len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj); return simple_read_from_buffer(buf, count, ppos, buffer, len); } /proc/xxx/oom_score:只读。经过oom_badness()计算得出对当前进程消耗页面数目,然后相对于totalpages归一化到1000。 static int proc_oom_score(struct seq_file *m, stru...
static ssize_t my_blob_wrapper_read(struct file *filp, char __user *user_buf, size_t count, loff_t *ppos) { struct my_blob_wrapper *blob = filp->private_data; return simple_read_from_buffer(user_buf, count, ppos, blob->data, blob->size);//此函数有libfs提供,与下面逻辑等价 // ...
simple_write_to_buffer助手的“对”是simple_read_from_buffer。该助手可用于.read方法的实现: 代码语言:javascript 复制 ssize_t pfsw_read(struct file filp*, char __user * user_data, size_t sz, loff_t *off) { // Here the helper does the whole work. // // 'buf_size' could be 'size...
h> /** * This is a simple example for using open(), write(), read(), lseek() and close(). */ int main(int argc, char *argv[]) { int fd; ssize_t wr_size, rd_size; char buffer[128]; char string_1[30], string_2[30] = "This is the second line!\n"; char *path =...
(copy_from_user(example_buffer, buf, count)) return -EFAULT; return count; } static ssize_t test_proc_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) { return simple_read_from_buffer(buf, size, ppos, example_buffer, strlen(example_buffer)); } static const ...
read函数用来从设备读取字符。该函数的形式必须和file_operations结构体中的形式相符: ssize_t(*read)(structfile*filep,char*buffer,size_tlen,loff_t*offset); filep参数是指向file结构体的指针。file结构体可以用来获取文件的必要相关信息。我们读取的数据被分配在用户空间中,地址通过第二个参数buffer给出。将要...
0x528c709d simple_read_from_buffer vmlinux EXPORT_SYMBOL 0xe83e74d0 class_device_destroy vmlinux EXPORT_SYMBOL_GPL 0xa681fe88 generate_random_uuid vmlinux EXPORT_SYMBOL 0x196f57d2 vfs_statfs vmlinux EXPORT_SYMBOL 0x6b37068c udp_ioctl vmlinux EXPORT_SYMBOL 0x27f1bc29 __nla_reserve...
read into this file. Change this folder according to your server #pos_file PATH /home/user1/fluent-test/demo_simple_match.log.pos # tag is used to correlate the directives. For example, source with corresponding filter and match directives. tag scom.log #reads the fields from the log ...
首先调用copy_from_user 将用户态参数拷贝至数组a 。但是问题在于,每个被调用的 API 的参数不尽相同,那么每次拷贝的字节在小如果断定? 来看其第三个参数nargs[call],其中 call 是操作码,后面有个大大的 switch...case就是判断它。对应的操作码定义在include/linux/net.h : #define SYS_SOCKET 1 /* sys_...
isotpserver : IP server for simple TCP/IP <-> ISO 15765-2 bridging (ASCII HEX) isotpperf : ISO15765-2 protocol performance visualisation isotptun : create a bi-directional IP tunnel on CAN via ISO-TP J1939/ISOBus tools j1939acd : address claim daemon ...