1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini start-stop-daemon implementation(s) for busybox
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4 | *
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5 | * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
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6 | * Adapted for busybox David Kimdon <dwhedon@gordian.com>
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7 | *
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8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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9 | */
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10 |
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11 | /*
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12 | This is how it is supposed to work:
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13 |
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14 | start-stop-daemon [OPTIONS] [--start|--stop] [[--] arguments...]
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15 |
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16 | One (only) of these must be given:
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17 | -S,--start Start
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18 | -K,--stop Stop
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19 |
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20 | Search for matching processes.
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21 | If --stop is given, stop all matching processes (by sending a signal).
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22 | If --start is given, start a new process unless a matching process was found.
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23 |
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24 | Options controlling process matching
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25 | (if multiple conditions are specified, all must match):
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26 | -u,--user USERNAME|UID Only consider this user's processes
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27 | -n,--name PROCESS_NAME Look for processes by matching PROCESS_NAME
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28 | with comm field in /proc/$PID/stat.
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29 | Only basename is compared:
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30 | "ntpd" == "./ntpd" == "/path/to/ntpd".
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31 | [TODO: can PROCESS_NAME be a full pathname? Should we require full match then
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32 | with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
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33 | -x,--exec EXECUTABLE Look for processes that were started with this
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34 | command in /proc/$PID/cmdline.
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35 | Unlike -n, we match against the full path:
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36 | "ntpd" != "./ntpd" != "/path/to/ntpd"
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37 | -p,--pidfile PID_FILE Look for processes with PID from this file
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38 |
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39 | Options which are valid for --start only:
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40 | -x,--exec EXECUTABLE Program to run (1st arg of execvp). Mandatory.
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41 | -a,--startas NAME argv[0] (defaults to EXECUTABLE)
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42 | -b,--background Put process into background
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43 | -N,--nicelevel N Add N to process' nice level
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44 | -c,--chuid USER[:[GRP]] Change to specified user [and group]
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45 | -m,--make-pidfile Write PID to the pidfile
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46 | (both -m and -p must be given!)
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47 |
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48 | Options which are valid for --stop only:
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49 | -s,--signal SIG Signal to send (default:TERM)
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50 | -t,--test Exit with status 0 if process is found
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51 | (we don't actually start or stop daemons)
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52 |
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53 | Misc options:
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54 | -o,--oknodo Exit with status 0 if nothing is done
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55 | -q,--quiet Quiet
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56 | -v,--verbose Verbose
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57 | */
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58 |
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59 | #include <sys/resource.h>
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60 |
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61 | /* Override ENABLE_FEATURE_PIDFILE */
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62 | #define WANT_PIDFILE 1
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63 | #include "libbb.h"
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64 |
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65 | struct pid_list {
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66 | struct pid_list *next;
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67 | pid_t pid;
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68 | };
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69 |
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70 | enum {
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71 | CTX_STOP = (1 << 0),
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72 | CTX_START = (1 << 1),
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73 | OPT_BACKGROUND = (1 << 2), // -b
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74 | OPT_QUIET = (1 << 3), // -q
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75 | OPT_TEST = (1 << 4), // -t
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76 | OPT_MAKEPID = (1 << 5), // -m
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77 | OPT_a = (1 << 6), // -a
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78 | OPT_n = (1 << 7), // -n
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79 | OPT_s = (1 << 8), // -s
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80 | OPT_u = (1 << 9), // -u
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81 | OPT_c = (1 << 10), // -c
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82 | OPT_x = (1 << 11), // -x
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83 | OPT_p = (1 << 12), // -p
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84 | OPT_OKNODO = (1 << 13) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
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85 | OPT_VERBOSE = (1 << 14) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
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86 | OPT_NICELEVEL = (1 << 15) * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
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87 | };
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88 | #define QUIET (option_mask32 & OPT_QUIET)
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89 | #define TEST (option_mask32 & OPT_TEST)
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90 |
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91 | struct globals {
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92 | struct pid_list *found_procs;
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93 | char *userspec;
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94 | char *cmdname;
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95 | char *execname;
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96 | char *pidfile;
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97 | char *execname_cmpbuf;
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98 | unsigned execname_sizeof;
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99 | int user_id;
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100 | smallint signal_nr;
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101 | } FIX_ALIASING;
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102 | #define G (*(struct globals*)&bb_common_bufsiz1)
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103 | #define userspec (G.userspec )
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104 | #define cmdname (G.cmdname )
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105 | #define execname (G.execname )
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106 | #define pidfile (G.pidfile )
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107 | #define user_id (G.user_id )
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108 | #define signal_nr (G.signal_nr )
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109 | #define INIT_G() do { \
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110 | user_id = -1; \
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111 | signal_nr = 15; \
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112 | } while (0)
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113 |
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114 | #ifdef OLDER_VERSION_OF_X
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115 | /* -x,--exec EXECUTABLE
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116 | * Look for processes with matching /proc/$PID/exe.
