LibC: Use the new pread syscall to implement pread

This new implementation of pread saves two lseek system calls and is
thread-safe thanks to it simply forwarding the call to the pread system
call.

1 files changed, 2 insertions, 6 deletions

diff --git a/Userland/Libraries/LibC/unistd.cpp b/Userland/Libraries/LibC/unistd.cpp
index e0af881505..88d28f759d 100644
--- a/Userland/Libraries/LibC/unistd.cpp
+++ b/Userland/Libraries/LibC/unistd.cpp
@@ -296,12 +296,8 @@ ssize_t read(int fd, void* buf, size_t count)
 
 ssize_t pread(int fd, void* buf, size_t count, off_t offset)
 {
-    // FIXME: This is not thread safe and should be implemented in the kernel instead.
-    off_t old_offset = lseek(fd, 0, SEEK_CUR);
-    lseek(fd, offset, SEEK_SET);
-    ssize_t nread = read(fd, buf, count);
-    lseek(fd, old_offset, SEEK_SET);
-    return nread;
+    int rc = syscall(SC_pread, fd, buf, count, offset);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
 ssize_t write(int fd, const void* buf, size_t count)