/* * sys_exec.c - Kernel function implementing the "exec" system call. * * Authors Alain Greiner (2016,2017) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #include #include #include #include #include #include #include #include ////////////////////////////////////////////////i////////////////////////////////////// // This static function is called by the sys_exec() function to register the .elf // pathname in the exec_info structure, from a string stored in user space. ////////////////////////////////////////////////i////////////////////////////////////// // @ exec_info : pointer on the exec_info structure. // @ pathname : string containing the path to the .elf file (user space). // return 0 if success / non-zero if one string too long, or too many strings. /////////////////////////////////////////////////////////////////////////////////////// static error_t process_exec_get_path( exec_info_t * exec_info, char * pathname ) { uint32_t length; // get string length length = hal_strlen_from_uspace( pathname ); if( length >= CONFIG_VFS_MAX_PATH_LENGTH ) return EINVAL; // copy string to exec_info hal_copy_from_uspace( &exec_info->path[0] , pathname , length ); return 0; } ////////////////////////////////////////////////i////////////////////////////////////// // This static function is called twice by the sys_exec() function : // - to register the main() arguments (args) in the exec_info structure. // - to register the environment variables (envs) in the exec_info structure. // In both cases the input is an array of string pointers in user space, // and a set of strings in user space. // We allocate one physical page to store a kernel copy of the array of pointers, // we allocate one or several physical pages to store the strings themselve, // and register these buffers and the number of strings in the exec_info structure. // The max number of strings is 1024 (for both args and envs). The numbers of pages // to store the (args) and (envs) strings are configuration parameters. /////////////////////////////////////////////////////////////////////////////////////// // @ exec_info : pointer on the exec_info structure. // @ is_args : true if called for (args) / false if called for (envs). // @ pointers : array of pointers on the strings (in user space). // @ return 0 if success / non-zero if too many strings or no more memory. /////////////////////////////////////////////////////////////////////////////////////// static error_t process_exec_get_strings( exec_info_t * exec_info, bool_t is_args, char ** u_pointers ) { uint32_t index; // string index uint32_t found_null; // NULL pointer found in array of pointers uint32_t length; // string length kmem_req_t req; // kmem request page_t * page; // page descriptor uint32_t order; // ln2( number of pages to store strings ) char ** k_pointers; // base of kernel array of pointers char * k_buf_ptr; // pointer on first empty slot in kernel strings buffer char * k_buf_base; // base address of the kernel strings buffer // compute ln2( number of pages for kernel strings buffer ) if( is_args ) order = bits_log2( CONFIG_VMM_ARGS_SIZE ); else order = bits_log2( CONFIG_VMM_ENVS_SIZE ); req.type = KMEM_PAGE; req.flags = AF_KERNEL | AF_ZERO; // allocate one physical page for kernel array of pointers req.type = 0; page = kmem_alloc( &req ); if( page == NULL ) return ENOMEM; k_pointers = ppm_page2base( page ); // allocate several physical pages to store the strings themselve req.type = order; page = kmem_alloc( &req ); if( page == NULL ) return ENOMEM; k_buf_base = ppm_page2base( page ); // copy the array of pointers to kernel buffer hal_copy_from_uspace( k_pointers, u_pointers, CONFIG_PPM_PAGE_SIZE ); // scan kernel array of pointers to copy the strings found_null = 0; k_buf_ptr = k_buf_base; for( index = 0 ; index < 1024 ; index++ ) { if( k_pointers[index] == NULL ) { found_null = 1; break; } // compute string length length = hal_strlen_from_uspace( k_pointers[index] ); // copy the user string to kernel buffer hal_copy_from_uspace( k_buf_ptr, k_pointers[index], length ); // update k_pointer[index] entry k_pointers[index] = k_buf_ptr; // increment pointer on kernel strings buffer k_buf_ptr += (length + 1); } // update into exec_info structure if( found_null && is_args ) { exec_info->args_pointers = k_pointers; exec_info->args_buf_base = k_buf_base; exec_info->args_nr = index; } else if( found_null && !is_args ) { exec_info->envs_pointers = k_pointers; exec_info->envs_buf_base = k_buf_base; exec_info->envs_buf_free = k_buf_ptr; exec_info->envs_nr = index; } else { return EINVAL; } return 0; } // end process_exec_get_strings() ///////////////////////////////////////////////////////////////////////////////////////// // Implementation note: // This function build an exec_info_t structure containing all informations // required to create the new process descriptor and the associated thread. // It calls the static process_exec_get_path() and process_exec_get_strings() functions // to copy the .elf pathname, the main() arguments and the environment variables from // user buffers to the exec_info_t structure, and call the process_make_exec() function. ///////////////////////////////////////////////////////////////////////////////////////// int sys_exec( char * filename, // .elf file pathname char ** args, // process arguments char ** envs ) // environment variables { exec_info_t exec_info; // structure to pass to process_make_exec() error_t error; paddr_t paddr; thread_t * this = CURRENT_THREAD; process_t * process = this->process; // check argument fileme error = vmm_v2p_translate( false , filename , &paddr ); if( error ) { printk("\n[ERROR] in %s : filename unmapped\n", __FUNCTION__ ); this->errno = EINVAL; return -1; } // check argument fileme error = vmm_v2p_translate( false , args , &paddr ); if( error ) { printk("\n[ERROR] in %s : args unmapped\n", __FUNCTION__ ); this->errno = EINVAL; return -1; } // check argument fileme error = vmm_v2p_translate( false , envs , &paddr ); if( error ) { printk("\n[ERROR] in %s : envs unmapped\n", __FUNCTION__ ); this->errno = EINVAL; return -1; } // compute client_cxy (local cluster) and server_cxy (target cluster) cxy_t cxy_server = CXY_FROM_PID( process->pid ); cxy_t cxy_client = local_cxy; bool_t is_local = (cxy_server == cxy_client); exec_dmsg("\n[INFO] %s starts for process %x on core %d in cluster %x" " / target_cluster = %x / cycle %d\n", __FUNCTION__, process->pid , CURRENT_CORE->lid, cxy_client, cxy_server, hal_time_stamp()); // initialize exec_info structure exec_info.pid = process->pid; exec_info.ppid = process->ppid; exec_info.fd_array_xp = XPTR( local_cxy , &process->fd_array ); exec_info.vfs_root_xp = process->vfs_root_xp; exec_info.vfs_cwd_xp = process->vfs_cwd_xp; exec_info.vfs_bin_xp = process->vfs_bin_xp; // check pathname and store it in exec_info structure error = process_exec_get_path( &exec_info , filename ); if ( error ) { printk("\n[ERROR] in %s : elf pathname too long\n", __FUNCTION__ ); this->errno = error; return -1; } // check and store args in exec_info structure error = process_exec_get_strings( &exec_info , true , args ); if( error ) { printk("\n[ERROR] in %s : cannot access args\n", __FUNCTION__ ); this->errno = error; return -1; } // check and store envs in exec_info structure error = process_exec_get_strings( &exec_info , false , envs ); if( error ) { printk("\n[ERROR] in %s : cannot access envs\n", __FUNCTION__ ); this->errno = error; return -1; } exec_dmsg("\n[INFO] %s starts exec for process %x at cycle %d\n", __FUNCTION__, process->pid, hal_time_stamp() ); if( is_local ) error = process_make_exec( &exec_info ); else rpc_process_exec_client( cxy_server , &exec_info , &error ); if( error ) { printk("\n[ERROR] in %s : cannot create new process %x\n", __FUNCTION__ , process->pid ); this->errno = error; return -1; } exec_dmsg("\n[INFO] %s completes exec for process %x at cycle %d\n", __FUNCTION__, process->pid , hal_time_stamp() ); // delete the calling thread an process thread_kill( CURRENT_THREAD ); process_kill( CURRENT_THREAD->process ); return 0; } // end sys_exec()