source: bootcd/isolinux/syslinux-6.03/com32/modules/linux.c

/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
 *   Copyright 2009-2012 Intel Corporation; author: H. Peter Anvin
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

/*
 * linux.c
 *
 * Sample module to load Linux kernels.  This module can also create
 * a file out of the DHCP return data if running under PXELINUX.
 *
 * If -dhcpinfo is specified, the DHCP info is written into the file
 * /dhcpinfo.dat in the initramfs.
 *
 * Usage: linux.c32 [-dhcpinfo] kernel arguments...
 */

#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <console.h>
#include <syslinux/loadfile.h>
#include <syslinux/linux.h>
#include <syslinux/pxe.h>

enum ldmode {
    ldmode_raw,
    ldmode_cpio,
    ldmodes
};

typedef int f_ldinitramfs(struct initramfs *, char *);

const char *progname = "linux.c32";

/* Find the last instance of a particular command line argument
   (which should include the final =; do not use for boolean arguments) */
static char *find_argument(char **argv, const char *argument)
{
    int la = strlen(argument);
    char **arg;
    char *ptr = NULL;

    for (arg = argv; *arg; arg++) {
        if (!strncmp(*arg, argument, la))
            ptr = *arg + la;
    }

    return ptr;
}

/* Find the next instance of a particular command line argument */
static char **find_arguments(char **argv, char **ptr,
                             const char *argument)
{
    int la = strlen(argument);
    char **arg;

    for (arg = argv; *arg; arg++) {
        if (!strncmp(*arg, argument, la)) {
            *ptr = *arg + la;
            break;
        }
    }

    /* Exhausted all arguments */
    if (!*arg)
        return NULL;

    return arg;
}

/* Search for a boolean argument; return its position, or 0 if not present */
static int find_boolean(char **argv, const char *argument)
{
    char **arg;

    for (arg = argv; *arg; arg++) {
        if (!strcmp(*arg, argument))
            return (arg - argv) + 1;
    }

    return 0;
}

/* Stitch together the command line from a set of argv's */
static char *make_cmdline(char **argv)
{
    char **arg;
    size_t bytes;
    char *cmdline, *p;

    bytes = 1;                  /* Just in case we have a zero-entry cmdline */
    for (arg = argv; *arg; arg++) {
        bytes += strlen(*arg) + 1;
    }

    p = cmdline = malloc(bytes);
    if (!cmdline)
        return NULL;

    for (arg = argv; *arg; arg++) {
        int len = strlen(*arg);
        memcpy(p, *arg, len);
        p[len] = ' ';
        p += len + 1;
    }

    if (p > cmdline)
        p--;                    /* Remove the last space */
    *p = '\0';

    return cmdline;
}

static f_ldinitramfs ldinitramfs_raw;
static int ldinitramfs_raw(struct initramfs *initramfs, char *fname)
{
    return initramfs_load_archive(initramfs, fname);
}

static f_ldinitramfs ldinitramfs_cpio;
static int ldinitramfs_cpio(struct initramfs *initramfs, char *fname)
{
    char *target_fname, *p;
    int do_mkdir, unmangle, rc;

    /* Choose target_fname based on presence of "@" syntax */
    target_fname = strchr(fname, '@');
    if (target_fname) {
        /* Temporarily mangle */
        unmangle = 1;
        *target_fname++ = '\0';

        /* Make parent directories? */
        do_mkdir = !!strchr(target_fname, '/');
    } else {
        unmangle = 0;

        /* Forget the source path */
        target_fname = fname;
        while ((p = strchr(target_fname, '/')))
            target_fname = p + 1;

        /* The user didn't specify a desired path */
        do_mkdir = 0;
    }

    /*
     * Load the file, encapsulate it with the desired path, make the
     * parent directories if the desired path contains them, add to initramfs
     */
    rc = initramfs_load_file(initramfs, fname, target_fname, do_mkdir, 0755);

    /* Unmangle, if needed*/
    if (unmangle)
        *--target_fname = '@';

    return rc;
}

/* It only makes sense to call this function from main */
static int process_initramfs_args(char *arg, struct initramfs *initramfs,
                                  const char *kernel_name, enum ldmode mode,
                                  bool opt_quiet)
{
    const char *mode_msg;
    f_ldinitramfs *ldinitramfs;
    char *p;

    switch (mode) {
    case ldmode_raw:
        mode_msg = "Loading";
        ldinitramfs = ldinitramfs_raw;
        break;
    case ldmode_cpio:
        mode_msg = "Encapsulating";
        ldinitramfs = ldinitramfs_cpio;
        break;
    case ldmodes:
    default:
        return 1;
    }

    do {
        p = strchr(arg, ',');
        if (p)
            *p = '\0';

        if (!opt_quiet)
            printf("%s %s... ", mode_msg, arg);
        errno = 0;
        if (ldinitramfs(initramfs, arg)) {
            if (opt_quiet)
                printf("Loading %s ", kernel_name);
            printf("failed: ");
            return 1;
        }
        if (!opt_quiet)
            printf("ok\n");

        if (p)
            *p++ = ',';
    } while ((arg = p));

