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         if (ref $config{ENV} eq 'HASH') {
  63                 foreach my $key (keys %{$config{ENV}}) {
  64                         my $val=$config{ENV}{$key};
  65                         utf8::encode($val) if utf8::is_utf8($val);
  66                         $val =~ s/([^A-Za-z0-9])/sprintf '""\\x%02x""', ord($1)/ge;
  67                         $envsave.=<<"EOF";
  68         addenv("$key", "$val");
  69 EOF
  70                 }
  71                 delete $config{ENV};
  72         }
  73
  74         my @wrapper_hooks;
  75         run_hooks(genwrapper => sub { push @wrapper_hooks, shift->() });
  76
  77         my $check_commit_hook="";
  78         my $pre_exec="";
  79         if ($config{post_commit}) {
  80                 # Optimise checking !commit_hook_enabled() ,
  81                 # so that ikiwiki does not have to be started if the
  82                 # hook is disabled.
  83                 #
  84                 # Note that perl's flock may be implemented using fcntl
  85                 # or lockf on some systems. If so, and if there is no
  86                 # interop between the locking systems, the true C flock will
  87                 # always succeed, and this optimisation won't work.
  88                 # The perl code will later correctly check the lock,
  89                 # so the right thing will still happen, though without
  90                 # the benefit of this optimisation.
  91                 $check_commit_hook=<<"EOF";
  92         {
  93                 int fd=open("$config{wikistatedir}/commitlock", O_CREAT | O_RDWR, 0666);
  94                 if (fd != -1) {
  95                         if (flock(fd, LOCK_SH | LOCK_NB) != 0)
  96                                 exit(0);
  97                         close(fd);
  98                 }
  99         }
 100 EOF
 101         }
 102         elsif ($config{cgi}) {
 103                 # Avoid more than one ikiwiki cgi running at a time by
 104                 # taking a cgi lock. Since ikiwiki uses several MB of
 105                 # memory, a pile up of processes could cause thrashing
 106                 # otherwise. The fd of the lock is stored in
 107                 # IKIWIKI_CGILOCK_FD so unlockwiki can close it.
 108                 #
 109                 # A lot of cgi wrapper processes can potentially build
 110                 # up and clog an otherwise unloaded web server. To
 111                 # partially avoid this, when a GET comes in and the lock
 112                 # is already held, rather than blocking a html page is
 113                 # constructed that retries. This is enabled by setting
 114                 # cgi_overload_delay.
 115                 if (defined $config{cgi_overload_delay} &&
 116                     $config{cgi_overload_delay} =~/^[0-9]+/) {
 117                         my $i=int($config{cgi_overload_delay});
 118                         $pre_exec.="#define CGI_OVERLOAD_DELAY $i\n"
 119                                 if $i > 0;
 120                         my $msg=gettext("Please wait");
 121                         $msg=~s/"/\\"/g;
 122                         $pre_exec.='#define CGI_PLEASE_WAIT_TITLE "'.$msg."\"\n";
 123                         if (defined $config{cgi_overload_message} && length $config{cgi_overload_message}) {
 124                                 $msg=$config{cgi_overload_message};
 125                                 $msg=~s/"/\\"/g;
 126                         }
 127                         $pre_exec.='#define CGI_PLEASE_WAIT_BODY "'.$msg."\"\n";
 128                 }
 129                 $pre_exec.=<<"EOF";
 130         lockfd=open("$config{wikistatedir}/cgilock", O_CREAT | O_RDWR, 0666);
 131         if (lockfd != -1) {
 132 #ifdef CGI_OVERLOAD_DELAY
 133                 char *request_method = getenv("REQUEST_METHOD");
 134                 if (request_method && strcmp(request_method, "GET") == 0) {
 135                         if (lockf(lockfd, F_TLOCK, 0) == 0) {
 136                                 set_cgilock_fd(lockfd);
 137                         }
 138                         else {
 139                                 printf("Content-Type: text/html\\nRefresh: %i; URL=%s\\n\\n<html><head><title>%s</title><head><body><p>%s</p></body></html>",
 140                                         CGI_OVERLOAD_DELAY,
 141                                         getenv("REQUEST_URI"),
 142                                         CGI_PLEASE_WAIT_TITLE,
 143                                         CGI_PLEASE_WAIT_BODY);
 144                                 exit(0);
 145                         }
 146                 }
 147                 else if (lockf(lockfd, F_LOCK, 0) == 0) {
 148                         set_cgilock_fd(lockfd);
 149                 }
 150 #else
 151                 if (lockf(lockfd, F_LOCK, 0) == 0) {
 152                         set_cgilock_fd(lockfd);
 153                 }
 154 #endif
 155         }
 156 EOF
 157         }
 158
 159         my $set_background_command='';
 160         if (defined $config{wrapper_background_command} &&
 161             length $config{wrapper_background_command}) {
 162                 my $background_command=delete $config{wrapper_background_command};
 163                 $background_command=~s/"/\\"/g;
