qubes-installer-qubes-os/isys/uncpio.c

/*
 * uncpio.c
 *
 * Copyright (C) 2007  Red Hat, Inc.  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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define HAVE_ALLOCA_H 1
#define MAJOR_IN_SYSMACROS 1

#if HAVE_ALLOCA_H
# include <alloca.h>
#endif

#define _(foo) (foo)

#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <utime.h>

#include "cpio.h"
#include "stubs.h"

#if MAJOR_IN_SYSMACROS 
#include <sys/sysmacros.h>
#elif MAJOR_IN_MKDEV 
#include <sys/mkdev.h>
#endif

#define CPIO_NEWC_MAGIC	"070701"
#define CPIO_CRC_MAGIC	"070702"
#define TRAILER		"TRAILER!!!"

/* FIXME: We don't translate between cpio and system mode bits! These
   should both be the same, but really odd things are going to happen if
   that's not true! */

/* We need to maintain our oun file pointer to allow padding */
struct ourfd {
    gzFile fd;
    size_t pos;
};

struct hardLink {
    struct hardLink * next;
    char ** files;		/* there are nlink of these, used by install */
    int * fileMaps;		/* used by build */
    dev_t dev;
    ino_t inode;
    int nlink;			
    int linksLeft;
    int createdPath;
    struct stat sb;
};

struct cpioCrcPhysicalHeader {
    char magic[6];
    char inode[8];
    char mode[8];
    char uid[8];
    char gid[8];
    char nlink[8];
    char mtime[8];
    char filesize[8];
    char devMajor[8];
    char devMinor[8];
    char rdevMajor[8];
    char rdevMinor[8];
    char namesize[8];
    char checksum[8];			/* ignored !! */
};

#define PHYS_HDR_SIZE	110		/* don't depend on sizeof(struct) */

struct cpioHeader {
    ino_t inode;
    mode_t mode;
    uid_t uid;
    gid_t gid;
    int nlink;
    time_t mtime;
    unsigned long size;
    dev_t dev, rdev;
    char * path;
};

static inline off_t ourread(struct ourfd * thefd, void * buf, size_t size) {
    off_t i;

    i = gunzip_read(thefd->fd, buf, size);
    thefd->pos += i;
    
    return i;
}

static inline void padinfd(struct ourfd * fd, int modulo) {
    int buf[10];
    int amount;
    
    amount = (modulo - fd->pos % modulo) % modulo;
    ourread(fd, buf, amount);
}

static inline int padoutfd(struct ourfd * fd, size_t * where, int modulo) {
    /*static int buf[10] = { '\0', '\0', '\0', '\0', '\0', 
			   '\0', '\0', '\0', '\0', '\0' };*/
    int amount;
    static int buf[512];

    amount = (modulo - *where % modulo) % modulo;
    *where += amount;

    if (gzip_write(fd->fd, buf, amount) != amount)
	return CPIOERR_WRITE_FAILED;

    return 0;
}

static int strntoul(const char * str, char ** endptr, int base, int num) {
    char * buf, * end;
    unsigned long ret;

    buf = alloca(num + 1);
    strncpy(buf, str, num);
    buf[num] = '\0';

    ret = strtoul(buf, &end, base);
    if (*end)
	*endptr = (char *)(str + (end - buf));	/* XXX discards const */
    else
	*endptr = "";

    return strtoul(buf, endptr, base);
}

#define GET_NUM_FIELD(phys, log) \
	log = strntoul(phys, &end, 16, sizeof(phys)); \
	if (*end) return CPIOERR_BAD_HEADER;
#define SET_NUM_FIELD(phys, val, space) \
	sprintf(space, "%8.8lx", (unsigned long) (val)); \
	memcpy(phys, space, 8);

static int getNextHeader(struct ourfd * fd, struct cpioHeader * chPtr,
			 struct cpioCrcPhysicalHeader * physHeaderPtr) {
    struct cpioCrcPhysicalHeader physHeader;
    int nameSize;
    char * end;
    int major, minor;

    if (ourread(fd, &physHeader, PHYS_HDR_SIZE) != PHYS_HDR_SIZE) 
	return CPIOERR_READ_FAILED;

    if (physHeaderPtr)
	memcpy(physHeaderPtr, &physHeader, PHYS_HDR_SIZE);

    if (strncmp(CPIO_CRC_MAGIC, physHeader.magic, strlen(CPIO_CRC_MAGIC)) &&
	strncmp(CPIO_NEWC_MAGIC, physHeader.magic, strlen(CPIO_NEWC_MAGIC)))
	return CPIOERR_BAD_MAGIC;

