为了更清楚的了解rtems的shell功能，这里以两个例子来演示shell功能。
根据login_check中的rtems_shell_login_check函数，可以发现通过getpwnam_r获取passwd，这里实际调用是getpw_r，如下：
static int getpw_r( const char *name, int uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result ) { FILE *fp; int match; _libcsupport_pwdgrp_init(); if ((fp = fopen("/etc/passwd", "r")) == NULL) rtems_set_errno_and_return_minus_one( EINVAL ); for(;;) { if (!_libcsupport_scanpw(fp, pwd, buffer, bufsize)) goto error_einval; if (name) { match = (strcmp(pwd->pw_name, name) == 0); } else { match = (pwd->pw_uid == uid); } if (match) { fclose(fp); *result = pwd; return 0; } } error_einval: fclose(fp); rtems_set_errno_and_return_minus_one( EINVAL ); }
所以我们知道rtems的账号信息在passwd文件，我们可以在Init中发现其创建了此文件
writeFile( "/etc/passwd", 0644, "root:$6$$FuPOhnllx6lhW2qqlnmWvZQLJ8Thr/09I7ESTdb9VbnTOn5.65" "/Vh2Mqa6FoKXwT0nHS/O7F0KfrDc6Svb/sH.:0:0:root::/:/bin/sh\n" "rtems::1:1:RTEMS Application::/:/bin/sh\n" "test:$1$$oPu1Xt2Pw0ngIc7LyDHqu1:2:2:test account::/:/bin/sh\n" "tty:*:3:3:tty owner::/:/bin/false\n" "chroot::4:2:chroot account::/chroot:/bin/sh\n" );
这里可以发现，如果我们新增一个用户，则在这里写入信息即可。需要注意的是密码被加密了。我们需要留意加密方式代码如下
crypt_add_format(&crypt_md5_format); crypt_add_format(&crypt_sha512_format); struct crypt_format crypt_md5_format = CRYPT_FORMAT_INITIALIZER(crypt_md5_r, "$1$"); struct crypt_format crypt_sha512_format = CRYPT_FORMAT_INITIALIZER(crypt_sha512_r, "$6$");
也就是我们可以通过md5和sha512两种方式加密
通过python3我们可以测试如下，假设我们设置密码是kylinos，则
>>> print(crypt.crypt("kylinos", "$1$")) $1$$PZwUkYqm0zRLtkgaIFzoq/ >>> print(crypt.crypt("kylinos", "$6$")) $6$$FXse0c1.Rfb8DWjwHmjUZNzufS4shiUUIVwzonK6LcfAlEWAYXPyxwfZhjV0C5.7tlU/ZUgh5e8GI2MPo7W02.
所以我们可以为rtems设置两个账户，一个是rtems，使用md5加密，一个是kylin，使用sha512加密
diff --git a/testsuites/samples/fileio/init.c b/testsuites/samples/fileio/init.c index 084d54d81a..a8e95874ef 100644 --- a/testsuites/samples/fileio/init.c +++ b/testsuites/samples/fileio/init.c @@ -584,10 +584,11 @@ static void fileio_start_shell(void) 0644, "root:$6$$FuPOhnllx6lhW2qqlnmWvZQLJ8Thr/09I7ESTdb9VbnTOn5.65" "/Vh2Mqa6FoKXwT0nHS/O7F0KfrDc6Svb/sH.:0:0:root::/:/bin/sh\n" - "rtems::1:1:RTEMS Application::/:/bin/sh\n" + "rtems:$1$$PZwUkYqm0zRLtkgaIFzoq/:1:1:RTEMS Application::/:/bin/sh\n" "test:$1$$oPu1Xt2Pw0ngIc7LyDHqu1:2:2:test account::/:/bin/sh\n" "tty:*:3:3:tty owner::/:/bin/false\n" "chroot::4:2:chroot account::/chroot:/bin/sh\n" + "kylin:$6$$FXse0c1.Rfb8DWjwHmjUZNzufS4shiUUIVwzonK6LcfAlEWAYXPyxwfZhjV0C5.7tlU/ZUgh5e8GI2MPo7W02.:5:5:KylinOS User::/:/bin/sh\n" );
构建验证即可。可以确认kylin 和 rtems两个账户的密码 kylinos都能登录。
为了使得rtems支持shell脚本执行，我们需要按照joel的方式编写脚本。我们可以在Init中通过writeScript和rtems_shell_write_file写入shell文件，如下
+ writeScript( + "/kylin", + "#! joel\n" + "echo Hello KylinOS\n" + ); + + rtems_shell_write_file( + "/kylin1", + "#! joel\n" + "echo Hello KylinOS\n" + );
编译后，运行如下：
SHLL [/] # ./kylin Hello KylinOS SHLL [/] # ./kylin1 Unable to execute //kylin1
可以发现rtems_shell_write_file的文件，及时内容正确，但是无法运行，我们需要为其添加权限,如下
SHLL [/] # chmod 0777 /kylin1 SHLL [/] # ./kylin1 Hello KylinOS
为了内置rtems的命令，可以通过自己实现命令的方式，主要如下：
首先我们添加一个c文件，用作kylin命令，路径为cpukit/libmisc/shell/main_kylin.c内容为：
static int rtems_shell_main_kylin(int argc, char *argv[]) { printf("Kylin Say: Hello World!\n"); return 0; } rtems_shell_cmd_t rtems_shell_KYLIN_Command = { "kylin", /* name */ "kylin # show message", /* usage */ "system1", /* topic */ rtems_shell_main_kylin , /* command */ NULL, /* alias */ NULL /* next */ };
然后我们为其增加到cmd初始化的数组中，改动如下：
diff --git a/cpukit/include/rtems/shellconfig.h b/cpukit/include/rtems/shellconfig.h index 489f281400..2b51967f7b 100644 --- a/cpukit/include/rtems/shellconfig.h +++ b/cpukit/include/rtems/shellconfig.h @@ -95,6 +95,7 @@ extern rtems_shell_cmd_t rtems_shell_HEXDUMP_Command; extern rtems_shell_cmd_t rtems_shell_DEBUGRFS_Command; extern rtems_shell_cmd_t rtems_shell_DF_Command; extern rtems_shell_cmd_t rtems_shell_MD5_Command; +extern rtems_shell_cmd_t rtems_shell_KYLIN_Command; extern rtems_shell_cmd_t rtems_shell_RTC_Command; extern rtems_shell_cmd_t rtems_shell_SPI_Command; @@ -606,6 +607,7 @@ extern rtems_shell_alias_t * const rtems_shell_Initial_aliases[]; #if defined(CONFIGURE_SHELL_USER_COMMANDS) CONFIGURE_SHELL_USER_COMMANDS, #endif + &rtems_shell_KYLIN_Command, NULL };
最后我们添加kylin命令的编译，如下
diff --git a/spec/build/cpukit/objshell.yml b/spec/build/cpukit/objshell.yml index 2eaf4e17cf..09fdbaab8a 100644 --- a/spec/build/cpukit/objshell.yml +++ b/spec/build/cpukit/objshell.yml @@ -38,6 +38,7 @@ source: - cpukit/libmisc/shell/main_chdir.c - cpukit/libmisc/shell/main_chmod.c - cpukit/libmisc/shell/main_chroot.c +- cpukit/libmisc/shell/main_kylin.c - cpukit/libmisc/shell/main_cmdchmod.c - cpukit/libmisc/shell/main_cmdchown.c - cpukit/libmisc/shell/main_cmdls.c
编译运行后，我们可以直接调用kylin命令如下：
SHLL [/] # kylin Kylin Say: Hello World!