this repo has no description
Add `exec` subcommand to `darling` executable
This subcommand allows you to execute a binary directly, without the
need for a shell.
authored by
Ariel Abreu
and committed by
Thomas A
b926434f
ad4e30fe
+149
-53
+23
-3
src/shellspawn/shellspawn.c
+23
-3
src/shellspawn/shellspawn.c
···
48
48
49
49
int main(int argc, const char** argv)
50
50
{
51
-
setupSigchild();
51
+
// in order to read the exit status of the process,
52
+
// we have to allow it to become a zombie, which is prevented
53
+
// when we set the SIGCHLD signal to SA_NOCLDWAIT
54
+
//setupSigchild();
52
55
setupSocket();
53
56
listenForConnections();
54
57
···
133
136
argv = (char**) malloc(sizeof(char*) * 3);
134
137
argv[0] = "/bin/bash";
135
138
argv[1] = "--login";
139
+
140
+
char* alloc_exec = NULL;
136
141
137
142
// Read commands from client
138
143
while (read_cmds)
···
238
243
239
244
break;
240
245
}
246
+
case SHELLSPAWN_SETEXEC:
247
+
{
248
+
argc = 0;
249
+
argv = realloc(argv, 0);
250
+
alloc_exec = param;
251
+
if (DBG) printf("setexec: %s\n", param);
252
+
break;
253
+
}
241
254
}
242
255
}
243
256
···
270
283
271
284
// In future, we may support spawning something else than Bash
272
285
// and check the provided shell against /etc/shells
273
-
execv("/bin/bash", argv);
286
+
execv(alloc_exec ? alloc_exec : "/bin/bash", argv);
274
287
275
288
rv = errno;
276
289
write(pipefd[1], &rv, sizeof(rv));
277
290
close(pipefd[1]);
278
291
279
292
exit(EXIT_FAILURE);
293
+
}
294
+
295
+
if (alloc_exec)
296
+
{
297
+
free(alloc_exec);
298
+
alloc_exec = NULL;
280
299
}
281
300
282
301
// Check that exec succeeded
···
379
398
380
399
// Reap the child
381
400
int wstatus;
382
-
waitpid(shell_pid, &wstatus, WEXITED);
401
+
if (waitpid(shell_pid, &wstatus, 0) != shell_pid)
402
+
perror("waitpid");
383
403
wstatus = WEXITSTATUS(wstatus);
384
404
385
405
// Report exit code back to the client
+2
-1
src/shellspawn/shellspawn.h
+2
-1
src/shellspawn/shellspawn.h
···
32
32
SHELLSPAWN_ADDARG = 1, // add shell argument
33
33
SHELLSPAWN_SETENV, // add env variable string
34
34
SHELLSPAWN_CHDIR,
35
-
SHELLSPAWN_GO, // execute the shell now, must also contain file descriptors
35
+
SHELLSPAWN_GO, // execute the shell/executable now, must also contain file descriptors
36
36
SHELLSPAWN_SIGNAL, // pass a signal from client
37
37
SHELLSPAWN_SETUIDGID, // set virtual uid and gid
38
+
SHELLSPAWN_SETEXEC, // set the executable to spawn (instead of a shell). must be given before any ADDARG commands.
38
39
};
39
40
40
41
struct __attribute__((packed)) shellspawn_cmd
+117
-49
src/startup/darling.c
+117
-49
src/startup/darling.c
···
1
1
/*
2
2
This file is part of Darling.