    GET_NUM_FIELD(physHeader.inode, chPtr->inode);
    GET_NUM_FIELD(physHeader.mode, chPtr->mode);
    GET_NUM_FIELD(physHeader.uid, chPtr->uid);
    GET_NUM_FIELD(physHeader.gid, chPtr->gid);
    GET_NUM_FIELD(physHeader.nlink, chPtr->nlink);
    GET_NUM_FIELD(physHeader.mtime, chPtr->mtime);
    GET_NUM_FIELD(physHeader.filesize, chPtr->size);

    GET_NUM_FIELD(physHeader.devMajor, major);
    GET_NUM_FIELD(physHeader.devMinor, minor);
    chPtr->dev = makedev(major, minor);

    GET_NUM_FIELD(physHeader.rdevMajor, major);
    GET_NUM_FIELD(physHeader.rdevMinor, minor);
    chPtr->rdev = makedev(major, minor);

    GET_NUM_FIELD(physHeader.namesize, nameSize);

    chPtr->path = malloc(nameSize + 1);
    if (ourread(fd, chPtr->path, nameSize) != nameSize) {
	free(chPtr->path);
	return CPIOERR_BAD_HEADER;
    }

    /* this is unecessary chPtr->path[nameSize] = '\0'; */

    padinfd(fd, 4);

    return 0;
}

int myCpioFileMapCmp(const void * a, const void * b) {
    const struct cpioFileMapping * first = a;
    const struct cpioFileMapping * second = b;

    return (strcmp(first->archivePath, second->archivePath));
}

/* This could trash files in the path! I'm not sure that's a good thing */
static int createDirectory(char * path, mode_t perms) {
    struct stat sb;
    int dounlink;

    if (!lstat(path, &sb)) {
	if (S_ISDIR(sb.st_mode)) {
	    return 0;
	} else if (S_ISLNK(sb.st_mode)) {
	    if (stat(path, &sb)) {
		if (errno != ENOENT) 
		    return CPIOERR_STAT_FAILED;
		dounlink = 1;
	    } else {
		if (S_ISDIR(sb.st_mode))
		    return 0;
		dounlink = 1;
	    }
	} else {
	    dounlink = 1;
	}

	if (dounlink && unlink(path)) {
	    return CPIOERR_UNLINK_FAILED;
	}
    }

    if (mkdir(path, 000))
	return CPIOERR_MKDIR_FAILED;

    if (chmod(path, perms))
	return CPIOERR_CHMOD_FAILED;

    return 0;
}

static int setInfo(struct cpioHeader * hdr) {
    int rc = 0;
    struct utimbuf stamp;

    stamp.actime = hdr->mtime; 
    stamp.modtime = hdr->mtime;

    if (!S_ISLNK(hdr->mode)) {
	if (!getuid() && chown(hdr->path, hdr->uid, hdr->gid))
	    rc = CPIOERR_CHOWN_FAILED;
	if (!rc && chmod(hdr->path, hdr->mode & 07777))
	    rc = CPIOERR_CHMOD_FAILED;
	if (!rc && utime(hdr->path, &stamp))
	    rc = CPIOERR_UTIME_FAILED;
    } else {
#       if ! CHOWN_FOLLOWS_SYMLINK
	    if (!getuid() && !rc && lchown(hdr->path, hdr->uid, hdr->gid))
		rc = CPIOERR_CHOWN_FAILED;
#       endif
    }

    return rc;
}

static int checkDirectory(char * filename) {
    static char * lastDir = NULL;
    static int lastDirLength = 0;
    static int lastDirAlloced = 0;
    int length = strlen(filename);
    char * buf;
    char * chptr;
    int rc = 0;

