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1 /* |
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2 * A fast client for Mercurial command server |
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3 * |
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4 * Copyright (c) 2011 Yuya Nishihara <yuya@tcha.org> |
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5 * |
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6 * This software may be used and distributed according to the terms of the |
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7 * GNU General Public License version 2 or any later version. |
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8 */ |
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9 |
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10 #include <assert.h> |
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11 #include <errno.h> |
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12 #include <fcntl.h> |
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13 #include <signal.h> |
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14 #include <stdio.h> |
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15 #include <stdlib.h> |
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16 #include <string.h> |
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17 #include <sys/stat.h> |
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18 #include <sys/types.h> |
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19 #include <sys/un.h> |
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20 #include <sys/wait.h> |
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21 #include <time.h> |
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22 #include <unistd.h> |
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23 |
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24 #include "hgclient.h" |
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25 #include "util.h" |
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26 |
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27 #ifndef UNIX_PATH_MAX |
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28 #define UNIX_PATH_MAX (sizeof(((struct sockaddr_un *)NULL)->sun_path)) |
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29 #endif |
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30 |
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31 struct cmdserveropts { |
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32 char sockname[UNIX_PATH_MAX]; |
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33 char lockfile[UNIX_PATH_MAX]; |
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34 char pidfile[UNIX_PATH_MAX]; |
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35 }; |
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36 |
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37 static void preparesockdir(const char *sockdir) |
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38 { |
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39 int r; |
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40 r = mkdir(sockdir, 0700); |
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41 if (r < 0 && errno != EEXIST) |
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42 abortmsg("cannot create sockdir %s (errno = %d)", |
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43 sockdir, errno); |
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44 |
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45 struct stat st; |
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46 r = lstat(sockdir, &st); |
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47 if (r < 0) |
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48 abortmsg("cannot stat %s (errno = %d)", sockdir, errno); |
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49 if (!S_ISDIR(st.st_mode)) |
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50 abortmsg("cannot create sockdir %s (file exists)", sockdir); |
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51 if (st.st_uid != geteuid() || st.st_mode & 0077) |
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52 abortmsg("insecure sockdir %s", sockdir); |
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53 } |
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54 |
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55 static void setcmdserveropts(struct cmdserveropts *opts) |
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56 { |
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57 int r; |
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58 char sockdir[UNIX_PATH_MAX]; |
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59 const char *envsockname = getenv("CHGSOCKNAME"); |
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60 if (!envsockname) { |
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61 /* by default, put socket file in secure directory |
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62 * (permission of socket file may be ignored on some Unices) */ |
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63 const char *tmpdir = getenv("TMPDIR"); |
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64 if (!tmpdir) |
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65 tmpdir = "/tmp"; |
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66 r = snprintf(sockdir, sizeof(sockdir), "%s/chg%d", |
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67 tmpdir, geteuid()); |
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68 if (r < 0 || (size_t)r >= sizeof(sockdir)) |
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69 abortmsg("too long TMPDIR (r = %d)", r); |
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70 preparesockdir(sockdir); |
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71 } |
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72 |
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73 const char *basename = (envsockname) ? envsockname : sockdir; |
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74 const char *sockfmt = (envsockname) ? "%s" : "%s/server"; |
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75 const char *lockfmt = (envsockname) ? "%s.lock" : "%s/lock"; |
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76 const char *pidfmt = (envsockname) ? "%s.pid" : "%s/pid"; |
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77 r = snprintf(opts->sockname, sizeof(opts->sockname), sockfmt, basename); |
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78 if (r < 0 || (size_t)r >= sizeof(opts->sockname)) |
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79 abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); |
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80 r = snprintf(opts->lockfile, sizeof(opts->lockfile), lockfmt, basename); |
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81 if (r < 0 || (size_t)r >= sizeof(opts->lockfile)) |
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82 abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); |
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83 r = snprintf(opts->pidfile, sizeof(opts->pidfile), pidfmt, basename); |
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84 if (r < 0 || (size_t)r >= sizeof(opts->pidfile)) |
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85 abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); |
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86 } |
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87 |
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88 /* |
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89 * Make lock file that indicates cmdserver process is about to start. Created |
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90 * lock file will be deleted by server. (0: success, -1: lock exists) |
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91 */ |
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92 static int lockcmdserver(const struct cmdserveropts *opts) |
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93 { |
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94 int r; |
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95 char info[32]; |
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96 r = snprintf(info, sizeof(info), "%d", getpid()); |
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97 if (r < 0 || (size_t)r >= sizeof(info)) |
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98 abortmsg("failed to format lock info"); |
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99 r = symlink(info, opts->lockfile); |
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100 if (r < 0 && errno != EEXIST) |
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101 abortmsg("failed to make lock %s (errno = %d)", |
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102 opts->lockfile, errno); |
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103 return r; |
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104 } |
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105 |