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117 | * Match is performed using device+inode.
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118 | */
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119 | static int pid_is_exec(pid_t pid)
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120 | {
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121 | struct stat st;
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122 | char buf[sizeof("/proc/%u/exe") + sizeof(int)*3];
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123 |
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124 | sprintf(buf, "/proc/%u/exe", (unsigned)pid);
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125 | if (stat(buf, &st) < 0)
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126 | return 0;
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127 | if (st.st_dev == execstat.st_dev
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128 | && st.st_ino == execstat.st_ino)
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129 | return 1;
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130 | return 0;
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131 | }
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132 | #endif
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133 |
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134 | static int pid_is_exec(pid_t pid)
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135 | {
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136 | ssize_t bytes;
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137 | char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
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138 |
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139 | sprintf(buf, "/proc/%u/cmdline", (unsigned)pid);
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140 | bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
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141 | if (bytes > 0) {
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142 | G.execname_cmpbuf[bytes] = '\0';
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143 | return strcmp(execname, G.execname_cmpbuf) == 0;
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144 | }
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145 | return 0;
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146 | }
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147 |
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148 | static int pid_is_name(pid_t pid)
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149 | {
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150 | /* /proc/PID/stat is "PID (comm_15_bytes_max) ..." */
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151 | char buf[32]; /* should be enough */
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152 | char *p, *pe;
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153 |
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154 | sprintf(buf, "/proc/%u/stat", (unsigned)pid);
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155 | if (open_read_close(buf, buf, sizeof(buf) - 1) < 0)
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156 | return 0;
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157 | buf[sizeof(buf) - 1] = '\0'; /* paranoia */
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158 | p = strchr(buf, '(');
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159 | if (!p)
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160 | return 0;
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161 | pe = strrchr(++p, ')');
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162 | if (!pe)
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163 | return 0;
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164 | *pe = '\0';
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165 | /* we require comm to match and to not be truncated */
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166 | /* in Linux, if comm is 15 chars, it may be a truncated
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167 | * name, so we don't allow that to match */
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168 | if (strlen(p) >= COMM_LEN - 1) /* COMM_LEN is 16 */
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169 | return 0;
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170 | return strcmp(p, cmdname) == 0;
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171 | }
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172 |
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173 | static int pid_is_user(int pid)
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174 | {
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175 | struct stat sb;
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176 | char buf[sizeof("/proc/") + sizeof(int)*3];
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177 |
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178 | sprintf(buf, "/proc/%u", (unsigned)pid);
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179 | if (stat(buf, &sb) != 0)
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180 | return 0;
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181 | return (sb.st_uid == (uid_t)user_id);
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182 | }
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183 |
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184 | static void check(int pid)
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185 | {
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186 | struct pid_list *p;
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187 |
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188 | if (execname && !pid_is_exec(pid)) {
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189 | return;
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190 | }
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191 | if (cmdname && !pid_is_name(pid)) {
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192 | return;
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193 | }
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194 | if (userspec && !pid_is_user(pid)) {
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195 | return;
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196 | }
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197 | p = xmalloc(sizeof(*p));
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198 | p->next = G.found_procs;
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199 | p->pid = pid;
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200 | G.found_procs = p;
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201 | }
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202 |
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203 | static void do_pidfile(void)
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204 | {
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205 | FILE *f;
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206 | unsigned pid;
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207 |
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208 | f = fopen_for_read(pidfile);
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209 | if (f) {
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210 | if (fscanf(f, "%u", &pid) == 1)
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211 | check(pid);
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212 | fclose(f);
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213 | } else if (errno != ENOENT)
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214 | bb_perror_msg_and_die("open pidfile %s", pidfile);
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215 | }
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216 |
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217 | static void do_procinit(void)
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218 | {
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219 | DIR *procdir;
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220 | struct dirent *entry;
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221 | int pid;
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222 |
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223 | if (pidfile) {
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224 | do_pidfile();
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225 | return;
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226 | }
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227 |
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228 | procdir = xopendir("/proc");
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229 |
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230 | pid = 0;
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231 | while (1) {
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232 | errno = 0; /* clear any previous error */
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233 | entry = readdir(procdir);
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234 | // TODO: this check is too generic, it's better
