1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Utility routines.
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4 | *
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5 | * Copyright (C) tons of folks. Tracking down who wrote what
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6 | * isn't something I'm going to worry about... If you wrote something
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7 | * here, please feel free to acknowledge your work.
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8 | *
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9 | * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
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10 | * Permission has been granted to redistribute this code under GPL.
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11 | *
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12 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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13 | */
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14 |
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15 | /* We are trying to not use printf, this benefits the case when selected
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16 | * applets are really simple. Example:
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17 | *
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18 | * $ ./busybox
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19 | * ...
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20 | * Currently defined functions:
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21 | * basename, false, true
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22 | *
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23 | * $ size busybox
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24 | * text data bss dec hex filename
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25 | * 4473 52 72 4597 11f5 busybox
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26 | *
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27 | * FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
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28 | */
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29 | #include "busybox.h"
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30 |
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31 | #if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
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32 | || defined(__APPLE__) \
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33 | )
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34 | # include <malloc.h> /* for mallopt */
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35 | #endif
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36 |
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37 |
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38 | /* Declare <applet>_main() */
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39 | #define PROTOTYPES
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40 | #include "applets.h"
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41 | #undef PROTOTYPES
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42 |
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43 | /* Include generated applet names, pointers to <applet>_main, etc */
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44 | #include "applet_tables.h"
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45 | /* ...and if applet_tables generator says we have only one applet... */
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46 | #ifdef SINGLE_APPLET_MAIN
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47 | # undef ENABLE_FEATURE_INDIVIDUAL
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48 | # define ENABLE_FEATURE_INDIVIDUAL 1
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49 | # undef IF_FEATURE_INDIVIDUAL
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50 | # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
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51 | #endif
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52 |
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53 | #include "usage_compressed.h"
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54 |
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55 | static void run_applet_and_exit(const char *name, char **argv) NORETURN;
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56 |
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57 | #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
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58 | static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
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59 | #else
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60 | # define usage_messages 0
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61 | #endif
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62 |
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63 | #if ENABLE_FEATURE_COMPRESS_USAGE
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64 |
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65 | static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
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66 | # include "bb_archive.h"
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67 | static const char *unpack_usage_messages(void)
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68 | {
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69 | char *outbuf = NULL;
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70 | bunzip_data *bd;
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71 | int i;
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72 |
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73 | i = start_bunzip(&bd,
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74 | /* src_fd: */ -1,
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75 | /* inbuf: */ packed_usage,
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76 | /* len: */ sizeof(packed_usage));
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77 | /* read_bunzip can longjmp to start_bunzip, and ultimately
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78 | * end up here with i != 0 on read data errors! Not trivial */
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79 | if (!i) {
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80 | /* Cannot use xmalloc: will leak bd in NOFORK case! */
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81 | outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
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82 | if (outbuf)
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83 | read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
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84 | }
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85 | dealloc_bunzip(bd);
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86 | return outbuf;
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87 | }
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88 | # define dealloc_usage_messages(s) free(s)
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89 |
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90 | #else
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91 |
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92 | # define unpack_usage_messages() usage_messages
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93 | # define dealloc_usage_messages(s) ((void)(s))
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94 |
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95 | #endif /* FEATURE_COMPRESS_USAGE */
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96 |
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97 |
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98 | void FAST_FUNC bb_show_usage(void)
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99 | {
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100 | if (ENABLE_SHOW_USAGE) {
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101 | #ifdef SINGLE_APPLET_STR
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102 | /* Imagine that this applet is "true". Dont suck in printf! */
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103 | const char *usage_string = unpack_usage_messages();
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104 |
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105 | if (*usage_string == '\b') {
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106 | full_write2_str("No help available.\n\n");
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107 | } else {
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108 | full_write2_str("Usage: "SINGLE_APPLET_STR" ");
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109 | full_write2_str(usage_string);
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110 | full_write2_str("\n\n");
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111 | }
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112 | if (ENABLE_FEATURE_CLEAN_UP)
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113 | dealloc_usage_messages((char*)usage_string);
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114 | #else
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115 | const char *p;
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116 | const char *usage_string = p = unpack_usage_messages();
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117 | int ap = find_applet_by_name(applet_name);
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118 |
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119 | if (ap < 0) /* never happens, paranoia */
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120 | xfunc_die();
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121 | while (ap) {
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122 | while (*p++) continue;
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123 | ap--;
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124 | }
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125 | full_write2_str(bb_banner);
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126 | full_write2_str(" multi-call binary.\n");
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127 | if (*p == '\b')
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128 | full_write2_str("\nNo help available.\n\n");
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129 | else {
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130 | full_write2_str("\nUsage: ");
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131 | full_write2_str(applet_name);
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132 | full_write2_str(" ");
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133 | full_write2_str(p);
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134 | full_write2_str("\n");
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135 | }
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136 | if (ENABLE_FEATURE_CLEAN_UP)
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137 | dealloc_usage_messages((char*)usage_string);
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138 | #endif
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139 | }
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140 | xfunc_die();
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141 | }
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142 |
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143 | int FAST_FUNC find_applet_by_name(const char *name)
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144 | {
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145 | unsigned i, max;
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146 | int j;
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147 | const char *p;
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148 |
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149 | /* The commented-out word-at-a-time code is ~40% faster, but +160 bytes.
