Preparing for release of 2.6.1pre-1

[rsync.git] / generator.c

/* -*- c-file-style: "linux" -*-

   rsync -- fast file replication program

   Copyright (C) 1996-2000 by Andrew Tridgell
   Copyright (C) Paul Mackerras 1996
   Copyright (C) 2002 by Martin Pool <mbp@samba.org>

   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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rsync.h"

extern int verbose;
extern int dry_run;
extern int relative_paths;
extern int preserve_links;
extern int am_root;
extern int preserve_devices;
extern int preserve_hard_links;
extern int preserve_perms;
extern int preserve_uid;
extern int preserve_gid;
extern int update_only;
extern int opt_ignore_existing;
extern int csum_length;
extern int ignore_times;
extern int size_only;
extern int io_timeout;
extern int protocol_version;
extern int always_checksum;
extern char *compare_dest;
extern int link_dest;


/* choose whether to skip a particular file */
static int skip_file(char *fname, struct file_struct *file, STRUCT_STAT *st)
{
        if (st->st_size != file->length) {
                return 0;
        }
        if (link_dest) {
                if (preserve_perms
                    && (st->st_mode & CHMOD_BITS) != (file->mode & CHMOD_BITS))
                        return 0;

                if (am_root && preserve_uid && st->st_uid != file->uid)
                        return 0;

                if (preserve_gid && file->gid != GID_NONE
                    && st->st_gid != file->gid)
                        return 0;
        }

        /* if always checksum is set then we use the checksum instead
           of the file time to determine whether to sync */
        if (always_checksum && S_ISREG(st->st_mode)) {
                char sum[MD4_SUM_LENGTH];
                char fnamecmpdest[MAXPATHLEN];

                if (compare_dest != NULL) {
                        if (access(fname, 0) != 0) {
                                pathjoin(fnamecmpdest, sizeof fnamecmpdest,
                                         compare_dest, fname);
                                fname = fnamecmpdest;
                        }
                }
                file_checksum(fname,sum,st->st_size);
                return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
                                                        : MD4_SUM_LENGTH) == 0;
        }

        if (size_only) {
                return 1;
        }

        if (ignore_times) {
                return 0;
        }

        return (cmp_modtime(st->st_mtime,file->modtime) == 0);
}


/*
 * NULL sum_struct means we have no checksums
 */
void write_sum_head(int f, struct sum_struct *sum)
{
        static struct sum_struct null_sum;

        if (sum == NULL)
                sum = &null_sum;

        write_int(f, sum->count);
        write_int(f, sum->blength);
        if (protocol_version >= 27)
                write_int(f, sum->s2length);
        write_int(f, sum->remainder);
}

/* 
 * set (initialize) the size entries in the per-file sum_struct
 * calulating dynamic block ans checksum sizes.
 *
 * This is only called from generate_and_send_sums() but is a seperate
 * function to encapsulate the logic.
 *
 * The block size is a rounded square root of file length.
 *
 * The checksum size is determined according to:
 *     blocksum_bits = BLOCKSUM_EXP + 2*log2(file_len) - log2(block_len)
 * provided by Donovan Baarda which gives a probability of rsync
 * algorithm corrupting data and falling back using the whole md4
 * checksums.
 *
 * This might be made one of several selectable heuristics.
 */

static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
{
        extern unsigned int block_size;
        unsigned int blength;
        int s2length;
        uint32 c;
        uint64 l;

        if (block_size) {
                blength = block_size;
        } else if (len <= BLOCK_SIZE * BLOCK_SIZE) {
                blength = BLOCK_SIZE;
        } else {
                l = len;
                c = 1;
                while (l >>= 2) {
                        c <<= 1;
                }
                blength = 0;
                do {
                        blength |= c;
                        if (len < (uint64)blength * blength)
                                blength &= ~c;
                        c >>= 1;
                } while (c >= 8);       /* round to multiple of 8 */
                blength = MAX(blength, BLOCK_SIZE);
        }

        if (protocol_version < 27) {
                s2length = csum_length;
        } else if (csum_length == SUM_LENGTH) {
                s2length = SUM_LENGTH;
        } else {
                int b = BLOCKSUM_BIAS;
                l = len;
                while (l >>= 1) {
                        b += 2;
                }
                c = blength;
                while (c >>= 1 && b) {
                        b--;
                }
                s2length = (b + 1 - 32 + 7) / 8; /* add a bit,
                                                  * subtract rollsum,
                                                  * round up
                                                  *    --optimize in compiler--
                                                  */
                s2length = MAX(s2length, csum_length);
                s2length = MIN(s2length, SUM_LENGTH);
        }

        sum->flength    = len;
        sum->blength    = blength;
        sum->s2length   = s2length;
        sum->count      = (len + (blength - 1)) / blength;
        sum->remainder  = (len % blength);

        if (sum->count && verbose > 2) {
                rprintf(FINFO, "count=%.0f rem=%u blength=%u s2length=%d flength=%.0f\n",
                        (double)sum->count, sum->remainder, sum->blength,
                        sum->s2length, (double)sum->flength);
        }
}

