Changeset 59f388a in mainline for uspace/lib/c/generic/io/io.c

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.

File:

• uspace/lib/c/generic/io/io.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;