/**************************************************************************** * libc/aio/lio_listio.c * * Copyright (C) 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "lib_internal.h" #include "aio/aio.h" #ifdef CONFIG_FS_AIO /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Configuration ************************************************************/ /**************************************************************************** * Private Types ****************************************************************************/ struct lio_sighand_s { FAR struct aiocb * const *list; /* List of I/O operations */ FAR struct sigevent *sig; /* Describes how to signal the caller */ int nent; /* Number or elements in list[] */ pid_t pid; /* ID of client */ sigset_t oprocmask; /* sigprocmask to restore */ struct sigaction oact; /* Signal handler to restore */ }; /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Public Variables ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: lio_checkio * * Description: * Check if all I/O operations in the list are complete. * * Input Parameters: * list - The list of I/O operations to be performed * nent - The number of elements in the list * * Returned Value: * Zero (OK) is returned if all I/O completed successfully. * -EINPROGRESS is returned if one or more I/Os have not yet completed. * The negated errno value if first error noted in the case where all I/O * completed but one or more I/Os completed with an error. * * Assumptions: * The scheduler is locked and no I/O can complete asynchronously with * the logic in this function. * ****************************************************************************/ static int lio_checkio(FAR struct aiocb * const *list, int nent) { FAR struct aiocb *aiocbp; int ret; int i; ret = OK; /* Assume success */ /* Check each entry in the list. Break out of the loop if any entry * has not completed. */ for (i = 0; i < nent; i++) { /* Skip over NULL entries */ aiocbp = list[i]; if (aiocbp) { /* Check if the I/O has completed */ if (aiocbp->aio_result == -EINPROGRESS) { /* No.. return -EINPROGRESS */ return -EINPROGRESS; } /* Check for an I/O error */ else if (aiocbp->aio_result < 0 && ret == OK) { /* Some other error other than -EINPROGRESS */ ret = aiocbp->aio_result; } } } /* All of the I/Os have completed */ return ret; } /**************************************************************************** * Name: lio_sighandler * * Description: * Handle the SIGPOLL signal. * * Input Parameters: * signo - The number of the signal that we caught (SIGPOLL) * info - Information accompanying the signal * context - Not used in NuttX * * Returned Value: * None * ****************************************************************************/ static void lio_sighandler(int signo, siginfo_t *info, void *ucontext) { FAR struct aiocb *aiocbp; FAR struct lio_sighand_s *sighand; int ret; DEBUGASSERT(signo == SIGPOLL && info); /* The info structure should contain a pointer to the AIO control block */ aiocbp = (FAR struct aiocb *)info->si_value.sival_ptr; DEBUGASSERT(aiocbp && aiocbp->aio_result != -EINPROGRESS); /* Recover our private data from the AIO control block */ sighand = (FAR struct lio_sighand_s *)aiocbp->aio_priv; DEBUGASSERT(sighand && sighand->list); aiocbp->aio_priv = NULL; /* Prevent any asynchronous I/O completions while the signal handler runs */ sched_lock(); /* Check if all of the pending I/O has completed */ ret = lio_checkio(sighand->list, sighand->nent); if (ret != -EINPROGRESS) { /* All pending I/O has completed */ /* Restore the signal handler */ (void)sigaction(SIGPOLL, &sighand->oact, NULL); /* Restore the sigprocmask */ (void)sigprocmask(SIG_SETMASK, &sighand->oprocmask, NULL); /* Signal the client */ if (sighand->sig->sigev_notify == SIGEV_SIGNAL) { #ifdef CONFIG_CAN_PASS_STRUCTS (void)sigqueue(sighand->pid, sighand->sig->sigev_signo, sighand->sig->sigev_value); #else (void)sigqueue(sighand->pid, sighand->sig->sigev_signo, sighand->sig->sigev_value.sival_ptr); #endif } /* And free the container */ lib_free(sighand); } sched_unlock(); } /**************************************************************************** * Name: lio_sigsetup * * Description: * Setup a signal handler to detect when until all I/O completes. * * Input Parameters: * list - The list of I/O operations to be performed * nent - The number of elements in the list * * Returned Value: * Zero (OK) is returned if all I/O completed successfully; Otherwise, a * negated errno value is returned corresponding to the first error * detected. * * Assumptions: * The scheduler is locked and no I/O can complete asynchronously with * the logic in this function. * ****************************************************************************/ static int lio_sigsetup(FAR struct aiocb * const *list, int nent, FAR struct sigevent *sig) { FAR struct aiocb *aiocbp; FAR struct lio_sighand_s *sighand; sigset_t sigset; struct sigaction act; int status; int i; /* Allocate a structure to pass data to the signal handler */ sighand = (FAR struct lio_sighand_s *)lib_zalloc(sizeof(struct lio_sighand_s)); if (!sighand) { fdbg("ERROR: lib_zalloc failed\n"); return -ENOMEM; } /* Initialize the allocated structure */ sighand->list = list; sighand->sig = sig; sighand->nent = nent; sighand->pid = getpid(); /* Save this structure as the private data attached to each aiocb */ for (i = 0; i < nent; i++) { /* Skip over NULL entries in the list */ aiocbp = list[i]; if (aiocbp) { FAR void *priv = NULL; /* Check if I/O is pending for this entry */ if (aiocbp->aio_result == -EINPROGRESS) { priv = (FAR void *)sighand; } aiocbp->aio_priv = priv; } } /* Make sure that SIGPOLL is not blocked */ (void)sigemptyset(&sigset); (void)sigaddset(&sigset, SIGPOLL); status = sigprocmask(SIG_UNBLOCK, &sigset, &sighand->oprocmask); if (status != OK) { int errcode = get_errno(); fdbg("ERROR sigprocmask failed: %d\n", errcode); DEBUGASSERT(errcode > 0); return -errcode; } /* Attach our signal handler */ printf("waiter_main: Registering signal handler\n" ); act.sa_sigaction = lio_sighandler; act.sa_flags = SA_SIGINFO; (void)sigfillset(&act.sa_mask); (void)sigdelset(&act.sa_mask, SIGPOLL); status = sigaction(SIGPOLL, &act, &sighand->oact); if (status != OK) { int errcode = get_errno(); fdbg("ERROR sigaction failed: %d\n", errcode); DEBUGASSERT(errcode > 0); return -errcode; } return OK; } /**************************************************************************** * Name: lio_waitall * * Description: * Wait for all I/O operations in the list to be complete. * * Input Parameters: * list - The list of I/O operations to be performed * nent - The number of elements in the list * * Returned Value: * Zero (OK) is returned if all I/O completed successfully; Otherwise, a * negated errno value is returned corresponding to the first error * detected. * * Assumptions: * The scheduler is locked and no I/O can complete asynchronously with * the logic in this function. * ****************************************************************************/ static int lio_waitall(FAR struct aiocb * const *list, int nent) { sigset_t set; int ret; /* Loop until all I/O completes */ for (;;) { /* Check if all I/O has completed */ ret = lio_checkio(list, nent); if (ret != -EINPROGRESS) { /* All I/O has completed.. We are finished. */ return ret; } /* Then wait for SIGPOLL -- indefinitely. * * NOTE: If completion of the I/O causes other signals to be generated * first, then this will wake up and return EINTR instead of success. */ sigemptyset(&set); sigaddset(&set, SIGPOLL); ret = sigwaitinfo(&set, NULL); if (ret < 0) { /* The most likely reason that we would get here is because some * unrelated signal has been received. */ int errcode = get_errno(); fdbg("ERROR: sigwaitinfo failed: %d\n", errcode); DEBUGASSERT(errcode > 0); return -errcode; } } } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: lio_listio * * Description: * The lio_listio() function initiates a list of I/O requests with a * single function call. * * The 'mode' argument takes one of the values LIO_WAIT or LIO_NOWAIT * declared in and determines whether the function returns when * the I/O operations have been completed, or as soon as the operations * have been queued. If the 'mode' argument is LIO_WAIT, the function will * wait until all I/O is complete and the 'sig' argument will be ignored. * * If the 'mode' argument is LIO_NOWAIT, the function will return * immediately, and asynchronous notification will occur, according to the * 'sig' argument, when all the I/O operations complete. If 'sig' is NULL, * then no asynchronous notification will occur. If 'sig' is not NULL, * asynchronous notification occurs when all the requests in 'list' have * completed. * * The I/O requests enumerated by 'list' are submitted in an unspecified * order. * * The 'list' argument is an array of pointers to aiocb structures. The * array contains 'nent 'elements. The array may contain NULL elements, * which will be ignored. * * If the buffer pointed to by 'list' or the aiocb structures pointed to * by the elements of the array 'list' become illegal addresses before all * asynchronous I/O completed and, if necessary, the notification is * sent, then the behavior is undefined. If the buffers pointed to by the * aio_buf member of the aiocb structure pointed to by the elements of * the array 'list' become illegal addresses prior to the asynchronous * I/O associated with that aiocb structure being completed, the behavior * is undefined. * * The aio_lio_opcode field of each aiocb structure specifies the * operation to be performed. The supported operations are LIO_READ, * LIO_WRITE, and LIO_NOP; these symbols are defined in . The * LIO_NOP operation causes the list entry to be ignored. If the * aio_lio_opcode element is equal to LIO_READ, then an I/O operation is * submitted as if by a call to aio_read() with the aiocbp equal to the * address of the aiocb structure. If the aio_lio_opcode element is equal * to LIO_WRITE, then an I/O operation is submitted as if by a call to * aio_write() with the aiocbp equal to the address of the aiocb * structure. * * The aio_fildes member specifies the file descriptor on which the * operation is to be performed. * * The aio_buf member specifies the address of the buffer to or from which * the data is transferred. * * The aio_nbytes member specifies the number of bytes of data to be * transferred. * * The members of the aiocb structure further describe the I/O operation * to be performed, in a manner identical to that of the corresponding * aiocb structure when used by the aio_read() and aio_write() functions. * * The 'nent' argument specifies how many elements are members of the list; * that is, the length of the array. * * Input Parameters: * mode - Either LIO_WAIT or LIO_NOWAIT * list - The list of I/O operations to be performed * nent - The number of elements in the list * sig - Used to notify the caller when the I/O is performed * asynchronously. * * Returned Value: * If the mode argument has the value LIO_NOWAIT, the lio_listio() * function will return the value zero if the I/O operations are * successfully queued; otherwise, the function will return the value * -1 and set errno to indicate the error. * * If the mode argument has the value LIO_WAIT, the lio_listio() function * will return the value zero when all the indicated I/O has completed * successfully. Otherwise, lio_listio() will return a value of -1 and * set errno to indicate the error. * * In either case, the return value only indicates the success or failure * of the lio_listio() call itself, not the status of the individual I/O * requests. In some cases one or more of the I/O requests contained in * the list may fail. Failure of an individual request does not prevent * completion of any other individual request. To determine the outcome * of each I/O request, the application must examine the error status * associated with each aiocb control block. The error statuses so * returned are identical to those returned as the result of an aio_read() * or aio_write() function. * * The lio_listio() function will fail if: * * EAGAIN - The resources necessary to queue all the I/O requests were * not available. The application may check the error status for each * aiocb to determine the individual request(s) that failed. * EAGAIN - The number of entries indicated by 'nent' would cause the * system-wide limit {AIO_MAX} to be exceeded. * EINVAL - The mode argument is not a proper value, or the value of * 'nent' was greater than {AIO_LISTIO_MAX}. * EINTR - A signal was delivered while waiting for all I/O requests to * complete during an LIO_WAIT operation. Note that, since each I/O * operation invoked by lio_listio() may possibly provoke a signal when * it completes, this error return may be caused by the completion of * one (or more) of the very I/O operations being awaited. Outstanding * I/O requests are not cancelled, and the application will examine * each list element to determine whether the request was initiated, * cancelled, or completed. * EIO - One or more of the individual I/O operations failed. The * application may check the error status for each aiocb structure to * determine the individual request(s) that failed. * * In addition to the errors returned by the lio_listio() function, if the * lio_listio() function succeeds or fails with errors of EAGAIN, EINTR, or * EIO, then some of the I/O specified by the list may have been initiated. * If the lio_listio() function fails with an error code other than EAGAIN, * EINTR, or EIO, no operations from the list will have been initiated. The * I/O operation indicated by each list element can encounter errors specific * to the individual read or write function being performed. In this event, * the error status for each aiocb control block contains the associated * error code. The error codes that can be set are the same as would be * set by a read() or write() function, with the following additional * error codes possible: * * EAGAIN - The requested I/O operation was not queued due to resource * limitations. * ECANCELED - The requested I/O was cancelled before the I/O completed * due to an explicit aio_cancel() request. * EFBIG - The aiocbp->aio_lio_opcode is LIO_WRITE, the file is a * regular file, aiocbp->aio_nbytes is greater than 0, and the * aiocbp->aio_offset is greater than or equal to the offset maximum * in the open file description associated with aiocbp->aio_fildes. * EINPROGRESS - The requested I/O is in progress. * EOVERFLOW - The aiocbp->aio_lio_opcode is LIO_READ, the file is a * regular file, aiocbp->aio_nbytes is greater than 0, and the * aiocbp->aio_offset is before the end-of-file and is greater than * or equal to the offset maximum in the open file description * associated with aiocbp->aio_fildes. * ****************************************************************************/ int lio_listio(int mode, FAR struct aiocb *const list[], int nent, FAR struct sigevent *sig) { FAR struct aiocb *aiocbp; int nqueued; int errcode; int retcode; int status; int ret; int i; DEBUGASSERT(mode == LIO_WAIT || mode == LIO_NOWAIT); DEBUGASSERT(list); nqueued = 0; /* No I/O operations yet queued */ ret = OK; /* Assume success */ /* Lock the scheduler so that no I/O events can complete on the worker * thread until we set our wait set up. Pre-emption will, of course, be * re-enabled while we are waiting for the signal. */ sched_lock(); /* Submit each asynchronous I/O operation in the list, skipping over NULL * entries. */ for (i = 0; i < nent; i++) { /* Skip over NULL entries */ aiocbp = list[i]; if (aiocbp) { /* Submit the operation according to its opcode */ status = OK; switch (aiocbp->aio_lio_opcode) { case LIO_NOP: { /* Mark the do-nothing operation complete */ aiocbp->aio_result = OK; } break; case LIO_READ: case LIO_WRITE: { if (aiocbp->aio_lio_opcode == LIO_READ) { /* Submit the asynchronous read operation */ status = aio_read(aiocbp); } else { /* Submit the asynchronous write operation */ status = aio_write(aiocbp); } if (status < 0) { /* Failed to queue the I/O. Set up the error return. */ errcode = get_errno(); fdbg("ERROR: aio_read/write failed: %d\n", errcode); DEBUGASSERT(errcode > 0); aiocbp->aio_result = -errcode; ret = ERROR; } else { /* Increment the count of successfully queue operations */ nqueued++; } } break; default: { /* Make the invalid operation complete with an error */ fdbg("ERROR: Unrecognized opcode: %d\n", aiocbp->aio_lio_opcode); aiocbp->aio_result = -EINVAL; ret = ERROR; } break; } } } /* If there was any failure in queuing the I/O, EIO will be returned */ retcode = EIO; /* Now what? Three possibilities: * * Case 1: mode == LIO_WAIT * * Ignore the sig argument; Do no return until all I/O completes. */ if (mode == LIO_WAIT) { /* Don't wait if all if no I/O was queue */ if (nqueued > 0) { /* Wait until all I/O completes. The scheduler will be unlocked * while we are waiting. */ status = lio_waitall(list, nent); if (status < 0 && ret != OK) { /* Something bad happened while waiting and this is the first * error to be reported. */ retcode = -status; ret = ERROR; } } } /* Case 2: mode == LIO_NOWAIT and sig != NULL * * If any I/O was queued, then setup to signal the caller when all of * the transfers complete. * * If no I/O was queue, then we I suppose that we need to signal the * caller ourself? */ else if (sig && sig->sigev_notify == SIGEV_SIGNAL) { if (nqueued > 0) { /* Setup a signal handler to detect when until all I/O completes. */ status = lio_sigsetup(list, nent, sig); if (status < 0 && ret != OK) { /* Something bad happened while setting up the signal and this * is the first error to be reported. */ retcode = -status; ret = ERROR; } } else { #ifdef CONFIG_CAN_PASS_STRUCTS status = sigqueue(getpid(), sig->sigev_signo, sig->sigev_value); #else status = sigqueue(getpid(), sig->sigev_signo, sig->sigev_value.sival_ptr); #endif if (status < 0 && ret != OK) { /* Something bad happened while signalling ourself and this is * the first error to be reported. */ retcode = get_errno(); ret = ERROR; } } } /* Case 3: mode == LIO_NOWAIT and sig == NULL * * Just return now. */ sched_unlock(); if (ret < 0) { set_errno(retcode); return ERROR; } return OK; } #endif /* CONFIG_FS_AIO */