C语言接口的写法（以toyls命令为例） 

 1 #include <unistd.h>
 2 
 3 #include <stdio.h>
 4 #include <stdlib.h>
 5 #include <string.h>
 6 
 7 #define CMDSIZE 4096
 8 
 9 static void prompt(void)
10 {
11     printf("[mysh]$ ");
12     fflush(stdout);
13 }
14 
15 static void getcmd(char *cmd, char **argv)
16 {
17     int i = 0;
18 
19     fgets(cmd, CMDSIZE, stdin);
20 
21     argv[i] = strtok(cmd, " \t\n");
22     for (i++; argv[i - 1] != NULL; i++) {
23         argv[i] = strtok(NULL, " \t\n");
24     }
25 }
26 
27 static void myexit(char **argv)
28 {
29     exit(0);
30 }
31 
32 static void mycd(char **argv)
33 {
34     chdir(argv[1]);
35 }
36 
37 #define NAMESIZE 256
38 struct {
39     void (*func)(char **);
40     char name[NAMESIZE];
41 } internal_list[] = {
42     {myexit, "exit"},
43     {mycd, "cd"},
44     {NULL, },
45 };
46 
47 static int internal_ind(const char *name)
48 {
49     int i;
50 
51     for (i = 0; internal_list[i].func != NULL; i++) {
52         if (strcmp(name, internal_list[i].name) == 0) {
53             return i;
54         }
55     }
56     return -1;
57 }
58 
59 int main(void)
60 {
61     char cmd[CMDSIZE];
62     char *argv[CMDSIZE / 2];
63     pid_t pid;
64     int ind;
65 
66     while (1) {
67         prompt();
68 
69         getcmd(cmd, argv);
70         if ((ind = internal_ind(argv[0])) != -1) {
71             internal_list[ind].func(argv);
72         } else {
73             pid = fork();
74             /* if error */
75             if (pid == 0) {
76                 execvp(argv[0], argv);
77                 perror(argv[0]);
78                 exit(1);
79             }
80             wait(NULL);
81         }
82     }
83 
84     return 0;
85 }
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posted @ 2015-03-16 15:10  prepat  阅读(800)  评论(0)    收藏  举报