3
3
4
-
Copyright (C) 2016-2020 Lubos Dolezel
4
+
Copyright (C) 2016-2023 Lubos Dolezel
5
5
6
6
Darling is free software: you can redistribute it and/or modify
7
7
it under the terms of the GNU General Public License as published by
···
202
202
}
203
203
else
204
204
{
205
+
bool doExec = strcmp(argv[1], "exec") == 0;
206
+
int argvIndex = doExec ? 2 : 1;
207
+
208
+
if (doExec && argc <= 2)
209
+
{
210
+
printf("'exec' subcommand requires a binary to execute.\n");
211
+
return 1;
212
+
}
213
+
205
214
char *fullPath;
206
-
char *path = realpath(argv[1], NULL);
215
+
char *path = realpath(argv[argvIndex], NULL);
207
216
208
217
if (path == NULL)
209
218
{
210
-
printf("'%s' is not a supported command or a file.\n", argv[1]);
219
+
printf("'%s' is not a supported command or a file.\n", argv[argvIndex]);
211
220
return 1;
212
221
}
213
222
···
216
225
strcat(fullPath, path);
217
226
free(path);
218
227
219
-
argv[1] = fullPath;
220
-
spawnShell((const char**) &argv[1]);
228
+
argv[argvIndex] = fullPath;
229
+
230
+
if (doExec)
231
+
spawnBinary(argv[argvIndex], (const char**) &argv[argvIndex]);
232
+
else
233
+
spawnShell((const char**) &argv[argvIndex]);
221
234
}
222
235
223
236
return 0;
···
532
545
return len;
533
546
}
534
547
535
-
void spawnShell(const char** argv)
548
+
int connectToShellspawn(void)
536
549
{
537
-
size_t total_len = 0;
538
-
int count;
539
-
char buffer2[4096];
540
-
int sockfd;
541
550
struct sockaddr_un addr;
542
-
char* buffer;
543
-
544
-
if (argv != NULL)
545
-
{
546
-
for (count = 0; argv[count] != NULL; count++)
547
-
total_len += escapeQuotes(NULL, argv[count]);
548
-
549
-
buffer = malloc(total_len + count*3);
550
-
551
-
char *to = buffer;
552
-
for (int i = 0; argv[i] != NULL; i++)
553
-
{
554
-
if (to != buffer)
555
-
to = stpcpy(to, " ");
556
-
to = stpcpy(to, "'");
557
-
to += escapeQuotes(to, argv[i]);
558
-
to = stpcpy(to, "'");
559
-
}
560
-
}
561
-
else
562
-
buffer = NULL;
551
+
int sockfd;
563
552
564
553
// Connect to the shellspawn daemon in the container
565
554
addr.sun_family = AF_UNIX;
···
585
574
exit(1);
586
575
}
587
576
577
+
return sockfd;
578
+
}
579
+
580
+
void setupShellspawnEnv(int sockfd)
581
+
{
582
+
char buffer2[4096];
583
+
588
584
// Push environment variables
589
585
pushShellspawnCommand(sockfd, SHELLSPAWN_SETENV,
590
586
"PATH=/usr/bin:"
···
610
606
611
607
snprintf(buffer2, sizeof(buffer2), "HOME=/Users/%s", login);
612
608
pushShellspawnCommand(sockfd, SHELLSPAWN_SETENV, buffer2);
609
+
}
613
610
614
-
// Push shell arguments
615
-
if (buffer != NULL)
616
-
{
617
-
pushShellspawnCommand(sockfd, SHELLSPAWN_ADDARG, "-c");
618
-
pushShellspawnCommand(sockfd, SHELLSPAWN_ADDARG, buffer);
619
-
620
-
free(buffer);
621
-
}
622
-
611
+
void setupWorkingDir(int sockfd)
612
+
{
613
+
char buffer2[4096];
623
614
snprintf(buffer2, sizeof(buffer2), SYSTEM_ROOT "%s", g_workingDirectory);
624
615
pushShellspawnCommand(sockfd, SHELLSPAWN_CHDIR, buffer2);
616
+
}
625
617
618
+
void setupIDs(int sockfd)
619
+
{
626
620
int ids[2] = { g_originalUid, g_originalGid };
627
621
pushShellspawnCommandData(sockfd, SHELLSPAWN_SETUIDGID, ids, sizeof(ids));
622
+
}
628
623
629
-
int fds[3], master = -1;
630
-
624
+
void setupFDs(int fds[3], int* master)
625
+
{
626
+
*master = -1;
627
+
631
628
if (isatty(STDIN_FILENO))
632
-
setupPtys(fds, &master);
629
+
setupPtys(fds, master);
633
630
else
634
-
fds[0] = dup(STDIN_FILENO); // dup() because we close() a few lines below
631
+
fds[0] = dup(STDIN_FILENO); // dup() because we close() after spawning
635
632
636
-
if (master == -1 || !isatty(STDOUT_FILENO))
633
+
if (*master == -1 || !isatty(STDOUT_FILENO))
637
634
fds[1] = STDOUT_FILENO;
638
-
