procps/sysctl.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
   4  *
   5  * Copyright 1999 George Staikos
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8  *
   9  * Changelog:
  10  *      v1.01:
  11  *              - added -p <preload> to preload values from a file
  12  *      v1.01.1
  13  *              - busybox applet aware by <solar@gentoo.org>
  14  *
  15  */
  16
  17 #include "libbb.h"
  18
  19 /*
  20  *    Function Prototypes
  21  */
  22 static int sysctl_read_setting(const char *setting, int output);
  23 static int sysctl_write_setting(const char *setting, int output);
  24 static int sysctl_preload_file(const char *filename, int output);
  25 static int sysctl_display_all(const char *path, int output, int show_table);
  26
  27 /*
  28  *    Globals...
  29  */
  30 static const char PROC_PATH[] ALIGN1 = "/proc/sys/";
  31 static const char DEFAULT_PRELOAD[] ALIGN1 = "/etc/sysctl.conf";
  32
  33 /* error messages */
  34 static const char ERR_UNKNOWN_PARAMETER[] ALIGN1 =
  35         "error: Unknown parameter '%s'\n";
  36 static const char ERR_MALFORMED_SETTING[] ALIGN1 =
  37         "error: Malformed setting '%s'\n";
  38 static const char ERR_NO_EQUALS[] ALIGN1 =
  39         "error: '%s' must be of the form name=value\n";
  40 static const char ERR_INVALID_KEY[] ALIGN1 =
  41         "error: '%s' is an unknown key\n";
  42 static const char ERR_UNKNOWN_WRITING[] ALIGN1 =
  43         "error: unknown error %d setting key '%s'\n";
  44 static const char ERR_UNKNOWN_READING[] ALIGN1 =
  45         "error: unknown error %d reading key '%s'\n";
  46 static const char ERR_PERMISSION_DENIED[] ALIGN1 =
  47         "error: permission denied on key '%s'\n";
  48 static const char ERR_PRELOAD_FILE[] ALIGN1 =
  49         "error: cannot open preload file '%s'\n";
  50 static const char WARN_BAD_LINE[] ALIGN1 =
  51         "warning: %s(%d): invalid syntax, continuing...\n";
  52
  53
  54 static void dwrite_str(int fd, const char *buf)
  55 {
  56         write(fd, buf, strlen(buf));
  57 }
  58
  59 /*
  60  *    sysctl_main()...
  61  */
  62 int sysctl_main(int argc, char **argv);
  63 int sysctl_main(int argc, char **argv)
  64 {
  65         int retval = 0;
  66         int output = 1;
  67         int write_mode = 0;
  68         int switches_allowed = 1;
  69
  70         if (argc < 2)
  71                 bb_show_usage();
  72
  73         argv++;
  74
  75         for (; argv && *argv && **argv; argv++) {
  76                 if (switches_allowed && **argv == '-') {        /* we have a switch */
  77                         switch ((*argv)[1]) {
  78                         case 'n':
  79                                 output = 0;
  80                                 break;
  81                         case 'w':
  82                                 write_mode = 1;
  83                                 switches_allowed = 0;
  84                                 break;
  85                         case 'p':
  86                                 argv++;
  87                                 return
  88                                         sysctl_preload_file(((argv && *argv
  89                                                                                   && **argv) ? *argv :
  90                                                                                  DEFAULT_PRELOAD), output);
  91                         case 'a':
  92                         case 'A':
  93                                 switches_allowed = 0;
  94                                 return sysctl_display_all(PROC_PATH, output,
  95                                                                                   ((*argv)[1] == 'a') ? 0 : 1);
  96                         case 'h':
  97                         case '?':
  98                                 bb_show_usage();
  99                         default:
 100                                 bb_error_msg(ERR_UNKNOWN_PARAMETER, *argv);
 101                                 bb_show_usage();
 102                         }
 103                 } else {
 104                         switches_allowed = 0;
 105                         if (write_mode)
