自制Linux必读c源码

如果您的自制linux安装盘总是不能成功进行安装,阅读一下下面的c代码,相信肯定会成功,

"源码面前了无秘密"便是如此.此代码属于 Red Hat Linux anaconda 安装程序的关键代码.

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/* * cdinstall.c - code to set up cdrom installs * * Erik Troan <[e-mail]> * Matt Wilson <[e-mail]> * Michael Fulbright <[e-mail]> * Jeremy Katz <[e-mail]> * * Copyright 1997 - 2002 Red Hat, Inc. * * This software may be freely redistributed under the terms of the GNU * General Public License. * * 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. */#include <ctype.h>#include <dirent.h>#include <errno.h>#include <fcntl.h>#include <newt.h>#include <stdlib.h>#include <string.h>#include <sys/mount.h>#include <sys/ioctl.h>#include <unistd.h>#include <asm/types.h>#include <linux/cdrom.h>#include "kickstart.h"#include "loader.h"#include "loadermisc.h"#include "log.h"#include "lang.h"#include "modules.h"#include "method.h"#include "cdinstall.h"#include "mediacheck.h"#include "../isys/probe.h"#include "../isys/imount.h"#include "../isys/isys.h"static int getISOStatusFromFD(int isofd, char *mediasum);/* ejects the CD device the device node /tmp/cdrom points at */void ejectCdrom(void) {  int ejectfd;  logMessage("ejecting /tmp/cdrom...");  if ((ejectfd = open("/tmp/cdrom", O_RDONLY | O_NONBLOCK, 0)) >= 0) {      if (ioctl(ejectfd, CDROMEJECT, 0))        logMessage("eject failed %d ", errno);      close(ejectfd);  } else {      logMessage("eject failed %d ", errno);  }}/* * Given cd device cddriver, this function will attempt to check its internal checksum. * * JKFIXME: this ignores "location", which should be fixed */static char * mediaCheckCdrom(char *cddriver) {    int rc;    int first;    devMakeInode(cddriver, "/tmp/cdrom");    first = 1;    do {char *descr;char *tstamp;int ejectcd;/* init every pass */ejectcd = 0;descr = NULL;/* if first time through, see if they want to eject the CD      *//* currently in the drive (most likely the CD they booted from) *//* and test a different disk.  Otherwise just test the disk in  *//* the drive since it was inserted in the previous pass through *//* this loop, so they want it tested.                           */if (first) {    first = 0;    rc = newtWinChoice(_("Media Check"), _("Test"), _("Eject CD"),       _("Choose /"%s/" to test the CD currently in " "the drive, or /"%s/" to eject the CD and " "insert another for testing."), _("Test"),       _("Eject CD"));    if (rc == 2)ejectcd = 1;}if (!ejectcd) {    /* XXX MSFFIXME: should check return code for error */    readStampFileFromIso("/tmp/cdrom", &tstamp, &descr);    mediaCheckFile("/tmp/cdrom", descr);    if (descr)free(descr);}ejectCdrom();rc = newtWinChoice(_("Media Check"), _("Test"), _("Continue"),   _("If you would like to test additional media, "     "insert the next CD and press /"%s/". "     "You do not have to test all CDs, although "     "it is recommended you do so at least once./n/n"     "To begin the installation process "     "insert CD #1 into the drive "     "and press /"%s/"."),   _("Test"), _("Continue"));if (rc == 2) {    unlink("/tmp/cdrom");    return NULL;} else {    continue;}    } while (1);        return NULL;}/* output an error message when CD in drive is not the correct one *//* Used by mountCdromStage2()                                      */static void wrongCDMessage(void) {    char *buf = sdupprintf(_("The %s CD was not found "     "in any of your CDROM drives. Please insert "     "the %s CD and press %s to retry."), getProductName(),   getProductName(), _("OK"));    newtWinMessage(_("Error"), _("OK"), buf, _("OK"));    free(buf);}/* Attempts to get a proper CD #1 in the drive *//* Is called after mediacheck is done so that we can proceed with the install *//* During mediacheck we have to have CD umount'd so it can be ejected *//*                                                                    *//* JKFIXME: Assumes CD is mounted as /mnt/source                      */static void mountCdromStage2(char *cddev) {    int gotcd1=0;    int rc;    devMakeInode(cddev, "/tmp/cdrom");    do {do {    if (doPwMount("/tmp/cdrom", "/mnt/source",   "iso9660", 1, 0, NULL, NULL, 0)) {ejectCdrom();wrongCDMessage();    } else {break;    }} while (1);rc = mountStage2("/mnt/source/RedHat/base/stage2.img");/* if