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150 | * "Faster" here saves ~0.5 microsecond of real time - not worth it.
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151 | */
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152 | #if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
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153 | uint32_t n32;
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154 |
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155 | /* Handle all names < 2 chars long early */
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156 | if (name[0] == '\0')
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157 | return -1; /* "" is not a valid applet name */
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158 | if (name[1] == '\0') {
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159 | if (!ENABLE_TEST)
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160 | return -1; /* 1-char name is not valid */
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161 | if (name[0] != ']')
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162 | return -1; /* 1-char name which isn't "[" is not valid */
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163 | /* applet "[" is always applet #0: */
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164 | return 0;
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165 | }
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166 | #endif
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167 |
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168 | p = applet_names;
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169 | i = 0;
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170 | #if KNOWN_APPNAME_OFFSETS <= 0
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171 | max = NUM_APPLETS;
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172 | #else
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173 | max = NUM_APPLETS * KNOWN_APPNAME_OFFSETS;
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174 | for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
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175 | const char *pp = applet_names + applet_nameofs[j];
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176 | if (strcmp(name, pp) >= 0) {
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177 | //bb_error_msg("name:'%s' >= pp:'%s'", name, pp);
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178 | p = pp;
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179 | i = max - NUM_APPLETS;
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180 | break;
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181 | }
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182 | max -= NUM_APPLETS;
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183 | }
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184 | max /= (unsigned)KNOWN_APPNAME_OFFSETS;
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185 | i /= (unsigned)KNOWN_APPNAME_OFFSETS;
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186 | //bb_error_msg("name:'%s' starting from:'%s' i:%u max:%u", name, p, i, max);
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187 | #endif
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188 |
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189 | /* Open-coded linear search without strcmp/strlen calls for speed */
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190 |
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191 | #if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
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192 | /* skip "[\0" name, it's surely not it */
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193 | if (ENABLE_TEST && LONE_CHAR(p, '['))
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194 | i++, p += 2;
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195 | /* All remaining applet names in p[] are at least 2 chars long */
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196 | /* name[] is also at least 2 chars long */
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197 |
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198 | n32 = (name[0] << 0) | (name[1] << 8) | (name[2] << 16);
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199 | while (i < max) {
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200 | uint32_t p32;
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201 | char ch;
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202 |
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203 | /* Quickly check match of the first 3 bytes */
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204 | move_from_unaligned32(p32, p);
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205 | p += 3;
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206 | if ((p32 & 0x00ffffff) != n32) {
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207 | /* Most likely case: 3 first bytes do not match */
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208 | i++;
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209 | if ((p32 & 0x00ff0000) == '\0')
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210 | continue; // p[2] was NUL
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211 | p++;
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212 | if ((p32 & 0xff000000) == '\0')
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213 | continue; // p[3] was NUL
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214 | /* p[0..3] aren't matching and none is NUL, check the rest */
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215 | while (*p++ != '\0')
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216 | continue;
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217 | continue;
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218 | }
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219 |
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220 | /* Unlikely branch: first 3 bytes ([0..2]) match */
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221 | if ((p32 & 0x00ff0000) == '\0') {
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222 | /* name is 2-byte long, it is full match */
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223 | //bb_error_msg("found:'%s' i:%u", name, i);
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224 | return i;
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225 | }
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226 | /* Check remaining bytes [3..NUL] */
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227 | ch = (p32 >> 24);
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228 | j = 3;
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229 | while (ch == name[j]) {
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230 | if (ch == '\0') {
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231 | //bb_error_msg("found:'%s' i:%u", name, i);
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232 | return i;
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233 | }
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234 | ch = *++p;
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235 | j++;
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236 | }
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237 | /* Not a match. Skip it, including NUL */
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238 | while (ch != '\0')
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239 | ch = *++p;
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240 | p++;
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241 | i++;
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242 | }
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243 | return -1;
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244 | #else
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245 | while (i < max) {
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246 | char ch;
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247 | j = 0;
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248 | /* Do we see "name\0" in applet_names[p] position? */
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249 | while ((ch = *p) == name[j]) {
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250 | if (ch == '\0') {
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251 | //bb_error_msg("found:'%s' i:%u", name, i);
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252 | return i; /* yes */
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253 | }
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254 | p++;
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255 | j++;
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256 | }
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257 | /* No.
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258 | * p => 1st non-matching char in applet_names[],
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259 | * skip to and including NUL.
