IkiWiki/Wrapper.pm

   1 #!/usr/bin/perl
   2
   3 package IkiWiki;
   4
   5 use warnings;
   6 use strict;
   7 use File::Spec;
   8 use Data::Dumper;
   9 use IkiWiki;
  10
  11 sub gen_wrappers () {
  12         debug(gettext("generating wrappers.."));
  13         my %origconfig=(%config);
  14         foreach my $wrapper (@{$config{wrappers}}) {
  15                 %config=(%origconfig, %{$wrapper});
  16                 $config{verbose}=$config{setupverbose}
  17                         if exists $config{setupverbose};
  18                 $config{syslog}=$config{setupsyslog}
  19                         if exists $config{setupsyslog};
  20                 delete @config{qw(setupsyslog setupverbose wrappers genwrappers rebuild)};
  21                 checkconfig();
  22                 if (! $config{cgi} && ! $config{post_commit} &&
  23                     ! $config{test_receive}) {
  24                         $config{post_commit}=1;
  25                 }
  26                 gen_wrapper();
  27         }
  28         %config=(%origconfig);
  29 }
  30
  31 sub gen_wrapper () {
  32         $config{srcdir}=File::Spec->rel2abs($config{srcdir});
  33         $config{destdir}=File::Spec->rel2abs($config{destdir});
  34         my $this=File::Spec->rel2abs($0);
  35         if (! -x $this) {
  36                 error(sprintf(gettext("%s doesn't seem to be executable"), $this));
  37         }
  38
  39         if ($config{setup}) {
  40                 error(gettext("cannot create a wrapper that uses a setup file"));
  41         }
  42         my $wrapper=possibly_foolish_untaint($config{wrapper});
  43         if (! defined $wrapper || ! length $wrapper) {
  44                 error(gettext("wrapper filename not specified"));
  45         }
  46         delete $config{wrapper};
  47
  48         my @envsave;
  49         push @envsave, qw{REMOTE_ADDR QUERY_STRING REQUEST_METHOD REQUEST_URI
  50                        CONTENT_TYPE CONTENT_LENGTH GATEWAY_INTERFACE
  51                        HTTP_COOKIE REMOTE_USER HTTPS REDIRECT_STATUS
  52                        HTTP_HOST SERVER_PORT HTTPS HTTP_ACCEPT
  53                        REDIRECT_URL} if $config{cgi};
  54         my $envsave="";
  55         foreach my $var (@envsave) {
  56                 $envsave.=<<"EOF";
  57         if ((s=getenv("$var")))
  58                 addenv("$var", s);
  59 EOF
  60         }
  61
  62         my @wrapper_hooks;
  63         run_hooks(genwrapper => sub { push @wrapper_hooks, shift->() });
  64
  65         my $check_commit_hook="";
  66         my $pre_exec="";
  67         if ($config{post_commit}) {
  68                 # Optimise checking !commit_hook_enabled() ,
  69                 # so that ikiwiki does not have to be started if the
  70                 # hook is disabled.
  71                 #
  72                 # Note that perl's flock may be implemented using fcntl
  73                 # or lockf on some systems. If so, and if there is no
  74                 # interop between the locking systems, the true C flock will
  75                 # always succeed, and this optimisation won't work.
  76                 # The perl code will later correctly check the lock,
  77                 # so the right thing will still happen, though without
  78                 # the benefit of this optimisation.
  79                 $check_commit_hook=<<"EOF";
  80         {
  81                 int fd=open("$config{wikistatedir}/commitlock", O_CREAT | O_RDWR, 0666);
  82                 if (fd != -1) {
  83                         if (flock(fd, LOCK_SH | LOCK_NB) != 0)
  84                                 exit(0);
  85                         close(fd);
  86                 }
  87         }
  88 EOF
  89         }
  90         elsif ($config{cgi}) {
  91                 # Avoid more than one ikiwiki cgi running at a time by
  92                 # taking a cgi lock. Since ikiwiki uses several MB of
  93                 # memory, a pile up of processes could cause thrashing
  94                 # otherwise. The fd of the lock is stored in
  95                 # IKIWIKI_CGILOCK_FD so unlockwiki can close it.
