/* * a loop that gets messages requesting work, carries out the work, and sends * replies. * * The entry points into this file are: * main: main program of the Virtual File System * reply: send a reply to a process after the requested work is done * * Changes for VFS: * Jul 2006 (Balazs Gerofi) */ #include "fs.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "file.h" #include "fproc.h" #include "param.h" #include #include "vmnt.h" #include "vnode.h" #if ENABLE_SYSCALL_STATS EXTERN unsigned long calls_stats[NCALLS]; #endif FORWARD _PROTOTYPE( void fs_init, (void) ); FORWARD _PROTOTYPE( void get_work, (void) ); FORWARD _PROTOTYPE( void init_root, (void) ); FORWARD _PROTOTYPE( void service_pm, (void) ); /*===========================================================================* * main * *===========================================================================*/ PUBLIC int main() { /* This is the main program of the file system. The main loop consists of * three major activities: getting new work, processing the work, and sending * the reply. This loop never terminates as long as the file system runs. */ int error; fs_init(); /* This is the main loop that gets work, processes it, and sends replies. */ while (TRUE) { get_work(); /* sets who and call_nr */ if (who_e == PM_PROC_NR && call_nr != PROC_EVENT) printf("FS: strange, got message %d from PM\n", call_nr); if (call_nr == DEV_REVIVE) { endpoint_t endpt; endpt = m_in.REP_ENDPT; if(endpt == FS_PROC_NR) { endpt = suspended_ep(m_in.m_source, m_in.REP_IO_GRANT); if(endpt == NONE) { printf("FS: proc with " "grant %d from %d not found (revive)\n", m_in.REP_IO_GRANT, m_in.m_source); continue; } } revive(endpt, m_in.REP_STATUS); continue; } if (call_nr == DEV_REOPEN_REPL) { reopen_reply(); continue; } if (call_nr == DEV_CLOSE_REPL) { close_reply(); continue; } if (call_nr == DEV_SEL_REPL1) { select_reply1(); continue; } if (call_nr == DEV_SEL_REPL2) { select_reply2(); continue; } /* Check for special control messages first. */ if ((call_nr & NOTIFY_MESSAGE)) { if (call_nr == PROC_EVENT) { /* PM tries to get FS to do something */ service_pm(); } else if (call_nr == SYN_ALARM) { /* Alarm timer expired. Used only for select(). * Check it. */ fs_expire_timers(m_in.NOTIFY_TIMESTAMP); } else { /* Device notifies us of an event. */ dev_status(&m_in); } #if 0 if (!check_vrefs()) { printf("after call %d from %d/%d\n", call_nr, who_p, who_e); panic(__FILE__, "check_vrefs failed at line", __LINE__); } #endif continue; } /* We only expect notify()s from tasks. */ if(who_p < 0) { printf("FS: ignoring message from %d (%d)\n", who_e, m_in.m_type); continue; } /* Now it's safe to set and check fp. */ fp = &fproc[who_p]; /* pointer to proc table struct */ super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */ /* Calls from VM. */ if(who_e == VM_PROC_NR) { int caught = 1; switch(call_nr) { case VM_VFS_OPEN: error = do_vm_open(); break; case VM_VFS_CLOSE: error = do_vm_close(); break; case VM_VFS_MMAP: error = do_vm_mmap(); break; default: caught = 0; break; } if(caught) { reply(who_e, error); continue; } } /* Other calls. */ switch(call_nr) { case DEVCTL: error= do_devctl(); if (error != SUSPEND) reply(who_e, error); break; case MAPDRIVER: error= do_mapdriver(); if (error != SUSPEND) reply(who_e, error); break; default: /* Call the internal function that does the