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106 static void execcmdserver(const struct cmdserveropts *opts) |
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107 { |
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108 const char *hgcmd = getenv("CHGHG"); |
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109 if (!hgcmd || hgcmd[0] == '\0') |
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110 hgcmd = getenv("HG"); |
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111 if (!hgcmd || hgcmd[0] == '\0') |
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112 hgcmd = "hg"; |
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113 |
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114 const char *argv[] = { |
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115 hgcmd, |
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116 "serve", |
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117 "--cwd", "/", |
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118 "--cmdserver", "chgunix", |
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119 "--address", opts->sockname, |
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120 "--daemon-pipefds", opts->lockfile, |
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121 "--pid-file", opts->pidfile, |
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122 "--config", "extensions.chgserver=", |
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123 /* wrap root ui so that it can be disabled/enabled by config */ |
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124 "--config", "progress.assume-tty=1", |
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125 NULL, |
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126 }; |
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127 if (execvp(hgcmd, (char **)argv) < 0) |
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128 abortmsg("failed to exec cmdserver (errno = %d)", errno); |
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129 } |
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130 |
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131 /* |
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132 * Sleep until lock file is deleted, i.e. cmdserver process starts listening. |
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133 * If pid is given, it also checks if the child process fails to start. |
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134 */ |
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135 static void waitcmdserver(const struct cmdserveropts *opts, pid_t pid) |
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136 { |
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137 static const struct timespec sleepreq = {0, 10 * 1000000}; |
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138 int pst = 0; |
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139 |
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140 for (unsigned int i = 0; i < 10 * 100; i++) { |
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141 int r; |
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142 struct stat lst; |
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143 |
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144 r = lstat(opts->lockfile, &lst); |
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145 if (r < 0 && errno == ENOENT) |
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146 return; /* lock file deleted by server */ |
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147 if (r < 0) |
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148 goto cleanup; |
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149 |
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150 if (pid > 0) { |
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151 /* collect zombie if child process fails to start */ |
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152 r = waitpid(pid, &pst, WNOHANG); |
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153 if (r != 0) |
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154 goto cleanup; |
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155 } |
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156 |
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157 nanosleep(&sleepreq, NULL); |
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158 } |
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159 |
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160 abortmsg("timed out waiting for cmdserver %s", opts->lockfile); |
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161 return; |
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162 |
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163 cleanup: |
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164 if (pid > 0) |
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165 /* lockfile should be made by this process */ |
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166 unlink(opts->lockfile); |
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167 if (WIFEXITED(pst)) { |
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168 abortmsg("cmdserver exited with status %d", WEXITSTATUS(pst)); |
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169 } else if (WIFSIGNALED(pst)) { |
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170 abortmsg("cmdserver killed by signal %d", WTERMSIG(pst)); |
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171 } else { |
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172 abortmsg("error white waiting cmdserver"); |
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173 } |
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174 } |
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175 |
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176 /* Spawn new background cmdserver */ |
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177 static void startcmdserver(const struct cmdserveropts *opts) |
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178 { |
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179 debugmsg("start cmdserver at %s", opts->sockname); |
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180 |
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181 if (lockcmdserver(opts) < 0) { |
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182 debugmsg("lock file exists, waiting..."); |
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183 waitcmdserver(opts, 0); |
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184 return; |
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185 } |
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186 |
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187 /* remove dead cmdserver socket if any */ |
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188 unlink(opts->sockname); |
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189 |
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190 pid_t pid = fork(); |
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191 if (pid < 0) |
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192 abortmsg("failed to fork cmdserver process"); |
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193 if (pid == 0) { |
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194 /* bypass uisetup() of pager extension */ |
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195 int nullfd = open("/dev/null", O_WRONLY); |
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196 if (nullfd >= 0) { |
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197 dup2(nullfd, fileno(stdout)); |
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198 close(nullfd); |
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199 } |
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200 execcmdserver(opts); |
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201 } else { |
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202 waitcmdserver(opts, pid); |
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203 } |
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204 } |
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205 |
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206 static void killcmdserver(const struct cmdserveropts *opts, int sig) |
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207 { |
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208 FILE *fp = fopen(opts->pidfile, "r"); |
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209 if (!fp) |
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210 abortmsg("cannot open %s (errno = %d)", opts->pidfile, errno); |
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211 int pid = 0; |
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212 int n = fscanf(fp, "%d", &pid); |
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213 fclose(fp); |
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214 if (n != 1 || pid <= 0) |
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215 abortmsg("cannot read pid from %s", opts->pidfile); |
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216 |