/**
 * Perhaps we want to just send an empty checksum set for this file,
 * which will force the whole thing to be literally transferred.
 *
 * When do we do this?  If the user's explicitly said they
 * want the whole thing, or if { they haven't explicitly
 * requested a delta, and it's local but not batch mode.}
 *
 * Whew. */
static BOOL disable_deltas_p(void)
{
        extern int whole_file;
        extern int local_server;
        extern int write_batch;

        if (whole_file > 0)
                return True;
        if (whole_file == 0 || write_batch)
                return False;
        return local_server;
}


/*
 * Generate and send a stream of signatures/checksums that describe a buffer
 *
 * Generate approximately one checksum every block_len bytes.
 */
static void generate_and_send_sums(struct map_struct *buf, size_t len, int f_out)
{
        size_t i;
        struct sum_struct sum;
        OFF_T offset = 0;

        sum_sizes_sqroot(&sum, len);

        write_sum_head(f_out, &sum);

        for (i = 0; i < sum.count; i++) {
                unsigned int n1 = MIN(len, sum.blength);
                char *map = map_ptr(buf, offset, n1);
                uint32 sum1 = get_checksum1(map, n1);
                char sum2[SUM_LENGTH];

                get_checksum2(map, n1, sum2);

                if (verbose > 3) {
                        rprintf(FINFO,
                                "chunk[%.0f] offset=%.0f len=%u sum1=%08lx\n",
                                (double)i, (double)offset, n1,
                                (unsigned long)sum1);
                }
                write_int(f_out, sum1);
                write_buf(f_out, sum2, sum.s2length);
                len -= n1;
                offset += n1;
        }
}



/**
 * Acts on file number @p i from @p flist, whose name is @p fname.
 *
 * First fixes up permissions, then generates checksums for the file.
 *
 * @note This comment was added later by mbp who was trying to work it
 * out.  It might be wrong.
 **/
void recv_generator(char *fname, struct file_struct *file, int i, int f_out)
{
        int fd;
        STRUCT_STAT st;
        struct map_struct *mapbuf;
        int statret;
        char *fnamecmp;
        char fnamecmpbuf[MAXPATHLEN];
        extern char *compare_dest;
        extern int list_only;
        extern int only_existing;
        extern int orig_umask;

        if (list_only)
                return;

        if (verbose > 2)
                rprintf(FINFO,"recv_generator(%s,%d)\n",fname,i);

        statret = link_stat(fname,&st);

        if (only_existing && statret == -1 && errno == ENOENT) {
                /* we only want to update existing files */
                if (verbose > 1) rprintf(FINFO, "not creating new file \"%s\"\n",fname);
                return;
        }

        if (statret == 0 &&
            !preserve_perms &&
            (S_ISDIR(st.st_mode) == S_ISDIR(file->mode))) {
                /* if the file exists already and we aren't perserving
                 * permissions then act as though the remote end sent
                 * us the file permissions we already have */
                file->mode = (file->mode & ~CHMOD_BITS)
                           | (st.st_mode & CHMOD_BITS);
        }

        if (S_ISDIR(file->mode)) {
                /* The file to be received is a directory, so we need
                 * to prepare appropriately.  If there is already a
                 * file of that name and it is *not* a directory, then
                 * we need to delete it.  If it doesn't exist, then
                 * recursively create it. */

