Improved the shell with pipes, background processes and semicolons.
It's really hacky, but it's an improvement.
This commit is contained in:
Jonas 'Sortie' Termansen
parent
0ed0082070
commit
98d1ccfa7d
195
utils/mxsh.cpp
195
utils/mxsh.cpp
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@ -10,6 +10,155 @@
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int status = 0;
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int runcommandline(const char** tokens)
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{
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int result = 127;
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size_t cmdnext = 0;
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size_t cmdstart;
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size_t cmdend;
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bool lastcmd = false;
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int pipein = 0;
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int pipeout = 1;
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int pipeinnext = 0;
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char* const* argv;
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size_t cmdlen;
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const char* execmode;
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const char* outputfile;
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pid_t childpid;
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bool internal;
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int internalresult;
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readcmd:
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cmdstart = cmdnext;
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for ( cmdend = cmdstart; true; cmdend++ )
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{
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const char* token = tokens[cmdend];
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if ( !token ||
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strcmp(token, ";") == 0 ||
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strcmp(token, "&") == 0 ||
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strcmp(token, "|") == 0 ||
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strcmp(token, ">") == 0 ||
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false )
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{
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break;
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}
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}
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cmdlen = cmdend - cmdstart;
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if ( !cmdlen ) { fprintf(stderr, "expected command\n"); goto out; }
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execmode = tokens[cmdend];
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if ( !execmode ) { lastcmd = true; execmode = ";"; }
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tokens[cmdend] = NULL;
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if ( strcmp(execmode, "|") == 0 )
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{
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int pipes[2];
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if ( pipe(pipes) ) { perror("pipe"); goto out; }
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if ( pipeout != 1 ) { close(pipeout); } pipeout = pipes[1];
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if ( pipeinnext != 0 ) { close(pipeinnext); } pipeinnext = pipes[0];
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}
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outputfile = NULL;
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if ( strcmp(execmode, ">") == 0 )
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{
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outputfile = tokens[cmdend+1];
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if ( !outputfile ) { fprintf(stderr, "expected filename\n"); goto out; }
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const char* nexttok = tokens[cmdend+2];
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if ( nexttok ) { fprintf(stderr, "too many filenames\n"); goto out; }
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}
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cmdnext = cmdend + 1;
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argv = (char* const*) (tokens + cmdstart);
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internal = false;
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internalresult = 0;
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if ( strcmp(argv[0], "cd") == 0 )
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{
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internal = true;
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const char* newdir = "/";
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if ( argv[1] ) { newdir = argv[1]; }
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if ( chdir(newdir) )
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{
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error(0, errno, "cd: %s", newdir);
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internalresult = 1;
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}
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}
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if ( strcmp(argv[0], "exit") == 0 )
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{
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int exitcode = argv[1] ? atoi(argv[1]) : 0;
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exit(exitcode);
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}
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childpid = internal ? getpid() : fork();
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if ( childpid < 0 ) { perror("fork"); goto out; }
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if ( childpid )
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{
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if ( pipein != 0 ) { close(pipein); pipein = 0; }
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if ( pipeout != 1 ) { close(pipeout); pipeout = 1; }
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if ( pipeinnext != 0 ) { pipein = pipeinnext; pipeinnext = 0; }
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if ( strcmp(execmode, "&") == 0 && !tokens[cmdnext] )
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{
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result = 0; goto out;
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}
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if ( strcmp(execmode, "&") == 0 || strcmp(execmode, "|") == 0 )
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{
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goto readcmd;
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}
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int status = internalresult;
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if ( !internal && waitpid(childpid, &status, 0) < 0 )
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{
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perror("waitpid");
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return 127;
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}
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if ( strcmp(execmode, ";") == 0 && tokens[cmdnext] && !lastcmd )
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{
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goto readcmd;
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}
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result = status;
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goto out;
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}
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if ( pipeinnext != 0 ) { close(pipeinnext); }
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if ( pipein != 0 )
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{
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close(0);
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dup(pipein);
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close(pipein);
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}
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if ( pipeout != 1 )
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{
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close(1);
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dup(pipeout);
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close(pipeout);
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}
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if ( outputfile )
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{
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close(1);
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if ( open(outputfile, O_CREAT | O_WRONLY | O_TRUNC | O_APPEND) < 0 )
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{
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error(127, errno, "%s", outputfile);
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}
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}
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execv(argv[0], argv);
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error(127, errno, "%s", argv[0]);
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return 127;
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out:
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if ( pipein != 0 ) { close(pipein); }
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if ( pipeout != 1 ) { close(pipeout); }
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if ( pipeinnext != 0 ) { close(pipeout); }
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return result;
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}
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void command()
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{
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unsigned termmode = TERMMODE_UNICODE
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@ -75,51 +224,9 @@ void command()
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if ( !argv[0] ) { return; }
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if ( strcmp(argv[0], "exit") == 0 )
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{
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const char* status = "1";
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if ( 1 < argc ) { status = argv[1]; }
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exit(atoi(status));
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}
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if ( strcmp(argv[0], "cd") == 0 )
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{
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status = 0;
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const char* newdir = "/";
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if ( 1 < argc ) { newdir = argv[1]; }
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if ( chdir(newdir) )
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{
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error(0, errno, "cd: %s", newdir);
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status = 1;
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}
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return;
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}
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pid_t child = fork();
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if ( child < 0 ) { perror("fork"); status = 1; return; }
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if ( child != 0 )
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{
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pid_t childpid = wait(&status);
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return;
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}
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if ( 3 <= argc )
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{
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if ( strcmp(argv[argc-2], ">") == 0 )
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{
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const char* file = argv[argc-1];
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int outfd = open(file, O_CREAT | O_WRONLY | O_TRUNC | O_APPEND);
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if ( outfd < 0 ) { error(127, errno, "%s", file); exit(127); }
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close(1);
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dup(outfd);
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close(outfd);
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argc -= 2;
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}
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}
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argv[argc] = NULL;
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execv(argv[0], (char* const*) argv);
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error(127, errno, "%s", argv[0]);
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status = runcommandline(argv);
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return;
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}
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int main(int argc, char* argv[])
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