[PATCH 6/6] telnetd: Remove CONFIGURE_MAXIMUM_PTYS

Chris Johns chrisj at rtems.org
Wed Sep 26 11:35:27 UTC 2018



On 26/9/18 6:30 pm, Sebastian Huber wrote:
> Add a rtems_telnetd_config_table::client_maximum member to the Telnet
> configuration.
> 
> Close #3528.
> ---
>  cpukit/include/rtems/confdefs.h |  22 ++------
>  cpukit/include/rtems/telnetd.h  |   8 +++
>  cpukit/telnetd/telnetd.c        | 111 +++++++++++++++++++++++-----------------
>  3 files changed, 75 insertions(+), 66 deletions(-)
> 
> diff --git a/cpukit/include/rtems/confdefs.h b/cpukit/include/rtems/confdefs.h
> index 763f54bca5..f59e0f7068 100644
> --- a/cpukit/include/rtems/confdefs.h
> +++ b/cpukit/include/rtems/confdefs.h
> @@ -155,24 +155,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
>    const uint32_t rtems_libio_number_iops = RTEMS_ARRAY_SIZE(rtems_libio_iops);
>  #endif
>  
> -/**
> - * This macro specifies the number of PTYs that can be concurrently
> - * active.
> - */
> -#ifndef CONFIGURE_MAXIMUM_PTYS
> -  #define CONFIGURE_MAXIMUM_PTYS 0
> -#endif
> -
> -/**
> - * This variable contains the maximum number of PTYs that can be
> - * concurrently active.
> - */
> -#ifdef CONFIGURE_INIT
> -  int rtems_telnetd_maximum_ptys = CONFIGURE_MAXIMUM_PTYS;
> -#else
> -  extern int rtems_telnetd_maximum_ptys;
> -#endif
> -
>  #ifdef CONFIGURE_SMP_MAXIMUM_PROCESSORS
>    #warning "CONFIGURE_SMP_MAXIMUM_PROCESSORS has been renamed to CONFIGURE_MAXIMUM_PROCESSORS since RTEMS 5.1"
>    #define CONFIGURE_MAXIMUM_PROCESSORS CONFIGURE_SMP_MAXIMUM_PROCESSORS
> @@ -3474,6 +3456,10 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
>    #warning "The CONFIGURE_MAXIMUM_POSIX_SPINLOCKS configuration option is obsolete since RTEMS 5.1"
>  #endif
>  
> +#ifdef CONFIGURE_MAXIMUM_PTYS
> +  #warning "The CONFIGURE_MAXIMUM_PTYS configuration option is obsolete since RTEMS 5.1"
> +#endif
> +
>  #ifdef CONFIGURE_TERMIOS_DISABLED
>    #warning "The CONFIGURE_TERMIOS_DISABLED configuration option is obsolete since RTEMS 5.1"
>  #endif
> diff --git a/cpukit/include/rtems/telnetd.h b/cpukit/include/rtems/telnetd.h
> index 19512fbe9c..2339bad8b6 100644
> --- a/cpukit/include/rtems/telnetd.h
> +++ b/cpukit/include/rtems/telnetd.h
> @@ -85,6 +85,14 @@ typedef struct {
>     * create other tasks for the shell which listen on sockets.
>     */
>    bool keep_stdio;
> +
> +  /**
> +   * @brief Maximum number of clients which can connect to the system at a
> +   * time.
> +   *
> +   * Use 0 for the default value.
> +   */
> +  uint16_t client_maximum;
>  } rtems_telnetd_config_table;
>  
>  /**
> diff --git a/cpukit/telnetd/telnetd.c b/cpukit/telnetd/telnetd.c
> index 1b0631e3a6..60eb1d075f 100644
> --- a/cpukit/telnetd/telnetd.c
> +++ b/cpukit/telnetd/telnetd.c
> @@ -62,11 +62,17 @@
>  
>  #define PARANOIA
>  
> +typedef struct telnetd_context telnetd_context;
> +
>  struct shell_args {
>    rtems_pty_context  pty;
> -  void              *arg;
>    char               peername[16];
> -  char               delete_myself;
> +  telnetd_context   *ctx;
> +};
> +
> +struct telnetd_context {
> +  rtems_telnetd_config_table config;
> +  uint16_t                   active_clients;
>  };
>  
>  typedef union uni_sa {
> @@ -85,7 +91,7 @@ rtems_id telnetd_dflt_spawn(
>  );
>  
>  /***********************************************************/
> -static rtems_telnetd_config_table *telnetd_config;
> +static telnetd_context telnetd_instance;
>  
>  /*
>   * chrisj: this variable was global and with no declared interface in a header
> @@ -102,33 +108,39 @@ static const rtems_id (*telnetd_spawn_task)(
>  ) = telnetd_dflt_spawn;
>  
>  static struct shell_args *grab_a_Connection(
> +  telnetd_context *ctx,
>    int des_socket,
>    uni_sa *srv,
>    char *peername,
>    int sz
>  )
>  {
> -  struct shell_args *args = NULL;
> +  struct shell_args *args;
>    socklen_t size_adr = sizeof(srv->sin);
>    int acp_sock;
>  
> +  if (ctx->active_clients >= ctx->config.client_maximum) {
> +    return NULL;
> +  }
> +
>    args = malloc(sizeof(*args));
>    if (args == NULL) {
>      perror("telnetd:malloc");
> -    goto bailout;
> +    return NULL;
>    }
>  
>    acp_sock = accept(des_socket,&srv->sa,&size_adr);
> -
>    if (acp_sock<0) {
>      perror("telnetd:accept");
> -    goto bailout;
> +    free(args);
> +    return NULL;
>    };
>  
>    if (telnet_get_pty(&args->pty, acp_sock) == NULL) {
>      syslog( LOG_DAEMON | LOG_ERR, "telnetd: unable to obtain PTY");
>      /* NOTE: failing 'do_get_pty()' closed the socket */
> -    goto bailout;
> +    free(args);
> +    return NULL;
>    }
>  
>    if (sockpeername(acp_sock, peername, sz))