    buf = alloca(length + 1);
    strcpy(buf, filename);

    for (chptr = buf + length - 1; chptr > buf; chptr--) {
	if (*chptr == '/') break;
    }

    if (chptr == buf) return 0;     /* /filename - no directories */

    *chptr = '\0';                  /* buffer is now just directories */

    length = strlen(buf);
    if (lastDirLength == length && !strcmp(buf, lastDir)) return 0;

    if (lastDirAlloced < (length + 1)) {
	lastDirAlloced = length + 100;
	lastDir = realloc(lastDir, lastDirAlloced);
    }

    strcpy(lastDir, buf);
    lastDirLength = length;

    for (chptr = buf + 1; *chptr; chptr++) {
	if (*chptr == '/') {
	    *chptr = '\0';
	    rc = createDirectory(buf, 0755);
	    *chptr = '/';
	    if (rc) return rc;
	}
    }
    rc = createDirectory(buf, 0755);

    return rc;
}

static int expandRegular(struct ourfd * fd, struct cpioHeader * hdr,
			 cpioCallback cb, void * cbData) {
    int out;
    char buf[8192];
    int bytesRead;
    unsigned long left = hdr->size;
    int rc = 0;
    struct cpioCallbackInfo cbInfo;
    struct stat sb;

    if (!lstat(hdr->path, &sb))
	if (unlink(hdr->path))
	    return CPIOERR_UNLINK_FAILED;

    out = open(hdr->path, O_CREAT | O_WRONLY, 0);
    if (out < 0) 
	return CPIOERR_OPEN_FAILED;

    cbInfo.file = hdr->path;
    cbInfo.fileSize = hdr->size;

    while (left) {
	bytesRead = ourread(fd, buf, left < sizeof(buf) ? left : sizeof(buf));
	if (bytesRead <= 0) {
	    rc = CPIOERR_READ_FAILED;
	    break;
	}

	if (write(out, buf, bytesRead) != bytesRead) {
	    rc = CPIOERR_COPY_FAILED;
	    break;
	}

	left -= bytesRead;

	/* don't call this with fileSize == fileComplete */
	if (!rc && cb && left) {
	    cbInfo.fileComplete = hdr->size - left;
	    cbInfo.bytesProcessed = fd->pos;
	    cb(&cbInfo, cbData);
	}
    }

    close(out);
    
    return rc;
}

static int expandSymlink(struct ourfd * fd, struct cpioHeader * hdr) {
    char buf[2048], buf2[2048];
    struct stat sb;
    int len;

    if ((hdr->size + 1)> sizeof(buf))
	return CPIOERR_INTERNAL;

    if (ourread(fd, buf, hdr->size) != hdr->size)
	return CPIOERR_READ_FAILED;

    buf[hdr->size] = '\0';

    if (!lstat(hdr->path, &sb)) {
	if (S_ISLNK(sb.st_mode)) {
	    len = readlink(hdr->path, buf2, sizeof(buf2) - 1);
	    if (len > 0) {
		buf2[len] = '\0';
		if (!strcmp(buf, buf2)) return 0;
	    }
	}

	if (unlink(hdr->path))
	    return CPIOERR_UNLINK_FAILED;
    }

    if (symlink(buf, hdr->path) < 0)
	return CPIOERR_SYMLINK_FAILED;

    return 0;
}

static int expandFifo(struct ourfd * fd, struct cpioHeader * hdr) {
    struct stat sb;

    if (!lstat(hdr->path, &sb)) {
	if (S_ISFIFO(sb.st_mode)) return 0;

	if (unlink(hdr->path))
	    return CPIOERR_UNLINK_FAILED;
    }

    if (mkfifo(hdr->path, 0))
	return CPIOERR_MKFIFO_FAILED;

    return 0; 
}

static int expandDevice(struct ourfd * fd, struct cpioHeader * hdr) {
    struct stat sb;

    if (!lstat(hdr->path, &sb)) {
	if ((S_ISCHR(sb.st_mode) || S_ISBLK(sb.st_mode)) && 
		(sb.st_rdev == hdr->rdev))
	    return 0;
	if (unlink(hdr->path))
	    return CPIOERR_UNLINK_FAILED;
    }

