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288 volume VI os16
104.9.28 kernel/proc/proc_sys_wait.c
Si veda la sezione 103.8.27.
1930001 |#include
1930002 |#include
1930003 |//----------------------------------------------------------------------
1930004 |pid_t
1930005 |proc_sys_wait (pid_t pid, int *status)
1930006 |{
1930007 | pid_t parent = pid;
1930008 | pid_t child;
1930009 | int child_available = 0;
1930010 | //
1930011 | // Find a dead child process.
1930012 | //
1930013 | for (child = 1; child < PROCESS_MAX; child++)
1930014 | {
1930015 | if (proc_table[child].ppid == parent)
1930016 | {
1930017 | child_available = 1; // Child found!
1930018 | if (proc_table[child].status == PROC_ZOMBIE)
1930019 | {
1930020 | break; // It is dead!
1930021 | }
1930022 | }
1930023 | }
1930024 | //
1930025 | // If the index ‘child’ is a valid process number,
1930026 | // a dead child was found.
1930027 | //
1930028 | if (child < PROCESS_MAX)
1930029 | {
1930030 | *status = proc_table[child].ret;
1930031 | proc_available (child);
1930032 | return (child);
1930033 | }
1930034 | else
1930035 | {
1930036 | if (child_available)
1930037 | {
1930038 | //
1930039 | // There are child, but all alive.
1930040 | //
1930041 | // Go to sleep.
1930042 | //
1930043 | proc_table[parent].status = PROC_SLEEPING;
1930044 | proc_table[parent].wakeup_events |= WAKEUP_EVENT_SIGNAL;
1930045 | proc_table[parent].wakeup_signal = SIGCHLD;
1930046 | return ((pid_t) 0);
1930047 | }
1930048 | else
1930049 | {
1930050 | //
1930051 | // There are no child at all.
1930052 | //
1930053 | errset (ECHILD);
1930054 | return ((pid_t) -1);
1930055 | }
1930056 | }
1930057 |}
104.9.29 kernel/proc/proc_table.c
Si veda la sezione 103.8.7.
1940001 |#include
1940002 |//----------------------------------------------------------------------
1940003 |proc_t proc_table[PROCESS_MAX];
104.9.30 kernel/proc/sysroutine.c
Si veda la sezione 103.8.28.
1950001 |#include
1950002 |#include
1950003 |#include
1950004 |//----------------------------------------------------------------------
1950005 |static void sysroutine_error_back (int *number, int *line,
1950006 | char *file_name);
1950007 |//----------------------------------------------------------------------
1950008 |void
1950009 |sysroutine (uint16_t *sp, segment_t *segment_d, uint16_t syscallnr,
1950010 | uint16_t msg_off, uint16_t msg_size)
1950011 |{
1950012 | pid_t pid = proc_find (*segment_d);
1950013 | addr_t msg_addr = address (*segment_d, msg_off);
1950014 | //
1950015 | // Inbox.
1950016 | //
1950017 | union {
1950018 | sysmsg_chdir_t chdir;
1950019 | sysmsg_chmod_t chmod;
1950020 | sysmsg_chown_t chown;
1950021 | sysmsg_clock_t clock;
1950022 | sysmsg_close_t close;
1950023 | sysmsg_dup_t dup;
1950024 | sysmsg_dup2_t dup2;
1950025 | sysmsg_exec_t exec;
1950026 | sysmsg_exit_t exit;
1950027 | sysmsg_fchmod_t fchmod;
1950028 | sysmsg_fchown_t fchown;
1950029 | sysmsg_fcntl_t fcntl;
1950030 | sysmsg_fork_t fork;
1950031 | sysmsg_fstat_t fstat;
1950032 | sysmsg_kill_t kill;
1950033 | sysmsg_link_t link;
1950034 | sysmsg_lseek_t lseek;
1950035 | sysmsg_mkdir_t mkdir;
1950036 | sysmsg_mknod_t mknod;
1950037 | sysmsg_mount_t mount;
1950038 | sysmsg_open_t open;
1950039 | sysmsg_read_t read;
1950040 | sysmsg_seteuid_t seteuid;
1950041 | sysmsg_setuid_t setuid;
Script e sorgenti del kernel 289
1950042 | sysmsg_signal_t signal;
1950043 | sysmsg_sleep_t sleep;
1950044 | sysmsg_stat_t stat;
1950045 | sysmsg_stime_t stime;
1950046 | sysmsg_time_t time;
1950047 | sysmsg_uarea_t uarea;
1950048 | sysmsg_umask_t umask;
1950049 | sysmsg_umount_t umount;
1950050 | sysmsg_unlink_t unlink;
1950051 | sysmsg_wait_t wait;
1950052 | sysmsg_write_t write;
1950053 | sysmsg_zpchar_t zpchar;
1950054 | sysmsg_zpstring_t zpstring;
1950055 | } msg;
1950056 | //
1950057 | // Verify if the system call was emitted from kernel code.