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260 | */
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261 | while (ch != '\0')
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262 | ch = *++p;
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263 | p++;
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264 | i++;
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265 | }
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266 | return -1;
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267 | #endif
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268 | }
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269 |
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270 |
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271 | void lbb_prepare(const char *applet
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272 | IF_FEATURE_INDIVIDUAL(, char **argv))
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273 | MAIN_EXTERNALLY_VISIBLE;
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274 | void lbb_prepare(const char *applet
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275 | IF_FEATURE_INDIVIDUAL(, char **argv))
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276 | {
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277 | #ifdef __GLIBC__
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278 | (*(int **)&bb_errno) = __errno_location();
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279 | barrier();
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280 | #endif
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281 | applet_name = applet;
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282 |
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283 | if (ENABLE_LOCALE_SUPPORT)
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284 | setlocale(LC_ALL, "");
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285 |
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286 | #if ENABLE_FEATURE_INDIVIDUAL
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287 | /* Redundant for busybox (run_applet_and_exit covers that case)
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288 | * but needed for "individual applet" mode */
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289 | if (argv[1]
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290 | && !argv[2]
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291 | && strcmp(argv[1], "--help") == 0
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292 | && !is_prefixed_with(applet, "busybox")
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293 | ) {
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294 | /* Special case. POSIX says "test --help"
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295 | * should be no different from e.g. "test --foo". */
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296 | if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
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297 | bb_show_usage();
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298 | }
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299 | #endif
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300 | }
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301 |
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302 | /* The code below can well be in applets/applets.c, as it is used only
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303 | * for busybox binary, not "individual" binaries.
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304 | * However, keeping it here and linking it into libbusybox.so
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305 | * (together with remaining tiny applets/applets.o)
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306 | * makes it possible to avoid --whole-archive at link time.
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307 | * This makes (shared busybox) + libbusybox smaller.
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308 | * (--gc-sections would be even better....)
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309 | */
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310 |
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311 | const char *applet_name;
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312 | #if !BB_MMU
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313 | bool re_execed;
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314 | #endif
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315 |
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316 |
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317 | /* If not built as a single-applet executable... */
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318 | #if !defined(SINGLE_APPLET_MAIN)
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319 |
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320 | IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
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321 |
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322 | # if ENABLE_FEATURE_SUID_CONFIG
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323 |
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324 | static struct suid_config_t {
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325 | /* next ptr must be first: this struct needs to be llist-compatible */
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326 | struct suid_config_t *m_next;
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327 | struct bb_uidgid_t m_ugid;
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328 | int m_applet;
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329 | mode_t m_mode;
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330 | } *suid_config;
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331 |
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332 | static bool suid_cfg_readable;
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333 |
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334 | /* check if u is member of group g */
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335 | static int ingroup(uid_t u, gid_t g)
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336 | {
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337 | struct group *grp = getgrgid(g);
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338 | if (grp) {
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339 | char **mem;
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340 | for (mem = grp->gr_mem; *mem; mem++) {
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341 | struct passwd *pwd = getpwnam(*mem);
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342 | if (pwd && (pwd->pw_uid == u))
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343 | return 1;
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344 | }
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345 | }
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346 | return 0;
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347 | }
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348 |
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349 | /* libbb candidate */
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350 | static char *get_trimmed_slice(char *s, char *e)
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351 | {
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352 | /* First, consider the value at e to be nul and back up until we
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353 | * reach a non-space char. Set the char after that (possibly at
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354 | * the original e) to nul. */
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355 | while (e-- > s) {
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356 | if (!isspace(*e)) {
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357 | break;
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358 | }
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359 | }
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360 | e[1] = '\0';
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361 |
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362 | /* Next, advance past all leading space and return a ptr to the
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363 | * first non-space char; possibly the terminating nul. */
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364 | return skip_whitespace(s);
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365 | }
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366 |
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367 | static void parse_config_file(void)
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368 | {
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369 | /* Don't depend on the tools to combine strings. */
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370 | static const char config_file[] ALIGN1 = "/etc/busybox.conf";
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371 |
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372 | struct suid_config_t *sct_head;
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373 | int applet_no;
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374 | FILE *f;
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375 | const char *errmsg;
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376 | unsigned lc;
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377 | smallint section;
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378 | struct stat st;
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379 |
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380 | ruid = getuid();
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381 | if (ruid == 0) /* run by root - don't need to even read config file */
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382 | return;
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383 |
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384 | if ((stat(config_file, &st) != 0) /* No config file? */
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385 | || !S_ISREG(st.st_mode) /* Not a regular file? */
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386 | || (st.st_uid != 0) /* Not owned by root? */
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387 | || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
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388 | || !(f = fopen_for_read(config_file)) /* Cannot open? */
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389 | ) {
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390 | return;
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391 | }
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392 |
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393 | suid_cfg_readable = 1;
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394 | sct_head = NULL;
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395 | section = lc = 0;
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396 |
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397 | while (1) {
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398 | char buffer[256];
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399 | char *s;
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400 |
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401 | if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
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402 | // Looks like bloat
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403 | //if (ferror(f)) { /* Make sure it wasn't a read error. */
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404 | // errmsg = "reading";
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405 | // goto pe_label;
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406 | //}
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407 | fclose(f);
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408 | suid_config = sct_head; /* Success, so set the pointer. */
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409 | return;
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410 | }
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411 |
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412 | s = buffer;
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413 | lc++; /* Got a (partial) line. */
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414 |
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415 | /* If a line is too long for our buffer, we consider it an error.
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416 | * The following test does mistreat one corner case though.
