sendmail/libsm/findfp.c

/*
 * Copyright (c) 2000-2002, 2006 Proofpoint, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: findfp.c,v 1.68 2013-11-22 20:51:42 ca Exp $")
#include <stdlib.h>
#include <unistd.h>
#include <sys/param.h>
#include <errno.h>
#include <string.h>
#include <syslog.h>
#include <sm/io.h>
#include <sm/assert.h>
#include <sm/heap.h>
#include <sm/string.h>
#include <sm/conf.h>
#include "local.h"
#include "glue.h"

bool    Sm_IO_DidInit;  /* IO system has been initialized? */

const char SmFileMagic[] = "sm_file";

/* An open type to map to fopen()-like behavior */
SM_FILE_T SmFtStdio_def =
    {SmFileMagic, 0, 0, 0, (SMRW|SMFBF), -1, {0, 0}, 0, 0, 0,
    sm_stdclose, sm_stdread, sm_stdseek, sm_stdwrite,
    sm_stdopen, sm_stdsetinfo, sm_stdgetinfo, SM_TIME_FOREVER,
    SM_TIME_BLOCK, "stdio" };

/* An open type to map to fdopen()-like behavior */
SM_FILE_T SmFtStdiofd_def =
    {SmFileMagic, 0, 0, 0, (SMRW|SMFBF), -1, {0, 0}, 0, 0, 0,
    sm_stdclose, sm_stdread, sm_stdseek, sm_stdwrite,
    sm_stdfdopen, sm_stdsetinfo, sm_stdgetinfo, SM_TIME_FOREVER,
    SM_TIME_BLOCK, "stdiofd" };

/* A string file type */
SM_FILE_T SmFtString_def =
    {SmFileMagic, 0, 0, 0, (SMRW|SMNBF), -1, {0, 0}, 0, 0, 0,
    sm_strclose, sm_strread, sm_strseek, sm_strwrite,
    sm_stropen, sm_strsetinfo, sm_strgetinfo, SM_TIME_FOREVER,
    SM_TIME_BLOCK, "string" };

#if 0
/* A file type for syslog communications */
SM_FILE_T SmFtSyslog_def =
    {SmFileMagic, 0, 0, 0, (SMRW|SMNBF), -1, {0, 0}, 0, 0, 0,
    sm_syslogclose, sm_syslogread, sm_syslogseek, sm_syslogwrite,
    sm_syslogopen, sm_syslogsetinfo, sm_sysloggetinfo, SM_TIME_FOREVER,
    SM_TIME_BLOCK, "syslog" };
#endif /* 0 */

#define NDYNAMIC 10     /* add ten more whenever necessary */

#define smio(flags, file, name)                     \
    {SmFileMagic, 0, 0, 0, flags, file, {0}, 0, SmIoF+file, 0,      \
    sm_stdclose, sm_stdread, sm_stdseek, sm_stdwrite,       \
    sm_stdopen, sm_stdsetinfo, sm_stdgetinfo, SM_TIME_FOREVER,  \
    SM_TIME_BLOCK, name}

/* sm_magic p r w flags file bf lbfsize cookie ival */
#define smstd(flags, file, name)                    \
    {SmFileMagic, 0, 0, 0, flags, -1, {0}, 0, 0, file,          \
    sm_stdioclose, sm_stdioread, sm_stdioseek, sm_stdiowrite,   \
    sm_stdioopen, sm_stdiosetinfo, sm_stdiogetinfo, SM_TIME_FOREVER,\
    SM_TIME_BLOCK, name}

/* A file type for interfacing to stdio FILE* streams. */
SM_FILE_T SmFtRealStdio_def = smstd(SMRW|SMNBF, -1, "realstdio");

                /* the usual - (stdin + stdout + stderr) */
static SM_FILE_T usual[SM_IO_OPEN_MAX - 3];
static struct sm_glue smuglue = { 0, SM_IO_OPEN_MAX - 3, usual };

/* List of builtin automagically already open file pointers */
SM_FILE_T SmIoF[6] =
{
    smio(SMRD|SMLBF, SMIOIN_FILENO, "smioin"),  /* smioin */
    smio(SMWR|SMLBF, SMIOOUT_FILENO, "smioout"),    /* smioout */
    smio(SMWR|SMNBF, SMIOERR_FILENO, "smioerr"),    /* smioerr */
    smstd(SMRD|SMNBF, SMIOIN_FILENO, "smiostdin"),  /* smiostdin */
    smstd(SMWR|SMNBF, SMIOOUT_FILENO, "smiostdout"),/* smiostdout */
    smstd(SMWR|SMNBF, SMIOERR_FILENO, "smiostderr") /* smiostderr */
};

/* Structure containing list of currently open file pointers */
struct sm_glue smglue = { &smuglue, 3, SmIoF };

