支持管道、重定向、*匹配的miniShell

先上成果图

源代码

仅供技术点的分享，抄袭者就算了，所以main.c就不贴了

/*

 * split_line.c

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "mini_shell.h"

#define is_delim(x) ((x)==' '||(x)=='\t')

char *new_str(char *s, int l) {

    char *rv = emalloc(l + 1);

    rv[l] = '\0';

    strncpy(rv, s, l);

    return rv;

}

// 返回shell中获取到的一行命令

char *next_cmd(char *prompt, FILE *fp) {

    char *buf;                /* the buffer		*/

    int buf_size = 0;            /* total size		*/

    int pos = 0;            /* current position	*/

    int c;                /* input char		*/

    printf("%s", prompt);                /* prompt user	*/

    while ((c = getc(fp)) != EOF) {

        /* need space? */

        if (pos + 1 >= buf_size) {        /* 1 for \0	*/

            if (buf_size == 0) buf = emalloc(BUFSIZ);    /* y: 1st time	*/

            else buf = erealloc(buf, buf_size + BUFSIZ);       /* or expand	*/

            buf_size += BUFSIZ;        /* update size	*/

        }

        /* end of command? */

        if (c == '\n') break;

        /* no, add to buffer */

        buf[pos++] = c;

    }

    if (c == EOF && pos == 0) return NULL;              /* EOF and no input	*/

    buf[pos] = '\0';

    return buf;

}

// 将每个句子依空格再次拆分

char **split_sentence(char *line) {

    char **args;

    int spots;            /* spots in table	*/

    int buf_space;            /* bytes in table	*/

    int arg_num = 0;            /* slots used		*/

    char *cp = line;            /* pos in string	*/

    char *start;

    int len;

    if (line == NULL)            /* handle special case	*/

        return NULL;

    args = emalloc(BUFSIZ);        /* initialize array	*/

    buf_space = BUFSIZ;

    spots = BUFSIZ / sizeof(char *);

    while (*cp != '\0') {

        while (is_delim(*cp))        /* skip leading spaces	*/

            cp++;

        if (*cp == '\0')        /* quit at end-o-string	*/

            break;

        /* make sure the array has room (+1 for NULL) */

        if (arg_num + 1 >= spots) {

            args = erealloc(args, buf_space + BUFSIZ);

            buf_space += BUFSIZ;

            spots += (BUFSIZ / sizeof(char *));

        }

        /* mark start, then find end of word */

        start = cp;

        len = 1;

        while (*++cp != '\0' && !(is_delim(*cp))) len++;

        args[arg_num++] = new_str(start, len);

    }

    args[arg_num] = NULL;

    return args;

}

// 依管道符将命令拆分为几个句子，如果没有管道符，则只有一个句子

char ***split_line(char *line) {

    if (!line) return NULL;

    char ***orders = emalloc(BUFSIZ);

    int buf_space = BUFSIZ;

    int spots = BUFSIZ / sizeof(char **);

    int sen_num = 0;

    char *p = line;

    do {

        while (is_delim(*p))        /* skip leading spaces	*/

            p++;

        if (*p == '\0')        /* quit at end-o-string	*/

            break;

        if (sen_num + 1 >= spots) {

            orders = erealloc(orders, buf_space + BUFSIZ);

            buf_space += BUFSIZ;

            spots += BUFSIZ / sizeof(char **);

        }

        char *end = p;

        while (*end != '\0' && *end != '|') end++;

        char *sentence = emalloc(end - p + 1);   // 由管道符隔开的为一个sentence

        strncpy(sentence, p, end - p);

        sentence[end - p] = 0;

        orders[sen_num++] = split_sentence(sentence);

        if (*end) p = end + 1;  // '|'

        else p = end;  // '\0'

    } while (*p);

    orders[sen_num] = 0;

    return orders;

}

// 释放在堆区申请的内存

void freelist(char ***list) {

    for (char ***t = list; *t; t++)

        for (char **tt = *t; *tt; tt++)

            free(*tt);

    for (char ***t = list; *t; t++)

        free(*t);

    free(list);