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235 | // to check for exact errno(s) which mean that we got stale entry
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236 | if (errno) /* Stale entry, process has died after opendir */
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237 | continue;
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238 | if (!entry) /* EOF, no more entries */
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239 | break;
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240 | pid = bb_strtou(entry->d_name, NULL, 10);
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241 | if (errno) /* NaN */
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242 | continue;
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243 | check(pid);
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244 | }
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245 | closedir(procdir);
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246 | if (!pid)
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247 | bb_error_msg_and_die("nothing in /proc - not mounted?");
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248 | }
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249 |
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250 | static int do_stop(void)
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251 | {
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252 | char *what;
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253 | struct pid_list *p;
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254 | int killed = 0;
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255 |
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256 | if (cmdname) {
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257 | if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
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258 | if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
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259 | } else if (execname) {
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260 | if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
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261 | if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
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262 | } else if (pidfile) {
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263 | what = xasprintf("process in pidfile '%s'", pidfile);
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264 | } else if (userspec) {
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265 | what = xasprintf("process(es) owned by '%s'", userspec);
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266 | } else {
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267 | bb_error_msg_and_die("internal error, please report");
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268 | }
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269 |
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270 | if (!G.found_procs) {
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271 | if (!QUIET)
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272 | printf("no %s found; none killed\n", what);
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273 | killed = -1;
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274 | goto ret;
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275 | }
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276 | for (p = G.found_procs; p; p = p->next) {
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277 | if (TEST || kill(p->pid, signal_nr) == 0) {
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278 | killed++;
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279 | } else {
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280 | p->pid = 0;
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281 | bb_perror_msg("warning: killing process %u", (unsigned)p->pid);
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282 | }
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283 | }
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284 | if (!QUIET && killed) {
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285 | printf("stopped %s (pid", what);
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286 | for (p = G.found_procs; p; p = p->next)
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287 | if (p->pid)
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288 | printf(" %u", (unsigned)p->pid);
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289 | puts(")");
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290 | }
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291 | ret:
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292 | if (ENABLE_FEATURE_CLEAN_UP)
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293 | free(what);
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294 | return killed;
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295 | }
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296 |
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297 | #if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
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298 | static const char start_stop_daemon_longopts[] ALIGN1 =
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299 | "stop\0" No_argument "K"
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300 | "start\0" No_argument "S"
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301 | "background\0" No_argument "b"
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302 | "quiet\0" No_argument "q"
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303 | "test\0" No_argument "t"
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304 | "make-pidfile\0" No_argument "m"
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305 | #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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306 | "oknodo\0" No_argument "o"
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307 | "verbose\0" No_argument "v"
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308 | "nicelevel\0" Required_argument "N"
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309 | #endif
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310 | "startas\0" Required_argument "a"
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311 | "name\0" Required_argument "n"
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312 | "signal\0" Required_argument "s"
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313 | "user\0" Required_argument "u"
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314 | "chuid\0" Required_argument "c"
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315 | "exec\0" Required_argument "x"
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316 | "pidfile\0" Required_argument "p"
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317 | #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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318 | "retry\0" Required_argument "R"
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319 | #endif
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320 | ;
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321 | #endif
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322 |
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323 | int start_stop_daemon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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324 | int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
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325 | {
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326 | unsigned opt;
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327 | char *signame;
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328 | char *startas;
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329 | char *chuid;
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330 | #ifdef OLDER_VERSION_OF_X
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331 | struct stat execstat;
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332 | #endif
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333 | #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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334 | // char *retry_arg = NULL;
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335 | // int retries = -1;
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336 | char *opt_N;
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337 | #endif
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338 |
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339 | INIT_G();
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340 |
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341 | #if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
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342 | applet_long_options = start_stop_daemon_longopts;
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343 | #endif
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344 |