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217 if (kill((pid_t)pid, sig) < 0) { |
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218 if (errno == ESRCH) |
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219 return; |
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220 abortmsg("cannot kill %d (errno = %d)", pid, errno); |
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221 } |
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222 } |
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223 |
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224 static pid_t peerpid = 0; |
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225 |
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226 static void forwardsignal(int sig) |
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227 { |
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228 assert(peerpid > 0); |
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229 if (kill(peerpid, sig) < 0) |
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230 abortmsg("cannot kill %d (errno = %d)", peerpid, errno); |
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231 debugmsg("forward signal %d", sig); |
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232 } |
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233 |
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234 static void setupsignalhandler(pid_t pid) |
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235 { |
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236 if (pid <= 0) |
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237 return; |
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238 peerpid = pid; |
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239 |
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240 struct sigaction sa; |
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241 memset(&sa, 0, sizeof(sa)); |
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242 sa.sa_handler = forwardsignal; |
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243 sa.sa_flags = SA_RESTART; |
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244 |
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245 sigaction(SIGHUP, &sa, NULL); |
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246 sigaction(SIGINT, &sa, NULL); |
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247 |
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248 /* terminate frontend by double SIGTERM in case of server freeze */ |
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249 sa.sa_flags |= SA_RESETHAND; |
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250 sigaction(SIGTERM, &sa, NULL); |
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251 } |
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252 |
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253 /* This implementation is based on hgext/pager.py (pre 369741ef7253) */ |
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254 static void setuppager(hgclient_t *hgc, const char *const args[], |
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255 size_t argsize) |
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256 { |
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257 const char *pagercmd = hgc_getpager(hgc, args, argsize); |
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258 if (!pagercmd) |
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259 return; |
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260 |
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261 int pipefds[2]; |
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262 if (pipe(pipefds) < 0) |
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263 return; |
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264 pid_t pid = fork(); |
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265 if (pid < 0) |
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266 goto error; |
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267 if (pid == 0) { |
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268 close(pipefds[0]); |
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269 if (dup2(pipefds[1], fileno(stdout)) < 0) |
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270 goto error; |
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271 if (isatty(fileno(stderr))) { |
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272 if (dup2(pipefds[1], fileno(stderr)) < 0) |
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273 goto error; |
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274 } |
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275 close(pipefds[1]); |
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276 hgc_attachio(hgc); /* reattach to pager */ |
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277 return; |
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278 } else { |
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279 dup2(pipefds[0], fileno(stdin)); |
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280 close(pipefds[0]); |
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281 close(pipefds[1]); |
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282 |
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283 int r = execlp("/bin/sh", "/bin/sh", "-c", pagercmd, NULL); |
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284 if (r < 0) { |
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285 abortmsg("cannot start pager '%s' (errno = %d)", |
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286 pagercmd, errno); |
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287 } |
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288 return; |
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289 } |
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290 |
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291 error: |
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292 close(pipefds[0]); |
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293 close(pipefds[1]); |
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294 abortmsg("failed to prepare pager (errno = %d)", errno); |
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295 } |
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296 |
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297 int main(int argc, const char *argv[], const char *envp[]) |
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298 { |
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299 if (getenv("CHGDEBUG")) |
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300 enabledebugmsg(); |
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301 |
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302 struct cmdserveropts opts; |
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303 setcmdserveropts(&opts); |
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304 |
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305 if (argc == 2) { |
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306 int sig = 0; |
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307 if (strcmp(argv[1], "--kill-chg-daemon") == 0) |
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308 sig = SIGTERM; |
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309 if (strcmp(argv[1], "--reload-chg-daemon") == 0) |
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310 sig = SIGHUP; |
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311 if (sig > 0) { |
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312 killcmdserver(&opts, sig); |
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313 return 0; |
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314 } |
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315 } |
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316 |
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317 hgclient_t *hgc = hgc_open(opts.sockname); |
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318 if (!hgc) { |
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319 startcmdserver(&opts); |
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320 hgc = hgc_open(opts.sockname); |
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321 } |
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322 if (!hgc) |
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323 abortmsg("cannot open hg client"); |
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324 |
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325 setupsignalhandler(hgc_peerpid(hgc)); |
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326 hgc_setenv(hgc, envp); |
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327 setuppager(hgc, argv + 1, argc - 1); |
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328 int exitcode = hgc_runcommand(hgc, argv + 1, argc - 1); |
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329 hgc_close(hgc); |
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330 return exitcode; |
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331 } |