fs_syscall.c 文件参考

浏览源代码.

函数
static int	CheckNewAttrTime (struct IATTR *attr, struct timespec times[TIMESPEC_TIMES_NUM])
static int	GetFullpathNull (int fd, const char *path, char **filePath)
	获取全路径 更多...
static int	UserIovItemCheck (const struct iovec *iov, const int iovcnt)
	用户空间 io向量地址范围检查 更多...
static int	UserIovCopy (struct iovec **iovBuf, const struct iovec *iov, const int iovcnt, int *valid_iovcnt)
static int	PollfdToSystem (struct pollfd *fds, nfds_t nfds, int **pollFdsBak)
static void	RestorePollfd (struct pollfd *fds, nfds_t nfds, const int *pollFds)
static int	UserPoll (struct pollfd *fds, nfds_t nfds, int timeout)
	使用poll方式 实现IO多路复用的机制 更多...
int	SysClose (int fd)
ssize_t	SysRead (int fd, void *buf, size_t nbytes)
	系统调用|读文件:从文件中读取nbytes长度的内容到buf中(用户空间) 更多...
ssize_t	SysWrite (int fd, const void *buf, size_t nbytes)
	系统调用|写文件:将buf中(用户空间)nbytes长度的内容写到文件中 更多...
int	SysOpen (const char *path, int oflags,...)
	系统调用|打开文件, 正常情况下返回进程的FD值 更多...
int	SysCreat (const char *pathname, mode_t mode)
	创建文件,从实现看 SysCreat 和 SysOpen 并没有太大的区别,只有打开方式的区别 SysCreat函数完全可以被SysOpen函数替代 更多...
int	SysLink (const char *oldpath, const char *newpath)
ssize_t	SysReadlink (const char *pathname, char *buf, size_t bufsize)
int	SysSymlink (const char *target, const char *linkpath)
int	SysUnlink (const char *pathname)
	删除链:删除由装入点管理的文件 更多...
int	SysExecve (const char *fileName, char *const *argv, char *const *envp)
	动态加载程序过程 更多...
int	SysFchdir (int fd)
int	SysChdir (const char *path)
off_t	SysLseek (int fd, off_t offset, int whence)
	移动文件指针 更多...
off64_t	SysLseek64 (int fd, int offsetHigh, int offsetLow, off64_t *result, int whence)
static int	NfsMountRef (const char *serverIpAndPath, const char *mountPath, unsigned int uid, unsigned int gid) __attribute__((weakref("nfs_mount")))
static int	NfsMount (const char *serverIpAndPath, const char *mountPath, unsigned int uid, unsigned int gid)
int	SysMount (const char *source, const char *target, const char *filesystemtype, unsigned long mountflags, const void *data)
	SysMount 挂载文件系统 挂载是指将一个存储设备挂接到一个已存在的路径上。我们要访问存储设备中的文件，必须将文件所在的分区挂载到一个已存在的路径上， 然后通过这个路径来访问存储设备。如果只有一个存储设备，则可以直接挂载到根目录 / 上,变成根文件系统 更多...
int	SysUmount (const char *target)
	卸载文件系统,当某个文件系统不需要再使用了，那么可以将它卸载掉。 更多...
int	SysAccess (const char *path, int amode)
	确定文件的可存取性 更多...
int	SysRename (const char *oldpath, const char *newpath)
	重命名文件 更多...
int	SysMkdir (const char *pathname, mode_t mode)
	创建目录 更多...
int	SysRmdir (const char *pathname)
	删除目录 更多...
int	SysDup (int fd)
void	SysSync (void)
	将内存缓冲区数据写回硬盘 更多...
int	SysUmount2 (const char *target, int flags)
	卸载文件系统 更多...
int	SysIoctl (int fd, int req, void *arg)
	I/O总控制函数 更多...
int	SysFcntl (int fd, int cmd, void *arg)
int	SysPipe (int pipefd[2])
int	SysDup2 (int fd1, int fd2)
	复制文件描述符 更多...
static int	SelectParamCheckCopy (fd_set *readfds, fd_set *writefds, fd_set *exceptfds, fd_set **fdsBuf)
	select()参数检查 更多...
int	SysSelect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
	SysSelect 系统调用|文件系统|select .鸿蒙liteos目前也支持epoll方式 更多...
int	SysTruncate (const char *path, off_t length)
	系统调用|文件系统|截断功能 更多...
int	SysTruncate64 (const char *path, off64_t length)
	系统调用|文件系统|截断功能 更多...
int	SysFtruncate (int fd, off_t length)
	系统调用|文件系统|截断功能 更多...
int	SysStatfs (const char *path, struct statfs *buf)
	获取指定路径下文件的文件系统信息 更多...
int	SysStatfs64 (const char *path, size_t sz, struct statfs *buf)
	获取文件系统信息 更多...
int	SysStat (const char *path, struct kstat *buf)
	获取文件状态信息 更多...
int	SysLstat (const char *path, struct kstat *buffer)
	参见SysStat 更多...
int	SysFstat (int fd, struct kstat *buf)
	参见SysStat 更多...
int	SysStatx (int fd, const char *restrict path, int flag, unsigned mask, struct statx *restrict stx)
int	SysFsync (int fd)
	把文件在内存中的部分写回磁盘 更多...
ssize_t	SysReadv (int fd, const struct iovec *iov, int iovcnt)
	通过FD读入数据到缓冲数组中,fd为进程描述符 更多...
ssize_t	SysWritev (int fd, const struct iovec *iov, int iovcnt)
	将缓冲数组里的数据写入文件 更多...
int	SysPoll (struct pollfd *fds, nfds_t nfds, int timeout)
	SysPoll I/O多路转换 更多...
int	SysPrctl (int option,...)
	对进程进行特定操作 更多...
ssize_t	SysPread64 (int fd, void *buf, size_t nbytes, off64_t offset)
	对进程进行特定操作 更多...
ssize_t	SysPwrite64 (int fd, const void *buf, size_t nbytes, off64_t offset)
char *	SysGetcwd (char *buf, size_t n)
ssize_t	SysSendFile (int outfd, int infd, off_t *offset, size_t count)
int	SysFtruncate64 (int fd, off64_t length)
int	SysOpenat (int dirfd, const char *path, int oflags,...)
int	SysMkdirat (int dirfd, const char *pathname, mode_t mode)
int	SysLinkat (int olddirfd, const char *oldpath, int newdirfd, const char *newpath, int flags)
int	SysSymlinkat (const char *target, int dirfd, const char *linkpath)
ssize_t	SysReadlinkat (int dirfd, const char *pathname, char *buf, size_t bufsize)
int	SysUnlinkat (int dirfd, const char *pathname, int flag)
int	SysRenameat (int oldfd, const char *oldpath, int newdfd, const char *newpath)
int	SysFallocate (int fd, int mode, off_t offset, off_t len)
int	SysFallocate64 (int fd, int mode, off64_t offset, off64_t len)
ssize_t	SysPreadv (int fd, const struct iovec *iov, int iovcnt, long loffset, long hoffset)
ssize_t	SysPwritev (int fd, const struct iovec *iov, int iovcnt, long loffset, long hoffset)
int	SysFormat (const char *dev, int sectors, int option)
int	SysFstat64 (int fd, struct kstat *buf)
int	SysFcntl64 (int fd, int cmd, void *arg)
int	SysGetdents64 (int fd, struct dirent *de_user, unsigned int count)
char *	SysRealpath (const char *path, char *resolved_path)
int	SysUtimensat (int fd, const char *path, struct timespec times[TIMESPEC_TIMES_NUM], int flag)
int	SysChmod (const char *pathname, mode_t mode)
int	SysFchmodat (int fd, const char *path, mode_t mode, int flag)
int	SysFchmod (int fd, mode_t mode)
int	SysFchownat (int fd, const char *path, uid_t owner, gid_t group, int flag)
int	SysFchown (int fd, uid_t owner, gid_t group)
int	SysChown (const char *pathname, uid_t owner, gid_t group)
int	SysFstatat64 (int dirfd, const char *restrict path, struct kstat *restrict buf, int flag)
int	SysFaccessat (int fd, const char *filename, int amode, int flag)
int	SysFstatfs (int fd, struct statfs *buf)
int	SysFstatfs64 (int fd, size_t sz, struct statfs *buf)
int	SysPpoll (struct pollfd *fds, nfds_t nfds, const struct timespec *tmo_p, const sigset_t *sigMask, int nsig)
int	SysPselect6 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, const struct timespec *timeout, const long data[2])
static int	DoEpollCreate1 (int flags)
int	SysEpollCreate (int size)
int	SysEpollCreate1 (int flags)
int	SysEpollCtl (int epfd, int op, int fd, struct epoll_event *ev)
int	SysEpollWait (int epfd, struct epoll_event *evs, int maxevents, int timeout)
int	SysEpollPwait (int epfd, struct epoll_event *evs, int maxevents, int timeout, const sigset_t *mask)

函数说明

CheckNewAttrTime()

static int CheckNewAttrTime ( struct IATTR *  attr, struct timespec  times[TIMESPEC_TIMES_NUM]  )

static

在文件 fs_syscall.c 第 63 行定义.