/*
**  SM_MOREGLUE -- adds more space for open file pointers
**
**  Parameters:
**      n -- number of new spaces for file pointers
**
**  Returns:
**      Raises an exception if no more memory.
**      Otherwise, returns a pointer to new spaces.
*/

static struct sm_glue *sm_moreglue_x __P((int));
static SM_FILE_T empty;

static struct sm_glue *
sm_moreglue_x(n)
    register int n;
{
    register struct sm_glue *g;
    register SM_FILE_T *p;

    g = (struct sm_glue *) sm_pmalloc_x(sizeof(*g) + SM_ALIGN_BITS +
                        n * sizeof(SM_FILE_T));
    p = (SM_FILE_T *) SM_ALIGN(g + 1);
    g->gl_next = NULL;
    g->gl_niobs = n;
    g->gl_iobs = p;
    while (--n >= 0)
        *p++ = empty;
    return g;
}

/*
**  SM_FP -- allocate and initialize an SM_FILE structure
**
**  Parameters:
**      t -- file type requested to be opened.
**      flags -- control flags for file type behavior
**      oldfp -- file pointer to reuse if available (optional)
**
**  Returns:
**      Raises exception on memory exhaustion.
**      Aborts if type is invalid.
**      Otherwise, returns file pointer for requested file type.
*/

SM_FILE_T *
sm_fp(t, flags, oldfp)
    const SM_FILE_T *t;
    const int flags;
    SM_FILE_T *oldfp;
{
    register SM_FILE_T *fp;
    register int n;
    register struct sm_glue *g;

    SM_REQUIRE(t->f_open && t->f_close && (t->f_read || t->f_write));

    if (!Sm_IO_DidInit)
        sm_init();

    if (oldfp != NULL)
    {
        fp = oldfp;
        goto found; /* for opening reusing an 'fp' */
    }

    for (g = &smglue;; g = g->gl_next)
    {
        for (fp = g->gl_iobs, n = g->gl_niobs; --n >= 0; fp++)
            if (fp->sm_magic == NULL)
                goto found;
        if (g->gl_next == NULL)
            g->gl_next = sm_moreglue_x(NDYNAMIC);
    }
found:
    fp->sm_magic = SmFileMagic; /* 'fp' now valid and in-use */
    fp->f_p = NULL;     /* no current pointer */
    fp->f_w = 0;        /* nothing to write */
    fp->f_r = 0;        /* nothing to read */
    fp->f_flags = flags;
    fp->f_file = -1;        /* no file */
    fp->f_bf.smb_base = NULL;   /* no buffer */
    fp->f_bf.smb_size = 0;  /* no buffer size with no buffer */
    fp->f_lbfsize = 0;  /* not line buffered */
    fp->f_flushfp = NULL;   /* no associated flush file */

    fp->f_cookie = fp;  /* default: *open* overrides cookie setting */
    fp->f_close = t->f_close;   /* assign close function */
    fp->f_read = t->f_read;     /* assign read function */
    fp->f_seek = t->f_seek;     /* assign seek function */
    fp->f_write = t->f_write;   /* assign write function */
    fp->f_open = t->f_open;     /* assign open function */
    fp->f_setinfo = t->f_setinfo;   /* assign setinfo function */
    fp->f_getinfo = t->f_getinfo;   /* assign getinfo function */
    fp->f_type = t->f_type;     /* file type */

    fp->f_ub.smb_base = NULL;   /* no ungetc buffer */
    fp->f_ub.smb_size = 0;      /* no size for no ungetc buffer */

    if (fp->f_timeout == SM_TIME_DEFAULT)
        fp->f_timeout = SM_TIME_FOREVER;
    else
        fp->f_timeout = t->f_timeout; /* traditional behavior */
    fp->f_timeoutstate = SM_TIME_BLOCK; /* by default */

    return fp;
}

/*
**  SM_CLEANUP -- cleanup function when exit called.
**
**  This function is registered via atexit().
**
**  Parameters:
**      none
**
**  Returns:
**      nothing.
**
**  Side Effects:
**      flushes open files before they are forced closed
*/

void
sm_cleanup()
{
    int timeout = SM_TIME_DEFAULT;

    (void) sm_fwalk(sm_flush, &timeout); /* `cheating' */
}

/*
**  SM_INIT -- called whenever sm_io's internal variables must be set up.
**
**  Parameters:
**      none
**
**  Returns:
**      none
**
**  Side Effects:
**      Registers sm_cleanup() using atexit().
*/

void
sm_init()
{
    if (Sm_IO_DidInit)  /* paranoia */
        return;

    /* more paranoia: initialize pointers in a static variable */
    empty.f_type = NULL;
    empty.sm_magic = NULL;

    /* make sure we clean up on exit */
    atexit(sm_cleanup);     /* conservative */
    Sm_IO_DidInit = true;
}