if (master == -1 || !isatty(STDERR_FILENO))
635
+
if (*master == -1 || !isatty(STDERR_FILENO))
639
636
fds[2] = STDERR_FILENO;
637
+
}
640
638
639
+
void spawnGo(int sockfd, int fds[3], int master)
640
+
{
641
641
pushShellspawnCommandFDs(sockfd, SHELLSPAWN_GO, fds);
642
642
close(fds[0]);
643
643
···
648
648
close(sockfd);
649
649
}
650
650
651
+
void spawnShell(const char** argv)
652
+
{
653
+
size_t total_len = 0;
654
+
int count;
655
+
int sockfd;
656
+
char* buffer;
657
+
int fds[3], master;
658
+
659
+
if (argv != NULL)
660
+
{
661
+
for (count = 0; argv[count] != NULL; count++)
662
+
total_len += escapeQuotes(NULL, argv[count]);
663
+
664
+
buffer = malloc(total_len + count*3);
665
+
666
+
char *to = buffer;
667
+
for (int i = 0; argv[i] != NULL; i++)
668
+
{
669
+
if (to != buffer)
670
+
to = stpcpy(to, " ");
671
+
to = stpcpy(to, "'");
672
+
to += escapeQuotes(to, argv[i]);
673
+
to = stpcpy(to, "'");
674
+
}
675
+
}
676
+
else
677
+
buffer = NULL;
678
+
679
+
sockfd = connectToShellspawn();
680
+
681
+
setupShellspawnEnv(sockfd);
682
+
683
+
// Push shell arguments
684
+
if (buffer != NULL)
685
+
{
686
+
pushShellspawnCommand(sockfd, SHELLSPAWN_ADDARG, "-c");
687
+
pushShellspawnCommand(sockfd, SHELLSPAWN_ADDARG, buffer);
688
+
689
+
free(buffer);
690
+
}
691
+
692
+
setupWorkingDir(sockfd);
693
+
setupIDs(sockfd);
694
+
setupFDs(fds, &master);
695
+
spawnGo(sockfd, fds, master);
696
+
}
697
+
698
+
void spawnBinary(const char* binary, const char** argv)
699
+
{
700
+
int fds[3], master;
701
+
int sockfd;
702
+
703
+
sockfd = connectToShellspawn();
704
+
setupShellspawnEnv(sockfd);
705
+
706
+
pushShellspawnCommand(sockfd, SHELLSPAWN_SETEXEC, binary);
707
+
708
+
for (; *argv != NULL; ++argv)
709
+
pushShellspawnCommand(sockfd, SHELLSPAWN_ADDARG, *argv);
710
+
711
+
setupWorkingDir(sockfd);
712
+
setupIDs(sockfd);
713
+
setupFDs(fds, &master);
714
+
spawnGo(sockfd, fds, master);
715
+
}
716
+
651
717
void showHelp(const char* argv0)
652
718
{
653
719
fprintf(stderr, "This is Darling, translation layer for macOS software.\n\n");
654
-
fprintf(stderr, "Copyright (C) 2012-2020 Lubos Dolezel\n\n");
720
+
fprintf(stderr, "Copyright (C) 2012-2023 Lubos Dolezel\n\n");
655
721
656
722
fprintf(stderr, "Usage:\n");
657
-
fprintf(stderr, "\t%s program-path [arguments...]\n", argv0);
723
+
fprintf(stderr, "\t%s <program-path> [arguments...]\n", argv0);
658
724
fprintf(stderr, "\t%s shell [arguments...]\n", argv0);
725
+
fprintf(stderr, "\t%s exec <program-path> [arguments...]\n", argv0);
726
+
fprintf(stderr, "\t%s shutdown\n", argv0);
659
727
fprintf(stderr, "\n");
660
728
fprintf(stderr, "Environment variables:\n"
661
729
"DPREFIX - specifies the location of Darling prefix, defaults to ~/.darling\n");
···
663
731
664
732
void showVersion(const char* argv0) {
665
733
fprintf(stderr, "%s " GIT_BRANCH " @ " GIT_COMMIT_HASH "\n", argv0);
666
-
fprintf(stderr, "Copyright (C) 2012-2020 Lubos Dolezel\n");
734
+
fprintf(stderr, "Copyright (C) 2012-2023 Lubos Dolezel\n");
667
735
}
668
736
669
737
void missingSetuidRoot(void)
+7
src/startup/darling.h
+7
src/startup/darling.h
···
40
40
// Creates the given directory, exit()ing if not possible
41
41
void createDir(const char* path);
42
42
43
+
int connectToShellspawn(void);
44
+
void setupShellspawnEnv(int shellspawnFD);
45
+
void setupWorkingDir(int shellspawnFD);
46
+
void setupIDs(int shellspawnFD);
47
+
void setupFDs(int fds[3], int* master);
48
+
void spawnGo(int shellspawnFD, int fds[3], int master);
43
49
void spawnShell(const char** argv);
50
+
void spawnBinary(const char* binary, const char** argv);
44
51
45
52
// Set up some environment variables
46
53
// As well as the working directory