backup.c

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/*****************************************************************************/
#include "libtpcmisc.h"
/*****************************************************************************/
 
/*****************************************************************************/
int backupExistingFile(
  char *filename,
  char *backup_ext,     
  char *status
) {
  char bakfile[FILENAME_MAX];
  int ret;
 
  // Check the input
  if(filename==NULL || strlen(filename)<1) {
    if(status!=NULL) sprintf(status, "invalid filename");
    return 1;
  }
 
  // Check if file exists; if not then no need to make any backup
  if(access(filename, 0) == -1) {
    if(status!=NULL) sprintf(status, "file does not pre-exist");
    return 0;
  }
  // Create filename for the backup file
  strlcpy(bakfile, filename, FILENAME_MAX);
  if(backup_ext==NULL) strlcat(bakfile, ".bak", FILENAME_MAX);
  else strlcat(bakfile, backup_ext, FILENAME_MAX);
  // If also backup file exists, then just delete it 
  if(access(bakfile, 0) != -1) {
    ret=remove(bakfile);
    if(ret!=0) {
      if(status!=NULL) sprintf(status, "cannot delete previous backup file");
      return 3;
    }
  }
  // Rename file
  ret=rename(filename, bakfile);
  if(ret!=0) {
    if(status!=NULL) sprintf(status, "cannot rename file as backup");
    return 5;
  }
  if(status!=NULL) sprintf(status, "file renamed as backup");
  return 0;
}  
/*****************************************************************************/
 
/*****************************************************************************/ 
int fileCopy(
  char *filename1,
  char *filename2,     
  char *status
) {
  FILE *from, *to;
  char c;
 
  // Check the input
  if(filename1==NULL || filename2==NULL) {
    if(status!=NULL) sprintf(status, "invalid filename");
    return 1;
  }
  // Open the file1 for reading
  if((from=fopen(filename1, "rb"))==NULL) {
    if(status!=NULL) sprintf(status, "cannot open file for read");
    return 2;
  }
  // Open file2 for writing
  if((to=fopen(filename2, "wb"))==NULL) {
    if(status!=NULL) sprintf(status, "cannot open file for write");
    fclose(from); return 3;
  }
  // Copy the file
  while(!feof(from)) {
    c=fgetc(from);
    if(ferror(from)) {
      if(status!=NULL) sprintf(status, "cannot read from file");
      fclose(from); fclose(to); (void)remove(filename2); return 4;
    }
    if(!feof(from)) fputc(c, to);
    if(ferror(to)) {
      if(status!=NULL) sprintf(status, "cannot write to file");
      fclose(from); fclose(to); (void)remove(filename2); return 6;
    }
  }
  // Close files
  if(fclose(from)==EOF) {
    if(status!=NULL) sprintf(status, "cannot close file");
    fclose(to); return 7;
  }
  if(fclose(to)==EOF) {
    if(status!=NULL) sprintf(status, "cannot close file");
    return 8;
  }
  return 0;
}
/*****************************************************************************/
 
/*****************************************************************************/