/*
**  SM_IO_SETINFO -- change info for an open file type (fp)
**
**  The generic SM_IO_WHAT_VECTORS is auto supplied for all file types.
**  If the request is to set info other than SM_IO_WHAT_VECTORS then
**  the request is passed on to the file type's specific setinfo vector.
**  WARNING: this is working on an active/open file type.
**
**  Parameters:
**      fp -- file to make the setting on
**      what -- type of information to set
**      valp -- structure to obtain info from
**
**  Returns:
**      0 on success
**      -1 on error and sets errno:
**          - when what != SM_IO_WHAT_VECTORS and setinfo vector
**              not set
**          - when vectored setinfo returns -1
*/

int
sm_io_setinfo(fp, what, valp)
    SM_FILE_T *fp;
    int what;
    void *valp;
{
    SM_FILE_T *v = (SM_FILE_T *) valp;

    SM_REQUIRE_ISA(fp, SmFileMagic);
    switch (what)
    {
      case SM_IO_WHAT_VECTORS:

        /*
        **  This is the "generic" available for all.
        **  This allows the function vectors to be replaced
        **  while the file type is active.
        */

        fp->f_close = v->f_close;
        fp->f_read = v->f_read;
        fp->f_seek = v->f_seek;
        fp->f_write = v->f_write;
        fp->f_open = v->f_open;
        fp->f_setinfo = v->f_setinfo;
        fp->f_getinfo = v->f_getinfo;
        sm_free(fp->f_type);
        fp->f_type = sm_strdup_x(v->f_type);
        return 0;
      case SM_IO_WHAT_TIMEOUT:
        fp->f_timeout = *((int *)valp);
        return 0;
    }

    /* Otherwise the vector will check it out */
    if (fp->f_setinfo == NULL)
    {
        errno = EINVAL;
        return -1;
    }
    else
        return (*fp->f_setinfo)(fp, what, valp);
}

/*
**  SM_IO_GETINFO -- get information for an active file type (fp)
**
**  This function supplies for all file types the answers for the
**      three requests SM_IO_WHAT_VECTORS, SM_IO_WHAT_TYPE and
**      SM_IO_WHAT_ISTYPE. Other requests are handled by the getinfo
**      vector if available for the open file type.
**  SM_IO_WHAT_VECTORS returns information for the file pointer vectors.
**  SM_IO_WHAT_TYPE returns the type identifier for the file pointer
**  SM_IO_WHAT_ISTYPE returns >0 if the passed in type matches the
**      file pointer's type.
**  SM_IO_IS_READABLE returns 1 if there is data available for reading,
**      0 otherwise.
**
**  Parameters:
**      fp -- file pointer for active file type
**      what -- type of information request
**      valp -- structure to place obtained info into
**
**  Returns:
**      -1 on error and sets errno:
**          - when valp==NULL and request expects otherwise
**          - when request is not SM_IO_WHAT_VECTORS and not
**              SM_IO_WHAT_TYPE and not SM_IO_WHAT_ISTYPE
**              and getinfo vector is NULL
**          - when getinfo type vector returns -1
**      >=0 on success
*/

int
sm_io_getinfo(fp, what, valp)
    SM_FILE_T *fp;
    int what;
    void *valp;
{
    SM_FILE_T *v = (SM_FILE_T *) valp;

    SM_REQUIRE_ISA(fp, SmFileMagic);

    switch (what)
    {
      case SM_IO_WHAT_VECTORS:
        if (valp == NULL)
        {
            errno = EINVAL;
            return -1;
        }

        /* This is the "generic" available for all */
        v->f_close = fp->f_close;
        v->f_read = fp->f_read;
        v->f_seek = fp->f_seek;
        v->f_write = fp->f_write;
        v->f_open = fp->f_open;
        v->f_setinfo = fp->f_setinfo;
        v->f_getinfo = fp->f_getinfo;
        v->f_type = fp->f_type;
        return 0;

      case SM_IO_WHAT_TYPE:
        if (valp == NULL)
        {
            errno = EINVAL;
            return -1;
        }
        valp = sm_strdup_x(fp->f_type);
        return 0;

      case SM_IO_WHAT_ISTYPE:
        if (valp == NULL)
        {
            errno = EINVAL;
            return -1;
        }
        return strcmp(fp->f_type, valp) == 0;

      case SM_IO_IS_READABLE:

        /* if there is data in the buffer, it must be readable */
        if (fp->f_r > 0)
            return 1;

        /* otherwise query the underlying file */
        break;

       case SM_IO_WHAT_TIMEOUT:
        *((int *) valp) = fp->f_timeout;
        return 0;

      case SM_IO_WHAT_FD:
        if (fp->f_file > -1)
            return fp->f_file;

        /* try the file type specific getinfo to see if it knows */
        break;
    }

    /* Otherwise the vector will check it out */
    if (fp->f_getinfo == NULL)
    {
        errno = EINVAL;
        return -1;
    }
    return (*fp->f_getinfo)(fp, what, valp);
}