{
    int ret = ENOERR;
    struct timespec stp = {0};
 
    if (times) {
        if (times[0].tv_nsec == UTIME_OMIT) {
            attr->attr_chg_valid &= ~CHG_ATIME;
        } else if (times[0].tv_nsec == UTIME_NOW) {
            ret = clock_gettime(CLOCK_REALTIME, &stp);
            if (ret < 0) {
                return -get_errno();
            }
            attr->attr_chg_atime = (unsigned int)stp.tv_sec;
            attr->attr_chg_valid |= CHG_ATIME;
        } else {
            attr->attr_chg_atime = (unsigned int)times[0].tv_sec;
            attr->attr_chg_valid |= CHG_ATIME;
        }
 
        if (times[1].tv_nsec == UTIME_OMIT) {
            attr->attr_chg_valid &= ~CHG_MTIME;
        } else if (times[1].tv_nsec == UTIME_NOW) {
            ret = clock_gettime(CLOCK_REALTIME, &stp);
            if (ret < 0) {
                return -get_errno();
            }
            attr->attr_chg_mtime = (unsigned int)stp.tv_sec;
            attr->attr_chg_valid |= CHG_MTIME;
        } else {
            attr->attr_chg_mtime = (unsigned int)times[1].tv_sec;
            attr->attr_chg_valid |= CHG_MTIME;
        }
    } else {
        ret = clock_gettime(CLOCK_REALTIME, &stp);
        if (ret < 0) {
            return -get_errno();
        }
        attr->attr_chg_atime = (unsigned int)stp.tv_sec;
        attr->attr_chg_mtime = (unsigned int)stp.tv_sec;
        attr->attr_chg_valid |= CHG_ATIME;
        attr->attr_chg_valid |= CHG_MTIME;
    }
 
    return ret;
}

函数调用图:

这是这个函数的调用关系图:

DoEpollCreate1()

static int DoEpollCreate1 ( int  flags )

static

在文件 fs_syscall.c 第 2731 行定义.

{
    int ret;
    int procFd;
 
    ret = epoll_create1(flags);
    if (ret < 0) {
        ret = -get_errno();
        return ret;
    }
 
    procFd = AllocAndAssocProcessFd((INTPTR)(ret), MIN_START_FD);
    if (procFd == -1) {
        epoll_close(ret);
        return -EMFILE;
    }
 
    return procFd;
}

函数调用图:

这是这个函数的调用关系图:

GetFullpathNull()

static int GetFullpathNull ( int  fd, const char *  path, char **  filePath  )

static

获取全路径

在文件 fs_syscall.c 第 110 行定义.

{
    int ret;
    char *fullPath = NULL;
    struct file *file = NULL;
 
    if ((fd != AT_FDCWD) && (path == NULL)) {
        fd = GetAssociatedSystemFd(fd);
        ret = fs_getfilep(fd, &file);
        if (ret < 0) {
            return -get_errno();
        }
        fullPath = strdup(file->f_path);
        if (fullPath == NULL) {
            ret = -ENOMEM;
        }
    } else {
        ret = GetFullpath(fd, path, &fullPath);
        if (ret < 0) {
            return ret;
        }
    }
 
    *filePath = fullPath;
    return ret;
}

函数调用图:

这是这个函数的调用关系图:

NfsMount()

static int NfsMount ( const char *  serverIpAndPath, const char *  mountPath, unsigned int  uid, unsigned int  gid  )

static

在文件 fs_syscall.c 第 637 行定义.

{
    int ret;
 
    if ((serverIpAndPath == NULL) || (mountPath == NULL)) {
        return -EINVAL;
    }
    ret = NfsMountRef(serverIpAndPath, mountPath, uid, gid);
    if (ret < 0) {
        ret = -get_errno();
    }
    return ret;
}

函数调用图:

这是这个函数的调用关系图:

NfsMountRef()

static int NfsMountRef ( const char *  serverIpAndPath, const char *  mountPath, unsigned int  uid, unsigned int  gid  )

static

这是这个函数的调用关系图:

PollfdToSystem()

static int PollfdToSystem ( struct pollfd *  fds, nfds_t  nfds, int **  pollFdsBak  )

static

在文件 fs_syscall.c 第 180 行定义.

{
    if ((nfds != 0 && fds == NULL) || (pollFdsBak == NULL)) {
        set_errno(EINVAL);
        return -1;
    }
    if (nfds == 0) {
        return 0;
    }
    int *pollFds = (int *)malloc(sizeof(int) * nfds);
    if (pollFds == NULL) {
        set_errno(ENOMEM);
        return -1;
    }
    for (int i = 0; i < nfds; ++i) {
        struct pollfd *p_fds = &fds[i];
        pollFds[i] = p_fds->fd;
        if (p_fds->fd < 0) {
            set_errno(EBADF);
            free(pollFds);
            return -1;
        }
        p_fds->fd = GetAssociatedSystemFd(p_fds->fd);
    }
    *pollFdsBak = pollFds;
    return 0;
}

函数调用图:

这是这个函数的调用关系图:

RestorePollfd()

static void RestorePollfd ( struct pollfd *  fds, nfds_t  nfds, const int *  pollFds  )

static

在文件 fs_syscall.c 第 208 行定义.

{
    if ((fds == NULL) || (pollFds == NULL)) {
        return;
    }
    for (int i = 0; i < nfds; ++i) {
        struct pollfd *p_fds = &fds[i];
        p_fds->fd = pollFds[i];
    }
}

这是这个函数的调用关系图:

SelectParamCheckCopy()

static int SelectParamCheckCopy ( fd_set *  readfds, fd_set *  writefds, fd_set *  exceptfds, fd_set **  fdsBuf  )

static

select()参数检查

在文件 fs_syscall.c 第 1076 行定义.

{
    fd_set *readfdsRet = NULL;
    fd_set *writefdsRet = NULL;
    fd_set *exceptfdsRet = NULL;
 
    *fdsBuf = (fd_set *)LOS_MemAlloc(OS_SYS_MEM_ADDR, sizeof(fd_set) * 3); /* 3: three param need check and copy */
    if (*fdsBuf == NULL) {
        return -ENOMEM;
    }
 
    readfdsRet = *fdsBuf;        /* LOS_MemAlloc 3 sizeof(fd_set) space,first use for readfds */
    writefdsRet = *fdsBuf + 1;   /* 1: LOS_MemAlloc 3 sizeof(fd_set) space,second use for writefds */
    exceptfdsRet = *fdsBuf + 2;  /* 2: LOS_MemAlloc 3 sizeof(fd_set) space,thired use for exceptfds */
 
    if (readfds != NULL) {
        if (LOS_ArchCopyFromUser(readfdsRet, readfds, sizeof(fd_set)) != 0) {
            (void)LOS_MemFree(OS_SYS_MEM_ADDR, *fdsBuf);
            return -EFAULT;
        }
    }
 
    if (writefds != NULL) {
        if (LOS_ArchCopyFromUser(writefdsRet, writefds, sizeof(fd_set)) != 0) {
            (void)LOS_MemFree(OS_SYS_MEM_ADDR, *fdsBuf);
            return -EFAULT;
        }
    }
 
    if (exceptfds != NULL) {
        if (LOS_ArchCopyFromUser(exceptfdsRet, exceptfds, sizeof(fd_set)) != 0) {
            (void)LOS_MemFree(OS_SYS_MEM_ADDR, *fdsBuf);
            return -EFAULT;
        }
    }
 
    return 0;
}

函数调用图:

这是这个函数的调用关系图:

SysAccess()

int SysAccess	(	const char *	path,
		int	amode
	)

确定文件的可存取性

在文件 fs_syscall.c 第 762 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = access(pathRet, amode);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
 
    return ret;
}

函数调用图:

SysChdir()

int SysChdir

(

const char *

path

)

在文件 fs_syscall.c 第 578 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = chdir(path ? pathRet : NULL);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysChmod()

int SysChmod	(	const char *	pathname,
		mode_t	mode
	)

在文件 fs_syscall.c 第 2337 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = chmod(pathRet, mode);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysChown()

int SysChown	(	const char *	pathname,
		uid_t	owner,
		gid_t	group
	)

在文件 fs_syscall.c 第 2495 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = chown(pathRet, owner, group);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysClose()

int SysClose

(

int

fd

)

在文件 fs_syscall.c 第 236 行定义.

{
    int ret;
 
    /* Process fd convert to system global fd */
    int sysfd = DisassociateProcessFd(fd);//先解除关联
 
    ret = close(sysfd);//关闭文件,个人认为应该先 close - > DisassociateProcessFd 
    if (ret < 0) {//关闭失败时
        AssociateSystemFd(fd, sysfd);//继续关联
        return -get_errno();
    }
    FreeProcessFd(fd);//释放进程fd
    return ret;
}

函数调用图:

SysCreat()

int SysCreat	(	const char *	pathname,
		mode_t	mode
	)

创建文件,从实现看 SysCreat 和 SysOpen 并没有太大的区别,只有打开方式的区别
SysCreat函数完全可以被SysOpen函数替代

参数

pathname
mode	常用标签如下: O_CREAT:若文件存在，此标志无用；若不存在，建新文件 O_TRUNC:若文件存在，则长度被截为0，属性不变 O_WRONLY:写文件 O_RDONLY:读文件 O_BINARY:此标志可显示地给出以二进制方式打开文件 O_TEXT :此标志可用于显示地给出以文本方式打开文件 O_RDWR :即读也写 O_APPEND:即读也写，但每次写总是在文件尾添加 *

返回

int

在文件 fs_syscall.c 第 372 行定义.

