exec.c File Reference

Command execution. More...

#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>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
int	execv (const char *command, char *const argv[])
	Execute command.
static char *	expand_command (const char *command)
	Expand variables within command line.
static int	split_args (char *args, char *argv[])
	Split command line into argv array.
int	system (const char *command)
	Execute command line.
static int	echo_exec (int argc, char **argv)
	The "echo" command.
Variables
int	optind
int	nextchar
struct command echo_command	__command
	"echo" command

---

Detailed Description

Command execution.

Definition in file exec.c.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

int execv	(	const char *	command,
		char *const	argv[]
	)

Execute command.

Parameters:

	command	Command name
	argv	Argument list

Return values:

rc

Command exit status

Execute the named command. Unlike a traditional POSIX execv(), this function returns the exit status of the command.

Definition at line 54 of file exec.c.

References COMMANDS, DBG, EINVAL, ENOEXEC, command::exec, for_each_table_entry, command::name, printf(), reset_getopt(), and strcmp().

Referenced by system(), and time_exec().

                                                       {
        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;
}

static char* expand_command

(

const char *

command

)

[static]

Expand variables within command line.

Parameters:

command

Command line

Return values:

expcmd

Expanded command line

The expanded command line is allocated with malloc() and the caller must eventually free() it.

Definition at line 97 of file exec.c.

References asprintf(), fetchf_named_setting(), free(), name, NULL, strdup(), and strstr().

Referenced by system().

                                                     {
        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;
}

static int split_args	(	char *	args,
		char *	argv[]
	)			[static]

Split command line into argv array.

Parameters:

	args	Command line
	argv	Argument array to populate, or NULL

Return values:

argc

Argument count

Splits the command line into whitespace-delimited arguments. If argv is non-NULL, any whitespace in the command line will be replaced with NULs.

Definition at line 169 of file exec.c.

References isspace().

Referenced by system().

                                                    {
        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;
}

int system

(

const char *

command

)

Execute command line.

Parameters:

command

Command line

Return values:

rc

Command exit status

Execute the named command and arguments.

Definition at line 202 of file exec.c.

References ENOMEM, execv(), expand_command(), free(), NULL, and split_args().

Referenced by int22(), pxenv_file_exec(), script_exec(), and shell().

                                   {
        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;
}

static int echo_exec	(	int	argc,
		char **	argv
	)			[static]

The "echo" command.

Parameters:

	argc	Argument count
	argv	Argument list

Return values:

rc

Exit code

Definition at line 237 of file exec.c.

References printf().

                                               {
        int i;

        for ( i = 1 ; i < argc ; i++ ) {
                printf ( "%s%s", ( ( i == 1 ) ? "" : " " ), argv[i] );
        }
        printf ( "\n" );
        return 0;
}

---

Variable Documentation

int optind

Definition at line 41 of file exec.c.

Referenced by dhcp_exec(), gdbstub_exec(), get_argv_argument(), getopt_long(), ifcommon_exec(), imgargs_exec(), imgexec_exec(), imgfetch_core_exec(), imgfree_exec(), imgload_exec(), imgstat_exec(), match_long_option(), match_short_option(), pxebs_exec(), reset_getopt(), route_exec(), and sanboot_exec().

int nextchar

Definition at line 42 of file exec.c.

Referenced by getopt_long(), match_short_option(), and reset_getopt().

struct command echo_command __command

Initial value:

 {
        .name = "echo",
        .exec = echo_exec,
}

"echo" command

Definition at line 248 of file exec.c.