}

void *emalloc(size_t n) {

    void *rv;

    if ((rv = malloc(n)) == NULL) fatal("out of memory", "", 1);

    return rv;

}

void *erealloc(void *p, size_t n) {

    void *rv;

    if ((rv = realloc(p, n)) == NULL)

        fatal("realloc() failed", "", 1);

    return rv;

}

/*

 * execute.c - code used by mini shell to execute commands

 */

#include    <stdio.h>

#include    <stdlib.h>

#include    <unistd.h>

#include    <string.h>

#include    <signal.h>

#include    <sys/wait.h>

#include    <sys/file.h>

#include    <glob.h>  // 利用glob()函数进行*的匹配

int redirect(char **cmd) {

    int ard = 0;  // append redirect, 追加重定向

    int rd = 0;  // 非追加重定向

    while (*cmd) {

        char *p = *cmd;

        int fd;

        if (ard || rd) {

            if (ard) fd = open(p, O_CREAT | O_APPEND | O_WRONLY, 0644);

            else fd = open(p, O_CREAT | O_TRUNC | O_WRONLY, 0644);

            dup2(fd, 1);

            close(fd);

            return 0;

        }

        while (*p && *p != '>') p++;

        if (*p) {  // 如果有重定向符 >

            *p = '\0', p++;

            if (*p == '>') ard = 1;  // 追加重定向

            else rd = 1;  // 不是追加重定向

            *cmd = NULL;

        }

        cmd++;

    }

    if (ard || rd) return -1;

    else return 0;

}

// 执行解析好的命令

int execute(char ***argv) {

    pid_t pid;

    int child_info = -1;

    int fds[2], fd = 0;

    while (*argv) {

        pipe(fds);

        if ((pid = fork()) == -1) perror("fork");

        else if (pid == 0) {

            close(fds[0]);

            dup2(fd, 0);

            if (*(argv + 1)) dup2(fds[1], 1);

            else {

                if (redirect(*argv) == -1) {  // 重定向后无内容

                    printf("zsh: parse error near `\\n'\n");

                    exit(1);

                }

            }

            signal(SIGINT, SIG_DFL);

            signal(SIGQUIT, SIG_DFL);

            glob_t buf;

            buf.gl_offs = buf.gl_pathc = 0;  // 初始化 offset 和 path_count

            // 计算offset，即第一个命令和后续命令选项的个数

            char **word = *argv;

            word++, buf.gl_offs++;  // 命令

            while (*word && **word == '-') word++, buf.gl_offs ++ ;  // 选项

            // GLOB_NOCHECK的作用是没有匹配的文件名时，使用模式串。用在 grep txt 类的命令中对 "txt" 的处理上

            if (*word) glob(*word++, GLOB_DOOFFS | GLOB_NOCHECK, NULL, &buf);  // 第一个参数

            while (*word) glob(*word++, GLOB_DOOFFS | GLOB_APPEND | GLOB_NOCHECK, NULL, &buf);  // 后续参数

            // 调用 glob() 会将 gl_pathv[] 的前offset个置为空，因此，要在调用 glob() 后对其赋值

            word = *argv, buf.gl_offs = 0;  // 重置

            buf.gl_pathv[buf.gl_offs++] = *word++;  // 命令

            while (*word && **word == '-') buf.gl_pathv[buf.gl_offs++] = *word++;  // 选项

            if (buf.gl_pathc) execvp((*argv)[0], &buf.gl_pathv[0]);  // 调用过glob()函数，即可能有*的情况

            else execvp((*argv)[0], *argv);  // 没调用过，则不会有*

            perror("cannot execute command");

            exit(1);

        } else {

            if (wait(&child_info) == -1) perror("wait");

            close(fds[1]);

            fd = fds[0];

            argv++;

        }

    }

    return child_info;

}

巴特西

支持管道、重定向、*匹配的miniShell

先上成果图

源代码

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