> @@ -141,13 +153,14 @@ static struct shell_args *grab_a_Connection(
>        args->pty.name);
>  #endif
>  
> -bailout:
> -
> +  ++ctx->active_clients;
> +  args->ctx = ctx;
>    return args;
>  }
>  
>  
> -static void release_a_Connection(char *devname, char *peername, FILE **pstd, int n)
> +static void release_a_Connection(telnetd_context *ctx, const char *devname,
> +  const char *peername, FILE **pstd, int n)
>  {
>  
>  #ifdef PARANOIA
> @@ -157,6 +170,8 @@ static void release_a_Connection(char *devname, char *peername, FILE **pstd, int
>        devname );
>  #endif
>  
> +  --ctx->active_clients;
> +
>    while (--n>=0)
>      if (pstd[n]) fclose(pstd[n]);
>  
> @@ -192,6 +207,7 @@ rtems_task_telnetd(void *task_argument)
>    int                size_adr;
>    struct shell_args *arg = NULL;
>    rtems_id           task_id;
> +  telnetd_context   *ctx = task_argument;
>  
>    if ((des_socket=socket(PF_INET,SOCK_STREAM,0))<0) {
>      perror("telnetd:socket");
> @@ -218,21 +234,21 @@ rtems_task_telnetd(void *task_argument)
>     * was started from the console anyway ..
>     */
>    do {
> -    if (telnetd_config->keep_stdio) {
> +    if (ctx->config.keep_stdio) {
>        bool start = true;
>        char device_name [32];
>  
>        ttyname_r( 1, device_name, sizeof( device_name));
> -      if (telnetd_config->login_check != NULL) {
> +      if (ctx->config.login_check != NULL) {
>          start = rtems_shell_login_prompt(
>            stdin,
>            stderr,
>            device_name,
> -          telnetd_config->login_check
> +          ctx->config.login_check
>          );
>        }
>        if (start) {
> -        telnetd_config->command( device_name, arg->arg);
> +        ctx->config.command( device_name, ctx->config.arg);
>        } else {
>          syslog(
>            LOG_AUTHPRIV | LOG_WARNING,
> @@ -241,7 +257,8 @@ rtems_task_telnetd(void *task_argument)
>          );
>        }
>      } else {
> -      arg = grab_a_Connection(des_socket, &srv, peername, sizeof(peername));
> +      arg = grab_a_Connection(ctx, des_socket, &srv, peername,
> +        sizeof(peername));
>  
>        if (arg == NULL) {
>          /* if something went wrong, sleep for some time */
> @@ -249,13 +266,12 @@ rtems_task_telnetd(void *task_argument)
>          continue;
>        }
>  
> -      arg->arg = telnetd_config->arg;
>        strncpy(arg->peername, peername, sizeof(arg->peername));
>  
>        task_id = telnetd_spawn_task(
>          arg->pty.name,
> -        telnetd_config->priority,
> -        telnetd_config->stack_size,
> +        ctx->config.priority,
> +        ctx->config.stack_size,
>          spawned_shell,
>          arg
>        );
> @@ -275,7 +291,7 @@ rtems_task_telnetd(void *task_argument)
>  
>          if ( !(dummy=fopen(arg->pty.name,"r+")) )
>            perror("Unable to dummy open the pty, losing a slot :-(");
> -        release_a_Connection(arg->pty.name, peername, &dummy, 1);
> +        release_a_Connection(ctx, arg->pty.name, peername, &dummy, 1);
>          free(arg);
>          sleep(2); /* don't accept connections too fast */
>        }
> @@ -293,62 +309,60 @@ rtems_task_telnetd(void *task_argument)
>  
>  rtems_status_code rtems_telnetd_start(const rtems_telnetd_config_table* config)
>  {
> +  telnetd_context *ctx = &telnetd_instance;
>    rtems_id task_id;
>  
> -  if (telnetd_config != NULL) {
> -    fprintf(stderr, "telnetd already started\n");
> -    return RTEMS_RESOURCE_IN_USE;
> -  }
> -
>    if (config->command == NULL) {
>      fprintf(stderr, "telnetd setup with invalid command\n");
>      return RTEMS_IO_ERROR;
>    }
>  
> -  telnetd_config = calloc(1, sizeof(*telnetd_config));
> -  if (telnetd_config == NULL) {
> -    fprintf(stderr, "telnetd cannot alloc telnetd config table\n");
> -    return RTEMS_NO_MEMORY;
> +  if (ctx->config.command != NULL) {
> +    fprintf(stderr, "telnetd already started\n");
> +    return RTEMS_RESOURCE_IN_USE;
>    }
>  
> -  *telnetd_config = *config;
> +  ctx->config = *config;
>  
>    /* Check priority */
>  #ifdef RTEMS_NETWORKING
> -  if (telnetd_config->priority <= 0) {
> -    telnetd_config->priority = rtems_bsdnet_config.network_task_priority;
> +  if (ctx->config.priority <= 0) {
> +    ctx->config.priority = rtems_bsdnet_config.network_task_priority;
>    }
>  #endif
> -  if (telnetd_config->priority < 2) {
> -    telnetd_config->priority = 100;
> +  if (ctx->config.priority < 2) {
> +    ctx->config.priority = 100;
>    }
>  
>    /* Check stack size */
> -  if (telnetd_config->stack_size <= 0) {
> -    telnetd_config->stack_size = (size_t)32 * 1024;
> +  if (ctx->config.stack_size <= 0) {

