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 our $program_to_wrap = $0;
  32 sub gen_wrapper () {
  33         $config{srcdir}=File::Spec->rel2abs($config{srcdir});
  34         $config{destdir}=File::Spec->rel2abs($config{destdir});
  35         my $this=File::Spec->rel2abs($program_to_wrap);
  36         if (! -x $this) {
  37                 error(sprintf(gettext("%s doesn't seem to be executable"), $this));
  38         }
  39
  40         if ($config{setup}) {
  41                 error(gettext("cannot create a wrapper that uses a setup file"));
  42         }
  43         my $wrapper=possibly_foolish_untaint($config{wrapper});
  44         if (! defined $wrapper || ! length $wrapper) {
  45                 error(gettext("wrapper filename not specified"));
  46         }
  47         delete $config{wrapper};
  48
  49         my @envsave;
  50         push @envsave, qw{REMOTE_ADDR QUERY_STRING REQUEST_METHOD REQUEST_URI
  51                        CONTENT_TYPE CONTENT_LENGTH GATEWAY_INTERFACE
  52                        HTTP_COOKIE REMOTE_USER HTTPS REDIRECT_STATUS
  53                        HTTP_HOST SERVER_PORT HTTPS HTTP_ACCEPT
  54                        REDIRECT_URL} if $config{cgi};
  55         my $envsave="";
  56         foreach my $var (@envsave) {
  57                 $envsave.=<<"EOF";
  58         if ((s=getenv("$var")))
  59                 addenv("$var", s);
  60 EOF
  61         }
  62
  63         my @wrapper_hooks;
  64         run_hooks(genwrapper => sub { push @wrapper_hooks, shift->() });
  65
  66         my $check_commit_hook="";
  67         my $pre_exec="";
  68         if ($config{post_commit}) {
  69                 # Optimise checking !commit_hook_enabled() ,
  70                 # so that ikiwiki does not have to be started if the
  71                 # hook is disabled.
  72                 #
  73                 # Note that perl's flock may be implemented using fcntl
  74                 # or lockf on some systems. If so, and if there is no
  75                 # interop between the locking systems, the true C flock will
  76                 # always succeed, and this optimisation won't work.
  77                 # The perl code will later correctly check the lock,
  78                 # so the right thing will still happen, though without
  79                 # the benefit of this optimisation.
  80                 $check_commit_hook=<<"EOF";
  81         {
  82                 int fd=open("$config{wikistatedir}/commitlock", O_CREAT | O_RDWR, 0666);
  83                 if (fd != -1) {
  84                         if (flock(fd, LOCK_SH | LOCK_NB) != 0)
  85                                 exit(0);
  86                         close(fd);
  87                 }
  88         }
  89 EOF
  90         }
  91         elsif ($config{cgi}) {
  92                 # Avoid more than one ikiwiki cgi running at a time by
  93                 # taking a cgi lock. Since ikiwiki uses several MB of
  94                 # memory, a pile up of processes could cause thrashing
  95                 # otherwise. The fd of the lock is stored in
  96                 # IKIWIKI_CGILOCK_FD so unlockwiki can close it.
  97                 #
  98                 # A lot of cgi wrapper processes can potentially build
  99                 # up and clog an otherwise unloaded web server. To
 100                 # partially avoid this, when a GET comes in and the lock
 101                 # is already held, rather than blocking a html page is
 102                 # constructed that retries. This is enabled by setting
 103                 # cgi_overload_delay.
 104                 if (defined $config{cgi_overload_delay} &&
 105                     $config{cgi_overload_delay} =~/^[0-9]+/) {
 106                         my $i=int($config{cgi_overload_delay});
 107                         $pre_exec.="#define CGI_OVERLOAD_DELAY $i\n"
 108                                 if $i > 0;
 109                         my $msg=gettext("Please wait");
 110                         $msg=~s/"/\\"/g;
 111                         $pre_exec.='#define CGI_PLEASE_WAIT_TITLE "'.$msg."\"\n";
 112                         if (defined $config{cgi_overload_message} && length $config{cgi_overload_message}) {
 113                                 $msg=$config{cgi_overload_message};
 114                                 $msg=~s/"/\\"/g;
 115                         }
 116                         $pre_exec.='#define CGI_PLEASE_WAIT_BODY "'.$msg."\"\n";
 117                 }
 118                 $pre_exec.=<<"EOF";
 119         lockfd=open("$config{wikistatedir}/cgilock", O_CREAT | O_RDWR, 0666);
 120         if (lockfd != -1) {
 121 #ifdef CGI_OVERLOAD_DELAY
 122                 char *request_method = getenv("REQUEST_METHOD");
 123                 if (request_method && strcmp(request_method, "GET") == 0) {
 124                         if (lockf(lockfd, F_TLOCK, 0) == 0) {
 125                                 set_cgilock_fd(lockfd);
 126                         }
 127                         else {
 128                                 printf("Content-Type: text/html\\nRefresh: %i; URL=%s\\n\\n<html><head><title>%s</title><head><body><p>%s</p></body></html>",
 129                                         CGI_OVERLOAD_DELAY,
 130                                         getenv("REQUEST_URI"),
 131                                         CGI_PLEASE_WAIT_TITLE,
 132                                         CGI_PLEASE_WAIT_BODY);
