hist and fc: only run edited commands if changes are saved.

src/cmd/ksh93/bltins/hist.c

@@ -33,6 +33,7 @@
 #if !SHOPT_SCRIPTONLY
 
 static void hist_subst(const char*, int fd, char*);
+static int hist_compare(int fdo, int initial_fdo);
 
 #if 0
  /* for the benefit of the dictionary generator */
@@ -42,10 +43,11 @@ int b_hist(int argc,char *argv[], Shbltin_t *context)
 {
  History_t *hp;
  char *arg;
- int flag,fdo;
- Sfio_t *outfile;
- char *fname;
+ int flag,fdo,initial_fdo;
+ Sfio_t *outfile,*initial_file;
+ char *fname,*initial_fname;
  int range[2], incr, index2, indx= -1;
+ char ran_editor = 0; /* editor-called flag */
  char *edit = 0; /* name of editor */
  char *replace = 0; /* replace old=new */
  int lflag = 0, nflag = 0, rflag = 0;
@@ -213,26 +215,50 @@ int b_hist(int argc,char *argv[], Shbltin_t *context)
  errormsg(SH_DICT,ERROR_system(1),e_create,fname);
  UNREACHABLE();
  }
+ if(!(initial_fname=pathtmp(NULL,0,0,NULL)))
+ {
+ errormsg(SH_DICT,ERROR_exit(1),e_create,"");
+ UNREACHABLE();
+ }
+ if((initial_fdo=open(initial_fname,O_CREAT|O_RDWR,S_IRUSR|S_IWUSR)) < 0)
+ {
+ errormsg(SH_DICT,ERROR_system(1),e_create,initial_fname);
+ UNREACHABLE();
+ }
  outfile= sfnew(NULL,sh.outbuff,IOBSIZE,fdo,SFIO_WRITE);
+ initial_file= sfnew(NULL,sh.outbuff,IOBSIZE,initial_fdo,SFIO_WRITE);
  arg = "\n";
  nflag++;
  }
  while(1)
  {
  if(nflag==0)
+ {
  sfprintf(outfile,"%d\t",range[flag]);
+ if(lflag==0)
+ sfprintf(initial_file,"%d\t",range[flag]);
+ }
  else if(lflag)
  sfputc(outfile,'\t');
  hist_list(sh.hist_ptr,outfile,hist_tell(sh.hist_ptr,range[flag]),0,arg);
  if(lflag)
  sh_sigcheck();
+ else
+ hist_list(sh.hist_ptr,initial_file,hist_tell(sh.hist_ptr,range[flag]),0,arg);
  if(range[flag] == range[1-flag])
  break;
  range[flag] += incr;
  }
- if(lflag)
+ if(lflag==0)
+ {
+ initial_fdo = sh_chkopen(initial_fname);
+ unlink(initial_fname);
+ free(initial_fname);
+ }
+ else
  return 0;
  sfclose(outfile);
+ sfclose(initial_file);
  hist_eof(hp);
  arg = edit;
  if(!arg && !(arg=nv_getval(sh_scoped(HISTEDIT))) && !(arg=nv_getval(sh_scoped(FCEDNOD))))
@@ -251,10 +277,9 @@ int b_hist(int argc,char *argv[], Shbltin_t *context)
  com[1] = fname;
  com[2] = 0;
  error_info.errors = sh_eval(sh_sfeval(com),0);
+ ran_editor = 1;
  }
  fdo = sh_chkopen(fname);
- unlink(fname);
- free(fname);
  /* don't history fc itself unless forked */
  error_info.flags |= ERROR_SILENT;
  if(!sh_isstate(SH_FORKED))
@@ -265,6 +290,7 @@ int b_hist(int argc,char *argv[], Shbltin_t *context)
  {
  hist_subst(error_info.id,fdo,replace);
  sh_close(fdo);
+ sh_close(initial_fdo);
  }
  else if(error_info.errors == 0)
  {
@@ -279,17 +305,34 @@ int b_hist(int argc,char *argv[], Shbltin_t *context)
  errormsg(SH_DICT,ERROR_exit(1),e_toodeep,"history");
  UNREACHABLE();
  }
- iop = sfnew(NULL,buff,IOBSIZE,fdo,SFIO_READ);
- sh_eval(iop,1); /* this will close fdo */
- hist_depth--;
+ if(!ran_editor)
+ {
+ iop = sfnew(NULL,buff,IOBSIZE,fdo,SFIO_READ);
+ sh_eval(iop,1); /* this will close fdo */
+ hist_depth--;
+ }
+ /* run the command post-editor only if it has been changed */
+ else if(hist_compare(fdo,initial_fdo))
+ {
+ fdo = sh_chkopen(fname);
+ iop = sfnew(NULL,buff,IOBSIZE,fdo,SFIO_READ);
+ sh_eval(iop,1);
+ hist_depth--;
+ }
+ else
+ sh_close(fdo);
+ sh_close(initial_fdo);
  }
  else
  {
  sh_close(fdo);
+ sh_close(initial_fdo);
  if(!sh_isoption(SH_VERBOSE))
  sh_offstate(SH_VERBOSE);
  sh_offstate(SH_HISTORY);
  }
+ unlink(fname);
+ free(fname);
  return sh.exitval;
 }
 
@@ -325,6 +368,37 @@ static void hist_subst(const char *command,int fd,char *replace)
  sh_eval(sfopen(NULL,sp,"s"),1);
 }
 
+/*
+ * check that a change has occurred after viewing the temporary file
+ * with the full editor
+ */
+static int hist_compare(int fdo, int initial_fdo)
+{
+ off_t size,initial_size;
+ char *string,*initial_string;
+ int c,d;
+ if((size = lseek(fdo,0,SEEK_END)) < 0 || (initial_size = lseek(initial_fdo,0,SEEK_END)) < 0)
+ return 1;
+ lseek(fdo,0,SEEK_SET);
+ lseek(initial_fdo,0,SEEK_SET);
+ c = (int)size;
+ d = (int)initial_size;
+ if(c != d)
+ return 1;
+ string = stkalloc(sh.stk,c+1);
+ initial_string = stkalloc(sh.stk,d+1);
+ if(read(fdo,string,c)!=c || read(initial_fdo,initial_string,d)!=d)
+ return 1;
+ string[c] = 0;
+ initial_string[c] = 0;
+ for(int x=0; x<=c; x++)
+ {
+ if(string[x] != initial_string[x])
+ return 1;
+ }
+ return 0;
+}
+
 #else
 
 int b_hist(int argc,char *argv[], Shbltin_t *context)

src/cmd/ksh93/data/builtins.c

@@ -1036,7 +1036,8 @@ const char sh_opthist[] =
  "editor returns a non-zero exit status, this will suppress the "
  "entry into the history list and the command re-execution. Command "
  "line variable assignments and redirections affect both the \f?\f "
- "command and the commands that are re-executed.]"
+ "command and the commands that are re-executed. If no change is "
+ "made in-editor, the command will not run. ]"
 "[+?\afirst\a and \alast\a define the range of commands. \afirst\a and "
  "\alast\a can be one of the following:]{"
  "[+\anumber\a?A positive number representing a command "

src/cmd/ksh93/sh.1

@@ -6962,7 +6962,7 @@ is not set, then
 .BR /bin/ed\^ )
 is used as the editor.
 When editing is complete, the edited command(s)
-is executed if the changes have been saved.
+is executed if changes have been made and saved.
 If
 .I last\^
 is not specified,