diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/core/exec.c')
| -rw-r--r-- | contrib/syslinux-4.02/gpxe/src/core/exec.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/core/exec.c b/contrib/syslinux-4.02/gpxe/src/core/exec.c new file mode 100644 index 0000000..6c16aa4 --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/core/exec.c @@ -0,0 +1,251 @@ +/* + * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <stdint.h> +#include <string.h> +#include <stdlib.h> +#include <stdio.h> +#include <ctype.h> +#include <unistd.h> +#include <getopt.h> +#include <errno.h> +#include <assert.h> +#include <gpxe/tables.h> +#include <gpxe/command.h> +#include <gpxe/settings.h> + +/** @file + * + * Command execution + * + */ + +/* Avoid dragging in getopt.o unless a command really uses it */ +int optind; +int nextchar; + +/** + * Execute command + * + * @v command Command name + * @v argv Argument list + * @ret rc Command exit status + * + * Execute the named command. Unlike a traditional POSIX execv(), + * this function returns the exit status of the command. + */ +int execv ( const char *command, char * const argv[] ) { + struct command *cmd; + int argc; + + /* Count number of arguments */ + for ( argc = 0 ; argv[argc] ; argc++ ) {} + + /* Sanity checks */ + if ( ! command ) { + DBG ( "No command\n" ); + return -EINVAL; + } + if ( ! argc ) { + DBG ( "%s: empty argument list\n", command ); + return -EINVAL; + } + + /* Reset getopt() library ready for use by the command. This + * is an artefact of the POSIX getopt() API within the context + * of Etherboot; see the documentation for reset_getopt() for + * details. + */ + reset_getopt(); + + /* Hand off to command implementation */ + for_each_table_entry ( cmd, COMMANDS ) { + if ( strcmp ( command, cmd->name ) == 0 ) + return cmd->exec ( argc, ( char ** ) argv ); + } + + printf ( "%s: command not found\n", command ); + return -ENOEXEC; +} + +/** + * Expand variables within command line + * + * @v command Command line + * @ret expcmd Expanded command line + * + * The expanded command line is allocated with malloc() and the caller + * must eventually free() it. + */ +static char * expand_command ( const char *command ) { + char *expcmd; + char *start; + char *end; + char *head; + char *name; + char *tail; + int setting_len; + int new_len; + char *tmp; + + /* Obtain temporary modifiable copy of command line */ + expcmd = strdup ( command ); + if ( ! expcmd ) + return NULL; + + /* Expand while expansions remain */ + while ( 1 ) { + + head = expcmd; + + /* Locate opener */ + start = strstr ( expcmd, "${" ); + if ( ! start ) + break; + *start = '\0'; + name = ( start + 2 ); + + /* Locate closer */ + end = strstr ( name, "}" ); + if ( ! end ) + break; + *end = '\0'; + tail = ( end + 1 ); + + /* Determine setting length */ + setting_len = fetchf_named_setting ( name, NULL, 0 ); + if ( setting_len < 0 ) + setting_len = 0; /* Treat error as empty setting */ + + /* Read setting into temporary buffer */ + { + char setting_buf[ setting_len + 1 ]; + + setting_buf[0] = '\0'; + fetchf_named_setting ( name, setting_buf, + sizeof ( setting_buf ) ); + + /* Construct expanded string and discard old string */ + tmp = expcmd; + new_len = asprintf ( &expcmd, "%s%s%s", + head, setting_buf, tail ); + free ( tmp ); + if ( new_len < 0 ) + return NULL; + } + } + + return expcmd; +} + +/** + * Split command line into argv array + * + * @v args Command line + * @v argv Argument array to populate, or NULL + * @ret argc Argument count + * + * Splits the command line into whitespace-delimited arguments. If @c + * argv is non-NULL, any whitespace in the command line will be + * replaced with NULs. + */ +static int split_args ( char *args, char * argv[] ) { + int argc = 0; + + while ( 1 ) { + /* Skip over any whitespace / convert to NUL */ + while ( isspace ( *args ) ) { + if ( argv ) + *args = '\0'; + args++; + } + /* Check for end of line */ + if ( ! *args ) + break; + /* We have found the start of the next argument */ + if ( argv ) + argv[argc] = args; + argc++; + /* Skip to start of next whitespace, if any */ + while ( *args && ! isspace ( *args ) ) { + args++; + } + } + return argc; +} + +/** + * Execute command line + * + * @v command Command line + * @ret rc Command exit status + * + * Execute the named command and arguments. + */ +int system ( const char *command ) { + char *args; + int argc; + int rc = 0; + + /* Perform variable expansion */ + args = expand_command ( command ); + if ( ! args ) + return -ENOMEM; + + /* Count arguments */ + argc = split_args ( args, NULL ); + + /* Create argv array and execute command */ + if ( argc ) { + char * argv[argc + 1]; + + split_args ( args, argv ); + argv[argc] = NULL; + + if ( argv[0][0] != '#' ) + rc = execv ( argv[0], argv ); + } + + free ( args ); + return rc; +} + +/** + * The "echo" command + * + * @v argc Argument count + * @v argv Argument list + * @ret rc Exit code + */ +static int echo_exec ( int argc, char **argv ) { + int i; + + for ( i = 1 ; i < argc ; i++ ) { + printf ( "%s%s", ( ( i == 1 ) ? "" : " " ), argv[i] ); + } + printf ( "\n" ); + return 0; +} + +/** "echo" command */ +struct command echo_command __command = { + .name = "echo", + .exec = echo_exec, +}; |