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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
--- ./backend/beh.c.orig 2023-01-24 19:38:24.000000000 -0600
+++ ./backend/beh.c 2023-05-19 13:08:27.724167656 -0500
@@ -22,12 +22,14 @@
#include "backend-private.h"
#include <cups/array.h>
#include <ctype.h>
+#include <sys/wait.h>
+
/*
* Local globals...
*/
-static int job_canceled = 0; /* Set to 1 on SIGTERM */
+static volatile int job_canceled = 0; /* Set to 1 on SIGTERM */
/*
* Local functions...
@@ -213,21 +215,44 @@
char **argv, /* I - Command-line arguments */
char *filename) { /* I - File name of input data */
const char *cups_serverbin; /* Location of programs */
+ char *backend_argv[8]; // Arguments for called CUPS backend
char scheme[1024], /* Scheme from URI */
*ptr, /* Pointer into scheme */
- cmdline[65536]; /* Backend command line */
- int retval;
+ backend_path[2048]; // Backend path
+ int pid,
+ wait_pid,
+ wait_status,
+ retval = 0;
+ int bytes;
+
/*
* Build the backend command line...
*/
- strncpy(scheme, uri, sizeof(scheme) - 1);
- if (strlen(uri) > 1023)
- scheme[1023] = '\0';
+ scheme[0] = '\0';
+ strncat(scheme, uri, sizeof(scheme) - 1);
if ((ptr = strchr(scheme, ':')) != NULL)
*ptr = '\0';
-
+ else
+ {
+ fprintf(stderr,
+ "ERROR: beh: Invalid URI, no colon (':') to mark end of scheme part.\n");
+ exit (CUPS_BACKEND_FAILED);
+ }
+ if (strchr(scheme, '/'))
+ {
+ fprintf(stderr,
+ "ERROR: beh: Invalid URI, scheme contains a slash ('/').\n");
+ exit (CUPS_BACKEND_FAILED);
+ }
+ if (!strcmp(scheme, ".") || !strcmp(scheme, ".."))
+ {
+ fprintf(stderr,
+ "ERROR: beh: Invalid URI, scheme (\"%s\") is a directory.\n",
+ scheme);
+ exit (CUPS_BACKEND_FAILED);
+ }
if ((cups_serverbin = getenv("CUPS_SERVERBIN")) == NULL)
cups_serverbin = CUPS_SERVERBIN;
@@ -235,16 +260,26 @@
fprintf(stderr,
"ERROR: beh: Direct output into a file not supported.\n");
exit (CUPS_BACKEND_FAILED);
- } else
- snprintf(cmdline, sizeof(cmdline),
- "%s/backend/%s '%s' '%s' '%s' '%s' '%s' %s",
- cups_serverbin, scheme, argv[1], argv[2], argv[3],
- /* Apply number of copies only if beh was called with a
- file name and not with the print data in stdin, as
- backends should handle copies only if they are called
- with a file name */
- (argc == 6 ? "1" : argv[4]),
- argv[5], filename);
+ }
+
+ backend_argv[0] = uri;
+ backend_argv[1] = argv[1];
+ backend_argv[2] = argv[2];
+ backend_argv[3] = argv[3];
+ backend_argv[4] = (argc == 6 ? "1" : argv[4]);
+ backend_argv[5] = argv[5];
+ backend_argv[6] = filename;
+ backend_argv[7] = NULL;
+
+ bytes = snprintf(backend_path, sizeof(backend_path),
+ "%s/backend/%s", cups_serverbin, scheme);
+ if (bytes < 0 || bytes >= sizeof(backend_path))
+ {
+ fprintf(stderr,
+ "ERROR: beh: Invalid scheme (\"%s\"), could not determing backend path.\n",
+ scheme);
+ exit (CUPS_BACKEND_FAILED);
+ }
/*
* Overwrite the device URI and run the actual backend...
@@ -253,17 +288,41 @@
setenv("DEVICE_URI", uri, 1);
fprintf(stderr,
- "DEBUG: beh: Executing backend command line \"%s\"...\n",
- cmdline);
+ "DEBUG: beh: Executing backend command line \"%s '%s' '%s' '%s' '%s' '%s'%s%s\"...\n",
+ backend_path, backend_argv[1], backend_argv[2], backend_argv[3],
+ backend_argv[4], backend_argv[5],
+ (backend_argv[6] && backend_argv[6][0] ? " " : ""),
+ (backend_argv[6] && backend_argv[6][0] ? backend_argv[6] : ""));
fprintf(stderr,
"DEBUG: beh: Using device URI: %s\n",
uri);
- retval = system(cmdline) >> 8;
+ if ((pid = fork()) == 0)
+ {
+ retval = execv(backend_path, backend_argv);
+
+ if (retval == -1)
+ fprintf(stderr, "ERROR: Unable to execute backend: %s\n",
+ strerror(errno));
+ exit (CUPS_BACKEND_FAILED);
+ }
+ else if (pid < 0)
+ {
+ fprintf(stderr, "ERROR: Unable to fork for backend\n");
+ return (CUPS_BACKEND_FAILED);
+ }
+
+ while ((wait_pid = wait(&wait_status)) < 0 && errno == EINTR);
- if (retval == -1)
- fprintf(stderr, "ERROR: Unable to execute backend command line: %s\n",
- strerror(errno));
+ if (wait_pid >= 0 && wait_status)
+ {
+ if (WIFEXITED(wait_status))
+ retval = WEXITSTATUS(wait_status);
+ else if (WTERMSIG(wait_status) != SIGTERM)
+ retval = WTERMSIG(wait_status);
+ else
+ retval = 0;
+ }
return (retval);
}
@@ -277,8 +336,10 @@
sigterm_handler(int sig) { /* I - Signal number (unused) */
(void)sig;
- fprintf(stderr,
- "DEBUG: beh: Job canceled.\n");
+ const char * const msg = "DEBUG: beh: Job canceled.\n";
+ // The if() is to eliminate the return value and silence the warning
+ // about an unused return value.
+ if (write(2, msg, strlen(msg)));
if (job_canceled)
_exit(CUPS_BACKEND_OK);
|
