libcmd/common/tee.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1992-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * David Korn
 * AT&T Bell Laboratories
 *
 * tee
 */

static const char usage[] =
"[-?\n@(#)$Id: tee (AT&T Research) 2009-06-19 $\n]"
USAGE_LICENSE
"[+NAME?tee - duplicate standard input]"
"[+DESCRIPTION?\btee\b copies standard input to standard output "
    "and to zero or more files.  The options determine whether "
    "the specified files are overwritten or appended to.  The "
    "\btee\b utility does not buffer output.  If writes to any "
    "\afile\a fail, writes to other files continue although \btee\b "
    "will exit with a non-zero exit status.]"
"[+?The number of \afile\a operands that can be specified is limited "
    "by the underlying operating system.]"
"[a:append?Append the standard input to the given files rather "
    "than overwriting them.]"
"[i:ignore-interrupts?Ignore SIGINT signal.]"
"[l:linebuffer?Set the standard output to be line buffered.]"
"\n"
"\n[file ...]\n"
"\n"
"[+EXIT STATUS?]{"
        "[+0?All files copies successfully.]"
        "[+>0?An error occurred.]"
"}"
"[+SEE ALSO?\bcat\b(1), \bsignal\b(3)]"
;

#include <cmd.h>
#include <ls.h>
#include <sig.h>

typedef struct Tee_s
{
    Sfdisc_t    disc;
    int     line;
    int     fd[1];
} Tee_t;

/*
 * This discipline writes to each file in the list given in handle
 */

static ssize_t
tee_write(Sfio_t* fp, const void* buf, size_t n, Sfdisc_t* handle)
{
    register const char*    bp;
    register const char*    ep;
    register int*       hp = ((Tee_t*)handle)->fd;
    register int        fd = sffileno(fp);
    register ssize_t    r;

    do
    {
        bp = (const char*)buf;
        ep = bp + n;
        while (bp < ep)
        {
            if ((r = write(fd, bp, ep - bp)) <= 0)
                return -1;
            bp += r;
        }
    } while ((fd = *hp++) >= 0);
    return n;
}

static void
tee_cleanup(register Tee_t* tp)
{
    register int*   hp;
    register int    n;

    if (tp)
    {
        sfdisc(sfstdout, NiL);
        if (tp->line >= 0)
            sfset(sfstdout, SF_LINE, tp->line);
        for (hp = tp->fd; (n = *hp) >= 0; hp++)
            close(n);
    }
}

int
b_tee(int argc, register char** argv, void* context)
{
    register Tee_t*     tp = 0;
    register int        oflag = O_WRONLY|O_TRUNC|O_CREAT|O_BINARY;
    register int*       hp;
    register char*      cp;
    int         line;

    if (argc <= 0)
    {
        if (context && (tp = (Tee_t*)sh_context(context)->data))
        {
            sh_context(context)->data = 0;
            tee_cleanup(tp);
        }
        return 0;
    }
    cmdinit(argc, argv, context, ERROR_CATALOG, ERROR_CALLBACK);
    line = -1;
    for (;;)
    {
        switch (optget(argv, usage))
        {
        case 'a':
            oflag &= ~O_TRUNC;
            oflag |= O_APPEND;
            continue;
        case 'i':
            signal(SIGINT, SIG_IGN);
            continue;
        case 'l':
            line = sfset(sfstdout, 0, 0) & SF_LINE;
            if ((line == 0) == (opt_info.num == 0))
                line = -1;
            else
                sfset(sfstdout, SF_LINE, !!opt_info.num);
            continue;
        case ':':
            error(2, "%s", opt_info.arg);
            break;
        case '?':
            error(ERROR_usage(2), "%s", opt_info.arg);
            break;
        }
        break;
    }
    if (error_info.errors)
        error(ERROR_usage(2), "%s", optusage(NiL));
    argv += opt_info.index;
    argc -= opt_info.index;
#if _ANCIENT_BSD_COMPATIBILITY
    if (*argv && streq(*argv, "-"))
    {
        signal(SIGINT, SIG_IGN);
        argv++;
        argc--;
    }
#endif
    if (argc > 0)
    {
        if (tp = (Tee_t*)stakalloc(sizeof(Tee_t) + argc * sizeof(int)))
        {
            memset(&tp->disc, 0, sizeof(tp->disc));
            tp->disc.writef = tee_write;
            if (context)
                sh_context(context)->data = (void*)tp;
            tp->line = line;
            hp = tp->fd;
            while (cp = *argv++)
            {
                if ((*hp = open(cp, oflag, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)) < 0)
                    error(ERROR_system(0), "%s: cannot create", cp);
                else
                    hp++;
            }
            if (hp == tp->fd)
                tp = 0;
            else
            {
                *hp = -1;
                sfdisc(sfstdout, &tp->disc);
            }
        }
        else
            error(ERROR_exit(0), "out of space");
    }
    if ((sfmove(sfstdin, sfstdout, SF_UNBOUND, -1) < 0 || !sfeof(sfstdin)) && errno != EPIPE)
        error(ERROR_system(0), "read error");
    if (sfsync(sfstdout))
        error(ERROR_system(0), "write error");
    tee_cleanup(tp);
    return error_info.errors;
}