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417 | * If the final line of the file does not end with a newline and
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418 | * yet exactly fills the buffer, it will be treated as too long
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419 | * even though there isn't really a problem. But it isn't really
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420 | * worth adding code to deal with such an unlikely situation, and
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421 | * we do err on the side of caution. Besides, the line would be
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422 | * too long if it did end with a newline. */
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423 | if (!strchr(s, '\n') && !feof(f)) {
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424 | errmsg = "line too long";
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425 | goto pe_label;
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426 | }
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427 |
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428 | /* Trim leading and trailing whitespace, ignoring comments, and
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429 | * check if the resulting string is empty. */
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430 | s = get_trimmed_slice(s, strchrnul(s, '#'));
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431 | if (!*s) {
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432 | continue;
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433 | }
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434 |
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435 | /* Check for a section header. */
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436 |
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437 | if (*s == '[') {
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438 | /* Unlike the old code, we ignore leading and trailing
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439 | * whitespace for the section name. We also require that
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440 | * there are no stray characters after the closing bracket. */
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441 | char *e = strchr(s, ']');
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442 | if (!e /* Missing right bracket? */
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443 | || e[1] /* Trailing characters? */
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444 | || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
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445 | ) {
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446 | errmsg = "section header";
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447 | goto pe_label;
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448 | }
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449 | /* Right now we only have one section so just check it.
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450 | * If more sections are added in the future, please don't
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451 | * resort to cascading ifs with multiple strcasecmp calls.
|
---|
452 | * That kind of bloated code is all too common. A loop
|
---|
453 | * and a string table would be a better choice unless the
|
---|
454 | * number of sections is very small. */
|
---|
455 | if (strcasecmp(s, "SUID") == 0) {
|
---|
456 | section = 1;
|
---|
457 | continue;
|
---|
458 | }
|
---|
459 | section = -1; /* Unknown section so set to skip. */
|
---|
460 | continue;
|
---|
461 | }
|
---|
462 |
|
---|
463 | /* Process sections. */
|
---|
464 |
|
---|
465 | if (section == 1) { /* SUID */
|
---|
466 | /* Since we trimmed leading and trailing space above, we're
|
---|
467 | * now looking for strings of the form
|
---|
468 | * <key>[::space::]*=[::space::]*<value>
|
---|
469 | * where both key and value could contain inner whitespace. */
|
---|
470 |
|
---|
471 | /* First get the key (an applet name in our case). */
|
---|
472 | char *e = strchr(s, '=');
|
---|
473 | if (e) {
|
---|
474 | s = get_trimmed_slice(s, e);
|
---|
475 | }
|
---|
476 | if (!e || !*s) { /* Missing '=' or empty key. */
|
---|
477 | errmsg = "keyword";
|
---|
478 | goto pe_label;
|
---|
479 | }
|
---|
480 |
|
---|
481 | /* Ok, we have an applet name. Process the rhs if this
|
---|
482 | * applet is currently built in and ignore it otherwise.
|
---|
483 | * Note: this can hide config file bugs which only pop
|
---|
484 | * up when the busybox configuration is changed. */
|
---|
485 | applet_no = find_applet_by_name(s);
|
---|
486 | if (applet_no >= 0) {
|
---|
487 | unsigned i;
|
---|
488 | struct suid_config_t *sct;
|
---|
489 |
|
---|
490 | /* Note: We currently don't check for duplicates!
|
---|
491 | * The last config line for each applet will be the
|
---|
492 | * one used since we insert at the head of the list.
|
---|
493 | * I suppose this could be considered a feature. */
|
---|
494 | sct = xzalloc(sizeof(*sct));
|
---|
495 | sct->m_applet = applet_no;
|
---|
496 | /*sct->m_mode = 0;*/
|
---|
497 | sct->m_next = sct_head;
|
---|
498 | sct_head = sct;
|
---|
499 |
|
---|
500 | /* Get the specified mode. */
|
---|
501 |
|
---|
502 | e = skip_whitespace(e+1);
|
---|
503 |
|
---|
504 | for (i = 0; i < 3; i++) {
|
---|
505 | /* There are 4 chars for each of user/group/other.
|
---|
506 | * "x-xx" instead of "x-" are to make
|
---|
507 | * "idx > 3" check catch invalid chars.
|
---|
508 | */
|
---|
509 | static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
|
---|
510 | static const unsigned short mode_mask[] ALIGN2 = {
|
---|
511 | S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
|
---|
512 | S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
|
---|
513 | S_IXOTH, 0 /* x- */
|
---|
514 | };
|
---|
515 | const char *q = strchrnul(mode_chars + 4*i, *e);
|
---|
516 | unsigned idx = q - (mode_chars + 4*i);
|
---|
517 | if (idx > 3) {
|
---|
518 | errmsg = "mode";
|
---|
519 | goto pe_label;
|
---|
520 | }
|
---|
521 | sct->m_mode |= mode_mask[q - mode_chars];
|
---|
522 | e++;
|
---|
523 | }
|
---|
524 |
|
---|
525 | /* Now get the user/group info. */
|
---|
526 |
|
---|
527 | s = skip_whitespace(e);
|
---|
528 | /* Default is 0.0, else parse USER.GROUP: */
|
---|
529 | if (*s) {
|
---|
530 | /* We require whitespace between mode and USER.GROUP */
|
---|
531 | if ((s == e) || !(e = strchr(s, '.'))) {
|
---|
532 | errmsg = "uid.gid";
|
---|
533 | goto pe_label;
|
---|
534 | }
|
---|
535 | *e = ':'; /* get_uidgid needs USER:GROUP syntax */
|
---|
536 | if (get_uidgid(&sct->m_ugid, s) == 0) {
|
---|
537 | errmsg = "unknown user/group";
|
---|
538 | goto pe_label;
|
---|
539 | }
|
---|
540 | }
|
---|
541 | }
|
---|
542 | continue;
|
---|
543 | }
|
---|
544 |
|
---|
545 | /* Unknown sections are ignored. */
|
---|
546 |
|
---|
547 | /* Encountering configuration lines prior to seeing a
|
---|
548 | * section header is treated as an error. This is how
|
---|
549 | * the old code worked, but it may not be desirable.