{
    int ret = 0;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    int procFd = AllocProcessFd();
    if (procFd  < 0) {
        ret = -EMFILE;
        goto OUT;
    }
    // 调用关系 open -> do_open chmod 666 
    ret = open((pathname ? pathRet : NULL), O_CREAT | O_TRUNC | O_WRONLY, mode);
    if (ret < 0) {
        FreeProcessFd(procFd);
        ret = -get_errno();
    } else {
        AssociateSystemFd(procFd, ret);
        ret = procFd;
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysDup()

int SysDup

(

int

fd

)

在文件 fs_syscall.c 第 871 行定义.

{
    int sysfd = GetAssociatedSystemFd(fd);
    /* Check if the param is valid, note that: socket fd is not support dup2 */
    if ((sysfd < 0) || (sysfd >= CONFIG_NFILE_DESCRIPTORS)) {
        return -EBADF;
    }
 
    int dupfd = AllocProcessFd();
    if (dupfd < 0) {
        return -EMFILE;
    }
 
    files_refer(sysfd);
    AssociateSystemFd(dupfd, sysfd);
    return dupfd;
}

函数调用图:

SysDup2()

int SysDup2	(	int	fd1,
		int	fd2
	)

复制文件描述符

在文件 fs_syscall.c 第 1038 行定义.

{
    int ret;
    int sysfd1 = GetAssociatedSystemFd(fd1);
    int sysfd2 = GetAssociatedSystemFd(fd2);
    //检查参数是否有效，注意：socket fd不支持dup2
    /* Check if the param is valid, note that: socket fd is not support dup2 */
    if ((sysfd1 < 0) || (sysfd1 >= CONFIG_NFILE_DESCRIPTORS) || (CheckProcessFd(fd2) != OK)) {//socket的fd必大于CONFIG_NFILE_DESCRIPTORS
        return -EBADF;
    }
 
    /* Handle special circumstances */
    if (fd1 == fd2) {
        return fd2;
    }
 
    ret = AllocSpecifiedProcessFd(fd2);
    if (ret != OK) {
        return ret;
    }
 
    /* close the sysfd2 in need */
    if (sysfd2 >= 0) {
        ret = close(sysfd2);
        if (ret < 0) {
            AssociateSystemFd(fd2, sysfd2);
            return -get_errno();
        }
    }
 
    files_refer(sysfd1);
    AssociateSystemFd(fd2, sysfd1);
 
    /* if fd1 is not equal to fd2, the FD_CLOEXEC flag associated with fd2 shall be cleared */
    ClearCloexecFlag(fd2);
    return fd2;
}

函数调用图:

SysEpollCreate()

int SysEpollCreate

(

int

size

)

在文件 fs_syscall.c 第 2751 行定义.

{
    (void)size;
    return DoEpollCreate1(0);
}

函数调用图:

SysEpollCreate1()

int SysEpollCreate1

(

int

flags

)

在文件 fs_syscall.c 第 2757 行定义.

{
    return DoEpollCreate1(flags);
}

函数调用图:

SysEpollCtl()

int SysEpollCtl	(	int	epfd,
		int	op,
		int	fd,
		struct epoll_event *	ev
	)

在文件 fs_syscall.c 第 2762 行定义.

{
    int ret;
 
    CHECK_ASPACE(ev, sizeof(struct epoll_event));
    CPY_FROM_USER(ev);
 
    fd = GetAssociatedSystemFd(fd);
    epfd = GetAssociatedSystemFd(epfd);
    if ((fd < 0) || (epfd < 0)) {
        ret = -EBADF;
        goto OUT;
    }
 
    ret = epoll_ctl(epfd, op, fd, ev);
    if (ret < 0) {
        ret = -EBADF;
        goto OUT;
    }
 
    CPY_TO_USER(ev);
OUT:
    return (ret == -1) ? -get_errno() : ret;
}

函数调用图:

SysEpollPwait()

int SysEpollPwait	(	int	epfd,
		struct epoll_event *	evs,
		int	maxevents,
		int	timeout,
		const sigset_t *	mask
	)

在文件 fs_syscall.c 第 2810 行定义.

{
    sigset_t_l origMask;
    sigset_t_l setl;
    int ret = 0;
 
    CHECK_ASPACE(mask, sizeof(sigset_t));
 
    if (mask != NULL) {
        ret = LOS_ArchCopyFromUser(&setl, mask, sizeof(sigset_t));
        if (ret != 0) {
            return -EFAULT;
        }
    }
 
    CHECK_ASPACE(evs, sizeof(struct epoll_event));
    CPY_FROM_USER(evs);
 
    epfd = GetAssociatedSystemFd(epfd);
    if (epfd < 0) {
        ret = -EBADF;
        goto OUT;
    }
 
    OsSigprocMask(SIG_SETMASK, &setl, &origMask);
    ret = epoll_wait(epfd, evs, maxevents, timeout);
    if (ret < 0) {
        ret = -get_errno();
    }
 
    OsSigprocMask(SIG_SETMASK, &origMask, NULL);
 
    CPY_TO_USER(evs);
OUT:
    return (ret == -1) ? -get_errno() : ret;
}

函数调用图:

SysEpollWait()

int SysEpollWait	(	int	epfd,
		struct epoll_event *	evs,
		int	maxevents,
		int	timeout
	)

在文件 fs_syscall.c 第 2787 行定义.

{
    int ret = 0;
 
    CHECK_ASPACE(evs, sizeof(struct epoll_event));
    CPY_FROM_USER(evs);
 
    epfd = GetAssociatedSystemFd(epfd);
    if  (epfd < 0) {
        ret = -EBADF;
        goto OUT;
    }
 
    ret = epoll_wait(epfd, evs, maxevents, timeout);
    if (ret < 0) {
        ret = -get_errno();
    }
 
    CPY_TO_USER(evs);
OUT:
    return (ret == -1) ? -get_errno() : ret;
}

函数调用图:

SysExecve()

int SysExecve	(	const char *	fileName,
		char *const *	argv,
		char *const *	envp
	)

动态加载程序过程

在文件 fs_syscall.c 第 548 行定义.

{
    return LOS_DoExecveFile(fileName, argv, envp);
}

函数调用图:

SysFaccessat()

int SysFaccessat	(	int	fd,
		const char *	filename,
		int	amode,
		int	flag
	)

在文件 fs_syscall.c 第 2566 行定义.

{
    int ret;
    struct stat buf;
    struct statfs fsBuf;
    char *fullDirectory = NULL;
 
    ret = GetFullpath(fd, filename, &fullDirectory);
    if (ret < 0) {
        goto OUT;
    }
 
    ret = statfs(fullDirectory, &fsBuf);
    if (ret != 0) {
        ret = -get_errno();
        goto OUT;
    }
 
    if ((fsBuf.f_flags & MS_RDONLY) && ((unsigned int)amode & W_OK)) {
        ret = -EROFS;
        goto OUT;
    }
 
    ret = stat(fullDirectory, &buf);
    if (ret != 0) {
        ret = -get_errno();
        goto OUT;
    }
 
    if (VfsPermissionCheck(buf.st_uid, buf.st_gid, buf.st_mode, amode)) {
        ret = -EACCES;
    }
 
OUT:
    PointerFree(fullDirectory);
 
    return ret;
}

函数调用图:

SysFallocate()

int SysFallocate	(	int	fd,
		int	mode,
		off_t	offset,
		off_t	len
	)

在文件 fs_syscall.c 第 2067 行定义.

{
    int ret;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = fallocate(fd, mode, offset, len);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFallocate64()

int SysFallocate64	(	int	fd,
		int	mode,
		off64_t	offset,
		off64_t	len
	)

在文件 fs_syscall.c 第 2081 行定义.

{
    int ret;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = fallocate64(fd, mode, offset, len);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFchdir()

int SysFchdir

(

int

fd

)

在文件 fs_syscall.c 第 554 行定义.

{
    int ret;
    int sysFd;
    struct file *file = NULL;
 
    sysFd = GetAssociatedSystemFd(fd);
    if (sysFd < 0) {
        return -EBADF;
    }
 
    ret = fs_getfilep(sysFd, &file);
    if (ret < 0) {
        return -get_errno();
    }
 
    ret = chdir(file->f_path);
    if (ret < 0) {
        ret = -get_errno();
    }
 
    return ret;
}

函数调用图:

SysFchmod()

int SysFchmod	(	int	fd,
		mode_t	mode
	)

在文件 fs_syscall.c 第 2400 行定义.

