FreeBSD/Linux Kernel Cross Reference
sys/compat/cloudabi32/cloudabi32_module.c

     /*-
      * Copyright (c) 2015 Nuxi, https://nuxi.nl/
      *
      * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/11.1/sys/compat/cloudabi32/cloudabi32_module.c 304564 2016-08-21 16:01:30Z ed $");
    
    #include <sys/param.h>
    #include <sys/imgact.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/proc.h>
    #include <sys/smp.h>
    #include <sys/sysctl.h>
    #include <sys/sysent.h>
    #include <sys/systm.h>
    
    #include <contrib/cloudabi/cloudabi32_types.h>
    
    #include <compat/cloudabi/cloudabi_util.h>
    
    #include <compat/cloudabi32/cloudabi32_util.h>
    
    extern char _binary_cloudabi32_vdso_o_start[];
    extern char _binary_cloudabi32_vdso_o_end[];
    
    register_t *
    cloudabi32_copyout_strings(struct image_params *imgp)
    {
            struct image_args *args;
            uintptr_t begin;
            size_t len;
    
            /* Copy out program arguments. */
            args = imgp->args;
            len = args->begin_envv - args->begin_argv;
            begin = rounddown2(imgp->sysent->sv_usrstack - len, sizeof(register_t));
            copyout(args->begin_argv, (void *)begin, len);
            return ((register_t *)begin);
    }
    
    int
    cloudabi32_fixup(register_t **stack_base, struct image_params *imgp)
    {
            char canarybuf[64];
            Elf32_Auxargs *args;
            struct thread *td;
            void *argdata, *canary;
            size_t argdatalen;
            int error;
    
            /*
             * CloudABI executables do not store the FreeBSD OS release
             * number in their header. Set the OS release number to the
             * latest version of FreeBSD, so that system calls behave as if
             * called natively.
             */
            td = curthread;
            td->td_proc->p_osrel = __FreeBSD_version;
    
            /* Store canary for stack smashing protection. */
            argdata = *stack_base;
            arc4rand(canarybuf, sizeof(canarybuf), 0);
            *stack_base -= howmany(sizeof(canarybuf), sizeof(register_t));
            canary = *stack_base;
            error = copyout(canarybuf, canary, sizeof(canarybuf));
            if (error != 0)
                    return (error);
    
            /*
             * Compute length of program arguments. As the argument data is
             * binary safe, we had to add a trailing null byte in
             * exec_copyin_data_fds(). Undo this by reducing the length.
             */
            args = (Elf32_Auxargs *)imgp->auxargs;
            argdatalen = imgp->args->begin_envv - imgp->args->begin_argv;
            if (argdatalen > 0)
                    --argdatalen;
   
           /* Write out an auxiliary vector. */
           cloudabi32_auxv_t auxv[] = {
   #define VAL(type, val)  { .a_type = (type), .a_val = (val) }
   #define PTR(type, ptr)  { .a_type = (type), .a_ptr = (uintptr_t)(ptr) }
                   PTR(CLOUDABI_AT_ARGDATA, argdata),
                   VAL(CLOUDABI_AT_ARGDATALEN, argdatalen),
                   VAL(CLOUDABI_AT_BASE, args->base),
                   PTR(CLOUDABI_AT_CANARY, canary),
                   VAL(CLOUDABI_AT_CANARYLEN, sizeof(canarybuf)),
                   VAL(CLOUDABI_AT_NCPUS, mp_ncpus),
                   VAL(CLOUDABI_AT_PAGESZ, args->pagesz),
                   PTR(CLOUDABI_AT_PHDR, args->phdr),
                   VAL(CLOUDABI_AT_PHNUM, args->phnum),
                   VAL(CLOUDABI_AT_TID, td->td_tid),
                   PTR(CLOUDABI_AT_SYSINFO_EHDR,
                       imgp->proc->p_sysent->sv_shared_page_base),
   #undef VAL
   #undef PTR
                   { .a_type = CLOUDABI_AT_NULL },
           };
           *stack_base -= howmany(sizeof(auxv), sizeof(register_t));
           error = copyout(auxv, *stack_base, sizeof(auxv));
           if (error != 0)
                   return (error);
   
           /* Reserve space for storing the TCB. */
           *stack_base -= howmany(sizeof(cloudabi32_tcb_t), sizeof(register_t));
           return (0);
   }
   
   static int
   cloudabi32_modevent(module_t mod, int type, void *data)
   {
   
           switch (type) {
           case MOD_LOAD:
                   cloudabi_vdso_init(cloudabi32_brand.sysvec,
                       _binary_cloudabi32_vdso_o_start,
                       _binary_cloudabi32_vdso_o_end);
                   if (elf32_insert_brand_entry(&cloudabi32_brand) < 0) {
                           printf("Failed to add CloudABI ELF brand handler\n");
                           return (EINVAL);
                   }
                   return (0);
           case MOD_UNLOAD:
                   if (elf32_brand_inuse(&cloudabi32_brand))
                           return (EBUSY);
                   if (elf32_remove_brand_entry(&cloudabi32_brand) < 0) {
                           printf("Failed to remove CloudABI ELF brand handler\n");
                           return (EINVAL);
                   }
                   cloudabi_vdso_destroy(cloudabi32_brand.sysvec);
                   return (0);
           default:
                   return (EOPNOTSUPP);
           }
   }
   
   static moduledata_t cloudabi32_module = {
           "cloudabi32",
           cloudabi32_modevent,
           NULL
   };
   
   DECLARE_MODULE_TIED(cloudabi32, cloudabi32_module, SI_SUB_EXEC, SI_ORDER_ANY);
   MODULE_DEPEND(cloudabi32, cloudabi, 1, 1, 1);
   FEATURE(cloudabi32, "CloudABI 32bit support");

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