work. */ if (call_nr < 0 || call_nr >= NCALLS) { error = SUSPEND; /* Not supposed to happen. */ printf("VFS: illegal %d system call by %d\n", call_nr, who_e); } else if (fp->fp_pid == PID_FREE) { error = ENOSYS; printf( "FS, bad process, who = %d, call_nr = %d, endpt1 = %d\n", who_e, call_nr, m_in.endpt1); } else { #if ENABLE_SYSCALL_STATS calls_stats[call_nr]++; #endif error = (*call_vec[call_nr])(); } /* Copy the results back to the user and send reply. */ if (error != SUSPEND) { reply(who_e, error); } } #if 0 if (!check_vrefs()) { printf("after call %d from %d/%d\n", call_nr, who_p, who_e); panic(__FILE__, "check_vrefs failed at line", __LINE__); } #endif } return(OK); /* shouldn't come here */ } /*===========================================================================* * get_work * *===========================================================================*/ PRIVATE void get_work() { /* Normally wait for new input. However, if 'reviving' is * nonzero, a suspended process must be awakened. */ int r, found_one, fd_nr; struct filp *f; register struct fproc *rp; while (reviving != 0) { found_one= FALSE; /* Revive a suspended process. */ for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++) if (rp->fp_pid != PID_FREE && rp->fp_revived == REVIVING) { found_one= TRUE; who_p = (int)(rp - fproc); who_e = rp->fp_endpoint; call_nr = rp->fp_fd & BYTE; m_in.fd = (rp->fp_fd >>8) & BYTE; m_in.buffer = rp->fp_buffer; m_in.nbytes = rp->fp_nbytes; rp->fp_suspended = NOT_SUSPENDED; /*no longer hanging*/ rp->fp_revived = NOT_REVIVING; reviving--; /* This should be a pipe I/O, not a device I/O. * If it is, it'll 'leak' grants. */ assert(!GRANT_VALID(rp->fp_grant)); if (rp->fp_task == -XPIPE) { fp= rp; fd_nr= (rp->fp_fd >> 8); f= get_filp(fd_nr); assert(f != NULL); r= rw_pipe((call_nr == READ) ? READING : WRITING, who_e, fd_nr, f, rp->fp_buffer, rp->fp_nbytes); if (r != SUSPEND) reply(who_e, r); continue; } return; } if (!found_one) panic(__FILE__,"get_work couldn't revive anyone", NO_NUM); } for(;;) { int r; /* Normal case. No one to revive. */ if ((r=receive(ANY, &m_in)) != OK) panic(__FILE__,"fs receive error", r); who_e = m_in.m_source; who_p = _ENDPOINT_P(who_e); if(who_p < -NR_TASKS || who_p >= NR_PROCS) panic(__FILE__,"receive process out of range", who_p); if(who_p >= 0 && fproc[who_p].fp_endpoint == NONE) { printf("FS: ignoring request from %d, endpointless slot %d (%d)\n", m_in.m_source, who_p, m_in.m_type); continue; } if(who_p >= 0 && fproc[who_p].fp_endpoint != who_e) { printf("FS: receive endpoint inconsistent (%d, %d, %d).\n", who_e, fproc[who_p].fp_endpoint, who_e); panic(__FILE__, "FS: inconsistent endpoint ", NO_NUM); continue; } call_nr = m_in.m_type; return; } } /*===========================================================================* * reply * *===========================================================================*/ PUBLIC void reply(whom, result) int whom; /* process to reply to */ int result; /* result of the call (usually OK or error #) */ { /* Send a reply to a user process. If the send fails, just ignore it. */ int s; #if 0 if (call_nr == SYMLINK) printf("vfs:reply: replying %d for call %d\n", result, call_nr); #endif m_out.reply_type = result; s = sendnb(whom, &m_out); if (s != OK) printf("VFS: couldn't send reply %d to %d: %d\n", result, whom, s); } /*===========================================================================* * fs_init * *===========================================================================*/ PRIVATE void fs_init() { /* Initialize global variables, tables, etc. */ int s; register struct fproc *rfp; struct vmnt *vmp; struct vnode *root_vp; message mess; /* Clear endpoint field */ last_login_fs_e = NONE; mount_m_in.m1_p3 = (char *) NONE; /* Initialize the process table with help of the process manager messages. * Expect one message for each system process with its slot number and pid. * When no more processes follow, the magic process number NONE is sent. * Then, stop and synchronize with the PM. */ do { if (OK != (s=receive(PM_PROC_NR, &mess))) panic(__FILE__,"FS couldn't receive from PM", s); if (NONE == mess.PR_ENDPT) break; rfp = &fproc[mess.PR_SLOT]; rfp->fp_pid = mess.PR_PID; rfp->fp_endpoint = mess.PR_ENDPT; rfp->fp_realuid = (uid_t) SYS_UID; rfp->fp_effuid = (uid_t) SYS_UID; rfp->fp_realgid = (gid_t) SYS_GID; rfp->fp_effgid = (gid_t) SYS_GID; rfp->fp_umask = ~0; rfp->fp_grant = GRANT_INVALID; } while (TRUE); /* continue until process NONE */ mess.m_type = OK; /* tell PM that we succeeded */ s = send(PM_PROC_NR, &mess); /* send synchronization message */ /* All process table entries have been set. Continue with FS initialization. * Certain relations must hold for the file system to work at all. Some * extra block_size requirements are checked at super-block-read-in time. */ if (OPEN_MAX > 127) panic(__FILE__,"OPEN_MAX > 127", NO_NUM); /* The following initializations are needed to let dev_opcl succeed .*/ fp = (struct fproc *) NULL; who_e = who_p = FS_PROC_NR; build_dmap(); /* build device table and map boot driver */ init_root(); /* init root device and load super block */ init_select(); /* init select() structures */ vmp = &vmnt[0]; /* Should be the root filesystem */ if (vmp->m_dev == NO_DEV) panic(__FILE__, "vfs:fs_init: no root filesystem", NO_NUM); root_vp= vmp->m_root_node; /* The root device can now be accessed; set process directories. */ for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) { FD_ZERO(&(rfp->fp_filp_inuse)); if (rfp->fp_pid != PID_FREE) { dup_vnode(root_vp); rfp->fp_rd = root_vp; dup_vnode(root_vp); rfp->fp_wd = root_vp; } else rfp->fp_endpoint = NONE; } system_hz = sys_hz(); } /*===========================================================================* * init_root * *===========================================================================*/ PRIVATE void init_root() { int r = OK; struct vmnt *vmp; struct vnode *root_node; struct dmap *dp; char *label; message m; struct node_details resX; /* Open the root device. */ root_dev = DEV_IMGRD; ROOT_FS_E = MFS_PROC_NR; /* Wait FS login message */ if (last_login_fs_e != ROOT_FS_E) { /* Wait FS login message */ if (receive(ROOT_FS_E, &m) != OK) { printf("VFS: Error receiving login request from FS_e %d\n", ROOT_FS_E); panic(__FILE__, "Error receiving login request from root filesystem\n", ROOT_FS_E); } if (m.m_type != FS_READY) { printf("VFS: Invalid login request from FS_e %d\n", ROOT_FS_E); panic(__FILE__, "Error receiving login request from root filesystem\n", ROOT_FS_E); } } last_login_fs_e = NONE; /* Initialize vmnt table */ for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) vmp->m_dev = NO_DEV; vmp = &vmnt[0]; /* We'll need a vnode for the root inode, check