|
---|
550 | * We may want to simply ignore such lines in case they
|
---|
551 | * are used in some future version of busybox. */
|
---|
552 | if (!section) {
|
---|
553 | errmsg = "keyword outside section";
|
---|
554 | goto pe_label;
|
---|
555 | }
|
---|
556 | } /* while (1) */
|
---|
557 |
|
---|
558 | pe_label:
|
---|
559 | fclose(f);
|
---|
560 | bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
|
---|
561 |
|
---|
562 | /* Release any allocated memory before returning. */
|
---|
563 | llist_free((llist_t*)sct_head, NULL);
|
---|
564 | }
|
---|
565 | # else
|
---|
566 | static inline void parse_config_file(void)
|
---|
567 | {
|
---|
568 | IF_FEATURE_SUID(ruid = getuid();)
|
---|
569 | }
|
---|
570 | # endif /* FEATURE_SUID_CONFIG */
|
---|
571 |
|
---|
572 |
|
---|
573 | # if ENABLE_FEATURE_SUID
|
---|
574 | static void check_suid(int applet_no)
|
---|
575 | {
|
---|
576 | gid_t rgid; /* real gid */
|
---|
577 |
|
---|
578 | if (ruid == 0) /* set by parse_config_file() */
|
---|
579 | return; /* run by root - no need to check more */
|
---|
580 | rgid = getgid();
|
---|
581 |
|
---|
582 | # if ENABLE_FEATURE_SUID_CONFIG
|
---|
583 | if (suid_cfg_readable) {
|
---|
584 | uid_t uid;
|
---|
585 | struct suid_config_t *sct;
|
---|
586 | mode_t m;
|
---|
587 |
|
---|
588 | for (sct = suid_config; sct; sct = sct->m_next) {
|
---|
589 | if (sct->m_applet == applet_no)
|
---|
590 | goto found;
|
---|
591 | }
|
---|
592 | goto check_need_suid;
|
---|
593 | found:
|
---|
594 | /* Is this user allowed to run this applet? */
|
---|
595 | m = sct->m_mode;
|
---|
596 | if (sct->m_ugid.uid == ruid)
|
---|
597 | /* same uid */
|
---|
598 | m >>= 6;
|
---|
599 | else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
|
---|
600 | /* same group / in group */
|
---|
601 | m >>= 3;
|
---|
602 | if (!(m & S_IXOTH)) /* is x bit not set? */
|
---|
603 | bb_error_msg_and_die("you have no permission to run this applet");
|
---|
604 |
|
---|
605 | /* We set effective AND saved ids. If saved-id is not set
|
---|
606 | * like we do below, seteuid(0) can still later succeed! */
|
---|
607 |
|
---|
608 | /* Are we directed to change gid
|
---|
609 | * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
|
---|
610 | */
|
---|
611 | if (sct->m_mode & S_ISGID)
|
---|
612 | rgid = sct->m_ugid.gid;
|
---|
613 | /* else: we will set egid = rgid, thus dropping sgid effect */
|
---|
614 | if (setresgid(-1, rgid, rgid))
|
---|
615 | bb_perror_msg_and_die("setresgid");
|
---|
616 |
|
---|
617 | /* Are we directed to change uid
|
---|
618 | * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
|
---|
619 | */
|
---|
620 | uid = ruid;
|
---|
621 | if (sct->m_mode & S_ISUID)
|
---|
622 | uid = sct->m_ugid.uid;
|
---|
623 | /* else: we will set euid = ruid, thus dropping suid effect */
|
---|
624 | if (setresuid(-1, uid, uid))
|
---|
625 | bb_perror_msg_and_die("setresuid");
|
---|
626 |
|
---|
627 | goto ret;
|
---|
628 | }
|
---|
629 | # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
|
---|
630 | {
|
---|
631 | static bool onetime = 0;
|
---|
632 |
|
---|
633 | if (!onetime) {
|
---|
634 | onetime = 1;
|
---|
635 | bb_error_msg("using fallback suid method");
|
---|
636 | }
|
---|
637 | }
|
---|
638 | # endif
|
---|
639 | check_need_suid:
|
---|
640 | # endif
|
---|
641 | if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
|
---|
642 | /* Real uid is not 0. If euid isn't 0 too, suid bit
|
---|
643 | * is most probably not set on our executable */
|
---|
644 | if (geteuid())
|
---|
645 | bb_error_msg_and_die("must be suid to work properly");
|
---|
646 | } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
|
---|
647 | xsetgid(rgid); /* drop all privileges */
|
---|
648 | xsetuid(ruid);
|
---|
649 | }
|
---|
650 | # if ENABLE_FEATURE_SUID_CONFIG
|
---|
651 | ret: ;
|
---|
652 | llist_free((llist_t*)suid_config, NULL);
|
---|