 133                                 exit(0);
 134                         }
 135                 }
 136                 else if (lockf(lockfd, F_LOCK, 0) == 0) {
 137                         set_cgilock_fd(lockfd);
 138                 }
 139 #else
 140                 if (lockf(lockfd, F_LOCK, 0) == 0) {
 141                         set_cgilock_fd(lockfd);
 142                 }
 143 #endif
 144         }
 145 EOF
 146         }
 147
 148         my $set_background_command='';
 149         if (defined $config{wrapper_background_command} &&
 150             length $config{wrapper_background_command}) {
 151                 my $background_command=delete $config{wrapper_background_command};
 152                 $set_background_command=~s/"/\\"/g;
 153                 $set_background_command='#define BACKGROUND_COMMAND "'.$background_command.'"';
 154         }
 155
 156         $Data::Dumper::Indent=0; # no newlines
 157         my $configstring=Data::Dumper->Dump([\%config], ['*config']);
 158         $configstring=~s/\\/\\\\/g;
 159         $configstring=~s/"/\\"/g;
 160         $configstring=~s/\n/\\n/g;
 161
 162         writefile(basename("$wrapper.c"), dirname($wrapper), <<"EOF");
 163 /* A wrapper for ikiwiki, can be safely made suid. */
 164 #include <stdio.h>
 165 #include <sys/types.h>
 166 #include <sys/stat.h>
 167 #include <fcntl.h>
 168 #include <unistd.h>
 169 #include <stdlib.h>
 170 #include <string.h>
 171 #include <sys/file.h>
 172
 173 extern char **environ;
 174 char *newenviron[$#envsave+7];
 175 int i=0;
 176
 177 void addenv(char *var, char *val) {
 178         char *s=malloc(strlen(var)+1+strlen(val)+1);
 179         if (!s)
 180                 perror("malloc");
 181         sprintf(s, "%s=%s", var, val);
 182         newenviron[i++]=s;
 183 }
 184
 185 void set_cgilock_fd (int lockfd) {
 186         char *fd_s=malloc(8);
 187         sprintf(fd_s, "%i", lockfd);
 188         setenv("IKIWIKI_CGILOCK_FD", fd_s, 1);
 189 }
 190
 191 int main (int argc, char **argv) {
 192         int lockfd=-1;
 193         char *s;
 194
 195 $check_commit_hook
 196 @wrapper_hooks
 197 $envsave
 198         newenviron[i++]="HOME=$ENV{HOME}";
 199         newenviron[i++]="PATH=$ENV{PATH}";
 200         newenviron[i++]="WRAPPED_OPTIONS=$configstring";
 201
 202 #ifdef __TINYC__
 203         /* old tcc versions do not support modifying environ directly */
 204         if (clearenv() != 0) {
 205                 perror("clearenv");
 206                 exit(1);
 207         }
 208         for (; i>0; i--)
 209                 putenv(newenviron[i-1]);
 210 #else
 211         newenviron[i]=NULL;
 212         environ=newenviron;
 213 #endif
 214
 215         if (setregid(getegid(), -1) != 0 &&
 216             setregid(getegid(), -1) != 0) {
 217                 perror("failed to drop real gid");
 218                 exit(1);
 219         }
 220         if (setreuid(geteuid(), -1) != 0 &&
 221             setreuid(geteuid(), -1) != 0) {
 222                 perror("failed to drop real uid");
 223                 exit(1);
 224         }
 225
 226 $pre_exec
 227
 228 $set_background_command
 229 #ifdef BACKGROUND_COMMAND
 230         if (lockfd != -1) {
 231                 close(lockfd);
 232         }
 233
 234         pid_t pid=fork();
 235         if (pid == -1) {
 236                 perror("fork");
 237                 exit(1);
 238         }
 239         else if (pid == 0) {
 240                 execl("$this", "$this", NULL);
 241                 perror("exec $this");
 242                 exit(1);
 243         }
 244         else {
 245                 waitpid(pid, NULL, 0);
 246
 247                 if (daemon(1, 0) == 0) {
 248                         system(BACKGROUND_COMMAND);
 249                         exit(0);
 250                 }
 251                 else {
 252                         perror("daemon");
 253                         exit(1);
 254                 }
 255         }
 256 #else
 257         execl("$this", "$this", NULL);
 258         perror("exec $this");
 259         exit(1);
 260 #endif
 261 }
 262 EOF
 263
 264         my @cc=exists $ENV{CC} ? possibly_foolish_untaint($ENV{CC}) : 'cc';
 265         push @cc, split(' ', possibly_foolish_untaint($ENV{CFLAGS})) if exists $ENV{CFLAGS};
 266         if (system(@cc, "$wrapper.c", "-o", "$wrapper.new") != 0) {
 267                 #translators: The parameter is a C filename.
 268                 error(sprintf(gettext("failed to compile %s"), "$wrapper.c"));
 269         }
 270         unlink("$wrapper.c");
 271         if (defined $config{wrappergroup}) {
 272                 my $gid=(getgrnam($config{wrappergroup}))[2];
 273                 if (! defined $gid) {
 274                         error(sprintf("bad wrappergroup"));
 275                 }
 276                 if (! chown(-1, $gid, "$wrapper.new")) {
 277                         error("chown $wrapper.new: $!");
 278                 }
 279         }
 280         if (defined $config{wrappermode} &&
 281             ! chmod(oct($config{wrappermode}), "$wrapper.new")) {
 282                 error("chmod $wrapper.new: $!");
 283         }
 284         if (! rename("$wrapper.new", $wrapper)) {
 285                 error("rename $wrapper.new $wrapper: $!");
 286         }
 287         #translators: The parameter is a filename.
 288         debug(sprintf(gettext("successfully generated %s"), $wrapper));
 289 }
 290
 291 1