whether there is one */ if ((root_node = get_free_vnode(__FILE__, __LINE__)) == NIL_VNODE) { panic(__FILE__,"Cannot get free vnode", r); } /* Get driver process' endpoint */ dp = &dmap[(root_dev >> MAJOR) & BYTE]; if (dp->dmap_driver == NONE) { panic(__FILE__,"No driver for root device", r); } label= dp->dmap_label; if (strlen(label) == 0) { panic(__FILE__, "vfs:init_root: no label for major", root_dev >> MAJOR); } /* Issue request */ r = req_readsuper(ROOT_FS_E, label, root_dev, 0 /*!readonly*/, 1 /*isroot*/, &resX); if (r != OK) { panic(__FILE__,"Cannot read superblock from root", r); } /* Fill in root node's fields */ root_node->v_fs_e = resX.fs_e; root_node->v_inode_nr = resX.inode_nr; root_node->v_mode = resX.fmode; root_node->v_size = resX.fsize; root_node->v_sdev = NO_DEV; root_node->v_fs_count = 1; root_node->v_ref_count = 1; /* Fill in max file size and blocksize for the vmnt */ vmp->m_fs_e = resX.fs_e; vmp->m_dev = root_dev; vmp->m_flags = 0; /* Root node is indeed on the partition */ root_node->v_vmnt = vmp; root_node->v_dev = vmp->m_dev; /* Root directory is not mounted on a vnode. */ vmp->m_mounted_on = NULL; vmp->m_root_node = root_node; } /*===========================================================================* * service_pm * *===========================================================================*/ PRIVATE void service_pm() { int r, call; struct vmnt *vmp; message m; /* Ask PM for work until there is nothing left to do */ for (;;) { m.m_type= PM_GET_WORK; r= sendrec(PM_PROC_NR, &m); if (r != OK) { panic("VFS", "service_pm: sendrec failed", r); } if (m.m_type == PM_IDLE) { break; } call= m.m_type; switch(call) { case PM_SETSID: pm_setsid(m.PM_SETSID_PROC); /* No need to report status to PM */ break; case PM_SETGID: pm_setgid(m.PM_SETGID_PROC, m.PM_SETGID_EGID, m.PM_SETGID_RGID); /* No need to report status to PM */ break; case PM_SETUID: pm_setuid(m.PM_SETUID_PROC, m.PM_SETUID_EGID, m.PM_SETUID_RGID); /* No need to report status to PM */ break; case PM_FORK: pm_fork(m.PM_FORK_PPROC, m.PM_FORK_CPROC, m.PM_FORK_CPID); /* No need to report status to PM */ break; case PM_EXIT: case PM_EXIT_TR: pm_exit(m.PM_EXIT_PROC); /* Reply dummy status to PM for synchronization */ m.m_type= (call == PM_EXIT_TR ? PM_EXIT_REPLY_TR : PM_EXIT_REPLY); /* Keep m.PM_EXIT_PROC */ r= send(PM_PROC_NR, &m); if (r != OK) panic(__FILE__, "service_pm: send failed", r); break; case PM_UNPAUSE: case PM_UNPAUSE_TR: unpause(m.PM_UNPAUSE_PROC); /* No need to report status to PM */ break; case PM_REBOOT: pm_reboot(); /* Reply dummy status to PM for synchronization */ m.m_type= PM_REBOOT_REPLY; r= send(PM_PROC_NR, &m); if (r != OK) panic(__FILE__, "service_pm: send failed", r); break; case PM_EXEC: r= pm_exec(m.PM_EXEC_PROC, m.PM_EXEC_PATH, m.PM_EXEC_PATH_LEN, m.PM_EXEC_FRAME, m.PM_EXEC_FRAME_LEN); /* Reply status to PM */ m.m_type= PM_EXEC_REPLY; /* Keep m.PM_EXEC_PROC */ m.PM_EXEC_STATUS= r; r= send(PM_PROC_NR, &m); if (r != OK) panic(__FILE__, "service_pm: send failed", r); break; case PM_DUMPCORE: r= pm_dumpcore(m.PM_CORE_PROC, (struct mem_map *)m.PM_CORE_SEGPTR); /* Reply status to PM */ m.m_type= PM_CORE_REPLY; /* Keep m.PM_CORE_PROC */ m.PM_CORE_STATUS= r; r= send(PM_PROC_NR, &m); if (r != OK) panic(__FILE__, "service_pm: send failed", r); break; default: panic("VFS", "service_pm: unknown call", m.m_type); } } }