dhcpd: Supports kernel mode compilation

[zs39]

Summary

The previous method of terminating the dhcp daemon via a global variable has been removed; instead, the kill pid command is used. Also, because the original dhcp_start method creates tasks via task_create, which is not supported in kernel mode, dhcp_start is not compiled in kernel mode. The daemon can be started in kernel mode using dhcpd xxx &.

Impact

The dhcpd_start and dhcpd_stop functions

Testing

Tested normally in flat mode

nsh> dhcpd_start eth0
nsh> ps
  TID   PID  PPID PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK COMMAND
    0     0     0   0 FIFO     Kthread   - Ready              0000000000000000 0069568 Idle_Task
    1     0     0 224 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067448 hpwork 0x400b8020 0x400b80a0
    2     0     0 100 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067448 lpwork 0x400b80e0 0x400b8160
    3     3     0 100 FIFO     Task      - Running            0000000000000000 0067488 nsh_main
    5     5     4 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0067464 dhcpd eth0
nsh> dhcpd_stop
nsh> ps
  TID   PID  PPID PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK COMMAND
    0     0     0   0 FIFO     Kthread   - Ready              0000000000000000 0069568 Idle_Task
    1     0     0 224 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067448 hpwork 0x400b8020 0x400b80a0
    2     0     0 100 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0067448 lpwork 0x400b80e0 0x400b8160
    3     3     0 100 FIFO     Task      - Running            0000000000000000 0067488 nsh_main
nsh> 

The build process works correctly in kernel mode and also functions properly on the internal QEMU platform.

ap> dhcpd wlan0 &
dhcpd [15:255]
ap> ps
  PID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK    USED FILLED    CPU COMMAND
    0     0   0 FIFO     Kthread   - Ready              0000000000000000 0008104 0000492   6.0%  39.0% CPU0 IDLE
    1     0 254 FIFO     Kthread   - Ready              0000000000000000 0008056 0000720   8.9%   0.8% hpwork 0x402009c0 0x40200a18
    2     0  90 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0008056 0000584   7.2%   0.0% lpwork 0x40200940 0x40200998
    4     4 255 FIFO     Task      - Running            0000000000000000 0032656 0001664   5.0%   0.9% /bin/init
    6     6 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0001872   1.8%   0.0% kvdbd
    7     7 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102288 0001496   1.4%  57.7% servicemanager
    9     9 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0007080   6.9%   0.0% mediad
   10    10 100 FIFO     Task      - Ready              0000000000000000 0102296 0004620   4.5%   1.3% systemd
   11    11 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0001072   1.0%   0.0% opteed
   12    12 100 FIFO     Task      - Waiting  Semaphore 0000000000020000 0102296 0000624   0.6%   0.0% telnetd
   13     6 100 FIFO     pthread   - Waiting  Semaphore 0000000000000000 0008104 0000544   6.7%   0.0% kvdbd 0x800010cd 0x820194ac
   14    14 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102264 0024880  24.3%   0.0% vappxms com.application.x4b.init
   15    15 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102288 0000624   0.6%   0.0% dhcpd wlan0
ap> dhcpd_stop
ap> ps
  PID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK    USED FILLED    CPU COMMAND
    0     0   0 FIFO     Kthread   - Ready              0000000000000000 0008104 0000492   6.0%  89.4% CPU0 IDLE
    1     0 254 FIFO     Kthread   - Ready              0000000000000000 0008056 0000720   8.9%   3.5% hpwork 0x402009c0 0x40200a18
    2     0  90 FIFO     Kthread   - Waiting  Semaphore 0000000000000000 0008056 0000584   7.2%   0.0% lpwork 0x40200940 0x40200998
    4     4 255 FIFO     Task      - Running            0000000000000000 0032656 0001664   5.0%   0.8% /bin/init
    6     6 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0001872   1.8%   0.0% kvdbd
    7     7 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102288 0001496   1.4%   0.0% servicemanager
    9     9 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0007080   6.9%   0.0% mediad
   10    10 100 FIFO     Task      - Ready              0000000000000000 0102296 0004620   4.5%   6.1% systemd
   11    11 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102296 0001072   1.0%   0.0% opteed
   12    12 100 FIFO     Task      - Waiting  Semaphore 0000000000020000 0102296 0000624   0.6%   0.0% telnetd
   13     6 100 FIFO     pthread   - Waiting  Semaphore 0000000000000000 0008104 0000544   6.7%   0.0% kvdbd 0x800010cd 0x820194ac
   14    14 100 FIFO     Task      - Waiting  Semaphore 0000000000000000 0102264 0024880  24.3%   0.0% vappxms com.application.x4b.init

[xiaoxiang781216]

@zs39 please fix:

../nuttx/tools/checkpatch.sh -c -u -m -g 9da2bc06961587ec0d288686099a3e75524f8cc3..HEAD
Used config files:
    1: .codespellrc
/home/runner/work/nuttx-apps/nuttx-apps/apps/netutils/dhcpd/dhcpd.c:1019: re-use ==> reuse
/home/runner/work/nuttx-apps/nuttx-apps/apps/netutils/dhcpd/dhcpd.c:1407: re-used ==> reused
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