{
    int ret;
    int sysFd;
    struct IATTR attr = {
        .attr_chg_mode = mode,
        .attr_chg_valid = CHG_MODE, /* change mode */
    };
    struct file *file = NULL;
 
    sysFd = GetAssociatedSystemFd(fd);
    if (sysFd < 0) {
        return -EBADF;
    }
 
    ret = fs_getfilep(sysFd, &file);
    if (ret < 0) {
        return -get_errno();
    }
 
    ret = chattr(file->f_path, &attr);
    if (ret < 0) {
        return -get_errno();
    }
 
    return ret;
}

函数调用图:

SysFchmodat()

int SysFchmodat	(	int	fd,
		const char *	path,
		mode_t	mode,
		int	flag
	)

在文件 fs_syscall.c 第 2361 行定义.

{
    int ret;
    char *pathRet = NULL;
    char *fullpath = NULL;
    struct IATTR attr = {
        .attr_chg_mode = mode,
        .attr_chg_valid = CHG_MODE,
    };
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (fd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        fd = GetAssociatedSystemFd(fd);
    }
 
    ret = vfs_normalize_pathat(fd, pathRet, &fullpath);
    if (ret < 0) {
        goto OUT;
    }
 
    ret = chattr(fullpath, &attr);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    PointerFree(pathRet);
    PointerFree(fullpath);
 
    return ret;
}

函数调用图:

SysFchown()

int SysFchown	(	int	fd,
		uid_t	owner,
		gid_t	group
	)

在文件 fs_syscall.c 第 2461 行定义.

{
    int ret;
    int sysFd;
    struct IATTR attr = {0};
    attr.attr_chg_valid = 0;
    struct file *file = NULL;
 
    sysFd = GetAssociatedSystemFd(fd);
    if (sysFd < 0) {
        return -EBADF;
    }
 
    ret = fs_getfilep(sysFd, &file);
    if (ret < 0) {
        return -get_errno();
    }
 
    if (owner != (uid_t)-1) {
        attr.attr_chg_uid = owner;
        attr.attr_chg_valid |= CHG_UID;
    }
    if (group != (gid_t)-1) {
        attr.attr_chg_gid = group;
        attr.attr_chg_valid |= CHG_GID;
    }
    ret = chattr(file->f_path, &attr);
    if (ret < 0) {
        ret = -get_errno();
    }
 
    return ret;
}

函数调用图:

SysFchownat()

int SysFchownat	(	int	fd,
		const char *	path,
		uid_t	owner,
		gid_t	group,
		int	flag
	)

在文件 fs_syscall.c 第 2428 行定义.

{
    int ret;
    char *fullpath = NULL;
    struct IATTR attr = {
        .attr_chg_valid = 0,
    };
 
    ret = GetFullpath(fd, path, &fullpath);
    if (ret < 0) {
        goto OUT;
    }
 
    if (owner != (uid_t)-1) {
        attr.attr_chg_uid = owner;
        attr.attr_chg_valid |= CHG_UID;
    }
    if (group != (gid_t)-1) {
        attr.attr_chg_gid = group;
        attr.attr_chg_valid |= CHG_GID;
    }
 
    ret = chattr(fullpath, &attr);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    PointerFree(fullpath);
 
    return ret;
}

函数调用图:

SysFcntl()

int SysFcntl	(	int	fd,
		int	cmd,
		void *	arg
	)

用来修改已经打开文件的属性的函数包含5个功能：
1.复制一个已有文件描述符，功能和dup和dup2相同，对应的cmd：F_DUPFD、F_DUPFD_CLOEXEC。
    当使用这两个cmd时，需要传入第三个参数，fcntl返回复制后的文件描述符，此返回值是之前未被占用的描述符，
    并且必须一个大于等于第三个参数值。
    F_DUPFD命令要求返回的文件描述符会清除对应的FD_CLOEXEC
    F_DUPFD_CLOEXEC要求设置新描述符的FD_CLOEXEC标志。

2.获取、设置文件描述符标志，对应的cmd：F_GETFD、F_SETFD。
    用于设置FD_CLOEXEC标志，此标志的含义是：当进程执行exec系统调用后此文件描述符会被自动关闭。

3.获取、设置文件访问状态标志，对应的cmd：F_GETFL、F_SETFL。
    获取当前打开文件的访问标志，设置对应的访问标志，一般常用来设置做非阻塞读写操作。

4.获取、设置记录锁功能，对应的cmd：F_GETLK、F_SETLK、F_SETLKW。

5.获取、设置异步I/O所有权，对应的cmd：F_GETOWN、F_SETOWN。
    获取和设置用来接收SIGIO/SIGURG信号的进程id或者进程组id。返回对应的进程id或者进程组id取负值。
 * 

参数

fd
cmd
arg

返回

int

在文件 fs_syscall.c 第 957 行定义.

{
    /* Process fd convert to system global fd */
    int sysfd = GetAssociatedSystemFd(fd);
 
    int ret = VfsFcntl(fd, cmd, arg);
    if (ret == CONTINE_NUTTX_FCNTL) {
        ret = fcntl(sysfd, cmd, arg);
    }
 
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFcntl64()

int SysFcntl64	(	int	fd,
		int	cmd,
		void *	arg
	)

在文件 fs_syscall.c 第 2223 行定义.

{
    /* Process fd convert to system global fd */
    int sysfd = GetAssociatedSystemFd(fd);
 
    int ret = VfsFcntl(fd, cmd, arg);
    if (ret == CONTINE_NUTTX_FCNTL) {
        ret = fcntl64(sysfd, cmd, arg);
    }
 
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFormat()

int SysFormat	(	const char *	dev,
		int	sectors,
		int	option
	)

在文件 fs_syscall.c 第 2173 行定义.

{
    int ret;
    char *devRet = NULL;
 
    if (!IsCapPermit(CAP_FS_FORMAT)) {
        return -EPERM;
    }
 
    if (dev != NULL) {
        ret = UserPathCopy(dev, &devRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = format((dev ? devRet : NULL), sectors, option);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (devRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, devRet);
    }
    return ret;
}

函数调用图:

SysFstat()

int SysFstat	(	int	fd,
		struct kstat *	buf
	)

参见SysStat

在文件 fs_syscall.c 第 1401 行定义.

{
    int ret;
    struct stat bufRet = {0};
    struct file *filep = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = fs_getfilep(fd, &filep);
    if (ret < 0) {
        return -get_errno();
    }
 
    if (filep->f_oflags & O_DIRECTORY) {
        return -EBADF;
    }
 
    ret = stat(filep->f_path, (buf ? (&bufRet) : NULL));
    if (ret < 0) {
        return -get_errno();
    }
 
    ret = LOS_ArchCopyToUser(buf, &bufRet, sizeof(struct kstat));
    if (ret != 0) {
        return -EFAULT;
    }
 
    return ret;
}

函数调用图:

SysFstat64()

int SysFstat64	(	int	fd,
		struct kstat *	buf
	)

在文件 fs_syscall.c 第 2202 行定义.

{
    int ret;
    struct stat64 bufRet = {0};
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = fstat64(fd, (buf ? (&bufRet) : NULL));
    if (ret < 0) {
        return -get_errno();
    }
 
    ret = LOS_ArchCopyToUser(buf, &bufRet, sizeof(struct kstat));
    if (ret != 0) {
        return -EFAULT;
    }
 
    return ret;
}

函数调用图:

SysFstatat64()

int SysFstatat64	(	int	dirfd,
		const char *restrict	path,
		struct kstat *restrict	buf,
		int	flag
	)

在文件 fs_syscall.c 第 2519 行定义.

{
    int ret;
    struct stat bufRet = {0};
    char *pathRet = NULL;
    char *fullpath = NULL;
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (dirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        dirfd = GetAssociatedSystemFd(dirfd);
    }
 
    ret = vfs_normalize_pathat(dirfd, pathRet, &fullpath);
    if (ret < 0) {
        goto OUT;
    }
 
    ret = stat(fullpath, &bufRet);
    if (ret < 0) {
        ret = -get_errno();
        goto OUT;
    }
 
    ret = LOS_ArchCopyToUser(buf, &bufRet, sizeof(struct kstat));
    if (ret != 0) {
        ret = -EFAULT;
        goto OUT;
    }
 
OUT:
    if (pathRet != NULL) {
        LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
 
    if (fullpath != NULL) {
        free(fullpath);
    }
    return ret;
}

函数调用图:

SysFstatfs()

int SysFstatfs	(	int	fd,
		struct statfs *	buf
	)

在文件 fs_syscall.c 第 2605 行定义.

{
    int ret;
    struct file *filep = NULL;
    struct statfs bufRet = {0};
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = fs_getfilep(fd, &filep);
    if (ret < 0) {
        ret = -get_errno();
        return ret;
    }
 
    ret = statfs(filep->f_path, &bufRet);
    if (ret < 0) {
        ret = -get_errno();
        return ret;
    }
 
    ret = LOS_ArchCopyToUser(buf, &bufRet, sizeof(struct statfs));
    if (ret != 0) {
        ret = -EFAULT;
    }
 
    return ret;
}

函数调用图:

这是这个函数的调用关系图:

SysFstatfs64()

int SysFstatfs64	(	int	fd,
		size_t	sz,
		struct statfs *	buf
	)

在文件 fs_syscall.c 第 2634 行定义.