Is stack_size size_t and so unsigned?

Chris

> +    ctx->config.stack_size = (size_t)32 * 1024;
> +  }
> +
> +  if (ctx->config.client_maximum == 0) {
> +    ctx->config.client_maximum = 5;
>    }
>  
>    /* Spawn task */
>    task_id = telnetd_spawn_task(
>      "TNTD",
> -    telnetd_config->priority,
> -    telnetd_config->stack_size,
> +    ctx->config.priority,
> +    ctx->config.stack_size,
>      rtems_task_telnetd,
> -    0
> +    ctx
>    );
>    if (task_id == RTEMS_ID_NONE) {
> -    free(telnetd_config);
> -    telnetd_config = NULL;
> +    ctx->config.command = NULL;
>      return RTEMS_IO_ERROR;
>    }
>  
>    /* Print status */
> -  if (!telnetd_config->keep_stdio) {
> +  if (!ctx->config.keep_stdio) {
>      fprintf(
>        stderr,
>        "telnetd started with stacksize = %u and priority = %d\n",
> -      (unsigned) telnetd_config->stack_size,
> -      (unsigned) telnetd_config->priority
> +      (unsigned) ctx->config.stack_size,
> +      (unsigned) ctx->config.priority
>      );
>    }
>  
> @@ -364,6 +378,7 @@ spawned_shell(void *targ)
>    FILE                *ostd[3]={ stdin, stdout, stderr };
>    int                  i=0;
>    struct shell_args  *arg = targ;
> +  telnetd_context    *ctx = arg->ctx;
>    bool login_failed = false;
>    bool start = true;
>  
> @@ -395,17 +410,17 @@ spawned_shell(void *targ)
>    stderr = nstd[2];
>  
>    /* call their routine */
> -  if (telnetd_config->login_check != NULL) {
> +  if (ctx->config.login_check != NULL) {
>      start = rtems_shell_login_prompt(
>        stdin,
>        stderr,
>        arg->pty.name,
> -      telnetd_config->login_check
> +      ctx->config.login_check
>      );
>      login_failed = !start;
>    }
>    if (start) {
> -    telnetd_config->command( arg->pty.name, arg->arg);
> +    ctx->config.command( arg->pty.name, ctx->config.arg);
>    }
>  
>    stdin  = ostd[0];
> @@ -421,7 +436,7 @@ spawned_shell(void *targ)
>    }
>  
>  cleanup:
> -  release_a_Connection(arg->pty.name, arg->peername, nstd, i);
> +  release_a_Connection(ctx, arg->pty.name, arg->peername, nstd, i);
>    free(arg);
>  }
>  
> 



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