  96                 #
  97                 # A lot of cgi wrapper processes can potentially build
  98                 # up and clog an otherwise unloaded web server. To
  99                 # partially avoid this, when a GET comes in and the lock
 100                 # is already held, rather than blocking a html page is
 101                 # constructed that retries. This is enabled by setting
 102                 # cgi_overload_delay.
 103                 if (defined $config{cgi_overload_delay} &&
 104                     $config{cgi_overload_delay} =~/^[0-9]+/) {
 105                         my $i=int($config{cgi_overload_delay});
 106                         $pre_exec.="#define CGI_OVERLOAD_DELAY $i\n"
 107                                 if $i > 0;
 108                         my $msg=gettext("Please wait");
 109                         $msg=~s/"/\\"/g;
 110                         $pre_exec.='#define CGI_PLEASE_WAIT_TITLE "'.$msg."\"\n";
 111                         if (defined $config{cgi_overload_message} && length $config{cgi_overload_message}) {
 112                                 $msg=$config{cgi_overload_message};
 113                                 $msg=~s/"/\\"/g;
 114                         }
 115                         $pre_exec.='#define CGI_PLEASE_WAIT_BODY "'.$msg."\"\n";
 116                 }
 117                 $pre_exec.=<<"EOF";
 118         lockfd=open("$config{wikistatedir}/cgilock", O_CREAT | O_RDWR, 0666);
 119         if (lockfd != -1) {
 120 #ifdef CGI_OVERLOAD_DELAY
 121                 char *request_method = getenv("REQUEST_METHOD");
 122                 if (request_method && strcmp(request_method, "GET") == 0) {
 123                         if (lockf(lockfd, F_TLOCK, 0) == 0) {
 124                                 set_cgilock_fd(lockfd);
 125                         }
 126                         else {
 127                                 printf("Content-Type: text/html\\nRefresh: %i; URL=%s\\n\\n<html><head><title>%s</title><head><body><p>%s</p></body></html>",
 128                                         CGI_OVERLOAD_DELAY,
 129                                         getenv("REQUEST_URI"),
 130                                         CGI_PLEASE_WAIT_TITLE,
 131                                         CGI_PLEASE_WAIT_BODY);
 132                                 exit(0);
 133                         }
 134                 }
 135                 else if (lockf(lockfd, F_LOCK, 0) == 0) {
 136                         set_cgilock_fd(lockfd);
 137                 }
 138 #else
 139                 if (lockf(lockfd, F_LOCK, 0) == 0) {
 140                         set_cgilock_fd(lockfd);
 141                 }
 142 #endif
 143         }
 144 EOF
 145         }
 146
 147         my $set_background_command='';
 148         if (defined $config{wrapper_background_command} &&
 149             length $config{wrapper_background_command}) {
 150                 my $background_command=delete $config{wrapper_background_command};
 151                 $set_background_command=~s/"/\\"/g;
 152                 $set_background_command='#define BACKGROUND_COMMAND "'.$background_command.'"';
 153         }
 154
 155         $Data::Dumper::Indent=0; # no newlines
 156         my $configstring=Data::Dumper->Dump([\%config], ['*config']);
 157         $configstring=~s/\\/\\\\/g;
 158         $configstring=~s/"/\\"/g;
 159         $configstring=~s/\n/\\n/g;
 160
 161         writefile(basename("$wrapper.c"), dirname($wrapper), <<"EOF");
 162 /* A wrapper for ikiwiki, can be safely made suid. */
 163 #include <stdio.h>
 164 #include <sys/types.h>
 165 #include <sys/stat.h>
 166 #include <fcntl.h>
 167 #include <unistd.h>
 168 #include <stdlib.h>
 169 #include <string.h>
 170 #include <sys/file.h>
 171
 172 extern char **environ;
 173 char *newenviron[$#envsave+7];
 174 int i=0;
 175