653 | # endif
|
---|
654 | }
|
---|
655 | # else
|
---|
656 | # define check_suid(x) ((void)0)
|
---|
657 | # endif /* FEATURE_SUID */
|
---|
658 |
|
---|
659 |
|
---|
660 | # if ENABLE_FEATURE_INSTALLER
|
---|
661 | static const char usr_bin [] ALIGN1 = "/usr/bin/";
|
---|
662 | static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
|
---|
663 | static const char *const install_dir[] = {
|
---|
664 | &usr_bin [8], /* "/" */
|
---|
665 | &usr_bin [4], /* "/bin/" */
|
---|
666 | &usr_sbin[4] /* "/sbin/" */
|
---|
667 | # if !ENABLE_INSTALL_NO_USR
|
---|
668 | ,usr_bin
|
---|
669 | ,usr_sbin
|
---|
670 | # endif
|
---|
671 | };
|
---|
672 |
|
---|
673 | /* create (sym)links for each applet */
|
---|
674 | static void install_links(const char *busybox, int use_symbolic_links,
|
---|
675 | char *custom_install_dir)
|
---|
676 | {
|
---|
677 | /* directory table
|
---|
678 | * this should be consistent w/ the enum,
|
---|
679 | * busybox.h::bb_install_loc_t, or else... */
|
---|
680 | int (*lf)(const char *, const char *);
|
---|
681 | char *fpc;
|
---|
682 | const char *appname = applet_names;
|
---|
683 | unsigned i;
|
---|
684 | int rc;
|
---|
685 |
|
---|
686 | lf = link;
|
---|
687 | if (use_symbolic_links)
|
---|
688 | lf = symlink;
|
---|
689 |
|
---|
690 | for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
|
---|
691 | fpc = concat_path_file(
|
---|
692 | custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
|
---|
693 | appname);
|
---|
694 | // debug: bb_error_msg("%slinking %s to busybox",
|
---|
695 | // use_symbolic_links ? "sym" : "", fpc);
|
---|
696 | rc = lf(busybox, fpc);
|
---|
697 | if (rc != 0 && errno != EEXIST) {
|
---|
698 | bb_simple_perror_msg(fpc);
|
---|
699 | }
|
---|
700 | free(fpc);
|
---|
701 | while (*appname++ != '\0')
|
---|
702 | continue;
|
---|
703 | }
|
---|
704 | }
|
---|
705 | # elif ENABLE_BUSYBOX
|
---|
706 | static void install_links(const char *busybox UNUSED_PARAM,
|
---|
707 | int use_symbolic_links UNUSED_PARAM,
|
---|
708 | char *custom_install_dir UNUSED_PARAM)
|
---|
709 | {
|
---|
710 | }
|
---|
711 | # endif
|
---|
712 |
|
---|
713 | # if ENABLE_BUSYBOX
|
---|
714 | /* If we were called as "busybox..." */
|
---|
715 | static int busybox_main(char **argv)
|
---|
716 | {
|
---|
717 | if (!argv[1]) {
|
---|
718 | /* Called without arguments */
|
---|
719 | const char *a;
|
---|
720 | int col;
|
---|
721 | unsigned output_width;
|
---|
722 | help:
|
---|
723 | output_width = 80;
|
---|
724 | if (ENABLE_FEATURE_AUTOWIDTH) {
|
---|
725 | /* Obtain the terminal width */
|
---|
726 | output_width = get_terminal_width(2);
|
---|
727 | }
|
---|
728 |
|
---|
729 | dup2(1, 2);
|
---|
730 | full_write2_str(bb_banner); /* reuse const string */
|
---|
731 | full_write2_str(" multi-call binary.\n"); /* reuse */
|
---|
732 | full_write2_str(
|
---|
733 | "BusyBox is copyrighted by many authors between 1998-2015.\n"
|
---|
734 | "Licensed under GPLv2. See source distribution for detailed\n"
|
---|
735 | "copyright notices.\n"
|
---|
736 | "\n"
|
---|
737 | "Usage: busybox [function [arguments]...]\n"
|
---|
738 | " or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
|
---|
739 | IF_FEATURE_INSTALLER(
|
---|
740 | " or: busybox --install [-s] [DIR]\n"
|
---|
741 | )
|
---|
742 | " or: function [arguments]...\n"
|
---|
743 | "\n"
|
---|
744 | IF_NOT_FEATURE_SH_STANDALONE(
|
---|
745 | "\tBusyBox is a multi-call binary that combines many common Unix\n"
|
---|
746 | "\tutilities into a single executable. Most people will create a\n"
|
---|
747 | "\tlink to busybox for each function they wish to use and BusyBox\n"
|
---|
748 | "\twill act like whatever it was invoked as.\n"
|
---|
749 | )
|
---|
750 | IF_FEATURE_SH_STANDALONE(
|
---|
751 | "\tBusyBox is a multi-call binary that combines many common Unix\n"
|
---|
752 | "\tutilities into a single executable. The shell in this build\n"
