使用fork和execvp函數從stdin行運行命令,製作一個簡單類型的shell。實現一個簡單的shell
但是,像ls
這樣的工作,但不是ls -all -S
。 它將執行ls
,但什麼都不會被打印ls -all
唯一的想法,我能想出的是,有一個「\ n」某處的命令,但我不知道怎麼把它弄出來甚至它在哪裏......
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
//Libs ^^^^ Defs vvvvvvvv
#define comlen 4096 //Max command length
#define comarg 32 //Max argument length
int main(int argc, char *argv[])
{
char buff; //command buffer
char* comand[comlen];
int i;
do
{
i = 0;
printf("simsh: ");
char* whtspc = strtok (fgets(&buff, comlen, stdin)," "); //get input and tokenize
printf("[%lu] :: %s------------\nEND OF BUFF TEST\n", strlen(&buff), &buff);
while (whtspc != NULL)
{
comand[i]=(char*)malloc((sizeof(char)*strlen(whtspc))); //alloctie mem for commands
strncpy(comand[i], whtspc, strlen(whtspc)-1); //coppy comand token to array index i
whtspc = strtok (NULL, " "); //grab next token
i++; //incriment
/*trying to change new line character to NULL so that commands can be passed properly*/
// if (comand[strlen(comand[i]) - 1] == "\n")
// {
// comand[strlen(comand[i]) - 1] = '\0';
// }
//breka out incase index oversteps
if (i == 4096)
break;
}
//last entry in command should be null
comand[i] = NULL;
//fork to run in background
pid_t pid = fork();
if (pid == 0)
{
//testing and pass comands to execvp
printf("START OF COMAND TEST\n!!!!!!!!!%s!!!!!!!!!!!!!!!!\n %lu\nEND OF COMAND TEST\n\n",comand[1], strlen(comand[0]));
execvp(comand[0], &comand);
}
else
{
//parent wait on child.
waitpid(pid, &i, WUNTRACED | WCONTINUED);
}
}
while(1);
return 0;
}
任何幫助將受到歡迎。
如果有幫助可言,這裏是代碼的終端輸出::
所有的simsh: ls
[3] :: ls
------------
END OF BUFF TEST
START OF COMAND TEST
!!!!!!!!!(null)!!!!!!!!!!!!!!!!
2
END OF COMAND TEST
chop_line.c chop_line.h list.c list.h Makefile Makefile~ One simsh1 simsh1.c simsh1.c~
simsh: ls -all
[2] :: ls------------
END OF BUFF TEST
START OF COMAND TEST
!!!!!!!!!-all!!!!!!!!!!!!!!!!
1
END OF COMAND TEST
simsh: echo
[5] :: echo
------------
END OF BUFF TEST
START OF COMAND TEST
!!!!!!!!!(null)!!!!!!!!!!!!!!!!
4
END OF COMAND TEST
simsh: echo all
[4] :: echo------------
END OF BUFF TEST
START OF COMAND TEST
!!!!!!!!!all!!!!!!!!!!!!!!!!
3
END OF COMAND TEST
simsh: echo echo
[4] :: echo------------
END OF BUFF TEST
START OF COMAND TEST
!!!!!!!!!echo!!!!!!!!!!!!!!!!
3
END OF COMAND TEST
你能更準確地描述出乎意料的行爲嗎? – hivert
當我執行諸如'ls'這樣的命令時,它可以工作,但是當我嘗試執行像'ls -all -S'這樣的命令時,它不執行命令。或者如果我做'回聲測試',它不會迴應「測試」。我不確定爲什麼 –
可能想查看[dash]的源代碼(http://git.kernel.org/cgit/utils/dash/dash.git/tree/src),它是一個小的posix shell沒有額外的。 – TechZilla