1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
// SPDX-License-Identifier: GPL-2.0-or-later
// SPDX-FileCopyrightText: 2021 Alyssa Ross <hi@alyssa.is>
#define _GNU_SOURCE
#include <argz.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdnoreturn.h>
#include <sysexits.h>
#include <unistd.h>
#include "config.h"
#include "exec.h"
#include "log.h"
noreturn static void ex_usage(void)
{
if (verbosity)
fprintf(stderr,
"Usage: %s [ -1 ] [ -q | -Q | -v ] cid port prog...\n",
program_invocation_short_name);
exit(EX_USAGE);
}
int main(int argc, char *argv[])
{
int opt;
bool alloc_failed = false;
size_t binder_opts_len = 0, daemon_opts_len = 0;
char *binder_opts = NULL, *daemon_opts = NULL;
// The heavy lifting here is done by vsockserver-socketbinder
// and vsockserverd. All this program does is munge argv
// appropriately to set the right options for each of those
// programs, and then exec into vsockserver-socketbinder.
// If allocation fails, we need to keep going until after
// we've parsed the arguments, so we know what our verbosity
// setting is, and consequently whether we should print an
// error message about the allocation failure.
alloc_failed |= argz_add(&binder_opts, &binder_opts_len,
BINDIR "/vsockserver-socketbinder")
|| argz_add(&daemon_opts, &daemon_opts_len,
BINDIR "/vsockserverd");
while ((opt = getopt(argc, argv, "+1qQv")) != -1) {
char *arg = NULL;
switch (opt) {
case '1':
case 'q':
case 'Q':
case 'v':
set_verbosity(opt);
alloc_failed |= asprintf(&arg, "-%c", opt) == -1
|| argz_add(&daemon_opts, &daemon_opts_len,
arg);
free(arg);
break;
default:
ex_usage();
}
}
// Now that verbosity is set, we can whether we were sitting
// on an allocation failure.
if (alloc_failed)
diee(EX_OSERR, "malloc");
// Now we don't have to keep checking alloc_failed before
// doing anything, and we can deal with allocation failures
// after this point by just terminating immediately.
// Check there are `cid' and `port' arguments to pass to
// vsockserver-socketbinder, and at least one `prog' argument
// to pass to vsockserverd.
if (optind > argc - 3)
ex_usage();
// Add `cid' and `port' arguments to binder options.
if (argz_add(&binder_opts, &binder_opts_len, "--")
|| argz_add(&binder_opts, &binder_opts_len, argv[optind++])
|| argz_add(&binder_opts, &binder_opts_len, argv[optind++]))
diee(EX_OSERR, "malloc");
// Add all of daemon_opts onto the end of binder_opts. It's
// okay to multiply to find the size because if it would
// overflow calloc would have failed earlier.
if (argz_append(&binder_opts, &binder_opts_len, daemon_opts,
daemon_opts_len))
diee(EX_OSERR, "malloc");
free(daemon_opts);
// Append `prog' to binder_opts. Technically this should be
// part of daemon_opts, but then we'd just be copying it into
// one place to immediately copy it elsewhere.
for (int i = optind; i < argc; i++)
if (argz_add(&binder_opts, &binder_opts_len, argv[i]))
diee(EX_OSERR, "malloc");
if (verbosity == all) {
char *opt = 0;
// Log the full argv before we exec it.
fprintf(stderr, "%s: executing", program_invocation_short_name);
while ((opt = argz_next(binder_opts, binder_opts_len, opt)))
fprintf(stderr, " %s", opt);
fputc('\n', stderr);
}
execzp(binder_opts, binder_opts, binder_opts_len);
diee(EX_OSERR, "execvp");
}
|