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authorAnton Kolesov <Anton.Kolesov@synopsys.com>2014-08-01 22:18:47 +0400
committerBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2014-08-18 12:01:36 +0200
commit361285886aa319a56c803f2fb783457f3e80f564 (patch)
treeac08937811c6701bb63951c10423146422193257 /test/stdio
parent95ec1755ef61629169a79a616ec478988bb6ce7d (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')
-rw-r--r--test/stdio/lseek_no_lfs.c22
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;
+}