    if (mknod(hdr->path, hdr->mode & (~0777), hdr->rdev))
	return CPIOERR_MKNOD_FAILED;
    
    return 0;
}

static void freeLink(struct hardLink * li) {
    int i;

    for (i = 0; i < li->nlink; i++) {
	if (li->files[i]) free(li->files[i]);
    }
    free(li->files);
}

static int createLinks(struct hardLink * li, const char ** failedFile) {
    int i;
    struct stat sb;

    for (i = 0; i < li->nlink; i++) {
	if (i == li->createdPath) continue;
	if (!li->files[i]) continue;

	if (!lstat(li->files[i], &sb)) {
	    if (unlink(li->files[i])) {
		*failedFile = strdup(li->files[i]);
		return CPIOERR_UNLINK_FAILED;
	    }
	}

	if (link(li->files[li->createdPath], li->files[i])) {
	    *failedFile = strdup(li->files[i]);
	    return CPIOERR_LINK_FAILED;
	}

	free(li->files[i]);
	li->files[i] = NULL;
	li->linksLeft--;
    }

    return 0;
}

static int eatBytes(struct ourfd * fd, unsigned long amount) {
    char buf[4096];
    unsigned long bite;
   
    while (amount) {
	bite = (amount > sizeof(buf)) ? sizeof(buf) : amount;
	if (ourread(fd, buf, bite) != bite)
	    return CPIOERR_READ_FAILED;
	amount -= bite;
    }

    return 0;
}

int myCpioInstallArchive(gzFile stream, struct cpioFileMapping * mappings, 
		       int numMappings, cpioCallback cb, void * cbData,
		       const char ** failedFile) {
    struct cpioHeader ch;
    struct ourfd fd;
    int rc = 0;
    int linkNum = 0;
    struct cpioFileMapping * map = NULL;
    struct cpioFileMapping needle;
    mode_t cpioMode;
    int olderr;
    struct cpioCallbackInfo cbInfo;
    struct hardLink * links = NULL;
    struct hardLink * li = NULL;

    fd.fd = stream;
    fd.pos = 0;

    *failedFile = NULL;

    do {
	if ((rc = getNextHeader(&fd, &ch, NULL))) {
	    fprintf(stderr, _("error %d reading header: %s\n"), rc, 
		    myCpioStrerror(rc));
	    return CPIOERR_BAD_HEADER;
	}

	if (!strcmp(ch.path, TRAILER)) {
	    free(ch.path);
	    break;
	}

	if (mappings) {
	    needle.archivePath = ch.path;
	    map = bsearch(&needle, mappings, numMappings, sizeof(needle),
			  myCpioFileMapCmp);
	}

	if (mappings && !map) {
	    eatBytes(&fd, ch.size);
	} else {
	    cpioMode = ch.mode;

	    if (map) {
		if (map->mapFlags & CPIO_MAP_PATH) {
		    free(ch.path);
		    ch.path = strdup(map->fsPath);
		} 

		if (map->mapFlags & CPIO_MAP_MODE)
		    ch.mode = map->finalMode;
		if (map->mapFlags & CPIO_MAP_UID)
		    ch.uid = map->finalUid;
		if (map->mapFlags & CPIO_MAP_GID)
		    ch.gid = map->finalGid;
	    }

	    /* This won't get hard linked symlinks right, but I can't seem 
	       to create those anyway */

	    if (S_ISREG(ch.mode) && ch.nlink > 1) {
		li = links;
		for (li = links; li; li = li->next) {
		    if (li->inode == ch.inode && li->dev == ch.dev) break;
		}

		if (!li) {
		    li = malloc(sizeof(*li));
		    li->inode = ch.inode;
		    li->dev = ch.dev;
		    li->nlink = ch.nlink;
		    li->linksLeft = ch.nlink;
		    li->createdPath = -1;
		    li->files = calloc(sizeof(char *), li->nlink);
		    li->next = links;
		    links = li;
		}

		for (linkNum = 0; linkNum < li->nlink; linkNum++)
		    if (!li->files[linkNum]) break;
		li->files[linkNum] = strdup(ch.path);
	    }
		
	    if ((ch.nlink > 1) && S_ISREG(ch.mode) && !ch.size &&
		li->createdPath == -1) {
		/* defer file creation */
	    } else if ((ch.nlink > 1) && S_ISREG(ch.mode) && 
		       (li->createdPath != -1)) {
		createLinks(li, failedFile);