|
---|
753 | "\tis configured to run built-in utilities without $PATH search.\n"
|
---|
754 | "\tYou don't need to install a link to busybox for each utility.\n"
|
---|
755 | "\tTo run external program, use full path (/sbin/ip instead of ip).\n"
|
---|
756 | )
|
---|
757 | "\n"
|
---|
758 | "Currently defined functions:\n"
|
---|
759 | );
|
---|
760 | col = 0;
|
---|
761 | a = applet_names;
|
---|
762 | /* prevent last comma to be in the very last pos */
|
---|
763 | output_width--;
|
---|
764 | while (*a) {
|
---|
765 | int len2 = strlen(a) + 2;
|
---|
766 | if (col >= (int)output_width - len2) {
|
---|
767 | full_write2_str(",\n");
|
---|
768 | col = 0;
|
---|
769 | }
|
---|
770 | if (col == 0) {
|
---|
771 | col = 6;
|
---|
772 | full_write2_str("\t");
|
---|
773 | } else {
|
---|
774 | full_write2_str(", ");
|
---|
775 | }
|
---|
776 | full_write2_str(a);
|
---|
777 | col += len2;
|
---|
778 | a += len2 - 1;
|
---|
779 | }
|
---|
780 | full_write2_str("\n\n");
|
---|
781 | return 0;
|
---|
782 | }
|
---|
783 |
|
---|
784 | if (is_prefixed_with(argv[1], "--list")) {
|
---|
785 | unsigned i = 0;
|
---|
786 | const char *a = applet_names;
|
---|
787 | dup2(1, 2);
|
---|
788 | while (*a) {
|
---|
789 | # if ENABLE_FEATURE_INSTALLER
|
---|
790 | if (argv[1][6]) /* --list-full? */
|
---|
791 | full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
|
---|
792 | # endif
|
---|
793 | full_write2_str(a);
|
---|
794 | full_write2_str("\n");
|
---|
795 | i++;
|
---|
796 | while (*a++ != '\0')
|
---|
797 | continue;
|
---|
798 | }
|
---|
799 | return 0;
|
---|
800 | }
|
---|
801 |
|
---|
802 | if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
|
---|
803 | int use_symbolic_links;
|
---|
804 | const char *busybox;
|
---|
805 |
|
---|
806 | busybox = xmalloc_readlink(bb_busybox_exec_path);
|
---|
807 | if (!busybox) {
|
---|
808 | /* bb_busybox_exec_path is usually "/proc/self/exe".
|
---|
809 | * In chroot, readlink("/proc/self/exe") usually fails.
|
---|
810 | * In such case, better use argv[0] as symlink target
|
---|
811 | * if it is a full path name.
|
---|
812 | */
|
---|
813 | if (argv[0][0] != '/')
|
---|
814 | bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
|
---|
815 | busybox = argv[0];
|
---|
816 | }
|
---|
817 | /* busybox --install [-s] [DIR]:
|
---|
818 | * -s: make symlinks
|
---|
819 | * DIR: directory to install links to
|
---|
820 | */
|
---|
821 | use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
|
---|
822 | install_links(busybox, use_symbolic_links, argv[2]);
|
---|
823 | return 0;
|
---|
824 | }
|
---|
825 |
|
---|
826 | if (strcmp(argv[1], "--help") == 0) {
|
---|
827 | /* "busybox --help [<applet>]" */
|
---|
828 | if (!argv[2])
|
---|
829 | goto help;
|
---|
830 | /* convert to "<applet> --help" */
|
---|
831 | argv[0] = argv[2];
|
---|
832 | argv[2] = NULL;
|
---|
833 | } else {
|
---|
834 | /* "busybox <applet> arg1 arg2 ..." */
|
---|
835 | argv++;
|
---|
836 | }
|
---|
837 | /* We support "busybox /a/path/to/applet args..." too. Allows for
|
---|
838 | * "#!/bin/busybox"-style wrappers */
|
---|
839 | applet_name = bb_get_last_path_component_nostrip(argv[0]);
|
---|
840 | run_applet_and_exit(applet_name, argv);
|
---|
841 | }
|
---|
842 | # endif
|
---|
843 |
|
---|
844 | void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
|
---|
845 | {
|
---|
846 | int argc = 1;
|
---|
847 |
|
---|
848 | while (argv[argc])
|
---|
849 | argc++;
|
---|
850 |
|
---|
851 | /* Reinit some shared global data */
|
---|
852 | xfunc_error_retval = EXIT_FAILURE;
|
---|
853 | applet_name = bb_get_last_path_component_nostrip(argv[0]);
|
---|
854 |
|
---|
855 | /* Special case. POSIX says "test --help"
|
---|
856 | * should be no different from e.g. "test --foo".
|
---|
857 | * Thus for "test", we skip --help check.
|
---|
858 | * "true" and "false" are also special.