{
    int ret;
 
    if (sz != sizeof(struct statfs)) {
        ret = -EINVAL;
        return ret;
    }
 
    ret = SysFstatfs(fd, buf);
 
    return ret;
}

函数调用图:

SysFsync()

int SysFsync

(

int

fd

)

把文件在内存中的部分写回磁盘

在文件 fs_syscall.c 第 1437 行定义.

{
    int ret;
    struct file *filep = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    /* Get the file structure corresponding to the file descriptor. */
    ret = fs_getfilep(fd, &filep);
    if (ret < 0) {
        /* The errno value has already been set */
        return -get_errno();
    }
 
    if (filep->f_oflags & O_DIRECTORY) {
        return -EBADF;
    }
 
    /* Perform the fsync operation */
    ret = file_fsync(filep);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFtruncate()

int SysFtruncate	(	int	fd,
		off_t	length
	)

系统调用|文件系统|截断功能

在文件 fs_syscall.c 第 1258 行定义.

{
    int ret;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = ftruncate(fd, length);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysFtruncate64()

int SysFtruncate64	(	int	fd,
		off64_t	length
	)

在文件 fs_syscall.c 第 1767 行定义.

{
    int ret;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = ftruncate64(fd, length);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysGetcwd()

char * SysGetcwd	(	char *	buf,
		size_t	n
	)

在文件 fs_syscall.c 第 1706 行定义.

{
    char *ret = NULL;
    char *bufRet = NULL;
    size_t bufLen = n;
    int retVal;
 
    if (bufLen > PATH_MAX) {
        bufLen = PATH_MAX;
    }
 
    bufRet = (char *)LOS_MemAlloc(OS_SYS_MEM_ADDR, bufLen);
    if (bufRet == NULL) {
        return (char *)(intptr_t)-ENOMEM;
    }
    (void)memset_s(bufRet, bufLen, 0, bufLen);
 
    ret = getcwd((buf ? bufRet : NULL), bufLen);
    if (ret == NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
        return (char *)(intptr_t)-get_errno();
    }
 
    retVal = LOS_ArchCopyToUser(buf, bufRet, bufLen);
    if (retVal != 0) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
        return (char *)(intptr_t)-EFAULT;
    }
    ret = buf;
 
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
    return ret;
}

函数调用图:

SysGetdents64()

int SysGetdents64	(	int	fd,
		struct dirent *	de_user,
		unsigned int	count
	)

在文件 fs_syscall.c 第 2239 行定义.

{
    if (!LOS_IsUserAddressRange((VADDR_T)(UINTPTR)de_user, count)) {
        return -EFAULT;
    }
 
    struct dirent *de_knl = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    int ret = do_readdir(fd, &de_knl, count);
    if (ret < 0) {
        return ret;
    }
    if (de_knl != NULL) {
        int cpy_ret = LOS_ArchCopyToUser(de_user, de_knl, ret);
        if (cpy_ret != 0)
        {
            return -EFAULT;
        }
    }
    return ret;
}

函数调用图:

SysIoctl()

int SysIoctl	(	int	fd,
		int	req,
		void *	arg
	)

I/O总控制函数

在文件 fs_syscall.c 第 902 行定义.

{
    int ret;
    unsigned int size = _IOC_SIZE((unsigned int)req);
    unsigned int dir = _IOC_DIR((unsigned int)req);
    if ((size == 0) && (dir != _IOC_NONE)) {
        return -EINVAL;
    }
 
    if ((dir != _IOC_NONE) && (((void *)(uintptr_t)arg) == NULL)) {
        return -EINVAL;
    }
 
    if ((dir & _IOC_READ) || (dir & _IOC_WRITE)) {
        if (!LOS_IsUserAddressRange((uintptr_t)arg, size)) {
            return -EFAULT;
        }
    }
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = ioctl(fd, req, arg);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysLink()

int SysLink	(	const char *	oldpath,
		const char *	newpath
	)

在文件 fs_syscall.c 第 406 行定义.

{
    int ret;
    char *oldpathRet = NULL;
    char *newpathRet = NULL;
 
    if (oldpath != NULL) {
        ret = UserPathCopy(oldpath, &oldpathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (newpath != NULL) {
        ret = UserPathCopy(newpath, &newpathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = link(oldpathRet, newpathRet);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (oldpathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, oldpathRet);
    }
    if (newpathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, newpathRet);
    }
    return ret;
}

函数调用图:

SysLinkat()

int SysLinkat	(	int	olddirfd,
		const char *	oldpath,
		int	newdirfd,
		const char *	newpath,
		int	flags
	)

在文件 fs_syscall.c 第 1870 行定义.

{
    int ret;
    char *oldpathRet = NULL;
    char *newpathRet = NULL;
 
    if (oldpath != NULL) {
        ret = UserPathCopy(oldpath, &oldpathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (newpath != NULL) {
        ret = UserPathCopy(newpath, &newpathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (olddirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        olddirfd = GetAssociatedSystemFd(olddirfd);
    }
 
    if (newdirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        newdirfd = GetAssociatedSystemFd(newdirfd);
    }
 
    ret = linkat(olddirfd, oldpathRet, newdirfd, newpathRet, flags);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (oldpathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, oldpathRet);
    }
    if (newpathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, newpathRet);
    }
    return ret;
}

函数调用图:

SysLseek()

off_t SysLseek	(	int	fd,
		off_t	offset,
		int	whence
	)

移动文件指针

在文件 fs_syscall.c 第 602 行定义.

{
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    return _lseek(fd, offset, whence);
}

函数调用图:

SysLseek64()

off64_t SysLseek64	(	int	fd,
		int	offsetHigh,
		int	offsetLow,
		off64_t *	result,
		int	whence
	)

在文件 fs_syscall.c 第 611 行定义.

{
    off64_t ret;
    off64_t res;
    int retVal;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    ret = _lseek64(fd, offsetHigh, offsetLow, &res, whence);
    if (ret != 0) {
        return ret;
    }
 
    retVal = LOS_ArchCopyToUser(result, &res, sizeof(off64_t));
    if (retVal != 0) {
        return -EFAULT;
    }
 
    return 0;
}

函数调用图:

SysLstat()

int SysLstat	(	const char *	path,
		struct kstat *	buffer
	)

参见SysStat

在文件 fs_syscall.c 第 1370 行定义.

{
    int ret;
    char *pathRet = NULL;
    struct stat bufRet = {0};
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = stat((path ? pathRet : NULL), (buffer ? (&bufRet) : NULL));
    if (ret < 0) {
        ret = -get_errno();
        goto OUT;
    }
 
    ret = LOS_ArchCopyToUser(buffer, &bufRet, sizeof(struct kstat));
    if (ret != 0) {
        ret = -EFAULT;
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysMkdir()

int SysMkdir	(	const char *	pathname,
		mode_t	mode
	)

创建目录

在文件 fs_syscall.c 第 823 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = do_mkdir(AT_FDCWD, (pathname ? pathRet : NULL), mode);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysMkdirat()

int SysMkdirat	(	int	dirfd,
		const char *	pathname,
		mode_t	mode
	)

在文件 fs_syscall.c 第 1841 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (dirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        dirfd = GetAssociatedSystemFd(dirfd);
    }
 
    ret = do_mkdir(dirfd, (pathname ? pathRet : NULL), mode);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysMount()

int SysMount	(	const char *	source,
		const char *	target,
		const char *	filesystemtype,
		unsigned long	mountflags,
		const void *	data
	)

SysMount 挂载文件系统 挂载是指将一个存储设备挂接到一个已存在的路径上。我们要访问存储设备中的文件，必须将文件所在的分区挂载到一个已存在的路径上， 然后通过这个路径来访问存储设备。如果只有一个存储设备，则可以直接挂载到根目录 / 上,变成根文件系统

参数

data	特定文件系统的私有数据
filesystemtype	挂载的文件系统类型
mountflags	读写标志位
source	已经格式化的块设备名称
target	挂载路径，即挂载点

返回

参见

在文件 fs_syscall.c 第 666 行定义.

{
    int ret;
    char *sourceRet = NULL;
    char *targetRet = NULL;
    char *dataRet = NULL;
    char fstypeRet[FILESYSTEM_TYPE_MAX + 1] = {0};
 
    if (!IsCapPermit(CAP_FS_MOUNT)) {
        return -EPERM;
    }
 
    if (target != NULL) {
        ret = UserPathCopy(target, &targetRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (filesystemtype != NULL) {
        ret = LOS_StrncpyFromUser(fstypeRet, filesystemtype, FILESYSTEM_TYPE_MAX + 1);
        if (ret < 0) {
            goto OUT;
        } else if (ret > FILESYSTEM_TYPE_MAX) {
            ret = -ENODEV;
            goto OUT;
        }
 
        if (strcmp(fstypeRet, "ramfs") && (source != NULL)) {
            ret = UserPathCopy(source, &sourceRet);
            if (ret != 0) {
                goto OUT;
            }
        }
#ifdef LOSCFG_FS_NFS
        if (strcmp(fstypeRet, "nfs") == 0) {
            ret = NfsMount(sourceRet, targetRet, 0, 0);
            goto OUT;
        }
#endif
    }
 
    if (data != NULL) {
        ret = UserPathCopy(data, &dataRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = mount(sourceRet, targetRet, (filesystemtype ? fstypeRet : NULL), mountflags, dataRet);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (sourceRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, sourceRet);
    }
    if (targetRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, targetRet);
    }
    if (dataRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, dataRet);
    }
    return ret;
}

函数调用图:

SysOpen()

int SysOpen	(	const char *	path,
		int	oflags,
			...
	)

系统调用|打开文件, 正常情况下返回进程的FD值

在文件 fs_syscall.c 第 294 行定义.

