source: trunk/kernel/syscalls/sys_exec.c @ 315

Last change on this file since 315 was 315, checked in by alain, 7 years ago

Redefine the fuctions ppm_base2page() / ppm_page2base() / ppm_page2ppn() / ppm_ppn2page() / ppm_base2ppn() / ppm_ppn2base(),
to use explicitely extended pointers.

File size: 10.1 KB
RevLine 
[1]1/*
[23]2 * sys_exec.c - Kernel function implementing the "exec" system call.
[302]3 *
[23]4 * Authors   Alain Greiner (2016,2017)
[1]5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
[14]24#include <kernel_config.h>
[1]25#include <hal_types.h>
[23]26#include <hal_uspace.h>
[1]27#include <errno.h>
28#include <printk.h>
29#include <core.h>
30#include <vfs.h>
31#include <cluster.h>
32#include <process.h>
33#include <thread.h>
34#include <vmm.h>
35#include <ppm.h>
36#include <rpc.h>
37
38
[302]39////////////////////////////////////////////////i//////////////////////////////////////
[1]40// This static function is called by the sys_exec() function to register the .elf
41// pathname in the exec_info  structure, from a string stored in user space.
[302]42////////////////////////////////////////////////i//////////////////////////////////////
[1]43// @ exec_info : pointer on the exec_info structure.
44// @ pathname  : string containing the path to the .elf file (user space).
[302]45// return 0 if success / non-zero if one string too long, or too many strings.
[1]46///////////////////////////////////////////////////////////////////////////////////////
47static error_t process_exec_get_path( exec_info_t  * exec_info,
48                                      char         * pathname )
49{
[302]50    error_t error;
[1]51
52    // copy string to exec_info
[302]53    error = hal_strcpy_from_uspace( &exec_info->path[0] , pathname ,
54                                    CONFIG_VFS_MAX_PATH_LENGTH );
55    if( error )
56        return EINVAL;
[1]57
58    return 0;
59}
60
[302]61////////////////////////////////////////////////i//////////////////////////////////////
[1]62// This static function is called twice by the sys_exec() function :
63// - to register the main() arguments (args) in the exec_info structure.
64// - to register the environment variables (envs) in the exec_info structure.
65// In both cases the input is an array of string pointers in user space,
[302]66// and a set of strings in user space.
[1]67// We allocate one physical page to store a kernel copy of the array of pointers,
68// we allocate one or several physical pages to store the strings themselve,
69// and register these buffers and the number of strings in the exec_info structure.
[302]70// The max number of strings is 1024 (for both args and envs). The numbers of pages
[1]71// to store the (args) and (envs) strings are configuration parameters.
[302]72///////////////////////////////////////////////////////////////////////////////////////
[1]73// @ exec_info : pointer on the exec_info structure.
74// @ is_args   : true if called for (args) / false if called for (envs).
75// @ pointers  : array of pointers on the strings (in user space).
[302]76// @ return 0 if success / non-zero if too many strings or no more memory.
[1]77///////////////////////////////////////////////////////////////////////////////////////
78static error_t process_exec_get_strings( exec_info_t  * exec_info,
79                                         bool_t         is_args,
[302]80                                         char        ** u_pointers )
[1]81{
82    uint32_t     index;       // string index
83    uint32_t     found_null;  // NULL pointer found in array of pointers
84    uint32_t     length;      // string length
85    kmem_req_t   req;         // kmem request
86    page_t     * page;        // page descriptor
[315]87    xptr_t       base_xp;     // extended pointer on page base
[1]88    uint32_t     order;       // ln2( number of pages to store strings )
[23]89    char      ** k_pointers;  // base of kernel array of pointers
90    char       * k_buf_ptr;   // pointer on first empty slot in kernel strings buffer
91    char       * k_buf_base;  // base address of the kernel strings buffer
[1]92
93    // compute ln2( number of pages for kernel strings buffer )
[23]94    if( is_args ) order = bits_log2( CONFIG_VMM_ARGS_SIZE );
95    else          order = bits_log2( CONFIG_VMM_ENVS_SIZE );
[1]96
[302]97    req.type   = KMEM_PAGE;
98    req.flags  = AF_KERNEL | AF_ZERO;
[1]99
100    // allocate one physical page for kernel array of pointers
101    req.type   = 0;
102    page       = kmem_alloc( &req );
[23]103
104    if( page == NULL ) return ENOMEM;
105
[315]106    base_xp = ppm_page2base( XPTR( local_cxy , page ) );
107    k_pointers = (char **)GET_PTR( base_xp );
[302]108
[1]109    // allocate several physical pages to store the strings themselve
110    req.type   = order;
111    page       = kmem_alloc( &req );
[23]112
113    if( page == NULL ) return ENOMEM;
114
[315]115    base_xp = ppm_page2base( XPTR( local_cxy , page ) );
116    k_buf_base = (char *)GET_PTR( base_xp );
[302]117
118    // copy the array of pointers to kernel buffer
119    hal_copy_from_uspace( k_pointers,
[1]120                          u_pointers,
121                          CONFIG_PPM_PAGE_SIZE );
122
[23]123    // scan kernel array of pointers to copy the strings
[1]124    found_null = 0;
[23]125    k_buf_ptr  = k_buf_base;
[1]126    for( index = 0 ; index < 1024 ; index++ )
127    {
[302]128        if( k_pointers[index] == NULL )
[1]129        {
130            found_null = 1;
131            break;
132        }
133
134        // compute string length
