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 static int param_set_trace_state(const char *val, struct kernel_param *kp)
15 {
16     int result = 0;
17 
18     if (!strncmp(val, "enable", sizeof("enable") - 1)) {
19         result = acpi_debug_trace(trace_method_name, trace_debug_level,
20                       trace_debug_layer, 0);
21         if (result)
22             result = -EBUSY;
23         goto exit;
24     }
25 
26     if (!strncmp(val, "disable", sizeof("disable") - 1)) {
27         int name = 0;
28         result = acpi_debug_trace((char *)&name, trace_debug_level,
29                       trace_debug_layer, 0);
30         if (result)
31             result = -EBUSY;
32         goto exit;
33     }
34 
35     if (!strncmp(val, "1", 1)) {
36         result = acpi_debug_trace(trace_method_name, trace_debug_level,
37                       trace_debug_layer, 1);
38         if (result)
39             result = -EBUSY;
40         goto exit;
41     }
42 
43     result = -EINVAL;
44 exit:
45     return result;
46 }
47                                                                                     
48 // 设置 从cmdline 分析到 trace_state 参数 调用param_set_trace_state, 将值传给 buffer
49 module_param_call(trace_state, param_set_trace_state, NULL, NULL, 0);

1 // init/main.c
2 
3 static int __init set_reset_devices(char *str)
4 {
5     reset_devices = 1;
6     return 1;
7 }
8 
9 __setup("reset_devices", set_reset_devices);

posted on 2019-01-19 16:33 listenerln 阅读(2227) 评论(0) 收藏举报