{
    int ret;
    int procFd;
    mode_t mode = DEFAULT_FILE_MODE; /* 0666: File read-write properties. */
    char *pathRet = NULL;
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            return ret;
        }
    }
 
    procFd = AllocProcessFd();//分配进程描述符
    if (procFd < 0) {
        ret = -EMFILE;
        goto ERROUT;
    }
 
    if (oflags & O_CLOEXEC) {
        SetCloexecFlag(procFd);
    }
 
    if ((unsigned int)oflags & O_DIRECTORY) {//目录标签
        ret = do_opendir(pathRet, oflags);//打开目录
    } else {
 
#ifdef LOSCFG_FILE_MODE //文件权限开关
    va_list ap;
 
    va_start(ap, oflags);
    mode = va_arg(ap, int);//可变参数读取mode值
    va_end(ap);
#endif
//当fd参数的值是AT_FDCWD，并且path参数是一个相对路径名，fstatat会计算相对于当前目录的path参数。
//如果path是一个绝对路径，fd参数就会被忽略
        ret = do_open(AT_FDCWD, pathRet, oflags, mode);//打开文件,返回系统描述符
    }
 
    if (ret < 0) {
        ret = -get_errno();
        goto ERROUT;
    }
 
    AssociateSystemFd(procFd, ret);//进程<->系统描述符 关联/绑定
    if (pathRet != NULL) {
        LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return procFd;//返回进程描述符
 
ERROUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    if (procFd >= 0) {
        FreeProcessFd(procFd);
    }
    return ret;
}

函数调用图:

SysOpenat()

int SysOpenat	(	int	dirfd,
		const char *	path,
		int	oflags,
			...
	)

在文件 fs_syscall.c 第 1781 行定义.

{
    int ret;
    int procFd;
    char *pathRet = NULL;
    mode_t mode;
#ifdef LOSCFG_FILE_MODE
    va_list ap;
 
    va_start(ap, oflags);
    mode = va_arg(ap, int);
    va_end(ap);
#else
    mode = 0666; /* 0666: File read-write properties. */
#endif
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            return ret;
        }
    }
 
    procFd = AllocProcessFd();
    if (procFd < 0) {
        ret = -EMFILE;
        goto ERROUT;
    }
 
    if (oflags & O_CLOEXEC) {
        SetCloexecFlag(procFd);
    }
 
    if (dirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        dirfd = GetAssociatedSystemFd(dirfd);
    }
 
    ret = do_open(dirfd, (path ? pathRet : NULL), oflags, mode);
    if (ret < 0) {
        ret = -get_errno();
        goto ERROUT;
    }
 
    AssociateSystemFd(procFd, ret);
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return procFd;
 
ERROUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    if (procFd >= 0) {
        FreeProcessFd(procFd);
    }
    return ret;
}

函数调用图:

SysPipe()

int SysPipe

(

int

pipefd[2]

)

   管道是一种最基本的IPC机制，作用于有血缘关系的进程之间，完成数据传递。
   调用pipe系统函数即可创建一个管道。有如下特质：

   1. 其本质是一个伪文件(实为内核缓冲区)
   2. 由两个文件描述符引用，一个表示读端，一个表示写端。
   3. 规定数据从管道的写端流入管道，从读端流出。

   管道的原理: 管道实为内核使用环形队列机制，借助内核缓冲区(4k)实现。
   管道的局限性：
       ① 数据自己读不能自己写。
       ② 数据一旦被读走，便不在管道中存在，不可反复读取。
       ③ 由于管道采用半双工通信方式。因此，数据只能在一个方向上流动。
       ④ 只能在有公共祖先的进程间使用管道。
   常见的通信方式有，单工通信、半双工通信、全双工通信。
* 

参数

pipefd

返回

int

在文件 fs_syscall.c 第 995 行定义.

{
    int ret;
    int pipeFdIntr[2] = {0}; /* 2 : pipe fds for read and write */
 
    int procFd0 = AllocProcessFd();//读端管道,像 stdin对应标准输入
    if (procFd0 < 0) {
        return -EMFILE;
    }
    int procFd1 = AllocProcessFd();//写端管道,像 stdout对应标准输出
    if (procFd1 < 0) {
        FreeProcessFd(procFd0);
        return -EMFILE;
    }
 
    ret = pipe(pipeFdIntr);//创建管道
    if (ret < 0) {
        FreeProcessFd(procFd0);
        FreeProcessFd(procFd1);
        return -get_errno();
    }
    int sysPipeFd0 = pipeFdIntr[0];
    int sysPipeFd1 = pipeFdIntr[1];
 
    AssociateSystemFd(procFd0, sysPipeFd0);//进程FD和系统FD绑定
    AssociateSystemFd(procFd1, sysPipeFd1);
 
    pipeFdIntr[0] = procFd0;
    pipeFdIntr[1] = procFd1;
 
    ret = LOS_ArchCopyToUser(pipefd, pipeFdIntr, sizeof(pipeFdIntr));//参数都走两个进程FD
    if (ret != 0) {
        FreeProcessFd(procFd0);
        FreeProcessFd(procFd1);
        close(sysPipeFd0);
        close(sysPipeFd1);
        return -EFAULT;
    }
    return ret;
}

函数调用图:

SysPoll()

int SysPoll	(	struct pollfd *	fds,
		nfds_t	nfds,
		int	timeout
	)

SysPoll I/O多路转换

参数

fds	fds是一个struct pollfd类型的数组，用于存放需要检测其状态的socket描述符，并且调用poll函数之后fds数组不会被清空； 一个pollfd结构体表示一个被监视的文件描述符，通过传递fds指示 poll() 监视多个文件描述符。
nfds	记录数组fds中描述符的总数量。
timeout	指定等待的毫秒数，无论 I/O 是否准备好，poll() 都会返回，和select函数是类似的。

返回

函数返回fds集合中就绪的读、写，或出错的描述符数量，返回0表示超时，返回-1表示出错； poll改变了文件描述符集合的描述方式，使用了pollfd结构而不是select的fd_set结构，使得poll支持的文件描述符集合限制远大于select的1024。 这也是和select不同的地方。

参见

在文件 fs_syscall.c 第 1552 行定义.

{
    int ret;
    struct pollfd *kfds = NULL;
 
    if ((nfds >= MAX_POLL_NFDS) || (nfds == 0) || (fds == NULL)) {
        return -EINVAL;
    }
 
    kfds = (struct pollfd *)malloc(sizeof(struct pollfd) * nfds);
    if (kfds != NULL) {
        if (LOS_ArchCopyFromUser(kfds, fds, sizeof(struct pollfd) * nfds) != 0) {
            ret = -EFAULT;
            goto OUT_KFD;
        }
    }
 
    int *pollFds = NULL;
    ret = PollfdToSystem(kfds, nfds, &pollFds);
    if (ret < 0) {
        ret = -get_errno();
        goto OUT_KFD;
    }
 
    ret = poll(kfds, nfds, timeout);
    if (ret < 0) {
        ret = -get_errno();
        goto OUT;
    }
 
    if (kfds != NULL) {
        RestorePollfd(kfds, nfds, pollFds);
        if (LOS_ArchCopyToUser(fds, kfds, sizeof(struct pollfd) * nfds) != 0) {
            ret = -EFAULT;
            goto OUT;
        }
    }
 
OUT:
    free(pollFds);
OUT_KFD:
    free(kfds);
    return ret;
}

函数调用图:

这是这个函数的调用关系图:

SysPpoll()

int SysPpoll	(	struct pollfd *	fds,
		nfds_t	nfds,
		const struct timespec *	tmo_p,
		const sigset_t *	sigMask,
		int	nsig
	)

在文件 fs_syscall.c 第 2648 行定义.

{
    int timeout, retVal;
    sigset_t_l origMask = {0};
    sigset_t_l set = {0};
 
    CHECK_ASPACE(tmo_p, sizeof(struct timespec));
    CPY_FROM_USER(tmo_p);
 
    if (tmo_p != NULL) {
        timeout = tmo_p->tv_sec * OS_SYS_US_PER_MS + tmo_p->tv_nsec / OS_SYS_NS_PER_MS;
        if (timeout < 0) {
            return -EINVAL;
        }
    } else {
        timeout = -1;
    }
 
    if (sigMask != NULL) {
        retVal = LOS_ArchCopyFromUser(&set, sigMask, sizeof(sigset_t));
        if (retVal != 0) {
            return -EFAULT;
        }
        (VOID)OsSigprocMask(SIG_SETMASK, &set, &origMask);
    } else {
        (VOID)OsSigprocMask(SIG_SETMASK, NULL, &origMask);
    }
 
    retVal = SysPoll(fds, nfds, timeout);
    (VOID)OsSigprocMask(SIG_SETMASK, &origMask, NULL);
 
    return retVal;
}

函数调用图:

SysPrctl()

int SysPrctl	(	int	option,
			...
	)

对进程进行特定操作

在文件 fs_syscall.c 第 1597 行定义.

