apps/sh/main.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <sys/types.h>
  20 #include <sys/wait.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <stdio.h>
  25 #include <sys/utsname.h>
  26 #include <pwd.h>
  27 #include <errno.h>
  28 #include <misc.h>
  29
  30 #include <readline/readline.h>
  31 #include <readline/history.h>
  32
  33 #define TERMINAL_DEVICE "/dev/console"
  34
  35 typedef struct {
  36   const char *cmd;
  37   int (*func)(char **argv);
  38 } shell_builtin_cmd_t;
  39
  40 typedef struct {
  41   pid_t pid;
  42   char *path;
  43   char **argv;
  44   int stdin;
  45   int stdout;
  46   int stderr;
  47 } shell_proc_t;
  48
  49 struct utsname utsname;
  50 struct passwd *passwd;
  51
  52 static void usage(char *cmd,int err) {
  53   FILE *out = err?stderr:stdout;
  54   fprintf(out,"Usage: %s\n");
  55 }
  56
  57 /**
  58  * Gets command from shell
  59  *  @return Command line
  60  */
  61 static char *shell_get_command() {
  62   char *cwd = getcwd(NULL,0);
  63   char *prompt;
  64   char *input;
  65
  66   asprintf(&prompt,"%s@%s:%s> ",passwd!=NULL?passwd->pw_name:"nobody",utsname.nodename,cwd);
  67   input = readline(prompt);
  68   if (input && input[0]!=0) add_history(input);
  69   else return NULL;
  70
  71   free(prompt);
  72   free(cwd);
  73   return input;
  74 }
  75
  76 /**
  77  * Converts a string with an octal number to an integer
  78  *  @param string String holding octal number
  79  *  @return String as integer
  80  */
  81 static int octal2num(char *str) {
  82   char buf[4];
  83   memcpy(buf,str,3);
  84   buf[3] = 0;
  85   int num = strtoul(buf,NULL,8);
  86   return num;
  87 }
  88
  89 /**
  90  * Parses an command line argument
  91  *  @param arg Command line argument
  92  *  @param len Length of argument
  93  *  @return Parse arguments
  94  */
  95 static char *shell_parse_arg(char *arg,size_t len) {
  96   char *new = malloc(len+1);
  97   size_t i,j;
  98
  99   for (i=0,j=0;i<len;i++,j++) {
 100     if (arg[i]=='\\' && i+1<len) {     // escape code
 101       i++;
 102       if (arg[i]=='\\') new[j] = '\\';      // backslash
 103       else if (arg[i]=='\"') new[j] = '\"'; // quotation mark
 104       else if (arg[i]=='a') new[j] = '\a';  // alert
 105       else if (arg[i]=='b') new[j] = '\b';  // backspace
 106       else if (arg[i]=='f') new[j] = '\f';  // form feed
 107       else if (arg[i]=='n') new[j] = '\n';  // new line
 108       else if (arg[i]=='r') new[j] = '\r';  // carriage return
 109       else if (arg[i]=='t') new[j] = '\t';  // horizontal tab
 110       else if (arg[i]=='v') new[j] = '\v';  // vertical tab
 111       else if (arg[i]=='0' && arg[i+1]!=0 && arg[i+2]!=0 && arg[i+3]!=0) {
 112                                             // character in octal
 113         new[j] = octal2num(arg+i+1);
 114       }
 115     }
 116     else new[j] = arg[i];
 117   }
 118
 119   new[j] = 0;
 120
 121   return new;
 122 }
 123
 124 /**
 125  * Parses a command line string
 126  *  @param cmd Command line string
 127  *  @return Argument vector
 128  */
 129 static char **shell_parse_cmd(char *cmd) {
 130   int quote = 0;
 131   char *cur = cmd;
 132   char *next;
 133   char **argv = NULL;
 134   int argc = 0;
 135
 136   // skip beginning spaces
 137   while (*cur==' ') cur++;
 138
 139   do {
 140     // find next space (or quotation mark)
 141     next = strchr(cur,quote?'\"':' ');
 142     if (next==NULL) next = cmd+strlen(cmd);
 143     // if next character is a quotation mark, activate qoute mode
 144     //if (*next=='\"') mode = 1;
 145
 146     // skip spaces
 147     //while (*next==' ') next++;
 148
 149     // add current to argv
 150     argv = realloc(argv,(argc+1)*sizeof(char*));
 151     argv[argc++] = shell_parse_arg(cur,next-cur);
 152     cur = next+1;
 153   } while (*next!=0);
 154
 155   argv = realloc(argv,(argc+1)*sizeof(char*));
 156   argv[argc] = NULL;
 157