    return 0;
}

static int setup_data_file(struct setup_data *setup_data,
                           uint32_t type, const char *filename,
                           bool opt_quiet)
{
    if (!opt_quiet)
        printf("Loading %s... ", filename);

    if (setup_data_load(setup_data, type, filename)) {
        if (opt_quiet)
            printf("Loading %s ", filename);
        printf("failed\n");
        return -1;
    }
            
    if (!opt_quiet)
        printf("ok\n");
    
    return 0;
}

int main(int argc, char *argv[])
{
    const char *kernel_name;
    struct initramfs *initramfs;
    struct setup_data *setup_data;
    char *cmdline;
    char *boot_image;
    void *kernel_data;
    size_t kernel_len;
    bool opt_dhcpinfo = false;
    bool opt_quiet = false;
    void *dhcpdata;
    size_t dhcplen;
    char **argp, **argl, *arg;

    (void)argc;
    argp = argv + 1;

    while ((arg = *argp) && arg[0] == '-') {
        if (!strcmp("-dhcpinfo", arg)) {
            opt_dhcpinfo = true;
        } else {
            fprintf(stderr, "%s: unknown option: %s\n", progname, arg);
            return 1;
        }
        argp++;
    }

    if (!arg) {
        fprintf(stderr, "%s: missing kernel name\n", progname);
        return 1;
    }

    kernel_name = arg;

    errno = 0;
    boot_image = malloc(strlen(kernel_name) + 12);
    if (!boot_image) {
        fprintf(stderr, "Error allocating BOOT_IMAGE string: ");
        goto bail;
    }
    strcpy(boot_image, "BOOT_IMAGE=");
    strcpy(boot_image + 11, kernel_name);
    /* argp now points to the kernel name, and the command line follows.
       Overwrite the kernel name with the BOOT_IMAGE= argument, and thus
       we have the final argument. */
    *argp = boot_image;

    if (find_boolean(argp, "quiet"))
        opt_quiet = true;

    if (!opt_quiet)
        printf("Loading %s... ", kernel_name);
    errno = 0;
    if (loadfile(kernel_name, &kernel_data, &kernel_len)) {
        if (opt_quiet)
            printf("Loading %s ", kernel_name);
        printf("failed: ");
        goto bail;
    }
    if (!opt_quiet)
        printf("ok\n");

    errno = 0;
    cmdline = make_cmdline(argp);
    if (!cmdline) {
        fprintf(stderr, "make_cmdline() failed: ");
        goto bail;
    }

    /* Initialize the initramfs chain */
    errno = 0;
    initramfs = initramfs_init();
    if (!initramfs) {
        fprintf(stderr, "initramfs_init() failed: ");
        goto bail;
    }

    /* Process initramfs arguments */
    if ((arg = find_argument(argp, "initrd="))) {
        if (process_initramfs_args(arg, initramfs, kernel_name, ldmode_raw,
                                   opt_quiet))
            goto bail;
    }

    argl = argv;
    while ((argl = find_arguments(argl, &arg, "initrd+="))) {
        argl++;
        if (process_initramfs_args(arg, initramfs, kernel_name, ldmode_raw,
                                   opt_quiet))
            goto bail;
    }

    argl = argv;
    while ((argl = find_arguments(argl, &arg, "initrdfile="))) {
        argl++;
        if (process_initramfs_args(arg, initramfs, kernel_name, ldmode_cpio,
                                   opt_quiet))
            goto bail;
    }

    /* Append the DHCP info */
    if (opt_dhcpinfo &&
        !pxe_get_cached_info(PXENV_PACKET_TYPE_DHCP_ACK, &dhcpdata, &dhcplen)) {
        errno = 0;
        if (initramfs_add_file(initramfs, dhcpdata, dhcplen, dhcplen,
                               "/dhcpinfo.dat", 0, 0755)) {
            fprintf(stderr, "Unable to add DHCP info: ");
            goto bail;
        }
    }

    /* Handle dtb and eventually other setup data */
    setup_data = setup_data_init();
    if (!setup_data)
        goto bail;

    argl = argv;
    while ((argl = find_arguments(argl, &arg, "dtb="))) {
        argl++;
        if (setup_data_file(setup_data, SETUP_DTB, arg, opt_quiet))
            goto bail;
    }

    argl = argv;
    while ((argl = find_arguments(argl, &arg, "blob."))) {
        uint32_t type;
        char *ep;

        argl++;
        type = strtoul(arg, &ep, 10);
        if (ep[0] != '=' || !ep[1])
            continue;

        if (!type)
            continue;

        if (setup_data_file(setup_data, type, ep+1, opt_quiet))
            goto bail;
    }

    /* This should not return... */
    errno = 0;
    syslinux_boot_linux(kernel_data, kernel_len, initramfs,
                        setup_data, cmdline);
    fprintf(stderr, "syslinux_boot_linux() failed: ");

bail:
    switch(errno) {
    case ENOENT:
        fprintf(stderr, "File not found\n");
        break;
    case ENOMEM:
        fprintf(stderr, "Out of memory\n");
        break;
    default:
        fprintf(stderr, "Error %d\n", errno);
        break;
    }
    fprintf(stderr, "%s: Boot aborted!\n", progname);
    return 1;
}