src/core/exec.c

   1 /*
   2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 #include <stdint.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <getopt.h>
  25 #include <errno.h>
  26 #include <assert.h>
  27 #include <gpxe/tables.h>
  28 #include <gpxe/command.h>
  29
  30 /** @file
  31  *
  32  * Command execution
  33  *
  34  */
  35
  36 static struct command commands[0]
  37         __table_start ( struct command, commands );
  38 static struct command commands_end[0]
  39         __table_end ( struct command, commands );
  40
  41 /* Avoid dragging in getopt.o unless a command really uses it */
  42 int optind;
  43 int nextchar;
  44
  45 /**
  46  * Execute command
  47  *
  48  * @v command           Command name
  49  * @v argv              Argument list
  50  * @ret rc              Command exit status
  51  *
  52  * Execute the named command.  Unlike a traditional POSIX execv(),
  53  * this function returns the exit status of the command.
  54  */
  55 int execv ( const char *command, char * const argv[] ) {
  56         struct command *cmd;
  57         int argc;
  58
  59         /* Count number of arguments */
  60         for ( argc = 0 ; argv[argc] ; argc++ ) {}
  61
  62         /* Sanity checks */
  63         if ( ! command ) {
  64                 DBG ( "No command\n" );
  65                 return -EINVAL;
  66         }
  67         if ( ! argc ) {
  68                 DBG ( "%s: empty argument list\n", command );
  69                 return -EINVAL;
  70         }
  71
  72         /* Reset getopt() library ready for use by the command.  This
  73          * is an artefact of the POSIX getopt() API within the context
  74          * of Etherboot; see the documentation for reset_getopt() for
  75          * details.
  76          */
  77         reset_getopt();
  78
  79         /* Hand off to command implementation */
  80         for ( cmd = commands ; cmd < commands_end ; cmd++ ) {
  81                 if ( strcmp ( command, cmd->name ) == 0 )
  82                         return cmd->exec ( argc, ( char ** ) argv );
  83         }
  84
  85         printf ( "%s: command not found\n", command );
  86         return -ENOEXEC;
  87 }
  88
  89 /**
  90  * Split command line into argv array
  91  *
  92  * @v args              Command line
  93  * @v argv              Argument array to populate, or NULL
  94  * @ret argc            Argument count
  95  *
  96  * Splits the command line into whitespace-delimited arguments.  If @c
  97  * argv is non-NULL, any whitespace in the command line will be
  98  * replaced with NULs.
  99  */
 100 static int split_args ( char *args, char * argv[] ) {
 101         int argc = 0;
 102
 103         while ( 1 ) {
 104                 /* Skip over any whitespace / convert to NUL */
 105                 while ( *args == ' ' ) {
 106                         if ( argv )
 107                                 *args = '\0';
 108                         args++;
 109                 }
 110                 /* Check for end of line */
 111                 if ( ! *args )
 112                         break;
 113                 /* We have found the start of the next argument */
 114                 if ( argv )
 115                         argv[argc] = args;
 116                 argc++;
 117                 /* Skip to start of next whitespace, if any */
 118                 while ( *args && ( *args != ' ' ) ) {
 119                         args++;
 120                 }
 121         }
 122         return argc;
 123 }
 124
 125 /**
 126  * Execute command line
 127  *
 128  * @v command           Command line
 129  * @ret rc              Command exit status
 130  *
 131  * Execute the named command and arguments.
 132  */
 133 int system ( const char *command ) {
 134         char *args;
 135         int argc;
 136         int rc = 0;
 137
 138         /* Obtain temporary modifiable copy of command line */
 139         args = strdup ( command );
 140         if ( ! args )
 141                 return -ENOMEM;
 142
 143         /* Count arguments */
 144         argc = split_args ( args, NULL );
 145
 146         /* Create argv array and execute command */
 147         if ( argc ) {
 148                 char * argv[argc + 1];
 149
 150                 split_args ( args, argv );
 151                 argv[argc] = NULL;
 152
 153                 if ( argv[0][0] != '#' )
 154                         rc = execv ( argv[0], argv );
 155         }
 156
 157         free ( args );
 158         return rc;
 159 }