 158   return argv;
 159 }
 160
 161 static int shell_builtin_exit(char **argv) {
 162   return 1;
 163 }
 164
 165 static int shell_builtin_cd(char **argv) {
 166   if (argv[1]!=NULL) {
 167     if (chdir(argv[1])==-1) fprintf(stderr,"sh: cd: %s: %s\n",argv[1],strerror(errno));
 168   }
 169   return 0;
 170 }
 171
 172 static int shell_builtin_help(char **argv) {
 173   printf("Built-in commands:\n"
 174          " exit              Exit shell\n"
 175          " cd DIR            Change working directory to DIR\n"
 176          " help              Show this help dialog\n"
 177          " version           Show version\n");
 178   return 0;
 179 }
 180
 181 static int shell_builtin_version(char **argv) {
 182   printf("%s %s\n",utsname.sysname,utsname.version);
 183   return 0;
 184 }
 185
 186 static int shell_run_builtin(char **argv) {
 187   shell_builtin_cmd_t shell_builtin_cmds[] = {
 188     { .cmd = "exit",    .func = shell_builtin_exit },
 189     { .cmd = "cd",      .func = shell_builtin_cd },
 190     { .cmd = "help",    .func = shell_builtin_help },
 191     { .cmd = "version", .func = shell_builtin_version }
 192   };
 193   size_t i;
 194
 195   for (i=0;i<sizeof(shell_builtin_cmds)/sizeof(shell_builtin_cmd_t);i++) {
 196     if (strcmp(argv[0],shell_builtin_cmds[i].cmd)==0) return shell_builtin_cmds[i].func(argv);
 197   }
 198
 199   return -1;
 200 }
 201
 202 static char *shell_find_path(char *cmd) {
 203   char *path;
 204   /// @todo read from PATH enviroment variable
 205   asprintf(&path,"/boot/bin/%s",cmd);
 206   return path;
 207 }
 208
 209 static int shell_run_binary(char **argv,int background) {
 210   shell_proc_t *proc = malloc(sizeof(shell_proc_t));
 211   proc->path = shell_find_path(argv[0]);
 212   proc->argv = argv;
 213   proc->pid = execute(proc->path,argv,&(proc->stdin),&(proc->stdout),&(proc->stderr));
 214
 215   if (proc->pid==-1) {
 216     free(proc->path);
 217     free(proc);
 218     return -1;
 219   }
 220
 221   if (background) {
 222
 223   }
 224   else {
 225     int status = 0;
 226     waitpid(proc->pid,&status,0);
 227
 228     close(proc->stdin);
 229     close(proc->stdout);
 230     close(proc->stderr);
 231     free(proc->path);
 232     free(proc);
 233
 234     if (status!=0) fprintf(stderr,"sh: %s: returned with %d\n",argv[0],status);
 235   }
 236
 237   return 0;
 238 }
 239
 240 /**
 241  * Runs shell interactive
 242  */
 243 static void shell_interactive() {
 244   int status = 0;
 245
 246   while (status!=1) {
 247     size_t i;
 248     char **argv;
 249     char *cmd = shell_get_command();
 250
 251     if (cmd==NULL) break;
 252     argv = shell_parse_cmd(cmd);
 253
 254     if ((status = shell_run_builtin(argv))==-1) {
 255       if (shell_run_binary(argv,0)==-1) fprintf(stderr,"sh: %s: command not found\n",argv[0]);
 256     }
 257
 258     free(cmd);
 259     for (i=0;argv[i];i++) free(argv[i]);
 260     free(argv);
 261   }
 262 }
 263
 264 int main(int argc,char *argv[]) {
 265   int c;
 266
 267   FILE *terminal = fopen(TERMINAL_DEVICE,"r+");
 268   if (terminal==NULL) return 1;
 269   FILE *stdin_bak = stdin;
 270   FILE *stdout_bak = stdout;
 271   FILE *stderr_bak = stderr;
 272   stdin = terminal;
 273   stdout = terminal;
 274   stderr = terminal;
 275
 276   while ((c = getopt(argc,argv,":hv"))!=-1) {
 277     switch(c) {
 278       case 'h':
 279         usage(argv[0],0);
 280         break;
 281       case 'v':
 282         printf("sh v0.1\n(c) 2008 Janosch Graef\n");
 283         return 0;
 284         break;
 285       case '?':
 286         fprintf(stderr,"Unrecognized option: -%c\n", optopt);
 287         usage(argv[0],1);
 288         break;
 289     }
 290   }
 291
 292   uname(&utsname);
 293   passwd = getpwuid(getuid());
 294   shell_interactive();
 295
 296   stdin = stdin_bak;
 297   stdout = stdout_bak;
 298   stderr = stderr_bak;
 299   fclose(terminal);
 300
 301   return 0;
 302 }