Write into the given process's address space.


#include <zircon/syscalls.h>

zx_status_t zx_process_write_memory(zx_handle_t handle,
                                    zx_vaddr_t vaddr,
                                    const void* buffer,
                                    size_t buffer_size,
                                    size_t* actual);


zx_process_write_memory() attempts to write memory of the specified process.

This function will eventually be replaced with something VMO-centric.

vaddr the address of the block of memory to write.

buffer pointer to a user buffer containing the bytes to write.

buffer_size number of bytes to attempt to write. buffer buffer must be large enough for at least this many bytes. buffer_size must be greater than zero and less than or equal to 64MB.

actual_size the actual number of bytes written is stored here. Less bytes than requested may be returned if vaddr+buffer_size extends beyond the memory mapped in the process.

To use the zx_process_write_memory() function, you must specify kernel.enable-debugging-syscalls=true on the kernel command line. Otherwise, the function returns ZX_ERR_NOT_SUPPORTED.


handle must be of type ZX_OBJ_TYPE_PROCESS and have ZX_RIGHT_WRITE.

Return value

zx_process_write_memory() returns ZX_OK on success. In the event of failure, a negative error value is returned, and the number of bytes written to buffer is undefined.


ZX_ERR_ACCESS_DENIED handle does not have the ZX_RIGHT_WRITE right or the address range to write falls into a protected area like the vDSO.

ZX_ERR_BAD_HANDLE handle is not a valid handle.

ZX_ERR_BAD_STATE the process's memory is not accessible (e.g., the process is being terminated), or the requested memory is not cacheable.

ZX_ERR_INVALID_ARGS buffer is an invalid pointer or NULL, or buffer_size is zero or greater than 64MB.

ZX_ERR_NOT_FOUND if the process does not have any memory at the requested address or ZX_ERR_OUT_OF_RANGE if the offset corresponding to vaddr within the mapped VMO is greater than or equal to the VMO size. These error codes are consistent with the error code that would be generated by a page fault at the same address (i.e. the synth_code in the page fault's exception report).

ZX_ERR_NOT_SUPPORTED kernel.enable-debugging-syscalls is not set to true on the kernel command line.

ZX_ERR_WRONG_TYPE handle is not a process handle.

See also