
-        stat_to_posix(st, &hst);
-        return 0;
+        return stat_to_posix(st, &hst);
 }
 
@@ -113 +121 @@
         if (rc < 0)
                 return -1;
-        stat_to_posix(st, &hst);
-        return 0;
+        return stat_to_posix(st, &hst);
 }
 

uspace/lib/posix/source/unistd.c

@@ -245 +245 @@
                 break;
         }
+        if (posix_pos[fildes] > INT64_MAX) {
+                /* The native width is too large for the POSIX interface. */
+                errno = ERANGE;
+                return -1;
+        }
         return posix_pos[fildes];
 }