{
    unsigned long name;
    va_list ap;
    errno_t err;
 
    va_start(ap, option);
    if (option != PR_SET_NAME) {
        PRINT_ERR("%s: %d, no support option : 0x%x\n", __FUNCTION__, __LINE__, option);
        err = EOPNOTSUPP;
        goto ERROR;
    }
 
    name = va_arg(ap, unsigned long);
    if (!LOS_IsUserAddress(name)) {
        err = EFAULT;
        goto ERROR;
    }
 
    err = OsSetTaskName(OsCurrTaskGet(), (const char *)(uintptr_t)name, TRUE);
    if (err != LOS_OK) {
        goto ERROR;
    }
 
    va_end(ap);
    return ENOERR;
 
ERROR:
    va_end(ap);
    return -err;
}

函数调用图:

SysPread64()

ssize_t SysPread64	(	int	fd,
		void *	buf,
		size_t	nbytes,
		off64_t	offset
	)

对进程进行特定操作

在文件 fs_syscall.c 第 1629 行定义.

{
    int ret, retVal;
    char *bufRet = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    if (nbytes == 0) {
        ret = pread64(fd, buf, nbytes, offset);
        if (ret < 0) {
            return -get_errno();
        } else {
            return ret;
        }
    }
 
    bufRet = (char *)LOS_MemAlloc(OS_SYS_MEM_ADDR, nbytes);
    if (bufRet == NULL) {
        return -ENOMEM;
    }
 
    ret = pread64(fd, (buf ? bufRet : NULL), nbytes, offset);
    if (ret < 0) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
        return -get_errno();
    }
 
    retVal = LOS_ArchCopyToUser(buf, bufRet, ret);
    if (retVal != 0) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
        return -EFAULT;
    }
 
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
    return ret;
}

函数调用图:

SysPreadv()

ssize_t SysPreadv	(	int	fd,
		const struct iovec *	iov,
		int	iovcnt,
		long	loffset,
		long	hoffset
	)

在文件 fs_syscall.c 第 2095 行定义.

{
    off_t offsetflag;
    offsetflag = (off_t)((unsigned long long)loffset | (((unsigned long long)hoffset) << HIGH_SHIFT_BIT));
 
    int ret;
    int valid_iovcnt = -1;
    struct iovec *iovRet = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
    if ((iov == NULL) || (iovcnt < 0) || (iovcnt > IOV_MAX)) {
        return -EINVAL;
    }
 
    if (iovcnt == 0) {
        return 0;
    }
 
    ret = UserIovCopy(&iovRet, iov, iovcnt, &valid_iovcnt);
    if (ret != 0) {
        return ret;
    }
 
    if (valid_iovcnt <= 0) {
        ret = -EFAULT;
        goto OUT_FREE;
    }
 
    ret = preadv(fd, iovRet, valid_iovcnt, offsetflag);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT_FREE:
    (void)(void)LOS_MemFree(OS_SYS_MEM_ADDR, iovRet);
    return ret;
}

函数调用图:

SysPselect6()

int SysPselect6	(	int	nfds,
		fd_set *	readfds,
		fd_set *	writefds,
		fd_set *	exceptfds,
		const struct timespec *	timeout,
		const long	data[2]
	)

在文件 fs_syscall.c 第 2682 行定义.

{
    int ret;
    int retVal;
    sigset_t_l origMask;
    sigset_t_l setl;
 
    CHECK_ASPACE(readfds, sizeof(fd_set));
    CHECK_ASPACE(writefds, sizeof(fd_set));
    CHECK_ASPACE(exceptfds, sizeof(fd_set));
    CHECK_ASPACE(timeout, sizeof(struct timeval));
 
    CPY_FROM_USER(readfds);
    CPY_FROM_USER(writefds);
    CPY_FROM_USER(exceptfds);
    DUP_FROM_USER(timeout, sizeof(struct timeval));
 
    if (timeout != NULL) {
        ((struct timeval *)timeout)->tv_usec = timeout->tv_nsec / 1000; /* 1000, convert ns to us */
    }
 
    if (data != NULL) {
        retVal = LOS_ArchCopyFromUser(&(setl.sig[0]), (int *)((UINTPTR)data[0]), sizeof(sigset_t));
        if (retVal != 0) {
            ret = -EFAULT;
            FREE_DUP(timeout);
            return ret;
        }
    }
 
    OsSigprocMask(SIG_SETMASK, &setl, &origMask);
    ret = do_select(nfds, readfds, writefds, exceptfds, (struct timeval *)timeout, UserPoll);
    if (ret < 0) {
        /* do not copy parameter back to user mode if do_select failed */
        ret = -get_errno();
        FREE_DUP(timeout);
        return ret;
    }
    OsSigprocMask(SIG_SETMASK, &origMask, NULL);
 
    CPY_TO_USER(readfds);
    CPY_TO_USER(writefds);
    CPY_TO_USER(exceptfds);
    FREE_DUP(timeout);
 
    return ret;
}

函数调用图:

SysPwrite64()

ssize_t SysPwrite64	(	int	fd,
		const void *	buf,
		size_t	nbytes,
		off64_t	offset
	)

在文件 fs_syscall.c 第 1667 行定义.

{
    int ret;
    char *bufRet = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
 
    if (nbytes == 0) {
        ret = pwrite64(fd, buf, nbytes, offset);
        if (ret < 0) {
            return -get_errno();
        }
        return ret;
    }
 
    bufRet = (char *)LOS_MemAlloc(OS_SYS_MEM_ADDR, nbytes);
    if (bufRet == NULL) {
        return -ENOMEM;
    }
 
    if (buf != NULL) {
        ret = LOS_ArchCopyFromUser(bufRet, buf, nbytes);
        if (ret != 0) {
            (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
            return -EFAULT;
        }
    }
 
    ret = pwrite64(fd, (buf ? bufRet : NULL), nbytes, offset);
    if (ret < 0) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
        return -get_errno();
    }
 
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, bufRet);
    return ret;
}

函数调用图:

SysPwritev()

ssize_t SysPwritev	(	int	fd,
		const struct iovec *	iov,
		int	iovcnt,
		long	loffset,
		long	hoffset
	)

在文件 fs_syscall.c 第 2134 行定义.

{
    off_t offsetflag;
    offsetflag = (off_t)((unsigned long long)loffset | (((unsigned long long)hoffset) << HIGH_SHIFT_BIT));
    int ret;
    int valid_iovcnt = -1;
    struct iovec *iovRet = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);
    if ((iov == NULL) || (iovcnt < 0) || (iovcnt > IOV_MAX)) {
        return -EINVAL;
    }
 
    if (iovcnt == 0) {
        return 0;
    }
 
    ret = UserIovCopy(&iovRet, iov, iovcnt, &valid_iovcnt);
    if (ret != 0) {
        return ret;
    }
 
    if (valid_iovcnt != iovcnt) {
        ret = -EFAULT;
        goto OUT_FREE;
    }
 
    ret = pwritev(fd, iovRet, valid_iovcnt, offsetflag);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT_FREE:
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, iovRet);
    return ret;
}

函数调用图:

SysRead()

ssize_t SysRead	(	int	fd,
		void *	buf,
		size_t	nbytes
	)

系统调用|读文件:从文件中读取nbytes长度的内容到buf中(用户空间)

在文件 fs_syscall.c 第 252 行定义.

{
    int ret;
 
    if (nbytes == 0) {
        return 0;
    }
    //[buf,buf+nbytes]地址必须在用户空间
    if (!LOS_IsUserAddressRange((vaddr_t)(UINTPTR)buf, nbytes)) {
        return -EFAULT;
    }
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);//获得关联的系统fd,因为真正的read,write是需要sysFd的
    ret = read(fd, buf, nbytes);
    if (ret < 0) {
        return -get_errno();
    }
    return ret;
}

函数调用图:

SysReadlink()

ssize_t SysReadlink	(	const char *	pathname,
		char *	buf,
		size_t	bufsize
	)

在文件 fs_syscall.c 第 441 行定义.

{
    ssize_t ret;
    char *pathRet = NULL;
 
    if (bufsize == 0) {
        return -EINVAL;
    }
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (!LOS_IsUserAddressRange((vaddr_t)(UINTPTR)buf, bufsize)) {
        ret = -EFAULT;
        goto OUT;
    }
 
    ret = readlink(pathRet, buf, bufsize);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysReadlinkat()

ssize_t SysReadlinkat	(	int	dirfd,
		const char *	pathname,
		char *	buf,
		size_t	bufsize
	)

在文件 fs_syscall.c 第 1956 行定义.