                if (dry_run) return; /* XXXX -- might cause inaccuracies?? -- mbp */
                if (statret == 0 && !S_ISDIR(st.st_mode)) {
                        if (robust_unlink(fname) != 0) {
                                rprintf(FERROR,
                                        "recv_generator: unlink %s to make room for directory: %s\n",
                                        full_fname(fname), strerror(errno));
                                return;
                        }
                        statret = -1;
                }
                if (statret != 0 && do_mkdir(fname,file->mode) != 0 && errno != EEXIST) {
                        if (!(relative_paths && errno==ENOENT &&
                              create_directory_path(fname, orig_umask)==0 &&
                              do_mkdir(fname,file->mode)==0)) {
                                rprintf(FERROR, "recv_generator: mkdir %s failed: %s\n",
                                        full_fname(fname), strerror(errno));
                        }
                }
                /* f_out is set to -1 when doing final directory
                   permission and modification time repair */
                if (set_perms(fname,file,NULL,0) && verbose && (f_out != -1))
                        rprintf(FINFO,"%s/\n",fname);
                return;
        }

        if (preserve_links && S_ISLNK(file->mode)) {
#if SUPPORT_LINKS
                char lnk[MAXPATHLEN];
                int l;
                extern int safe_symlinks;

                if (safe_symlinks && unsafe_symlink(file->u.link, fname)) {
                        if (verbose) {
                                rprintf(FINFO, "ignoring unsafe symlink %s -> \"%s\"\n",
                                        full_fname(fname), file->u.link);
                        }
                        return;
                }
                if (statret == 0) {
                        l = readlink(fname,lnk,MAXPATHLEN-1);
                        if (l > 0) {
                                lnk[l] = 0;
                                /* A link already pointing to the
                                 * right place -- no further action
                                 * required. */
                                if (strcmp(lnk,file->u.link) == 0) {
                                        set_perms(fname,file,&st,1);
                                        return;
                                }
                        }
                        /* Not a symlink, so delete whatever's
                         * already there and put a new symlink
                         * in place. */
                        delete_file(fname);
                }
                if (do_symlink(file->u.link,fname) != 0) {
                        rprintf(FERROR, "symlink %s -> \"%s\" failed: %s\n",
                                full_fname(fname), file->u.link, strerror(errno));
                } else {
                        set_perms(fname,file,NULL,0);
                        if (verbose) {
                                rprintf(FINFO,"%s -> %s\n", fname,file->u.link);
                        }
                }
#endif
                return;
        }

#ifdef HAVE_MKNOD
        if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
                if (statret != 0 ||
                    st.st_mode != file->mode ||
                    (DEV64_T)st.st_rdev != file->u.rdev) {
                        delete_file(fname);
                        if (verbose > 2)
                                rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
                                        fname,(int)file->mode,(int)file->u.rdev);
                        if (do_mknod(fname,file->mode,file->u.rdev) != 0) {
                                rprintf(FERROR, "mknod %s failed: %s\n",
                                        full_fname(fname), strerror(errno));
                        } else {
                                set_perms(fname,file,NULL,0);
                                if (verbose)
                                        rprintf(FINFO,"%s\n",fname);
                        }
                } else {
                        set_perms(fname,file,&st,1);
                }
                return;
        }
#endif

        if (preserve_hard_links && hard_link_check(file, HL_CHECK_MASTER))
                return;

        if (!S_ISREG(file->mode)) {
                rprintf(FINFO, "skipping non-regular file \"%s\"\n",fname);
                return;
        }

        fnamecmp = fname;

        if (statret == -1 && compare_dest != NULL) {
                /* try the file at compare_dest instead */
                int saveerrno = errno;
                pathjoin(fnamecmpbuf, sizeof fnamecmpbuf, compare_dest, fname);
                statret = link_stat(fnamecmpbuf,&st);
                if (!S_ISREG(st.st_mode))
                        statret = -1;
                if (statret == -1)
                        errno = saveerrno;
#if HAVE_LINK
                else if (link_dest && !dry_run) {
                        if (do_link(fnamecmpbuf, fname) != 0) {
                                if (verbose > 0) {
                                        rprintf(FINFO,"link %s => %s : %s\n",
                                                fnamecmpbuf, fname,
                                                strerror(errno));
                                }
                        }
                        fnamecmp = fnamecmpbuf;
                }
#endif
                else
                        fnamecmp = fnamecmpbuf;
        }

        if (statret == -1) {
                if (preserve_hard_links && hard_link_check(file, HL_SKIP))
                        return;
                if (errno == ENOENT) {
                        write_int(f_out,i);
                        if (!dry_run) write_sum_head(f_out, NULL);
                } else if (verbose > 1) {
                        rprintf(FERROR,
                                "recv_generator: failed to open %s: %s\n",
                                full_fname(fname), strerror(errno));
                }
                return;
        }

        if (!S_ISREG(st.st_mode)) {
                if (delete_file(fname) != 0) {
                        return;
                }

