linux kernel 从cmdline 提取值

 1 // 从cmdline 提取 rootfsname= 的值到 val_buf                                         
 2 char val_buf[64];
 3 #define ROOTFS_CMDLINE "rootfsname="
 4 
 5 static void __init gluebi_read_cmdline (void)
 6 {
 7     rootfsmtd_ptr = strstr(saved_command_line, ROOTFS_CMDLINE);
 8     if (rootfsmtd_ptr) {
 9         sscanf(rootfsmtd_ptr, ROOTFS_CMDLINE"%s", val_buf);
10         printk("Gluebi: Found kernel commandline option 'rootfsname=%s'\n", val_buf);
11     }   
12 }

 1 // drivers/acpi/sysfs.c
 2 static int param_get_trace_state(char *buffer, struct kernel_param *kp)
 3 {
 4     if (!acpi_gbl_trace_method_name)
 5         return sprintf(buffer, "disable");
 6     else {
 7         if (acpi_gbl_trace_flags & 1)
 8             return sprintf(buffer, "1");
 9         else
10             return sprintf(buffer, "enable");
11     }
12     return 0;
13 }                                                                                    
14 // 设置 从cmdline 分析到 trace_state 参数 调用param_set_trace_state, 将值传给 buffer
15 module_param_call(trace_state, param_set_trace_state, NULL, NULL, 0);