		/* this only happens for cpio archives which contain
		   hardlinks w/ the contents of each hardlink being
		   listed (intead of the data being given just once. This
		   shouldn't happen, but I've made it happen w/ buggy
		   code, so what the heck? GNU cpio handles this well fwiw */
		if (ch.size) eatBytes(&fd, ch.size);
	    } else {
		rc = checkDirectory(ch.path);

		if (!rc) {
		    if (S_ISREG(ch.mode))
			rc = expandRegular(&fd, &ch, cb, cbData);
		    else if (S_ISDIR(ch.mode))
			rc = createDirectory(ch.path, 000);
		    else if (S_ISLNK(ch.mode))
			rc = expandSymlink(&fd, &ch);
		    else if (S_ISFIFO(ch.mode))
			rc = expandFifo(&fd, &ch);
		    else if (S_ISCHR(ch.mode) || S_ISBLK(ch.mode))
			rc = expandDevice(&fd, &ch);
		    else if (S_ISSOCK(ch.mode)) {
			/* this mimicks cpio but probably isnt' right */
			rc = expandFifo(&fd, &ch);
		    } else {
			rc = CPIOERR_INTERNAL;
		    }
		}

		if (!rc)
		    rc = setInfo(&ch);

		if (S_ISREG(ch.mode) && ch.nlink > 1) {
		    li->createdPath = linkNum;
		    li->linksLeft--;
		    rc = createLinks(li, failedFile);
		}
	    }

	    if (rc && !*failedFile) {
		*failedFile = strdup(ch.path);

		olderr = errno;
		unlink(ch.path);
		errno = olderr;
	    }
	}

	padinfd(&fd, 4);

	if (!rc && cb) {
	    cbInfo.file = ch.path;
	    cbInfo.fileSize = ch.size;
	    cbInfo.fileComplete = ch.size;
	    cbInfo.bytesProcessed = fd.pos;
	    cb(&cbInfo, cbData);
	}

	free(ch.path);
    } while (1 && !rc);

    li = links;
    while (li && !rc) {
	if (li->linksLeft) {
	    if (li->createdPath == -1)
		rc = CPIOERR_INTERNAL;
	    else 
		rc = createLinks(li, failedFile);
	}

	freeLink(li);

	links = li;
	li = li->next;
	free(links);
	links = li;
    }

    li = links;
    /* if an error got us here links will still be eating some memory */
    while (li) {
	freeLink(li);
	links = li;
	li = li->next;
	free(links);
    }

    return rc;
}

const char * myCpioStrerror(int rc)
{
    static char msg[256];
    char *s;
    int l, myerrno = errno;

    strcpy(msg, "cpio: ");
    switch (rc) {
    default:
	s = msg + strlen(msg);
	sprintf(s, _("(error 0x%x)"), rc);
	s = NULL;
	break;
    case CPIOERR_BAD_MAGIC:	s = _("Bad magic");		break;
    case CPIOERR_BAD_HEADER:	s = _("Bad header");		break;

    case CPIOERR_OPEN_FAILED:	s = "open";	break;
    case CPIOERR_CHMOD_FAILED:	s = "chmod";	break;
    case CPIOERR_CHOWN_FAILED:	s = "chown";	break;
    case CPIOERR_WRITE_FAILED:	s = "write";	break;
    case CPIOERR_UTIME_FAILED:	s = "utime";	break;
    case CPIOERR_UNLINK_FAILED:	s = "unlink";	break;
    case CPIOERR_SYMLINK_FAILED: s = "symlink";	break;
    case CPIOERR_STAT_FAILED:	s = "stat";	break;
    case CPIOERR_MKDIR_FAILED:	s = "mkdir";	break;
    case CPIOERR_MKNOD_FAILED:	s = "mknod";	break;
    case CPIOERR_MKFIFO_FAILED:	s = "mkfifo";	break;
    case CPIOERR_LINK_FAILED:	s = "link";	break;
    case CPIOERR_READLINK_FAILED: s = "readlink";	break;
    case CPIOERR_READ_FAILED:	s = "read";	break;
    case CPIOERR_COPY_FAILED:	s = "copy";	break;

