Michael Brown
2009-Feb-16 08:49 UTC
[syslinux] [PATCH] cmd.c32: new module to just execute a command
Trivial module to execute an arbitrary command. --- com32/modules/Makefile | 2 +- com32/modules/cmd.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+), 1 deletions(-) create mode 100644 com32/modules/cmd.c diff --git a/com32/modules/Makefile b/com32/modules/Makefile index 2739a39..930e89b 100644 --- a/com32/modules/Makefile +++ b/com32/modules/Makefile @@ -20,7 +20,7 @@ include ../MCONFIG MODULES = chain.c32 config.c32 ethersel.c32 mboot.c32 dmitest.c32 \ cpuidtest.c32 \ pcitest.c32 elf.c32 linux.c32 reboot.c32 pmload.c32 meminfo.c32 \ - sdi.c32 sanboot.c32 ifcpu64.c32 vesainfo.c32 kbdmap.c32 + sdi.c32 sanboot.c32 ifcpu64.c32 vesainfo.c32 kbdmap.c32 cmd.c32 TESTFILES diff --git a/com32/modules/cmd.c b/com32/modules/cmd.c new file mode 100644 index 0000000..f0b0a96 --- /dev/null +++ b/com32/modules/cmd.c @@ -0,0 +1,42 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2008 Michael Brown - All Rights Reserved + * + * 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, Inc., 51 Franklin St, Fifth Floor, + * Boston MA 02110-1301, USA; either version 2 of the License, or + * (at your option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * cmd.c + * + * Execute arbitrary commands + */ + +#include <string.h> +#include <alloca.h> +#include <console.h> +#include <com32.h> + +int main(int argc, const char *argv[]) +{ + size_t len = 0; + char *cmd; + char *tmp; + int i; + + openconsole(&dev_stdcon_r, &dev_stdcon_w); + + for (i = 1; i < argc; i++) + len += strlen(argv[i]) + 1; + + tmp = cmd = alloca(len); + + for (i = 1; i < argc; i++) + tmp += sprintf(tmp, "%s%s", argv[i], (i == argc-1) ? "" : " "); + + syslinux_run_command(cmd); +} -- 1.5.4.3
Gene Cumm
2009-Feb-16 14:45 UTC
[syslinux] [PATCH] cmd.c32: new module to just execute a command
On Mon, Feb 16, 2009 at 3:49 AM, Michael Brown <mcb30 at etherboot.org> wrote:> Trivial module to execute an arbitrary command.Similar in function to the alias module I created back in October. The key differences I notice are that yours appears simpler, mine could also be tested as a Linux binary, yours uses sprintf versus mine using memcpy and mine would definitely not pass a command string that was too long to syslinux_run_command(). I'm not sure if it's even theoretically possible to even do so though. It's probably an unnecessary but paranoid check. I originally created mine because I often had multiple labels doing similar tasks with either no or minor variations (short name vs long name; main vs add an additional parameter) and there's no way for one label to call another (as far as I could tell). Including something that provides this functionality into Syslinux would probably provide benefit for anyone that has multiple similar labels. -- -Gene "No one ever says, 'I can't read that ASCII E-mail you sent me.'"
Michael Brown
2009-Feb-17 06:15 UTC
[syslinux] [PATCH] cmd.c32: new module to just execute a command
On Monday 16 February 2009 14:45:36 Gene Cumm wrote:> On Mon, Feb 16, 2009 at 3:49 AM, Michael Brown <mcb30 at etherboot.org> wrote: > > Trivial module to execute an arbitrary command. > > Similar in function to the alias module I created back in October. > The key differences I notice are that yours appears simpler, mine > could also be tested as a Linux binary, yours uses sprintf versus mine > using memcpy and mine would definitely not pass a command string that > was too long to syslinux_run_command().Is there an upper limit on the length of command strings? Michael
Sebastian Herbszt
2009-Feb-17 22:03 UTC
[syslinux] [PATCH] cmd.c32: new module to just execute a command
Michael Brown wrote:> On Monday 16 February 2009 14:45:36 Gene Cumm wrote: >> On Mon, Feb 16, 2009 at 3:49 AM, Michael Brown <mcb30 at etherboot.org> wrote: >> > Trivial module to execute an arbitrary command. >> >> Similar in function to the alias module I created back in October. >> The key differences I notice are that yours appears simpler, mine >> could also be tested as a Linux binary, yours uses sprintf versus mine >> using memcpy and mine would definitely not pass a command string that >> was too long to syslinux_run_command(). > > Is there an upper limit on the length of command strings?syslinux_run_command() uses INT 22h AX=0003h (com32/lib/syslinux/run_command.c) which copies the command line from ES:BX to "command_line" (core/comboot.inc). parseconfig.inc:command_line resb max_cmd_len+2 ; Command line buffer config.inc:max_cmd_len equ 2047 ; Must be &3; 2047 is the kernel limit - Sebastian
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