 106                                 retval = sysctl_write_setting(*argv, output);
 107                         else
 108                                 sysctl_read_setting(*argv, output);
 109                 }
 110         }
 111         return retval;
 112 }                                               /* end sysctl_main() */
 113
 114
 115
 116 /*
 117  *     sysctl_preload_file
 118  *      preload the sysctl's from a conf file
 119  *           - we parse the file and then reform it (strip out whitespace)
 120  */
 121 #define PRELOAD_BUF 256
 122
 123 int sysctl_preload_file(const char *filename, int output)
 124 {
 125         int lineno = 0;
 126         char oneline[PRELOAD_BUF];
 127         char buffer[PRELOAD_BUF];
 128         char *name, *value, *ptr;
 129         FILE *fp = NULL;
 130
 131         if (!filename || ((fp = fopen(filename, "r")) == NULL)) {
 132                 bb_error_msg_and_die(ERR_PRELOAD_FILE, filename);
 133         }
 134
 135         while (fgets(oneline, sizeof(oneline) - 1, fp)) {
 136                 oneline[sizeof(oneline) - 1] = '\0';
 137                 lineno++;
 138                 trim(oneline);
 139                 ptr = (char *) oneline;
 140
 141                 if (*ptr == '#' || *ptr == ';')
 142                         continue;
 143
 144                 if (strlen(ptr) < 2)
 145                         continue;
 146
 147                 name = strtok(ptr, "=");
 148                 if (!name || !*name) {
 149                         bb_error_msg(WARN_BAD_LINE, filename, lineno);
 150                         continue;
 151                 }
 152
 153                 trim(name);
 154
 155                 value = strtok(NULL, "\n\r");
 156                 if (!value || !*value) {
 157                         bb_error_msg(WARN_BAD_LINE, filename, lineno);
 158                         continue;
 159                 }
 160
 161                 while ((*value == ' ' || *value == '\t') && *value != 0)
 162                         value++;
 163                 /* safe because sizeof(oneline) == sizeof(buffer) */
 164                 sprintf(buffer, "%s=%s", name, value);
 165                 sysctl_write_setting(buffer, output);
 166         }
 167         fclose(fp);
 168         return 0;
 169 }                                               /* end sysctl_preload_file() */
 170
 171
 172 /*
 173  *     Write a single sysctl setting
 174  */
 175 int sysctl_write_setting(const char *setting, int output)
 176 {
 177         int retval = 0;
 178         const char *name = setting;
 179         const char *value;
 180         const char *equals;
 181         char *tmpname, *outname, *cptr;
 182         int fd = -1;
 183
 184         if (!name)                      /* probably dont' want to display this  err */
 185                 return 0;
 186
 187         if (!(equals = strchr(setting, '='))) {
 188                 bb_error_msg(ERR_NO_EQUALS, setting);
 189                 return -1;
 190         }
 191
 192         value = equals + sizeof(char);  /* point to the value in name=value */
 193
 194         if (!*name || !*value || name == equals) {
 195                 bb_error_msg(ERR_MALFORMED_SETTING, setting);
 196                 return -2;
 197         }
 198
 199         tmpname = xasprintf("%s%.*s", PROC_PATH, (int)(equals - name), name);
 200         outname = xstrdup(tmpname + strlen(PROC_PATH));
 201
 202         while ((cptr = strchr(tmpname, '.')) != NULL)
 203                 *cptr = '/';
 204
 205         while ((cptr = strchr(outname, '/')) != NULL)
 206                 *cptr = '.';
 207
 208         fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 209         if (fd < 0) {
 210                 switch (errno) {
 211                 case ENOENT:
 212                         bb_error_msg(ERR_INVALID_KEY, outname);
 213                         break;
 214                 case EACCES:
 215                         bb_perror_msg(ERR_PERMISSION_DENIED, outname);
 216                         break;
 217                 default:
 218                         bb_error_msg(ERR_UNKNOWN_WRITING, errno, outname);
 219                         break;
 220                 }
 221                 retval = -1;