 164                 $set_background_command='#define BACKGROUND_COMMAND "'.$background_command.'"';
 165         }
 166
 167         $Data::Dumper::Indent=0; # no newlines
 168         my $configstring=Data::Dumper->Dump([\%config], ['*config']);
 169         $configstring=~s/\\/\\\\/g;
 170         $configstring=~s/"/\\"/g;
 171         $configstring=~s/\n/\\n/g;
 172
 173         writefile(basename("$wrapper.c"), dirname($wrapper), <<"EOF");
 174 /* A wrapper for ikiwiki, can be safely made suid. */
 175 #include <stdio.h>
 176 #include <sys/types.h>
 177 #include <sys/stat.h>
 178 #include <fcntl.h>
 179 #include <unistd.h>
 180 #include <stdlib.h>
 181 #include <string.h>
 182 #include <sys/file.h>
 183
 184 extern char **environ;
 185 int newenvironlen=0;
 186 /* Array of length newenvironlen+1 (+1 for NULL) */
 187 char **newenviron=NULL;
 188
 189 void addenv(char *var, char *val) {
 190         char *s;
 191
 192         if (newenviron) {
 193                 newenviron=realloc(newenviron, (newenvironlen+2) * sizeof(char *));
 194         }
 195         else {
 196                 newenviron=calloc(newenvironlen+2, sizeof(char *));
 197         }
 198
 199         if (!newenviron) {
 200                 perror("realloc");
 201                 exit(1);
 202         }
 203
 204         s=malloc(strlen(var)+1+strlen(val)+1);
 205         if (!s) {
 206                 perror("malloc");
 207                 exit(1);
 208         }
 209         else {
 210                 sprintf(s, "%s=%s", var, val);
 211                 newenviron[newenvironlen++]=s;
 212         }
 213 }
 214
 215 void set_cgilock_fd (int lockfd) {
 216         char fd_s[12];
 217         sprintf(fd_s, "%i", lockfd);
 218         if (setenv("IKIWIKI_CGILOCK_FD", fd_s, 1) != 0) {
 219                 perror("setenv");
 220                 exit(1);
 221         }
 222 }
 223
 224 int main (int argc, char **argv) {
 225         int lockfd=-1;
 226         char *s;
 227
 228 $check_commit_hook
 229 @wrapper_hooks
 230 $envsave
 231         addenv("HOME", "$ENV{HOME}");
 232         addenv("PATH", "$ENV{PATH}");
 233         addenv("WRAPPED_OPTIONS", "$configstring");
 234
 235 #ifdef __TINYC__
 236         /* old tcc versions do not support modifying environ directly */
 237         if (clearenv() != 0) {
 238                 perror("clearenv");
 239                 exit(1);
 240         }
 241         for (; newenvironlen>0; newenvironlen--)
 242                 putenv(newenviron[newenvironlen-1]);
 243 #else
 244         newenviron[newenvironlen]=NULL;
 245         environ=newenviron;
 246 #endif
 247
 248         if (setregid(getegid(), -1) != 0 &&
 249             setregid(getegid(), -1) != 0) {
 250                 perror("failed to drop real gid");
 251                 exit(1);
 252         }
 253         if (setreuid(geteuid(), -1) != 0 &&
 254             setreuid(geteuid(), -1) != 0) {
 255                 perror("failed to drop real uid");
 256                 exit(1);
 257         }
 258
 259 $pre_exec
 260
 261 $set_background_command
 262 #ifdef BACKGROUND_COMMAND
 263         if (lockfd != -1) {
 264                 close(lockfd);
 265         }
 266
 267         pid_t pid=fork();
 268         if (pid == -1) {
 269                 perror("fork");
 270                 exit(1);
 271         }
 272         else if (pid == 0) {
 273                 execl("$this", "$this", NULL);
 274                 perror("exec $this");
 275                 exit(1);
 276         }
 277         else {
 278                 waitpid(pid, NULL, 0);
 279
 280                 if (daemon(1, 0) == 0) {
 281                         system(BACKGROUND_COMMAND);
 282                         exit(0);
 283                 }
 284                 else {
 285                         perror("daemon");
 286                         exit(1);
 287                 }
 288         }
 289 #else
 290         execl("$this", "$this", NULL);
 291         perror("exec $this");
 292         exit(1);
 293 #endif
 294 }
 295 EOF
 296
 297         my @cc=exists $ENV{CC} ? possibly_foolish_untaint($ENV{CC}) : 'cc';
 298         push @cc, split(' ', possibly_foolish_untaint($ENV{CFLAGS})) if exists $ENV{CFLAGS};
 299         if (system(@cc, "$wrapper.c", "-o", "$wrapper.new") != 0) {
 300                 #translators: The parameter is a C filename.
 301                 error(sprintf(gettext("failed to compile %s"), "$wrapper.c"));
 302         }
 303         unlink("$wrapper.c");
 304         if (defined $config{wrappergroup}) {
 305                 my $gid=(getgrnam($config{wrappergroup}))[2];
 306                 if (! defined $gid) {
 307                         error(sprintf("bad wrappergroup"));
 308                 }
 309                 if (! chown(-1, $gid, "$wrapper.new")) {
 310                         error("chown $wrapper.new: $!");
 311                 }
 312         }
 313         if (defined $config{wrappermode} &&
 314             ! chmod(oct($config{wrappermode}), "$wrapper.new")) {
 315                 error("chmod $wrapper.new: $!");
 316         }
 317         if (! rename("$wrapper.new", $wrapper)) {
 318                 error("rename $wrapper.new $wrapper: $!");
 319         }
 320         #translators: The parameter is a filename.
 321         debug(sprintf(gettext("successfully generated %s"), $wrapper));
 322 }
 323
 324 1