lib/colors.c

   1 /*
   2  * Copyright (c) 2016 6WIND S.A.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /* Handle color setup for output. */
  18
  19 #include <config.h>
  20
  21 #include "colors.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "util.h"
  27
  28 struct color_key {
  29     const char *name;
  30     char **var_ptr;
  31 };
  32
  33 /* Returns a pointer to the variable containing a given color. */
  34 static char **get_color(const struct color_key color_dic[], const char * name);
  35
  36 /* Extract user-defined colors from OVS_COLORS environment variable. */
  37 static void colors_parse_from_env(const struct color_key color_dic[]);
  38
  39 /* Global holder for colors. Declared in header file. */
  40 struct colors colors = { "", "", "", "", "", "", "", "" };
  41
  42 static char **
  43 get_color(const struct color_key color_dic[], const char *name)
  44 {
  45     const struct color_key *color;
  46     for (color = color_dic; color->name; color++) {
  47         if (!strcmp(color->name, name)) {
  48             return color->var_ptr;
  49         }
  50     }
  51     return NULL;
  52 }
  53
  54 void
  55 colors_init(bool enable_color)
  56 {
  57     /* If colored output is not enabled, just keep empty strings for color
  58      * markers, including end marker.
  59      */
  60     if (!enable_color) {
  61         return;
  62     }
  63
  64     /* Color IDs to use in OVS_COLORS environment variable to overwrite
  65      * defaults with custom colors.
  66      */
  67     const struct color_key color_dic[] = {
  68         { "ac", &colors.actions },
  69         { "dr", &colors.drop },
  70         { "le", &colors.learn },
  71         { "pm", &colors.param },
  72         { "pr", &colors.paren },
  73         { "sp", &colors.special },
  74         { "vl", &colors.value },
  75         { NULL, NULL }
  76     };
  77
  78     /* Actual color to use. First we define default values. */
  79     colors.actions = "\33[1;31m\33[K";  /* bold red */
  80     colors.drop    = "\33[34m\33[K";    /* blue */
  81     colors.learn   = "\33[31m\33[K";    /* red */
  82     colors.param   = "\33[36m\33[K";    /* cyan */
  83     colors.paren   = "\33[35m\33[K";    /* magenta */
  84     colors.special = "\33[33m\33[K";    /* yellow */
  85     colors.value   = "\33[32m\33[K";    /* green */
  86     colors.end     = "\33[m\33[K";      /* end marker */
  87
  88     /* Now, overwrite with user-defined color markers. */
  89     colors_parse_from_env(color_dic);
  90 }
  91
  92 /* Colorized output: get user-defined colors from OVS_COLORS environment
  93  * variable. This must be a string of the form:
  94  *     ac=01;31:r=34:le=:pm=02;32:pr=01;30
  95  * (see color_dic[] in colors_init() function for all color names)
  96  * If a color is missing from this string, default value is used instead.
  97  * If a color name is assigned an empty or incorrect value (i.e. something
  98  * containing characters other than decimals and ';'), fields using this color
  99  * will not be highlighted.
 100  * If a color is assigned more than once, the last (rightmost) value appearing
 101  * in the string is kept.
 102  * Unknown color names are ignored so as to ensure forward compatibility.
 103  * (Feeling adventurous? Try combining markers: "ac=1;3;5;7;38;2;30;150;100".)
 104  */
 105 static void
 106 colors_parse_from_env(const struct color_key color_dic[])
 107 {
 108     const char *color_str = getenv("OVS_COLORS");
 109     if (color_str == NULL || *color_str == '\0') {
 110         return;
 111     }
 112
 113     /* Loop on tokens: they are separated by columns ':' */
 114     char *s = xstrdup(color_str);
 115     char *s_head = s;
 116     for (char *token = strsep(&s, ":");
 117          token != NULL;
 118          token = strsep(&s, ":")) {
 119         char *name = strsep(&token, "=");
 120         for (char *ptr = token; ptr != NULL && *ptr != '\0'; ptr++) {
 121             /* We accept only decimals and ';' for color marker. */
 122             if (*ptr == ';' || (*ptr >= '0' && *ptr <= '9')) {
 123                 continue;
 124             }
 125             name = NULL;
 126             break;
 127         }
 128         if (name != NULL) {
 129             /* We found a name and marker contains only decimals and ';'.
 130              * Try to get a pointer to associated color variable. */
 131             char **color_var_ptr = get_color(color_dic, name);
 132             /* If we know that color, update its value. */
 133             if (color_var_ptr != NULL) {
 134                 *color_var_ptr = xasprintf("\33[%sm\33[K", token);
 135             }
 136         }
 137     }
 138     free(s_head);
 139 }