take.c

来自「unix环境高级编程的源代码」· C语言 代码 · 共 86 行

#include    "call.h"

#define    CTRLA    001        /* eof designator for take */

static int         rem_read(int);
static char         rem_buf[MAXLINE];
static char        *rem_ptr;
static int         rem_cnt = 0;

/* Copy a file from remote to local. */

void
take(int remfd)
{
    int        n, linecnt;
    char    c, cmd[MAXLINE];
    FILE    *fpout;

    if (prompt_read("~[take] ", take_put_args) < 0) {
        printf("usage: [take] <sourcefile> <destfile>\n\r");
        return;
    }

            /* open local output file */
    if ( (fpout = fopen(dst, "w")) == NULL) {
        err_ret("can't open %s for writing", dst);
        putc('\r', stderr);
        fflush(stderr);
        return;
    }

            /* send cat/echo command to remote host */
    sprintf(cmd, "cat %s; echo %c\r", src, CTRLA);
    n = strlen(cmd);
    if (write(remfd, cmd, n) != n)
        err_sys("write error");

            /* read echo of cat/echo command line from remote host */
    rem_cnt = 0;        /* initialize rem_read() */
    for ( ; ; ) {
        if ( (c = rem_read(remfd)) == 0)
            return;        /* line has dropped */
        if (c == '\n')
            break;        /* end of echo line */
    }

            /* read file from remote host */
    linecnt = 0;
    for ( ; ; ) {
        if ( (c = rem_read(remfd)) == 0)
            break;            /* line has dropped */
        if (c == CTRLA)
            break;            /* all done */
        if (c == '\r')
            continue;        /* ignore returns */
        if (c == '\n')        /* but newlines are written to file */
            printf("\r%d", ++linecnt);
        if (putc(c, fpout) == EOF)
            break;            /* output error */
    }
    if (ferror(fpout) || fclose(fpout) == EOF) {
        err_msg("output error to local file");
        putc('\r', stderr);
        fflush(stderr);
    }
    c = '\n';
    write(remfd, &c, 1);
}

/* Read from remote.  Read up to MAXLINE, but parcel out one
 * character at a time. */

int
rem_read(int remfd)
{
    if (rem_cnt <= 0) {
        if ( (rem_cnt = read(remfd, rem_buf, MAXLINE)) < 0)
            err_sys("read error");
        else if (rem_cnt == 0)
            return(0);
        rem_ptr = rem_buf;
    }
    rem_cnt--;
    return(*rem_ptr++ & 0177);
}