25개 이상의 토픽을 선택하실 수 없습니다.
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
254 lines
5.8 KiB
254 lines
5.8 KiB
#include <ulib.h>
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#include <stdio.h>
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#include <string.h>
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#include <dir.h>
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#include <file.h>
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#include <error.h>
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#include <unistd.h>
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#define printf(...) fprintf(1, __VA_ARGS__)
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#define putc(c) printf("%c", c)
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#define BUFSIZE 4096
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#define WHITESPACE " \t\r\n"
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#define SYMBOLS "<|>&;"
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char shcwd[BUFSIZE];
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int
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gettoken(char **p1, char **p2) {
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char *s;
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if ((s = *p1) == NULL) {
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return 0;
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}
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while (strchr(WHITESPACE, *s) != NULL) {
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*s ++ = '\0';
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}
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if (*s == '\0') {
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return 0;
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}
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*p2 = s;
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int token = 'w';
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if (strchr(SYMBOLS, *s) != NULL) {
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token = *s, *s ++ = '\0';
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}
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else {
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bool flag = 0;
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while (*s != '\0' && (flag || strchr(WHITESPACE SYMBOLS, *s) == NULL)) {
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if (*s == '"') {
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*s = ' ', flag = !flag;
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}
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s ++;
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}
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}
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*p1 = (*s != '\0' ? s : NULL);
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return token;
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}
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char *
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readline(const char *prompt) {
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static char buffer[BUFSIZE];
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if (prompt != NULL) {
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printf("%s", prompt);
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}
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int ret, i = 0;
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while (1) {
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char c;
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if ((ret = read(0, &c, sizeof(char))) < 0) {
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return NULL;
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}
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else if (ret == 0) {
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if (i > 0) {
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buffer[i] = '\0';
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break;
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}
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return NULL;
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}
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if (c == 3) {
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return NULL;
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}
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else if (c >= ' ' && i < BUFSIZE - 1) {
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putc(c);
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buffer[i ++] = c;
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}
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else if (c == '\b' && i > 0) {
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putc(c);
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i --;
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}
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else if (c == '\n' || c == '\r') {
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putc(c);
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buffer[i] = '\0';
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break;
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}
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}
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return buffer;
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}
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void
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usage(void) {
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printf("usage: sh [command-file]\n");
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}
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int
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reopen(int fd2, const char *filename, uint32_t open_flags) {
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int ret, fd1;
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close(fd2);
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if ((ret = open(filename, open_flags)) >= 0 && ret != fd2) {
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close(fd2);
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fd1 = ret, ret = dup2(fd1, fd2);
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close(fd1);
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}
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return ret < 0 ? ret : 0;
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}
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int
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testfile(const char *name) {
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int ret;
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if ((ret = open(name, O_RDONLY)) < 0) {
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return ret;
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}
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close(ret);
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return 0;
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}
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int
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runcmd(char *cmd) {
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static char argv0[BUFSIZE];
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const char *argv[EXEC_MAX_ARG_NUM + 1];
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char *t;
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int argc, token, ret, p[2];
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again:
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argc = 0;
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while (1) {
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switch (token = gettoken(&cmd, &t)) {
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case 'w':
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if (argc == EXEC_MAX_ARG_NUM) {
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printf("sh error: too many arguments\n");
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return -1;
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}
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argv[argc ++] = t;
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break;
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case '<':
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if (gettoken(&cmd, &t) != 'w') {
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printf("sh error: syntax error: < not followed by word\n");
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return -1;
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}
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if ((ret = reopen(0, t, O_RDONLY)) != 0) {
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return ret;
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}
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break;
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case '>':
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if (gettoken(&cmd, &t) != 'w') {
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printf("sh error: syntax error: > not followed by word\n");
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return -1;
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}
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if ((ret = reopen(1, t, O_RDWR | O_TRUNC | O_CREAT)) != 0) {
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return ret;
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}
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break;
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case '|':
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// if ((ret = pipe(p)) != 0) {
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// return ret;
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// }
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if ((ret = fork()) == 0) {
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close(0);
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if ((ret = dup2(p[0], 0)) < 0) {
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return ret;
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}
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close(p[0]), close(p[1]);
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goto again;
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}
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else {
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if (ret < 0) {
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return ret;
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}
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close(1);
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if ((ret = dup2(p[1], 1)) < 0) {
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return ret;
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}
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close(p[0]), close(p[1]);
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goto runit;
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}
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break;
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case 0:
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goto runit;
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case ';':
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if ((ret = fork()) == 0) {
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goto runit;
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}
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else {
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if (ret < 0) {
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return ret;
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}
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waitpid(ret, NULL);
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goto again;
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}
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break;
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default:
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printf("sh error: bad return %d from gettoken\n", token);
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return -1;
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}
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}
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runit:
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if (argc == 0) {
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return 0;
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}
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else if (strcmp(argv[0], "cd") == 0) {
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if (argc != 2) {
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return -1;
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}
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strcpy(shcwd, argv[1]);
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return 0;
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}
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if ((ret = testfile(argv[0])) != 0) {
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if (ret != -E_NOENT) {
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return ret;
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}
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snprintf(argv0, sizeof(argv0), "/%s", argv[0]);
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argv[0] = argv0;
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}
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argv[argc] = NULL;
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return __exec(NULL, argv);
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}
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int
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main(int argc, char **argv) {
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printf("user sh is running!!!");
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int ret, interactive = 1;
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if (argc == 2) {
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if ((ret = reopen(0, argv[1], O_RDONLY)) != 0) {
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return ret;
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}
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interactive = 0;
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}
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else if (argc > 2) {
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usage();
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return -1;
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}
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//shcwd = malloc(BUFSIZE);
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assert(shcwd != NULL);
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char *buffer;
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while ((buffer = readline((interactive) ? "$ " : NULL)) != NULL) {
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shcwd[0] = '\0';
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int pid;
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if ((pid = fork()) == 0) {
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ret = runcmd(buffer);
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exit(ret);
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}
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assert(pid >= 0);
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if (waitpid(pid, &ret) == 0) {
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if (ret == 0 && shcwd[0] != '\0') {
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ret = 0;
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}
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if (ret != 0) {
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printf("error: %d - %e\n", ret, ret);
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}
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}
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}
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return 0;
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}
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