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Annotation of freem/src/fs.c, revision 1.2

1.1       snw         1: /*
                      2:  *                            *
                      3:  *                           * *
                      4:  *                          *   *
                      5:  *                     ***************
                      6:  *                      * *       * *
                      7:  *                       *  MUMPS  *
                      8:  *                      * *       * *
                      9:  *                     ***************
                     10:  *                          *   *
                     11:  *                           * *
                     12:  *                            *
                     13:  *
                     14:  *   fs.c
                     15:  *    filesystem support functions
                     16:  *
                     17:  *  
1.2     ! snw        18:  *   Author: Serena Willis <snw@coherent-logic.com>
1.1       snw        19:  *    Copyright (C) 1998 MUG Deutschland
                     20:  *    Copyright (C) 2024 Coherent Logic Development LLC
                     21:  *
                     22:  *
                     23:  *   This file is part of FreeM.
                     24:  *
                     25:  *   FreeM is free software: you can redistribute it and/or modify
                     26:  *   it under the terms of the GNU Affero Public License as published by
                     27:  *   the Free Software Foundation, either version 3 of the License, or
                     28:  *   (at your option) any later version.
                     29:  *
                     30:  *   FreeM is distributed in the hope that it will be useful,
                     31:  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
                     32:  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     33:  *   GNU Affero Public License for more details.
                     34:  *
                     35:  *   You should have received a copy of the GNU Affero Public License
                     36:  *   along with FreeM.  If not, see <https://www.gnu.org/licenses/>.
                     37:  *
                     38:  **/
                     39: 
                     40: #include <fcntl.h>
                     41: #include <unistd.h>
                     42: #include <errno.h>
                     43: #include "fs.h"
                     44: 
                     45: int cp(const char *to, const char *from)
                     46: {
                     47:     int fd_to, fd_from;
                     48:     char buf[4096];
                     49:     ssize_t nread;
                     50:     int saved_errno;
                     51: 
                     52:     fd_from = open(from, O_RDONLY);
                     53:     if (fd_from < 0)
                     54:         return -1;
                     55: 
                     56:     fd_to = open(to, O_WRONLY | O_CREAT | O_EXCL, 0666);
                     57:     if (fd_to < 0)
                     58:         goto out_error;
                     59: 
                     60:     while (nread = read(fd_from, buf, sizeof buf), nread > 0)
                     61:     {
                     62:         char *out_ptr = buf;
                     63:         ssize_t nwritten;
                     64: 
                     65:         do {
                     66:             nwritten = write(fd_to, out_ptr, nread);
                     67: 
                     68:             if (nwritten >= 0)
                     69:             {
                     70:                 nread -= nwritten;
                     71:                 out_ptr += nwritten;
                     72:             }
                     73:             else if (errno != EINTR)
                     74:             {
                     75:                 goto out_error;
                     76:             }
                     77:         } while (nread > 0);
                     78:     }
                     79: 
                     80:     if (nread == 0)
                     81:     {
                     82:         if (close(fd_to) < 0)
                     83:         {
                     84:             fd_to = -1;
                     85:             goto out_error;
                     86:         }
                     87:         close(fd_from);
                     88: 
                     89:         /* Success! */
                     90:         return 0;
                     91:     }
                     92: 
                     93:   out_error:
                     94:     saved_errno = errno;
                     95: 
                     96:     close(fd_from);
                     97:     if (fd_to >= 0)
                     98:         close(fd_to);
                     99: 
                    100:     errno = saved_errno;
                    101:     return -1;
                    102: }