 176 void addenv(char *var, char *val) {
 177         char *s=malloc(strlen(var)+1+strlen(val)+1);
 178         if (!s)
 179                 perror("malloc");
 180         sprintf(s, "%s=%s", var, val);
 181         newenviron[i++]=s;
 182 }
 183
 184 set_cgilock_fd (int lockfd) {
 185         char *fd_s=malloc(8);
 186         sprintf(fd_s, "%i", lockfd);
 187         setenv("IKIWIKI_CGILOCK_FD", fd_s, 1);
 188 }
 189
 190 int main (int argc, char **argv) {
 191         int lockfd=-1;
 192         char *s;
 193
 194 $check_commit_hook
 195 @wrapper_hooks
 196 $envsave
 197         newenviron[i++]="HOME=$ENV{HOME}";
 198         newenviron[i++]="PATH=$ENV{PATH}";
 199         newenviron[i++]="WRAPPED_OPTIONS=$configstring";
 200
 201 #ifdef __TINYC__
 202         /* old tcc versions do not support modifying environ directly */
 203         if (clearenv() != 0) {
 204                 perror("clearenv");
 205                 exit(1);
 206         }
 207         for (; i>0; i--)
 208                 putenv(newenviron[i-1]);
 209 #else
 210         newenviron[i]=NULL;
 211         environ=newenviron;
 212 #endif
 213
 214         if (setregid(getegid(), -1) != 0 &&
 215             setregid(getegid(), -1) != 0) {
 216                 perror("failed to drop real gid");
 217                 exit(1);
 218         }
 219         if (setreuid(geteuid(), -1) != 0 &&
 220             setreuid(geteuid(), -1) != 0) {
 221                 perror("failed to drop real uid");
 222                 exit(1);
 223         }
 224
 225 $pre_exec
 226
 227 $set_background_command
 228 #ifdef BACKGROUND_COMMAND
 229         if (lockfd != -1) {
 230                 close(lockfd);
 231         }
 232
 233         pid_t pid=fork();
 234         if (pid == -1) {
 235                 perror("fork");
 236                 exit(1);
 237         }
 238         else if (pid == 0) {
 239                 execl("$this", "$this", NULL);
 240                 perror("exec $this");
 241                 exit(1);
 242         }
 243         else {
 244                 waitpid(pid, NULL, 0);
 245
 246                 if (daemon(1, 0) == 0) {
 247                         system(BACKGROUND_COMMAND);
 248                         exit(0);
 249                 }
 250                 else {
 251                         perror("daemon");
 252                         exit(1);
 253                 }
 254         }
 255 #else
 256         execl("$this", "$this", NULL);
 257         perror("exec $this");
 258         exit(1);
 259 #endif
 260 }
 261 EOF
 262
 263         my @cc=exists $ENV{CC} ? possibly_foolish_untaint($ENV{CC}) : 'cc';
 264         push @cc, split(' ', possibly_foolish_untaint($ENV{CFLAGS})) if exists $ENV{CFLAGS};
 265         if (system(@cc, "$wrapper.c", "-o", "$wrapper.new") != 0) {
 266                 #translators: The parameter is a C filename.
 267                 error(sprintf(gettext("failed to compile %s"), "$wrapper.c"));
 268         }
 269         unlink("$wrapper.c");
 270         if (defined $config{wrappergroup}) {
 271                 my $gid=(getgrnam($config{wrappergroup}))[2];
 272                 if (! defined $gid) {
 273                         error(sprintf("bad wrappergroup"));
 274                 }
 275                 if (! chown(-1, $gid, "$wrapper.new")) {
 276                         error("chown $wrapper.new: $!");
 277                 }
 278         }
 279         if (defined $config{wrappermode} &&
 280             ! chmod(oct($config{wrappermode}), "$wrapper.new")) {
 281                 error("chmod $wrapper.new: $!");
 282         }
 283         if (! rename("$wrapper.new", $wrapper)) {
 284                 error("rename $wrapper.new $wrapper: $!");
 285         }
 286         #translators: The parameter is a filename.
 287         debug(sprintf(gettext("successfully generated %s"), $wrapper));
 288 }
 289
 290 1