    case CPIOERR_INTERNAL:	s = _("Internal error");	break;
    case CPIOERR_HDR_SIZE:	s = _("Header size too big");	break;
    case CPIOERR_UNKNOWN_FILETYPE: s = _("Unknown file type");	break;
    }

    l = sizeof(msg) - strlen(msg) - 1;
    if (s != NULL) {
	if (l > 0) strncat(msg, s, l);
	l -= strlen(s);
    }
    if (rc & CPIOERR_CHECK_ERRNO) {
	s = _(" failed - ");
	if (l > 0) strncat(msg, s, l);
	l -= strlen(s);
	if (l > 0) strncat(msg, strerror(myerrno), l);
    }
    return msg;
}

static int copyFile(struct ourfd * inFd, struct ourfd * outFd, 
	     struct cpioHeader * chp, struct cpioCrcPhysicalHeader * pHdr) {
    char buf[8192];
    int amount;
    size_t size = chp->size;

    amount = strlen(chp->path) + 1;
    memcpy(pHdr->magic, CPIO_NEWC_MAGIC, sizeof(pHdr->magic));

    gzip_write(outFd->fd, pHdr, PHYS_HDR_SIZE);
    gzip_write(outFd->fd, chp->path, amount);

    outFd->pos += PHYS_HDR_SIZE + amount;

    padoutfd(outFd, &outFd->pos, 4);

    while (size) {
	amount = ourread(inFd, buf, size > sizeof(buf) ? sizeof(buf) : size);
	gzip_write(outFd->fd, buf, amount);
	size -= amount;
    }

    outFd->pos += chp->size;

    padoutfd(outFd, &outFd->pos, 4);

    return 0;
}

int myCpioFilterArchive(gzFile inStream, gzFile outStream, char ** patterns) {
    struct ourfd inFd, outFd;
    char ** aPattern;
    struct cpioHeader ch;
    int rc;
    struct cpioCrcPhysicalHeader pHeader;

    inFd.fd = inStream;
    inFd.pos = 0;
    outFd.fd = outStream;
    outFd.pos = 0;

    do {
	if ((rc = getNextHeader(&inFd, &ch, &pHeader))) {
	    fprintf(stderr, _("error %d reading header: %s\n"), rc, 
		    myCpioStrerror(rc));
	    return CPIOERR_BAD_HEADER;
	}

	if (!strcmp(ch.path, TRAILER)) {
	    free(ch.path);
	    break;
	}

	for (aPattern = patterns; *aPattern; aPattern++)
	    if (!fnmatch(*aPattern, ch.path, FNM_PATHNAME | FNM_PERIOD))
		break;

	if (!*aPattern)
	    eatBytes(&inFd, ch.size);
	else
	    copyFile(&inFd, &outFd, &ch, &pHeader);

	padinfd(&inFd, 4);

	free(ch.path);
    } while (1 && !rc);

    memset(&pHeader, '0', sizeof(pHeader));
    memcpy(pHeader.magic, CPIO_NEWC_MAGIC, sizeof(pHeader.magic));
    memcpy(pHeader.nlink, "00000001", 8);
    memcpy(pHeader.namesize, "0000000b", 8);
    gzip_write(outFd.fd, &pHeader, PHYS_HDR_SIZE);
    gzip_write(outFd.fd, "TRAILER!!!", 11);

    outFd.pos += PHYS_HDR_SIZE + 11;

    if ((rc = padoutfd(&outFd, &outFd.pos, 4)))
	return rc;

    if ((rc = padoutfd(&outFd, &outFd.pos, 512)))
	return rc;

    return 0;
}