we failed, umount /mnt/source and keep going */if (rc) {    umount("/mnt/source");    ejectCdrom();    wrongCDMessage();} else {    gotcd1 = 1;}    } while (!gotcd1);}/* reads iso status from device cddriver */static int getISOStatusFromCDROM(char *cddriver, char *mediasum) {    int isofd;    int isostatus;    devMakeInode(cddriver, "/tmp/cdrom");    isofd = open("/tmp/cdrom", O_RDONLY);    if (isofd < 0) {logMessage("Could not check iso status: %s", strerror(errno));unlink("/tmp/cdrom");return 0;    }    isostatus = getISOStatusFromFD(isofd, mediasum);    close(isofd);    unlink("/tmp/cdrom");    return isostatus;}/* get support status *//* if returns 1 we found status, and mediasum will be checksum */static int getISOStatusFromFD(int isofd, char *mediasum) {    unsigned char tmpsum[33];    int skipsectors, isostatus;    long long isosize, pvd_offset;    if (mediasum)mediasum[0] = '/0';    if ((pvd_offset = parsepvd(isofd, tmpsum, &skipsectors, &isosize, &isostatus)) < 0) {logMessage("Could not parse pvd");return 0;    }    if (mediasum)strcpy(mediasum, tmpsum);    return isostatus;}/* writes iso status info to file '/tmp/isoinfo' for later use */static void writeISOStatus(int status, char *mediasum) {    FILE *f;    if (!(f = fopen("/tmp/isoinfo", "w")))return;    fprintf(f, "ISOSTATUS=%d/n", status);    fprintf(f, "MEDIASUM=%s/n", mediasum);    fclose(f);}/* ask about doing media check *//* JKFIXME: Assumes CD is mounted as /mnt/source                      */static void queryCDMediaCheck(char *dev, int flags) {  int rc;  char mediasum[33];  int isostatus;  /* dont bother to test in automated installs */  if (FL_KICKSTART(flags))      return;  /* see what status is */  isostatus = getISOStatusFromCDROM(dev, mediasum);  writeISOStatus(isostatus, mediasum);  /* see if we should check image(s) */  /* in rescue mode only test if they explicitly asked to */  if ((!isostatus && !FL_RESCUE(flags)) || FL_MEDIACHECK(flags)) {        startNewt(flags);    rc = newtWinChoice(_("CD Found"), _("OK"),       _("Skip"),        _("To begin testing the CD media before installation press %s./n/n" "Choose %s to skip the media test and start the installation."), _("OK"), _("Skip"));    if (rc != 2) {            /* unmount CD now we've identified */      /* a valid disc #1 is present */      umountStage2();      umount("/mnt/source");            /* test CD(s) */      mediaCheckCdrom(dev);            /* remount stage2 from CD #1 and proceed */      mountCdromStage2(dev);    }  }}/* set up a cdrom, nominally for installation  * * location: where to mount the cdrom at JKFIXME: ignored * flags: usual loader flags * interactive: whether or not to prompt about questions/errors (1 is yes) * * loaderData is the kickstart info, can be NULL meaning no info * * side effect: found cdrom is mounted as /mnt/source.  stage2 mounted * as /mnt/runtime. */char * setupCdrom(char * location,                   struct knownDevices * kd,   struct loaderData_s * loaderData,                  moduleInfoSet modInfo,                   moduleList modLoaded,                   moduleDeps modDeps,                   int flags,                  int interactive) {    int i, rc;    int foundinvalid = 0;    char * buf;#if 0    if (FL_TESTING(flags) && interactive) {        for (i = 0; i < kd->numKnown; i++) {            if (kd->known[i].class != CLASS_CDROM) continue;    buf = malloc(200);    sprintf(buf, "cdrom://%s:/mnt/source", kd->known[i].name);    return buf;}    }#endif        /* JKFIXME: ASSERT -- we have a cdrom device when we get here */    do {        for (i = 0; i < kd->numKnown; i++) {            if (kd->known[i].class != CLASS_CDROM) continue;            logMessage("trying to mount device %s", kd->known[i].name);            devMakeInode(kd->known[i].name, "/tmp/cdrom");            if (!doPwMount("/tmp/cdrom", "/mnt/source", "iso9660", 1, 0,                            NULL, NULL, 0)) {                if (!access("/mnt/source/RedHat/base/stage2.img", R_OK) &&    (FL_RESCUE(flags) || !access("/mnt/source/.discinfo", R_OK))) {                    rc = mountStage2("/mnt/source/RedHat/base/stage2.img");                    /* if we failed, umount /mnt/source and keep going */                    if (rc) {                        