diff options
author | Anton Kolesov <Anton.Kolesov@synopsys.com> | 2014-08-01 22:18:47 +0400 |
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committer | Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> | 2014-08-18 12:01:36 +0200 |
commit | 361285886aa319a56c803f2fb783457f3e80f564 (patch) | |
tree | ac08937811c6701bb63951c10423146422193257 /test/stdio/lseek_no_lfs.c | |
parent | 95ec1755ef61629169a79a616ec478988bb6ce7d (diff) |
lseek: Correct order of offset arguments
There was a runtime error in systems without large file support. Call
fseek(fd, 4096, SEEK_SET) has been failing with EINVAL, though it was
succeeding for offset = 4092. This has been happening because llseek system
call accepts 64-bit value as an offset argument and lseek function has been
ordering 32-bits words that form this offset value, according to the
endianness. However this ordering to match endianness is not required,
because llseek doesn't accept one 64-bit offset argument, it accepts two
32-bit offset argument, then stitches them into one following its
endianness. As a result on little endian system, order of words has been
swapped two time: in libc and in kernel. Thus call to fseek with offset 4096
(0x1000) was doing a system call to llseek with offset 0x1000_0000_0000. I'm
not entirely sure why then offset = 4092 hasn't been failing then.
This patch removes malicious swap of words when calling llseek.
Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Diffstat (limited to 'test/stdio/lseek_no_lfs.c')
-rw-r--r-- | test/stdio/lseek_no_lfs.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/test/stdio/lseek_no_lfs.c b/test/stdio/lseek_no_lfs.c new file mode 100644 index 000000000..54daf6b48 --- /dev/null +++ b/test/stdio/lseek_no_lfs.c @@ -0,0 +1,22 @@ +#include <stdio.h> +#include <string.h> +#include <errno.h> + +int main(int argc, char *argv[]) +{ + FILE * f = fopen(argv[0], "rb"); + if (!f) + { + printf("Error: Can't open %s, reason: %s\n", argv[0], strerror(errno)); + return 1; + } + + if (fseek(f, (unsigned)4096, (int)SEEK_SET) == -1) + { + printf("Test failed, fseek return fail code. errno=%u (%s)\n", errno, strerror(errno)); + return 1; + } + + fclose(f); + return 0; +} |