---

generator.c

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/* -*- 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 update_only;
extern int opt_ignore_existing;
extern int block_size;
extern int csum_length;
extern int ignore_times;
extern int size_only;
extern int io_timeout;
extern int remote_version;
extern int always_checksum;
extern int modify_window;
extern char *compare_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 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) {
                                snprintf(fnamecmpdest,MAXPATHLEN,"%s/%s",
                                                    compare_dest,fname);
                                fname = fnamecmpdest;
                        }
                }
                file_checksum(fname,sum,st->st_size);
                if (remote_version < 21) {
                        return (memcmp(sum,file->sum,2) == 0);
                } else {
                        return (memcmp(sum,file->sum,MD4_SUM_LENGTH) == 0);
                }
        }

        if (size_only) {
                return 1;
        }

        if (ignore_times) {
                return 0;
        }

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


/* use a larger block size for really big files */
static int adapt_block_size(struct file_struct *file, int bsize)
{
        int ret;

        if (bsize != BLOCK_SIZE) return bsize;

        ret = file->length / (10000); /* rough heuristic */
        ret = ret & ~15; /* multiple of 16 */
        if (ret < bsize) ret = bsize;
        if (ret > CHUNK_SIZE/2) ret = CHUNK_SIZE/2;
        return ret;
}


/*
  send a sums struct down a fd
  */
static void send_sums(struct sum_struct *s, int f_out)
{
        if (s) {
                size_t i;

                /* tell the other guy how many we are going to be
                   doing and how many bytes there are in the last
                   chunk */
                write_int(f_out, s->count);
                write_int(f_out, s->n);
                write_int(f_out, s->remainder);

                for (i = 0; i < s->count; i++) {
                        write_int(f_out, s->sums[i].sum1);
                        write_buf(f_out, s->sums[i].sum2, csum_length);
                }
        } else {
                /* we don't have checksums */
                write_int(f_out, 0);
                write_int(f_out, block_size);
                write_int(f_out, 0);
        }
}


/**
 * 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, no_whole_file;
        extern int local_server;
        extern int write_batch;

        assert(whole_file == 0 || whole_file == 1);

        /* whole_file and no_whole_file are never both on at the same time */

        if (whole_file)
                return True;
        else if (no_whole_file)
                return False;
        else if (write_batch)
                return False;
        else
                return local_server;
}


/**
 * Generate a stream of signatures/checksums that describe a buffer.
 *
 * Generate approximately one checksum every @p n bytes.
 *
 * @return Newly-allocated sum_struct
 **/
static struct sum_struct *generate_sums(struct map_struct *buf, OFF_T len,
                                        int n)
{
        int i;
        struct sum_struct *s;
        int count;
        int block_len = n;
        int remainder = (len % block_len);
        OFF_T offset = 0;

        count = (len + (block_len - 1)) / block_len;

        s = (struct sum_struct *) malloc(sizeof(*s));
        if (!s)
                out_of_memory("generate_sums");

        s->count = count;
        s->remainder = remainder;
        s->n = n;
        s->flength = len;

        if (count == 0) {
                s->sums = NULL;
                return s;
        }

        if (verbose > 3) {
                rprintf(FINFO, "count=%ld rem=%ld n=%ld flength=%.0f\n",
                        (long) s->count, (long) s->remainder,
                        (long) s->n, (double) s->flength);
        }

        s->sums = (struct sum_buf *) malloc(sizeof(s->sums[0]) * s->count);
        if (!s->sums)
                out_of_memory("generate_sums");

        for (i = 0; i < count; i++) {
                int n1 = MIN(len, n);
                char *map = map_ptr(buf, offset, n1);

                s->sums[i].sum1 = get_checksum1(map, n1);
                get_checksum2(map, n1, s->sums[i].sum2);

                s->sums[i].offset = offset;
                s->sums[i].len = n1;
                s->sums[i].i = i;

                if (verbose > 3)
                        rprintf(FINFO,
                                "chunk[%d] offset=%.0f len=%d sum1=%08x\n",
                                i, (double) s->sums[i].offset,
                                s->sums[i].len, s->sums[i].sum1);

