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1281
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1 /* sysctl.c - A utility to read and manipulate the sysctl parameters.
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2 *
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3 * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
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4 * Copyright 2014 Kyungwan Han <asura321@gmail.com>
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5 *
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6 * No Standard
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7
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8 USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_USR|TOYFLAG_BIN))
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9
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10 config SYSCTL
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11 bool "sysctl"
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12 default n
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13 help
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14 usage: sysctl [OPTIONS] [KEY[=VALUE]]...
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15
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16 -a, A Show all values
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17 -e Don't warn about unknown keys
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18 -N Show only key names
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19 -n Show only key values
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20 -p FILE Set values from FILE (default /etc/sysctl.conf)
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21 -q Set values silently
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22 -w Set values
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23 */
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24 #define FOR_sysctl
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25 #include "toys.h"
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26
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27 #define PROC_SYS_DIR "/proc/sys"
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28 #define MAX_BYTES_LINE 1024
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29
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30 static void parse_key_name_value(char *param, char **key_name, char **key_value)
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31 {
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32 char *name, *value;
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33
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34 if (!(name = strchr(param, '='))) goto show_error_msg;
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35 value = name;
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36 value++;
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37 if (!(*value)) goto show_error_msg;
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38 *name = '\0';
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39 *key_name = param;
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40 *key_value = value;
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41 return;
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42 show_error_msg:
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43 error_msg("error: '%s' must be of the form name=value", param);
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44 }
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45
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46 static void replace_char(char *str, char old, char new)
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47 {
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48 char *tmp = str;
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49
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50 for (; *tmp; tmp++)
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51 if (*tmp == old) *tmp = new;
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52 }
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53
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54 static void handle_file_error(char *key_name)
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55 {
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56 replace_char(key_name, '/', '.');
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57 if (errno == ENOENT) {
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58 if (!(toys.optflags & FLAG_e))
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59 error_msg("error: '%s' is an unknown key", key_name);
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60 else toys.exitval = 1;
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61 } else perror_msg("error: %s key '%s'", (toys.optflags & FLAG_w) ?
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62 "setting" : "reading", key_name);
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63 }
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64
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65 static void write_to_file(char *fpath, char *key_name, char *key_value)
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66 {
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67 int fd;
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68
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69 replace_char(key_name, '.', '/');
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70 sprintf(toybuf, "%s/%s", fpath, key_name);
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71 if ((fd = open(toybuf, O_WRONLY)) < 0) {
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72 handle_file_error(key_name);
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73 return;
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74 }
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75 xwrite(fd, key_value, strlen(key_value));
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76 xclose(fd);
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77 if (!(toys.optflags & FLAG_q)) {
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78 replace_char(key_name, '/', '.');
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79 if (toys.optflags & FLAG_N) xprintf("%s\n", key_name);
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80 else if (toys.optflags & FLAG_n) xprintf("%s\n", key_value);
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81 else xprintf("%s = %s\n", key_name, key_value);
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82 }
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83 }
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84
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85 static char *get_key_value(char *buff, int *offset)
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86 {
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87 char *line, *tmp = (char *) (buff + *offset);
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88 int index = 0, multiplier = 1;
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89
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90 if (!(*tmp)) return NULL;
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91 line = (char *) xmalloc(sizeof(char) * MAX_BYTES_LINE);
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92 for (; *tmp != '\n'; tmp++) {
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93 line[index++] = *tmp;
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94 if (MAX_BYTES_LINE == index) { // buffer overflow
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95 multiplier++;
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96 line = (char *) xrealloc(line, multiplier * MAX_BYTES_LINE);
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97 }
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98 }
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99 line[index++] = '\0';
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100 *offset += index;
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101 return line;
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102 }
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103
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104 // Open file for each and every key name and read file contents
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105 void read_key_values(char *fpath)
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106 {
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107 char *key_value, *fdata, *key_name, *tmp = xstrdup(fpath);
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108 int offset = 0;
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109
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110 key_name = (tmp + strlen(PROC_SYS_DIR) + 1);
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111 replace_char(key_name, '/', '.');
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112 if (!(fdata = readfile(fpath, NULL, 0))) {
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113 handle_file_error(key_name);
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114 free(tmp);
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115 return;
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116 }
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117 if (toys.optflags & FLAG_N) {
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118 xprintf("%s\n", key_name);
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119 free(tmp);
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120 free(fdata);
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121 return;
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122 }
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123 for (; (key_value = get_key_value(fdata, &offset)); free(key_value)) {
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124 if (!(toys.optflags & FLAG_q)) {
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125 if (!(toys.optflags & FLAG_n)) xprintf("%s = ", key_name);
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126 xprintf("%s\n", key_value);
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127 }
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128 }
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129 free(tmp);
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130 free(fdata);
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131 }
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132
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133 static void trim_spaces(char **param)
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134 {
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135 int len = 0;
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136 char *str = *param, *p_start = str, *p_end;
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137
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138 if (p_start) { // start pointer to string
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139 p_end = str + strlen(str) - 1; // end pointer to string
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140 while (*p_start == ' ') p_start++;
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141 str = p_start;
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142 while (*p_end == ' ') p_end--;
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143 p_end++;
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144 *p_end = '\0';
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145 len = (int) (p_end - str) + 1;
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146 memmove(*param, str, len);
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147 }
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148 }
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149
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150 // Read config file and write values to there corresponding key name files
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151 static void read_config_file(char *fname)
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152 {
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153 char *line, *name = NULL, *value = NULL;
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154 int fd = xopen(fname, O_RDONLY);
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155
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156 for (; (line = get_line(fd)); free(line), name = NULL, value = NULL) {
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157 char *ptr = line;
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158
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159 while (*ptr == ' ' || *ptr == '\t') ptr++;
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160 if (*ptr != '#' && *ptr != ';' && *ptr !='\n' && *ptr) {
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161 parse_key_name_value(ptr, &name, &value);
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162 trim_spaces(&name);
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163 trim_spaces(&value);
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164 if (name && value) write_to_file(PROC_SYS_DIR, name, value);
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165 }
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166 }
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167 xclose(fd);
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168 }
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169
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170 static int do_process(struct dirtree *dt)
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171 {
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172 char *fpath;
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173
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174 if (!dirtree_notdotdot(dt)) return 0; // Skip . and ..
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175 if (S_ISDIR(dt->st.st_mode)) return DIRTREE_RECURSE;
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176 if ((fpath = dirtree_path(dt, 0))) {
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177 read_key_values(fpath);
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178 free(fpath);
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179 }
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180 return 0;
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181 }
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182
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183 void sysctl_main()
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184 {
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185 char *name = NULL, *value = NULL, **args = NULL;
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186
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187 if (toys.optflags & FLAG_a) {
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188 dirtree_read(PROC_SYS_DIR, do_process);
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189 return;
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190 }
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191 if (toys.optflags & FLAG_p) {
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192 if (*toys.optargs) read_config_file(*toys.optargs);
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193 else read_config_file("/etc/sysctl.conf");
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194 return;
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195 }
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196 if (toys.optflags & FLAG_w) {
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197 for (args = toys.optargs; *args; args++, name = NULL, value = NULL) {
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198 parse_key_name_value(*args, &name, &value);
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199 if (name && value) write_to_file(PROC_SYS_DIR, name, value);
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200 }
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201 return;
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202 }
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203 for (args = toys.optargs; *args; args++) {
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204 replace_char(*args, '.', '/');
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205 sprintf(toybuf, "%s/%s", PROC_SYS_DIR, *args);
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206 read_key_values(toybuf);
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207 }
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208 }
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