[syslinux] whichsys.c32: execute specific command, based on Syslinux bootloader variant

[Gert Hulselmans]

I wrote a new module "whichsys.c32" which detemines which command to
execute, based on the Syslinux bootloader variant.

In the near future it should/can be replaced by a lua script.
But for people who want small binaries: whichsys.c32 is +/- eighty times
smaller than lua.c32, atm.

  Usage:    whichsys.c32 [-iso- command] [-pxe- command] [-sys- command]
  Examples: whichsys.c32 -iso- chain.c32 hd0 -sys- chain.c32 hd1 swap
            whichsys.c32 -iso- config iso.cfg -sys- sys.cfg -pxe- pxe.cfg

http://git.zytor.com/?p=users/gerth/syslinux.git;a=commit;h=66c3eb4f6fc622fc3326956adfb0c6e23342b98f

- Gert Hulselmans

---
 com32/modules/Makefile   |    2 +-
 com32/modules/whichsys.c |  128
++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 129 insertions(+), 1 deletions(-)
 create mode 100644 com32/modules/whichsys.c

diff --git a/com32/modules/Makefile b/com32/modules/Makefile
index f42ce96..2d47913 100644
--- a/com32/modules/Makefile
+++ b/com32/modules/Makefile
@@ -22,7 +22,7 @@ MODULES	  = chain.c32 config.c32 ethersel.c32
dmitest.c32 cpuidtest.c32 \
 	    disk.c32 pcitest.c32 elf.c32 linux.c32 reboot.c32 pmload.c32 \
 	    meminfo.c32 sdi.c32 sanboot.c32 ifcpu64.c32 vesainfo.c32 \
 	    kbdmap.c32 cmd.c32 vpdtest.c32 host.c32 ls.c32 gpxecmd.c32 \
-	    ifcpu.c32 cpuid.c32 cat.c32 pwd.c32 ifplop.c32
+	    ifcpu.c32 cpuid.c32 cat.c32 pwd.c32 ifplop.c32 whichsys.c32

 TESTFILES =

diff --git a/com32/modules/whichsys.c b/com32/modules/whichsys.c
new file mode 100644
index 0000000..c186722
--- /dev/null
+++ b/com32/modules/whichsys.c
@@ -0,0 +1,128 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2010 Gert Hulselmans - 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.
+ *
+ *
----------------------------------------------------------------------- */
+
+/*
+ * whichsys.c
+ *
+ * Detemine which command to execute, based on the Syslinux bootloader
variant
+ * from which you run it.
+ *
+ * Usage:    whichsys.c32 [-iso- command] [-pxe- command] [-sys- command]
+ * Examples: whichsys.c32 -iso- chain.c32 hd0 -sys- chain.c32 hd1 swap
+ *           whichsys.c32 -iso- config iso.cfg -sys- sys.cfg -pxe- pxe.cfg
+ *
+ */
+
+#include <stdio.h>
+#include <alloca.h>
+#include <console.h>
+#include <string.h>
+#include <syslinux/boot.h>
+#include "syslinux/config.h"
+
+
+static struct syslinux_parameter {
+    char **arg[1];
+    bool option;
+} isolinux, pxelinux, syslinux;
+
+/* XXX: this really should be librarized */
+static void boot_args(char **args)
+{
+    int len = 0, a = 0;
+    char **pp;
+    const char *p;
+    char c, *q, *str;
+
+    for (pp = args; *pp; pp++)
+	len += strlen(*pp) + 1;
+
+    q = str = alloca(len);
+    for (pp = args; *pp; pp++) {
+	p = *pp;
+	while ((c = *p++))
+	    *q++ = c;
+	*q++ = ' ';
+	a = 1;
+    }
+    q -= a;
+    *q = '\0';
+
+    if (!str[0])
+	syslinux_run_default();
+    else
+	syslinux_run_command(str);
+}
+
+static void usage(void)
+{
+    static const char usage[] = "\
+Usage:    whichsys.c32 [-iso- command] [-pxe- command] [-sys- command]\n\
+Examples: whichsys.c32 -iso- chain.c32 hd0 -sys- chain.c32 hd1 swap\n\
+          whichsys.c32 -iso- config iso.cfg -sys- sys.cfg -pxe- pxe.cfg\n";
+    fprintf(stderr, usage);
+}
+
+int main(int argc, char *argv[])
+{
+    const union syslinux_derivative_info *sdi;
+
+    int arg = 0;
+
+    openconsole(&dev_null_r, &dev_stdcon_w);
+
+    /* If no argument got passed, let's show the usage */
+    if (argc == 1) {
+	    usage();
+	    return 0;
+    }
+
+    arg++;
+
+    while (arg < argc) {
+	if (!strcmp(argv[arg], "-iso-")) {
+	    argv[arg] = NULL;
+	    isolinux.arg[0] = &argv[arg + 1];
+	    isolinux.option = true;
+	}
+	if (!strcmp(argv[arg], "-pxe-")) {
+	    argv[arg] = NULL;
+	    pxelinux.arg[0] = &argv[arg + 1];
+	    pxelinux.option = true;
+	}
+	if (!strcmp(argv[arg], "-sys-")) {
+	    argv[arg] = NULL;
+	    syslinux.arg[0] = &argv[arg + 1];
+	    syslinux.option = true;
+	}
+	arg++;
+    }
+
+    sdi = syslinux_derivative_info();
+
+    switch (sdi->c.filesystem) {
+	case SYSLINUX_FS_ISOLINUX:
+	    isolinux.option ? boot_args(isolinux.arg[0]) : fprintf(stderr, "No
command specified for ISOLINUX.\n\n"); usage();
+	    break;
+	case SYSLINUX_FS_PXELINUX:
+	    pxelinux.option ? boot_args(pxelinux.arg[0]) : fprintf(stderr, "No
command specified for PXELINUX.\n\n"); usage();
+	    break;
+	case SYSLINUX_FS_SYSLINUX:
+	    syslinux.option ? boot_args(syslinux.arg[0]) : fprintf(stderr, "No
command specified for SYSLINUX.\n\n"); usage();
+	    break;
+	case SYSLINUX_FS_UNKNOWN:
+	default:
+	    fprintf(stderr, "Unknown Syslinux filesystem\n\n");
+    }
+
+    return -1;
+}
-- 
1.6.3.3