 222         } else {
 223                 dwrite_str(fd, value);
 224                 close(fd);
 225                 if (output) {
 226                         dwrite_str(STDOUT_FILENO, outname);
 227                         dwrite_str(STDOUT_FILENO, " = ");
 228                 }
 229                 dwrite_str(STDOUT_FILENO, value);
 230                 dwrite_str(STDOUT_FILENO, "\n");
 231         }
 232
 233         /* cleanup */
 234         free(tmpname);
 235         free(outname);
 236         return retval;
 237 }                                               /* end sysctl_write_setting() */
 238
 239
 240 /*
 241  *     Read a sysctl setting
 242  *
 243  */
 244 int sysctl_read_setting(const char *setting, int output)
 245 {
 246         int retval = 0;
 247         char *tmpname, *outname, *cptr;
 248         char inbuf[1025];
 249         const char *name = setting;
 250         FILE *fp;
 251
 252         if (!setting || !*setting)
 253                 bb_error_msg(ERR_INVALID_KEY, setting);
 254
 255         tmpname = concat_path_file(PROC_PATH, name);
 256         outname = xstrdup(tmpname + strlen(PROC_PATH));
 257
 258         while ((cptr = strchr(tmpname, '.')) != NULL)
 259                 *cptr = '/';
 260         while ((cptr = strchr(outname, '/')) != NULL)
 261                 *cptr = '.';
 262
 263         if ((fp = fopen(tmpname, "r")) == NULL) {
 264                 switch (errno) {
 265                 case ENOENT:
 266                         bb_error_msg(ERR_INVALID_KEY, outname);
 267                         break;
 268                 case EACCES:
 269                         bb_error_msg(ERR_PERMISSION_DENIED, outname);
 270                         break;
 271                 default:
 272                         bb_error_msg(ERR_UNKNOWN_READING, errno, outname);
 273                         break;
 274                 }
 275                 retval = -1;
 276         } else {
 277                 while (fgets(inbuf, sizeof(inbuf) - 1, fp)) {
 278                         if (output) {
 279                                 dwrite_str(STDOUT_FILENO, outname);
 280                                 dwrite_str(STDOUT_FILENO, " = ");
 281                         }
 282                         dwrite_str(STDOUT_FILENO, inbuf);
 283                 }
 284                 fclose(fp);
 285         }
 286
 287         free(tmpname);
 288         free(outname);
 289         return retval;
 290 }                                               /* end sysctl_read_setting() */
 291
 292
 293
 294 /*
 295  *     Display all the sysctl settings
 296  *
 297  */
 298 int sysctl_display_all(const char *path, int output, int show_table)
 299 {
 300         int retval = 0;
 301         int retval2;
 302         DIR *dp;
 303         struct dirent *de;
 304         char *tmpdir;
 305         struct stat ts;
 306
 307         dp = opendir(path);
 308         if (!dp) {
 309                 retval = -1;
 310         } else {
 311                 while ((de = readdir(dp)) != NULL) {
 312                         tmpdir = concat_subpath_file(path, de->d_name);
 313                         if (tmpdir == NULL)
 314                                 continue;
 315                         retval2 = stat(tmpdir, &ts);
 316                         if (retval2 != 0)
 317                                 bb_perror_msg(tmpdir);
 318                         else {
 319                                 if (S_ISDIR(ts.st_mode)) {
 320                                         sysctl_display_all(tmpdir, output, show_table);
 321                                 } else
 322                                         retval |=
 323                                                 sysctl_read_setting(tmpdir + strlen(PROC_PATH),
 324                                                                                         output);
 325
 326                         }
 327                         free(tmpdir);
 328                 }                               /* end while */
 329                 closedir(dp);
 330         }
 331
 332         return retval;
 333 }                                               /* end sysctl_display_all() */