1950058 | // The kernel can emit only some particular system call:
1950059 | // SYS_NULL, to let other processes run;
1950060 | // SYS_FORK, to let fork itself;
1950061 | // SYS_EXEC, to replace a forked copy of itself.
1950062 | //
1950063 | if (pid == 0)
1950064 | {
1950065 | //
1950066 | // This is the kernel code!
1950067 | //
1950068 | if ( syscallnr != SYS_0
1950069 | && syscallnr != SYS_FORK
1950070 | && syscallnr != SYS_EXEC)
1950071 | {
1950072 | k_printf ("kernel panic: the system call %i ", syscallnr);
1950073 | k_printf ("was received while running in kernel space!\n");
1950074 | }
1950075 | }
1950076 | //
1950077 | // Entering a system call, the kernel variable ‘errno’ must be
1950078 | // reset, otherwise, a previous kernel code error might be returned
1950079 | // to the applications.
1950080 | //
1950081 | errno = 0;
1950082 | errln = 0;
1950083 | errfn[0] = 0;
1950084 | //
1950085 | // Get message.
1950086 | //
1950087 | dev_io (pid, DEV_MEM, DEV_READ, msg_addr, &msg, msg_size, NULL);
1950088 | //
1950089 | // Do the request from the received system call.
1950090 | //
1950091 | switch (syscallnr)
1950092 | {
1950093 | case SYS_0:
1950094 | break;
1950095 | case SYS_CHDIR:
1950096 | msg.chdir.ret = path_chdir (pid, msg.chdir.path);
1950097 | sysroutine_error_back (&msg.chdir.errno, &msg.chdir.errln,
1950098 | msg.chdir.errfn);
1950099 | break;
1950100 | case SYS_CHMOD:
1950101 | msg.chmod.ret = path_chmod (pid, msg.chmod.path,
1950102 | msg.chmod.mode);
1950103 | sysroutine_error_back (&msg.chmod.errno, &msg.chmod.errln,
1950104 | msg.chmod.errfn);
1950105 | break;
1950106 | case SYS_CHOWN:
1950107 | msg.chown.ret = path_chown (pid, msg.chown.path,
1950108 | msg.chown.uid,
1950109 | msg.chown.gid);
1950110 | sysroutine_error_back (&msg.chown.errno, &msg.chown.errln,
1950111 | msg.chown.errfn);
1950112 | break;
1950113 | case SYS_CLOCK:
1950114 | msg.clock.ret = k_clock ();
1950115 | break;
1950116 | case SYS_CLOSE:
1950117 | msg.close.ret = fd_close (pid, msg.close.fdn);
1950118 | sysroutine_error_back (&msg.close.errno, &msg.close.errln,
1950119 | msg.close.errfn);
1950120 | break;
1950121 | case SYS_DUP:
1950122 | msg.dup.ret = fd_dup (pid, msg.dup.fdn_old, 0);
1950123 | sysroutine_error_back (&msg.dup.errno, &msg.dup.errln,
1950124 | msg.dup.errfn);
1950125 | break;
1950126 | case SYS_DUP2:
1950127 | msg.dup2.ret = fd_dup2 (pid, msg.dup2.fdn_old,
1950128 | msg.dup2.fdn_new);
1950129 | sysroutine_error_back (&msg.dup2.errno, &msg.dup2.errln,
1950130 | msg.dup2.errfn);
1950131 | break;
1950132 | case SYS_EXEC:
1950133 | msg.exec.ret = proc_sys_exec (sp, segment_d, pid,
1950134 | msg.exec.path,
1950135 | msg.exec.argc,
1950136 | msg.exec.arg_data,
1950137 | msg.exec.envc,
1950138 | msg.exec.env_data);
1950139 | msg.exec.uid = proc_table[pid].uid;
1950140 | msg.exec.euid = proc_table[pid].euid;
1950141 | sysroutine_error_back (&msg.exec.errno, &msg.exec.errln,
1950142 | msg.exec.errfn);
1950143 | break;
1950144 | case SYS_EXIT:
1950145 | if (pid == 0)
1950146 | {
1950147 | k_printf ("kernel alert: "
1950148 | "the kernel cannot exit!\n");
1950149 | }
1950150 | else
1950151 | {
1950152 | proc_sys_exit (pid, msg.exit.status);
1950153 | }
1950154 | break;
1950155 | case SYS_FCHMOD:
1950156 | msg.fchmod.ret = fd_chmod (pid, msg.fchmod.fdn,
1950157 | msg.fchmod.mode);