|
---|
859 | */
|
---|
860 | if (1
|
---|
861 | #if defined APPLET_NO_test
|
---|
862 | && applet_no != APPLET_NO_test
|
---|
863 | #endif
|
---|
864 | #if defined APPLET_NO_true
|
---|
865 | && applet_no != APPLET_NO_true
|
---|
866 | #endif
|
---|
867 | #if defined APPLET_NO_false
|
---|
868 | && applet_no != APPLET_NO_false
|
---|
869 | #endif
|
---|
870 | ) {
|
---|
871 | if (argc == 2 && strcmp(argv[1], "--help") == 0) {
|
---|
872 | /* Make "foo --help" exit with 0: */
|
---|
873 | xfunc_error_retval = 0;
|
---|
874 | bb_show_usage();
|
---|
875 | }
|
---|
876 | }
|
---|
877 | if (ENABLE_FEATURE_SUID)
|
---|
878 | check_suid(applet_no);
|
---|
879 | exit(applet_main[applet_no](argc, argv));
|
---|
880 | }
|
---|
881 |
|
---|
882 | static NORETURN void run_applet_and_exit(const char *name, char **argv)
|
---|
883 | {
|
---|
884 | int applet;
|
---|
885 |
|
---|
886 | # if ENABLE_BUSYBOX
|
---|
887 | if (is_prefixed_with(name, "busybox"))
|
---|
888 | exit(busybox_main(argv));
|
---|
889 | # endif
|
---|
890 | /* find_applet_by_name() search is more expensive, so goes second */
|
---|
891 | applet = find_applet_by_name(name);
|
---|
892 | if (applet >= 0)
|
---|
893 | run_applet_no_and_exit(applet, argv);
|
---|
894 |
|
---|
895 | /*bb_error_msg_and_die("applet not found"); - links in printf */
|
---|
896 | full_write2_str(applet_name);
|
---|
897 | full_write2_str(": applet not found\n");
|
---|
898 | /* POSIX: "If a command is not found, the exit status shall be 127" */
|
---|
899 | exit(127);
|
---|
900 | }
|
---|
901 |
|
---|
902 | #endif /* !defined(SINGLE_APPLET_MAIN) */
|
---|
903 |
|
---|
904 |
|
---|
905 |
|
---|
906 | #if ENABLE_BUILD_LIBBUSYBOX
|
---|
907 | int lbb_main(char **argv)
|
---|
908 | #else
|
---|
909 | int main(int argc UNUSED_PARAM, char **argv)
|
---|
910 | #endif
|
---|
911 | {
|
---|
912 | #if 0
|
---|
913 | /* TODO: find a use for a block of memory between end of .bss
|
---|
914 | * and end of page. For example, I'm getting "_end:0x812e698 2408 bytes"
|
---|
915 | * - more than 2k of wasted memory (in this particular build)
|
---|
916 | * *per each running process*!
|
---|
917 | * (If your linker does not generate "_end" name, weak attribute
|
---|
918 | * makes &_end == NULL, end_len == 0 here.)
|
---|
919 | */
|
---|
920 | extern char _end[] __attribute__((weak));
|
---|
921 | unsigned end_len = (-(int)_end) & 0xfff;
|
---|
922 | printf("_end:%p %u bytes\n", &_end, end_len);
|
---|
923 | #endif
|
---|
924 |
|
---|
925 | /* Tweak malloc for reduced memory consumption */
|
---|
926 | #ifdef M_TRIM_THRESHOLD
|
---|
927 | /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
|
---|
928 | * to keep before releasing to the OS
|
---|
929 | * Default is way too big: 256k
|
---|
930 | */
|
---|
931 | mallopt(M_TRIM_THRESHOLD, 8 * 1024);
|
---|
932 | #endif
|
---|
933 | #ifdef M_MMAP_THRESHOLD
|
---|
934 | /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
|
---|
935 | * Default is too big: 256k
|
---|
936 | */
|
---|
937 | mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
|
---|
938 | #endif
|
---|
939 |
|
---|
940 | #if !BB_MMU
|
---|
941 | /* NOMMU re-exec trick sets high-order bit in first byte of name */
|
---|
942 | if (argv[0][0] & 0x80) {
|
---|
943 | re_execed = 1;
|
---|
944 | argv[0][0] &= 0x7f;
|
---|
945 | }
|
---|
946 | #endif
|
---|
947 |
|
---|
948 | #if defined(SINGLE_APPLET_MAIN)
|
---|
949 | /* Only one applet is selected in .config */
|
---|
950 | if (argv[1] && is_prefixed_with(argv[0], "busybox")) {
|
---|
951 | /* "busybox <applet> <params>" should still work as expected */
|
---|
952 | argv++;
|
---|
953 | }
|
---|
954 | /* applet_names in this case is just "applet\0\0" */
|
---|
955 | lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
|
---|
956 | return SINGLE_APPLET_MAIN(argc, argv);
|
---|
957 | #else
|
---|
958 | lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
|
---|
959 |
|
---|
960 | #if !ENABLE_BUSYBOX
|
---|
961 | if (argv[1] && is_prefixed_with(bb_basename(argv[0]), "busybox"))
|
---|
962 | argv++;
|
---|
963 | #endif
|
---|
964 | applet_name = argv[0];
|
---|
965 | if (applet_name[0] == '-')
|
---|
966 | applet_name++;
|
---|
967 | applet_name = bb_basename(applet_name);
|
---|
968 |
|
---|
969 | parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
|
---|
970 |
|
---|
971 | run_applet_and_exit(applet_name, argv);
|
---|
972 | #endif
|
---|
973 | }
|
---|