[302]135        length = hal_strlen_from_uspace( k_pointers[index] );
136
[1]137        // copy the user string to kernel buffer
[23]138        hal_copy_from_uspace( k_buf_ptr,
139                              k_pointers[index],
[1]140                              length );
141
142        // update k_pointer[index] entry
[23]143        k_pointers[index] = k_buf_ptr;
[1]144
145        // increment pointer on kernel strings buffer
[23]146        k_buf_ptr += (length + 1);
[1]147    }
148
[302]149    // update into exec_info structure
[1]150    if( found_null && is_args )
151    {
152        exec_info->args_pointers  =  k_pointers;
[23]153        exec_info->args_buf_base  =  k_buf_base;
[1]154        exec_info->args_nr        =  index;
155    }
156    else if( found_null && !is_args )
157    {
158        exec_info->envs_pointers  =  k_pointers;
[23]159        exec_info->envs_buf_base  =  k_buf_base;
160        exec_info->envs_buf_free  =  k_buf_ptr;
[1]161        exec_info->envs_nr        =  index;
162    }
[302]163    else
[1]164    {
165        return EINVAL;
166    }
167
168    return 0;
169} // end process_exec_get_strings()
170
171/////////////////////////////////////////////////////////////////////////////////////////
172// Implementation note:
173// This function build an exec_info_t structure containing all informations
174// required to create the new process descriptor and the associated thread.
175// It calls the static process_exec_get_path() and process_exec_get_strings() functions
176// to copy the .elf pathname, the main() arguments and the environment variables from
[23]177// user buffers to the exec_info_t structure, and call the process_make_exec() function.
[1]178/////////////////////////////////////////////////////////////////////////////////////////
179int sys_exec( char  * filename,     // .elf file pathname
[23]180              char ** args,         // process arguments
181              char ** envs )        // environment variables
[1]182{
183    exec_info_t  exec_info;         // structure to pass to process_make_exec()
[302]184    error_t      error;
[23]185    paddr_t      paddr;
[1]186
[23]187    thread_t   * this    = CURRENT_THREAD;
[302]188    process_t  * process = this->process;
[23]189
190    // check argument fileme
191    error = vmm_v2p_translate( false , filename , &paddr );
192
[302]193    if( error )
[1]194    {
[23]195        printk("\n[ERROR] in %s : filename unmapped\n", __FUNCTION__ );
196        this->errno = EINVAL;
197        return -1;
[1]198    }
199
[23]200    // check argument fileme
201    error = vmm_v2p_translate( false , args , &paddr );
202
[302]203    if( error )
[23]204    {
205        printk("\n[ERROR] in %s : args unmapped\n", __FUNCTION__ );
206        this->errno = EINVAL;
207        return -1;
208    }
209
210    // check argument fileme
211    error = vmm_v2p_translate( false , envs , &paddr );
212
[302]213    if( error )
[23]214    {
215        printk("\n[ERROR] in %s : envs unmapped\n", __FUNCTION__ );
216        this->errno = EINVAL;
217        return -1;
218    }
219
[1]220    // compute client_cxy (local cluster) and server_cxy (target cluster)
221    cxy_t     cxy_server = CXY_FROM_PID( process->pid );
222    cxy_t     cxy_client = local_cxy;
223    bool_t    is_local   = (cxy_server == cxy_client);
224
225    exec_dmsg("\n[INFO] %s starts for process %x on core %d in cluster %x"
226                 " / target_cluster = %x / cycle %d\n",
[302]227                 __FUNCTION__, process->pid , CURRENT_CORE->lid,
[101]228                 cxy_client, cxy_server, hal_get_cycles());
[1]229
[302]230    // register reference parent process in exec_info
[101]231    exec_info.parent_xp   = process->ref_xp;
[1]232
[302]233    // check pathname and store it in exec_info structure
234    error = process_exec_get_path( &exec_info , filename );
[1]235
[302]236    if ( error )
[1]237    {
[23]238        printk("\n[ERROR] in %s : elf pathname too long\n", __FUNCTION__ );
239        this->errno = error;
240        return -1;
241    }
[1]242
[302]243    // check and store args in exec_info structure
244    error = process_exec_get_strings( &exec_info , true , args );
[1]245
[302]246    if( error )
[23]247    {
248        printk("\n[ERROR] in %s : cannot access args\n", __FUNCTION__ );
249        this->errno = error;
250        return -1;
[1]251    }
[23]252
[302]253    // check and store envs in exec_info structure
254    error = process_exec_get_strings( &exec_info , false , envs );
255
256    if( error )
[1]257    {
[23]258        printk("\n[ERROR] in %s : cannot access envs\n", __FUNCTION__ );
259        this->errno = error;
260        return -1;
261    }
[302]262
[23]263    exec_dmsg("\n[INFO] %s starts exec for process %x at cycle %d\n",
[101]264              __FUNCTION__, process->pid, hal_get_cycles() );
[1]265
[23]266    if( is_local )  error = process_make_exec( &exec_info );
267    else            rpc_process_exec_client( cxy_server , &exec_info , &error );
[1]268
[23]269    if( error )
270    {
271        printk("\n[ERROR] in %s : cannot create new process %x\n",
272               __FUNCTION__ , process->pid );
273        this->errno = error;
274        return -1;
[1]275    }
276
[23]277    exec_dmsg("\n[INFO] %s completes exec for process %x at cycle %d\n",
[101]278              __FUNCTION__, process->pid , hal_get_cycles() );
[23]279
280    // delete the calling thread an process
[1]281    thread_kill( CURRENT_THREAD );
[23]282    process_kill( CURRENT_THREAD->process );
[1]283
284    return 0;
[23]285
[1]286} // end sys_exec()
287
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