{"id":3549,"date":"2017-08-19T08:31:21","date_gmt":"2017-08-19T00:31:21","guid":{"rendered":"https:\/\/ixyzero.com\/blog\/?p=3549"},"modified":"2017-08-19T08:31:21","modified_gmt":"2017-08-19T00:31:21","slug":"linux%e4%b8%8b%e7%94%a8c%e8%af%ad%e8%a8%80%e5%b0%86%e6%96%87%e4%bb%b6%e5%86%85%e5%ae%b9%e8%af%bb%e5%85%a5%e6%95%b0%e7%bb%84","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/3549.html","title":{"rendered":"Linux\u4e0b\u7528C\u8bed\u8a00\u5c06\u6587\u4ef6\u5185\u5bb9\u8bfb\u5165\u6570\u7ec4"},"content":{"rendered":"

=Start=<\/p>\n

\u7f18\u7531\uff1a<\/h4>\n

\u5b66\u4e60\u3001\u603b\u7ed3\u9700\u8981<\/p>\n

\u6b63\u6587\uff1a<\/h4>\n

\u53c2\u8003\u89e3\u7b54\uff1a<\/h5>\n
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#include <unistd.h><\/code><\/div>\n
#include <string.h><\/code><\/div>\n
#include <stdlib.h><\/code><\/div>\n
#include <stdio.h><\/code><\/div>\n
<\/div>\n
#define MAX_LINES\u00a0<\/code>32<\/code><\/div>\n
#define LINE_SIZE\u00a0<\/code>128<\/code><\/div>\n
char<\/code>\u00a0lines[MAX_LINES][LINE_SIZE];<\/code><\/div>\n
<\/div>\n
int<\/code>\u00a0read_file_to_array() {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>FILE *fp;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>fp = fopen(<\/code>\"\/tmp\/paths.txt\"<\/code>,\u00a0<\/code>\"r\"<\/code>);\u00a0<\/code>\/* path_s = \/etc\/passwd, \/etc\/shadow, \/etc\/hosts, \/bin\/ps *\/<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fp == NULL) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>perror(<\/code>\"fopen\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a0-<\/code>1<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0*line = NULL, *index = NULL;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0path_str[<\/code>1024<\/code>] = {<\/code>0<\/code>}, *path_str_p, *token = NULL, delim[] =\u00a0<\/code>\", \"<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>size_t len =\u00a0<\/code>0<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>ssize_t nread;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0i =\u00a0<\/code>0<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>while<\/code>\u00a0((nread = getline(&line, &len, fp)) != -<\/code>1<\/code>) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(strncmp(line,\u00a0<\/code>\"path_s\"<\/code>,\u00a0<\/code>6<\/code>) ==\u00a0<\/code>0<\/code>) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>index = strchr(line,\u00a0<\/code>'='<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(index) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>line[strcspn(line,\u00a0<\/code>\"\\r\\n\"<\/code>)] =\u00a0<\/code>0<\/code>;\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ remove trailing newline character<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"path_s = '%s'\\n\"<\/code>, line);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>strncpy(path_str, index+<\/code>1<\/code>, nread-<\/code>7<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>path_str_p = path_str;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>token = strsep(&path_str_p, delim);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>while<\/code>(token != NULL){<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(token[<\/code>0<\/code>] !=\u00a0<\/code>'\\0'<\/code>) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"\\tpath = '%s'\\n\"<\/code>, token);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(i < MAX_LINES) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>strncpy(lines[i], token, LINE_SIZE);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>i++;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>token = strsep(&path_str_p, delim);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>break<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>(line)<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>free(line);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>fclose(fp);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a0i;<\/code><\/div>\n
}<\/code><\/div>\n
<\/div>\n
int<\/code>\u00a0main(<\/code>int<\/code>\u00a0argc,\u00a0<\/code>char<\/code>\u00a0const<\/code>\u00a0*argv[])<\/code><\/div>\n
{<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0i, ret;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>ret = read_file_to_array();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"\\npath counts = %d\\n\"<\/code>, ret);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>for<\/code>\u00a0(i =\u00a0<\/code>0<\/code>; i < ret; ++i) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ printf(\"#%d\\n\", i);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(lines[i][<\/code>0<\/code>] !=\u00a0<\/code>'\\0'<\/code>) {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"line[%d] = '%s'\\n\"<\/code>, i, lines[i]);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a00<\/code>;<\/code><\/div>\n
}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

&<\/p>\n

Linux\u4e0bC\u8bed\u8a00\u4e2d\u5982\u4f55\u5220\u9664\u884c\u5c3e\u7684\u6362\u884c\u7b26\uff1f<\/h6>\n
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line[strcspn(line,\u00a0<\/code>\"\\r\\n\"<\/code>)] =\u00a0<\/code>0<\/code>;\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ remove trailing newline character<\/code><\/div>\n
\/*<\/code><\/div>\n
#include <string.h><\/code><\/div>\n
<\/div>\n
strspn, strcspn - get length of a prefix substring<\/code><\/div>\n
<\/div>\n
<\/div>\n
size_t strspn(const char *s, const char *accept);<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>The strspn() function calculates the length (in bytes) of the initial segment of s which consists entirely of bytes in accept. strspn()\u51fd\u6570\u8ba1\u7b97\u5728\u5b57\u7b26\u4e32s\u4e2d\u5305\u542b\u6574\u4e2aaccept\u5b57\u7b26\u4e32\u7684\u5b50\u4e32\u957f\u5ea6\u3002<\/code><\/div>\n
<\/div>\n
size_t strcspn(const char *s, const char *reject);<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>The strcspn() function calculates the length of the initial segment of s which consists entirely of bytes not in reject. strcspn()\u51fd\u6570\u8ba1\u7b97\u5728\u5b57\u7b26\u4e32s\u4e2d\u4e0d\u5305\u542breject\u5b57\u7b26\u4e32\u4e2d\u5b57\u7b26\u7684\u5b50\u4e32\u957f\u5ea6\u3002<\/code><\/div>\n
*\/<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n