usr.bin/sdiff/edit.c

   1 /*      $NetBSD: edit.c,v 1.4 2011/09/01 07:18:51 plunky Exp $  */
   2 /*      $OpenBSD: edit.c,v 1.14 2006/05/25 03:20:32 ray Exp $ */
   3
   4 /*
   5  * Written by Raymond Lai <ray@cyth.net>.
   6  * Public domain.
   7  */
   8
   9 #include <sys/types.h>
  10 #include <sys/wait.h>
  11
  12 #include <ctype.h>
  13 #include <err.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18
  19 #include "common.h"
  20 #include "extern.h"
  21
  22 static void edit(const char *);
  23
  24 /*
  25  * Takes the name of a file and opens it with an editor.
  26  */
  27 static void
  28 edit(const char *filename)
  29 {
  30         int status;
  31         pid_t pid;
  32         const char *editor;
  33
  34         editor = getenv("VISUAL");
  35         if (editor == NULL)
  36                 editor = getenv("EDITOR");
  37         if (editor == NULL)
  38                 editor = "vi";
  39
  40         /* Start editor on temporary file. */
  41         switch (pid = fork()) {
  42         case 0:
  43                 /* child */
  44                 execlp(editor, editor, filename, (void *)NULL);
  45                 warn("could not execute editor: %s", editor);
  46                 cleanup(filename);
  47         case -1:
  48                 warn("could not fork");
  49                 cleanup(filename);
  50         }
  51
  52         /* parent */
  53         /* Wait for editor to exit. */
  54         if (waitpid(pid, &status, 0) == -1) {
  55                 warn("waitpid");
  56                 cleanup(filename);
  57         }
  58
  59         /* Check that editor terminated normally. */
  60         if (!WIFEXITED(status)) {
  61                 warn("%s terminated abnormally", editor);
  62                 cleanup(filename);
  63         }
  64 }
  65
  66 /*
  67  * Parse edit command.  Returns 0 on success, -1 on error.
  68  */
  69 int
  70 eparse(const char *cmd, const char *left, const char *right)
  71 {
  72         FILE *file;
  73         size_t nread, nwritten;
  74         int fd;
  75         char *filename;
  76         char buf[BUFSIZ], *text;
  77
  78         /* Skip whitespace. */
  79         while (isspace((int)(*cmd)))
  80                 ++cmd;
  81
  82         text = NULL;
  83         switch (*cmd) {
  84         case '\0':
  85                 /* Edit empty file. */
  86                 break;
  87
  88         case 'b':
  89                 /* Both strings. */
  90                 if (left == NULL)
  91                         goto RIGHT;
  92                 if (right == NULL)
  93                         goto LEFT;
  94
  95                 /* Neither column is blank, so print both. */
  96                 if (asprintf(&text, "%s\n%s\n", left, right) == -1)
  97                         err(2, "could not allocate memory");
  98                 break;
  99
 100         case 'l':
 101 LEFT:
 102                 /* Skip if there is no left column. */
 103                 if (left == NULL)
 104                         break;
 105
 106                 if (asprintf(&text, "%s\n", left) == -1)
 107                         err(2, "could not allocate memory");
 108
 109                 break;
 110
 111         case 'r':
 112 RIGHT:
 113                 /* Skip if there is no right column. */
 114                 if (right == NULL)
 115                         break;
 116
 117                 if (asprintf(&text, "%s\n", right) == -1)
 118                         err(2, "could not allocate memory");
 119
 120                 break;
 121
 122         default:
 123                 return (-1);
 124         }
 125
 126         /* Create temp file. */
 127         if (asprintf(&filename, "%s/sdiff.XXXXXXXXXX", tmpdir) == -1)
 128                 err(2, "asprintf");
 129         if ((fd = mkstemp(filename)) == -1)
 130                 err(2, "mkstemp");
 131         if (text != NULL) {
 132                 size_t len;
 133
 134                 len = strlen(text);
 135                 if ((size_t)write(fd, text, len) != len) {
 136                         warn("error writing to temp file");
 137                         cleanup(filename);
 138                 }
 139         }
 140         close(fd);
 141
 142         /* text is no longer used. */
 143         free(text);
 144
 145         /* Edit temp file. */
 146         edit(filename);
 147
 148         /* Open temporary file. */
 149         if (!(file = fopen(filename, "r"))) {
 150                 warn("could not open edited file: %s", filename);
 151                 cleanup(filename);
 152         }
 153
 154         /* Copy temporary file contents to output file. */
 155         for (nread = sizeof(buf); nread == sizeof(buf);) {
 156                 nread = fread(buf, sizeof(*buf), sizeof(buf), file);
 157                 /* Test for error or end of file. */
 158                 if (nread != sizeof(buf) &&
 159                     (ferror(file) || !feof(file))) {
 160                         warnx("error reading edited file: %s", filename);
 161                         cleanup(filename);
 162                 }
 163
 164                 /*
 165                  * If we have nothing to read, break out of loop
 166                  * instead of writing nothing.
 167                  */
 168                 if (!nread)
 169                         break;
 170
 171                 /* Write data we just read. */
 172                 nwritten = fwrite(buf, sizeof(*buf), nread, outfile);
 173                 if (nwritten != nread) {
 174                         warnx("error writing to output file");
 175                         cleanup(filename);
 176                 }
 177         }
 178
 179         /* We've reached the end of the temporary file, so remove it. */
 180         if (unlink(filename))
 181                 warn("could not delete: %s", filename);
 182         fclose(file);
 183
 184         free(filename);
 185
 186         return (0);
 187 }