umount("/mnt/source");                        if (rc == -1) foundinvalid = 1;                        continue;                    }                    /* do the media check */                    queryCDMediaCheck(kd->known[i].name, flags);                    buf = malloc(200);                    sprintf(buf, "cdrom://%s:/mnt/source", kd->known[i].name);                    return buf;                }/* this wasnt the CD we were looking for, clean up and *//* try the next CD drive                               */umount("/mnt/source");                unlink("/tmp/cdrom");            }         }         if (interactive) {            char * buf;            if (foundinvalid)                buf = sdupprintf(_("No %s CD was found which matches your "                                   "boot media.  Please insert the %s CD "                                   "and press %s to retry."), getProductName(),                                 getProductName(), _("OK"));            else                buf = sdupprintf(_("The %s CD was not found in any of your "                                   "CDROM drives. Please insert the %s CD "                                   "and press %s to retry."), getProductName(),                                 getProductName(), _("OK"));            rc = newtWinChoice(_("CD Not Found"),                               _("OK"), _("Back"), buf, _("OK"));            free(buf);            if (rc == 2) return NULL;        } else {            /* we can't ask them about it, so just return not found */            return NULL;        }    } while (1);    return NULL;}/* try to find a Red Hat CD non-interactively */char * findRedHatCD(char * location,                     struct knownDevices * kd,                     moduleInfoSet modInfo,                     moduleList modLoaded,                     moduleDeps modDeps,                     int flags) {    return setupCdrom(location, kd, NULL, modInfo, modLoaded, modDeps, flags, 0);}/* look for a Red Hat CD and mount it.  if we have problems, ask */char * mountCdromImage(struct installMethod * method,                       char * location, struct knownDevices * kd,                       struct loaderData_s * loaderData,                       moduleInfoSet modInfo, moduleList modLoaded,                       moduleDeps * modDepsPtr, int flags) {    return setupCdrom(location, kd, loaderData, modInfo, modLoaded, *modDepsPtr, flags, 1);}void setKickstartCD(struct knownDevices * kd,                     struct loaderData_s * loaderData, int argc,    char ** argv, int * flagsPtr) {    logMessage("kickstartFromCD");    loaderData->method = strdup("cdrom");}#ifdefSDSCintkickstartFromCD(char *kssrc, struct knownDevices * kd, int flags){inti;char*p, *kspath;logMessage("kickstartFromCD:getting kickstart file from CDROM");/* * format is ks=cdrom:[/path/to/ks.cfg] */kspath = "";p = strchr(kssrc, ':');if (p) {kspath = p + 1;}if (!p || strlen(kspath) < 1) {kspath = "/ks.cfg";}for (i = 0; i < kd->numKnown; i++) {if (kd->known[i].class == CLASS_CDROM) {logMessage("kickstartFromCD:trying CD device (%s)",kd->known[i].name);if (getKickstartFromBlockDevice(kd->known[i].name,kspath) == 0) {/* * success */return(0);}}}/* * if made it here, then couldn't find the kickstart file on the CD */logMessage("kickstartFromCD:Couldn't find kickstart file on CD");return 1;}#elseint kickstartFromCD(char *kssrc, struct knownDevices * kd, int flags) {    int rc;    int i;    char *p, *kspath;    logMessage("getting kickstart file from first CDROM");    for (i = 0; i < kd->numKnown; i++)if (kd->known[i].class == CLASS_CDROM)    break;    if (i >= kd->numKnown) {logMessage("No CDROM devices found!");return 1;    }    /* format is ks=cdrom:[/path/to/ks.cfg] */    kspath = "";    p = strchr(kssrc, ':');    if (p)kspath = p + 1;    if (!p || strlen(kspath) < 1)kspath = "/ks.cfg";    if ((rc=getKickstartFromBlockDevice(kd->known[i].name, kspath))) {if (rc == 3) {    startNewt(flags);    newtWinMessage(_("Error"), _("OK"),   _("Cannot find kickstart file on CDROM."));}return 1;    }    return 0;}#endif

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其他一些c源码下载http://download.clarkconnect.com/home/2.1/

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