Unverified Commit b0fa8e12 authored by Tommaso Tocci's avatar Tommaso Tocci
Browse files

Intercept access & lseek

parent 3b930bbb

include/client/hooks.hpp

+2 −0
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ int hook_stat(const char* path, struct stat* buf); 
int hook_read(int fd, void* buf, size_t count);

int hook_write(int fd, void* buf, size_t count);

int hook_unlink(const char* path);

int hook_access(const char* path, int mask);

int hook_lseek(unsigned int fd, off_t offset, unsigned int whence);





#endif

src/client/adafs_functions.cpp

+6 −0
Original line number Diff line number Diff line
@@ -244,12 +244,15 @@ off64_t adafs_lseek(int fd, off64_t offset, int whence) { 
off64_t adafs_lseek(shared_ptr<OpenFile> adafs_fd, off64_t offset, int whence) {

    switch (whence) {

        case SEEK_SET:

            CTX->log()->debug("{}() whence is SEEK_SET", __func__);

            adafs_fd->pos(offset);

            break;

        case SEEK_CUR:

            CTX->log()->debug("{}() whence is SEEK_CUR", __func__);

            adafs_fd->pos(adafs_fd->pos() + offset);

            break;

        case SEEK_END: {

            CTX->log()->debug("{}() whence is SEEK_END", __func__);

            off64_t file_size;

            auto err = rpc_send::get_metadentry_size(adafs_fd->path(), file_size);

            if (err < 0) {
@@ -260,14 +263,17 @@ off64_t adafs_lseek(shared_ptr<OpenFile> adafs_fd, off64_t offset, int whence) { 
            break;

        }

        case SEEK_DATA:

            CTX->log()->warn("{}() SEEK_DATA whence is not supported", __func__);

            // We do not support this whence yet

            errno = EINVAL;

            return -1;

        case SEEK_HOLE:

            CTX->log()->warn("{}() SEEK_HOLE whence is not supported", __func__);

            // We do not support this whence yet

            errno = EINVAL;

            return -1;

        default:

            CTX->log()->warn("{}() unknown whence {}", __func__, whence);

            errno = EINVAL;

            return -1;

    }

src/client/hooks.cpp

+29 −0
Original line number Diff line number Diff line
@@ -109,3 +109,32 @@ int hook_unlink(const char* path) { 
    }

    return syscall_no_intercept(SYS_unlink, rel_path.c_str());

}



int hook_access(const char* path, int mask) {

    CTX->log()->trace("{}() called path '{}', mask {}", __func__, path, mask);

    std::string rel_path;

    if (CTX->relativize_path(path, rel_path)) {

        auto ret = adafs_access(rel_path, mask);

        if(ret < 0) {

            return -errno;

        }

        return ret;

    }

    return syscall_no_intercept(SYS_access, rel_path.c_str(), mask);

}



int hook_lseek(unsigned int fd, off_t offset, unsigned int whence) {

    CTX->log()->trace("{}() called with fd {}, offset {}, whence {}", __func__, fd, offset, whence);

    if (CTX->file_map()->exist(fd)) {

        auto off_ret = adafs_lseek(fd, static_cast<off64_t>(offset), whence);

        if (off_ret > std::numeric_limits<off_t>::max()) {

            return -EOVERFLOW;

        } else if(off_ret < 0) {

            return -errno;

        }

        CTX->log()->trace("{}() returning {}", __func__, off_ret);

        return off_ret;

    }

   return syscall_no_intercept(SYS_lseek, fd, offset, whence);

}

src/client/intercept.cpp

+11 −1
Original line number Diff line number Diff line
@@ -75,7 +75,17 @@ static inline int hook(long syscall_number, 
        *result = hook_unlink(reinterpret_cast<char*>(arg0));

        break;



    default:

    case SYS_access:

        *result = hook_access(reinterpret_cast<char*>(arg0),

                              static_cast<int>(arg1));

        break;



    case SYS_lseek:

        *result = hook_lseek(static_cast<unsigned int>(arg0),

                             static_cast<off_t>(arg1),

                             static_cast<unsigned int>(arg2));

        break;



        /*

         * Ignore any other syscalls

         * i.e.: pass them on to the kernel