                /* now pretend the file didn't exist */
                if (preserve_hard_links && hard_link_check(file, HL_SKIP))
                        return;
                write_int(f_out,i);
                if (!dry_run) write_sum_head(f_out, NULL);
                return;
        }

        if (opt_ignore_existing && fnamecmp == fname) {
                if (verbose > 1)
                        rprintf(FINFO,"%s exists\n",fname);
                return;
        }

        if (update_only && cmp_modtime(st.st_mtime,file->modtime)>0 && fnamecmp == fname) {
                if (verbose > 1)
                        rprintf(FINFO,"%s is newer\n",fname);
                return;
        }

        if (skip_file(fname, file, &st)) {
                if (fnamecmp == fname)
                        set_perms(fname,file,&st,1);
                return;
        }

        if (dry_run) {
                write_int(f_out,i);
                return;
        }

        if (disable_deltas_p()) {
                write_int(f_out,i);
                write_sum_head(f_out, NULL);
                return;
        }

        /* open the file */
        fd = do_open(fnamecmp, O_RDONLY, 0);

        if (fd == -1) {
                rprintf(FERROR, "failed to open %s, continuing: %s\n",
                        full_fname(fnamecmp), strerror(errno));
                /* pretend the file didn't exist */
                if (preserve_hard_links && hard_link_check(file, HL_SKIP))
                        return;
                write_int(f_out,i);
                write_sum_head(f_out, NULL);
                return;
        }

        if (st.st_size > 0)
                mapbuf = map_file(fd,st.st_size);
        else
                mapbuf = NULL;

        if (verbose > 3) {
                rprintf(FINFO,"gen mapped %s of size %.0f\n", fnamecmp,
                        (double)st.st_size);
        }

        if (verbose > 2)
                rprintf(FINFO, "generating and sending sums for %d\n", i);

        write_int(f_out,i);
        generate_and_send_sums(mapbuf, st.st_size, f_out);

        close(fd);
        if (mapbuf) unmap_file(mapbuf);
}


void generate_files(int f, struct file_list *flist, char *local_name)
{
        int i;
        int phase=0;
        char fbuf[MAXPATHLEN];

        if (verbose > 2) {
                rprintf(FINFO, "generator starting pid=%ld count=%d\n",
                        (long)getpid(), flist->count);
        }

        if (verbose >= 2) {
                rprintf(FINFO,
                        disable_deltas_p()
                        ? "delta-transmission disabled for local transfer or --whole-file\n"
                        : "delta transmission enabled\n");
        }

        /* we expect to just sit around now, so don't exit on a
           timeout. If we really get a timeout then the other process should
           exit */
        io_timeout = 0;

        for (i = 0; i < flist->count; i++) {
                struct file_struct *file = flist->files[i];
                struct file_struct copy;

                if (!file->basename)
                        continue;
                /* we need to ensure that any directories we create have writeable
                   permissions initially so that we can create the files within
                   them. This is then fixed after the files are transferred */
                if (!am_root && S_ISDIR(file->mode) && !(file->mode & S_IWUSR)) {
                        copy = *file;
                        /* XXX: Could this be causing a problem on SCO?  Perhaps their
                         * handling of permissions is strange? */
                        copy.mode |= S_IWUSR; /* user write */
                        file = &copy;
                }

                recv_generator(local_name ? local_name : f_name_to(file, fbuf),
                               file, i, f);
        }

        phase++;
        csum_length = SUM_LENGTH;
        ignore_times=1;

        if (verbose > 2)
                rprintf(FINFO,"generate_files phase=%d\n",phase);

        write_int(f,-1);

        /* files can cycle through the system more than once
         * to catch initial checksum errors */
        while ((i = get_redo_num()) != -1) {
                struct file_struct *file = flist->files[i];
                recv_generator(local_name ? local_name : f_name_to(file, fbuf),
                               file, i, f);
        }

        phase++;
        if (verbose > 2)
                rprintf(FINFO,"generate_files phase=%d\n",phase);

        write_int(f,-1);

        if (preserve_hard_links)
                do_hard_links();

        /* now we need to fix any directory permissions that were
         * modified during the transfer */
        for (i = 0; i < flist->count; i++) {
                struct file_struct *file = flist->files[i];
                if (!file->basename || !S_ISDIR(file->mode)) continue;
                recv_generator(local_name ? local_name : f_name(file),
                               file, i, -1);
        }

        if (verbose > 2)
                rprintf(FINFO,"generate_files finished\n");
}