                len -= n1;
                offset += n1;
        }

        return s;
}



/**
 * 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_list *flist, int i, int f_out)
{  
        int fd;
        STRUCT_STAT st;
        struct map_struct *buf;
        struct sum_struct *s;
        int statret;
        struct file_struct *file = flist->files[i];
        char *fnamecmp;
        char fnamecmpbuf[MAXPATHLEN];
        extern char *compare_dest;
        extern int list_only;
        extern int preserve_perms;
        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
                   presmissions then act as though the remote end sent
                   us the file permissions we already have */
                file->mode = (file->mode & _S_IFMT) | (st.st_mode & ~_S_IFMT);
        }

        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, RSYNC_NAME
                                        ": recv_generator: unlink \"%s\" to make room for directory: %s\n",
                                        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, RSYNC_NAME ": recv_generator: mkdir \"%s\": %s (2)\n",
                                        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->link, fname)) {
                        if (verbose) {
                                rprintf(FINFO,"ignoring unsafe symlink \"%s\" -> \"%s\"\n",
                                        fname,file->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->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->link,fname) != 0) {
                        rprintf(FERROR,RSYNC_NAME": symlink \"%s\" -> \"%s\": %s\n",
                                fname,file->link,strerror(errno));
                } else {
                        set_perms(fname,file,NULL,0);
                        if (verbose) {
                                rprintf(FINFO,"%s -> %s\n", fname,file->link);
                        }
                }
#endif
                return;
        }

#ifdef HAVE_MKNOD
        if (am_root && preserve_devices && IS_DEVICE(file->mode)) {
                if (statret != 0 || 
                    st.st_mode != file->mode ||
                    st.st_rdev != file->rdev) { 
                        delete_file(fname);
                        if (verbose > 2)
                                rprintf(FINFO,"mknod(%s,0%o,0x%x)\n",
                                        fname,(int)file->mode,(int)file->rdev);
                        if (do_mknod(fname,file->mode,file->rdev) != 0) {
                                rprintf(FERROR,"mknod %s : %s\n",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 && check_hard_link(file)) {
                if (verbose > 1)
                        rprintf(FINFO, "recv_generator: \"%s\" is a hard link\n",f_name(file));
                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;
                snprintf(fnamecmpbuf,MAXPATHLEN,"%s/%s",compare_dest,fname);
                statret = link_stat(fnamecmpbuf,&st);
                if (!S_ISREG(st.st_mode))
                        statret = -1;
                if (statret == -1)
                        errno = saveerrno;
                else
                        fnamecmp = fnamecmpbuf;
        }

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

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

                /* now pretend the file didn't exist */
                write_int(f_out,i);
                if (!dry_run) send_sums(NULL,f_out);    
                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);
                send_sums(NULL,f_out);    
                return;
        }

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

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

        if (st.st_size > 0) {
                buf = map_file(fd,st.st_size);
        } else {
                buf = NULL;
        }

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

        s = generate_sums(buf,st.st_size,adapt_block_size(file, block_size));

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

        write_int(f_out,i);
        send_sums(s,f_out);

        close(fd);
        if (buf) unmap_file(buf);

        free_sums(s);
}



void generate_files(int f,struct file_list *flist,char *local_name,int f_recv)
{
        int i;
        int phase=0;

        if (verbose > 2)
                rprintf(FINFO,"generator starting pid=%d count=%d\n",
                        (int)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];
                mode_t saved_mode = file->mode;
                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; /* user write */
                        /* XXX: Could this be causing a problem on SCO?  Perhaps their
                         * handling of permissions is strange? */
                }

                recv_generator(local_name?local_name:f_name(file),
                               flist,i,f);

                file->mode = saved_mode;
        }

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

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

        write_int(f,-1);

        if (remote_version >= 13) {
                /* in newer versions of the protocol the files can cycle through
                   the system more than once to catch initial checksum errors */
                for (i=read_int(f_recv); i != -1; i=read_int(f_recv)) {
                        struct file_struct *file = flist->files[i];
                        recv_generator(local_name?local_name:f_name(file),
                                       flist,i,f);    
                }

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

                write_int(f,-1);
        }
}

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