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345 | /* -K or -S is required; they are mutually exclusive */
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346 | /* -p is required if -m is given */
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347 | /* -xpun (at least one) is required if -K is given */
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348 | /* -xa (at least one) is required if -S is given */
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349 | /* -q turns off -v */
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350 | opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa"
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351 | IF_FEATURE_START_STOP_DAEMON_FANCY("q-v");
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352 | opt = getopt32(argv, "KSbqtma:n:s:u:c:x:p:"
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353 | IF_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
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354 | &startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
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355 | IF_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
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356 | /* We accept and ignore -R <param> / --retry <param> */
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357 | IF_FEATURE_START_STOP_DAEMON_FANCY(,NULL)
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358 | );
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359 |
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360 | if (opt & OPT_s) {
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361 | signal_nr = get_signum(signame);
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362 | if (signal_nr < 0) bb_show_usage();
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363 | }
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364 |
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365 | if (!(opt & OPT_a))
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366 | startas = execname;
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367 | if (!execname) /* in case -a is given and -x is not */
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368 | execname = startas;
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369 | if (execname) {
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370 | G.execname_sizeof = strlen(execname) + 1;
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371 | G.execname_cmpbuf = xmalloc(G.execname_sizeof + 1);
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372 | }
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373 |
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374 | // IF_FEATURE_START_STOP_DAEMON_FANCY(
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375 | // if (retry_arg)
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376 | // retries = xatoi_positive(retry_arg);
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377 | // )
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378 | //argc -= optind;
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379 | argv += optind;
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380 |
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381 | if (userspec) {
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382 | user_id = bb_strtou(userspec, NULL, 10);
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383 | if (errno)
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384 | user_id = xuname2uid(userspec);
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385 | }
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386 | /* Both start and stop need to know current processes */
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387 | do_procinit();
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388 |
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389 | if (opt & CTX_STOP) {
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390 | int i = do_stop();
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391 | return (opt & OPT_OKNODO) ? 0 : (i <= 0);
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392 | }
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393 |
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394 | if (G.found_procs) {
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395 | if (!QUIET)
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396 | printf("%s is already running\n%u\n", execname, (unsigned)G.found_procs->pid);
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397 | return !(opt & OPT_OKNODO);
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398 | }
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399 |
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400 | #ifdef OLDER_VERSION_OF_X
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401 | if (execname)
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402 | xstat(execname, &execstat);
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403 | #endif
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404 |
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405 | *--argv = startas;
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406 | if (opt & OPT_BACKGROUND) {
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407 | #if BB_MMU
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408 | bb_daemonize(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
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409 | /* DAEMON_DEVNULL_STDIO is superfluous -
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410 | * it's always done by bb_daemonize() */
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411 | #else
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412 | pid_t pid = xvfork();
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413 | if (pid != 0) {
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414 | /* parent */
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415 | /* why _exit? the child may have changed the stack,
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416 | * so "return 0" may do bad things */
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417 | _exit(EXIT_SUCCESS);
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418 | }
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419 | /* Child */
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420 | setsid(); /* detach from controlling tty */
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421 | /* Redirect stdio to /dev/null, close extra FDs.
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422 | * We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
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423 | bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO
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424 | + DAEMON_CLOSE_EXTRA_FDS
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425 | + DAEMON_ONLY_SANITIZE,
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426 | NULL /* argv, unused */ );
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427 | #endif
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428 | }
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429 | if (opt & OPT_MAKEPID) {
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430 | /* User wants _us_ to make the pidfile */
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431 | write_pidfile(pidfile);
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432 | }
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433 | if (opt & OPT_c) {
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434 | struct bb_uidgid_t ugid = { -1, -1 };
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435 | parse_chown_usergroup_or_die(&ugid, chuid);
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436 | if (ugid.gid != (gid_t) -1) xsetgid(ugid.gid);
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437 | if (ugid.uid != (uid_t) -1) xsetuid(ugid.uid);
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438 | }
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439 | #if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
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440 | if (opt & OPT_NICELEVEL) {
|
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441 | /* Set process priority */
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442 | int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
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443 | if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
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444 | bb_perror_msg_and_die("setpriority(%d)", prio);
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445 | }
|
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446 | }
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447 | #endif
|
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448 | execvp(startas, argv);
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449 | bb_perror_msg_and_die("can't execute '%s'", startas);
|
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450 | }
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