{
    ssize_t ret;
    char *pathRet = NULL;
 
    if (bufsize == 0) {
        return -EINVAL;
    }
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (dirfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        dirfd = GetAssociatedSystemFd(dirfd);
    }
 
    if (!LOS_IsUserAddressRange((vaddr_t)(UINTPTR)buf, bufsize)) {
        ret = -EFAULT;
        goto OUT;
    }
 
    ret = readlinkat(dirfd, pathRet, buf, bufsize);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysReadv()

ssize_t SysReadv	(	int	fd,
		const struct iovec *	iov,
		int	iovcnt
	)

通过FD读入数据到缓冲数组中,fd为进程描述符

在文件 fs_syscall.c 第 1464 行定义.

{
    int ret;
    int valid_iovcnt = -1;
    struct iovec *iovRet = NULL;
 
    /* Process fd convert to system global fd */
    fd = GetAssociatedSystemFd(fd);//进程FD转成系统FD
    if ((iov == NULL) || (iovcnt < 0) || (iovcnt > IOV_MAX)) {
        return -EINVAL;
    }
 
    if (iovcnt == 0) {
        return 0;
    }
 
    ret = UserIovCopy(&iovRet, iov, iovcnt, &valid_iovcnt);
    if (ret != 0) {
        return ret;
    }
 
    if (valid_iovcnt <= 0) {
        ret = -EFAULT;
        goto OUT;
    }
 
    ret = vfs_readv(fd, iovRet, valid_iovcnt, NULL);
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, iovRet);
    return ret;
}

函数调用图:

SysRealpath()

char * SysRealpath	(	const char *	path,
		char *	resolved_path
	)

在文件 fs_syscall.c 第 2264 行定义.

{
    char *pathRet = NULL;
    char *resolved_pathRet = NULL;
    char *result = NULL;
    int ret;
 
    if (resolved_path == NULL) {
        return (char *)(intptr_t)-EINVAL;
    }
 
    if (path != NULL) {
        ret = UserPathCopy(path, &pathRet);
        if (ret != 0) {
            result = (char *)(intptr_t)ret;
            goto OUT;
        }
    }
 
    resolved_pathRet = realpath((path ? pathRet : NULL), NULL);
    if (resolved_pathRet == NULL) {
        result = (char *)(intptr_t)-get_errno();
        goto OUT;
    }
 
    ret = LOS_ArchCopyToUser(resolved_path, resolved_pathRet, strlen(resolved_pathRet) + 1);
    if (ret != 0) {
        result = (char *)(intptr_t)-EFAULT;
        goto OUT;
    }
    result = resolved_path;
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    if (resolved_pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, resolved_pathRet);
    }
    return result;
}

函数调用图:

SysRename()

int SysRename	(	const char *	oldpath,
		const char *	newpath
	)

重命名文件

在文件 fs_syscall.c 第 787 行定义.

{
    int ret;
    char *pathOldRet = NULL;
    char *pathNewRet = NULL;
 
    if (oldpath != NULL) {
        ret = UserPathCopy(oldpath, &pathOldRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (newpath != NULL) {
        ret = UserPathCopy(newpath, &pathNewRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = do_rename(AT_FDCWD, (oldpath ? pathOldRet : NULL), AT_FDCWD,
                    (newpath ? pathNewRet : NULL));
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathOldRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathOldRet);
    }
    if (pathNewRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathNewRet);
    }
    return ret;
}

函数调用图:

SysRenameat()

int SysRenameat	(	int	oldfd,
		const char *	oldpath,
		int	newdfd,
		const char *	newpath
	)

在文件 fs_syscall.c 第 2023 行定义.

{
    int ret;
    char *pathOldRet = NULL;
    char *pathNewRet = NULL;
 
    if (oldpath != NULL) {
        ret = UserPathCopy(oldpath, &pathOldRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (newpath != NULL) {
        ret = UserPathCopy(newpath, &pathNewRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    if (oldfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        oldfd = GetAssociatedSystemFd(oldfd);
    }
    if (newdfd != AT_FDCWD) {
        /* Process fd convert to system global fd */
        newdfd = GetAssociatedSystemFd(newdfd);
    }
 
    ret = do_rename(oldfd, (oldpath ? pathOldRet : NULL), newdfd, (newpath ? pathNewRet : NULL));
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathOldRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathOldRet);
    }
    if (pathNewRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathNewRet);
    }
    return ret;
}

函数调用图:

SysRmdir()

int SysRmdir

(

const char *

pathname

)

删除目录

在文件 fs_syscall.c 第 847 行定义.

{
    int ret;
    char *pathRet = NULL;
 
    if (pathname != NULL) {
        ret = UserPathCopy(pathname, &pathRet);
        if (ret != 0) {
            goto OUT;
        }
    }
 
    ret = do_rmdir(AT_FDCWD, (pathname ? pathRet : NULL));
    if (ret < 0) {
        ret = -get_errno();
    }
 
OUT:
    if (pathRet != NULL) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, pathRet);
    }
    return ret;
}

函数调用图:

SysSelect()

int SysSelect	(	int	nfds,
		fd_set *	readfds,
		fd_set *	writefds,
		fd_set *	exceptfds,
		struct timeval *	timeout
	)

SysSelect 系统调用|文件系统|select .鸿蒙liteos目前也支持epoll方式

参数

exceptfds	文件集将监视文件集中的任何文件是否发生错误，可用于其他的用途， 例如，监视带外数据OOB，带外数据使用MSG_OOB标志发送到套接字上。当select函数返回的时候， exceptfds将清除其中的其他文件描述符，只留下标记有OOB数据的文件描述符。
nfds	select监视的文件句柄数，一般设为要监视各文件中的最大文件描述符值加1。
readfds	文件描述符集合监视文件集中的任何文件是否有数据可读，当select函数返回的时候， readfds将清除其中不可读的文件描述符，只留下可读的文件描述符。
timeout	参数是一个指向 struct timeval 类型的指针，它可以使 select()在等待 timeout 时间后 若没有文件描述符准备好则返回。其timeval结构用于指定这段时间的秒数和微秒数。它可以使select处于三种状态： (1) 若将NULL以形参传入，即不传入时间结构，就是将select置于阻塞状态，一定等到监视文件描述符集合中某个文件描述符发生变化为止； (2) 若将时间值设为0秒0毫秒，就变成一个纯粹的非阻塞函数，不管文件描述符是否有变化，都立刻返回继续执行，文件无变化返回0，有变化返回一个正值； (3) timeout的值大于0，这就是等待的超时时间，即select在timeout时间内阻塞，超时时间之内有事件到来就返回了，否则在超时后不管怎样一定返回，返回值同上述。
writefds	文件描述符集合监视文件集中的任何文件是否有数据可写，当select函数返回的时候， writefds将清除其中不可写的文件描述符，只留下可写的文件描述符。

返回

参见

在文件 fs_syscall.c 第 1135 行定义.

{
    int ret;
    fd_set *fdsRet = NULL;
    fd_set *readfdsRet = NULL;
    fd_set *writefdsRet = NULL;
    fd_set *exceptfdsRet = NULL;
    struct timeval timeoutRet = {0};
 
    ret = SelectParamCheckCopy(readfds, writefds, exceptfds, &fdsRet);//检查参数
    if (ret != 0) {
        return ret;
    }
 
    readfdsRet = fdsRet;        /* LOS_MemAlloc 3 sizeof(fd_set) space,first use for readfds */
    writefdsRet = fdsRet + 1;   /* 1: LOS_MemAlloc 3 sizeof(fd_set) space,second use for writefds */
    exceptfdsRet = fdsRet + 2;  /* 2: LOS_MemAlloc 3 sizeof(fd_set) space,thired use for exceptfds */
 
    if (timeout != NULL) {
        if (LOS_ArchCopyFromUser(&timeoutRet, timeout, sizeof(struct timeval)) != 0) {
            goto ERROUT;
        }
    }
    //poll()是在NuttX下执行此类监视操作的基本API
    ret = do_select(nfds, (readfds ? readfdsRet : NULL), (writefds ? writefdsRet : NULL),
                 (exceptfds ? exceptfdsRet : NULL), (timeout ? (&timeoutRet) : NULL), UserPoll);
    if (ret < 0) {
        (void)LOS_MemFree(OS_SYS_MEM_ADDR, fdsRet);
        return -get_errno();
    }
 
    if (readfds != NULL) {
        if (LOS_ArchCopyToUser(readfds, readfdsRet, sizeof(fd_set)) != 0) {
            goto ERROUT;
        }
    }
 
    if (writefds != NULL) {
        if (LOS_ArchCopyToUser(writefds, writefdsRet, sizeof(fd_set)) != 0) {
            goto ERROUT;
        }
    }
 
    if (exceptfds != 0) {
        if (LOS_ArchCopyToUser(exceptfds, exceptfdsRet, sizeof(fd_set)) != 0) {
            goto ERROUT;
        }
    }
 
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, fdsRet);
    return ret;
 
ERROUT:
    (void)LOS_MemFree(OS_SYS_MEM_ADDR, fdsRet);
    return -EFAULT;
}

函数调用图: