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ed486911 | 1 | /* |
f7faf1f5 | 2 | * "$Id: runloop.c 5594 2006-05-27 03:14:03Z mike $" |
ed486911 | 3 | * |
4 | * Common run loop API for the Common UNIX Printing System (CUPS). | |
5 | * | |
6 | * Copyright 2006 by Easy Software Products, all rights reserved. | |
7 | * | |
8 | * These coded instructions, statements, and computer programs are the | |
9 | * property of Easy Software Products and are protected by Federal | |
10 | * copyright law. Distribution and use rights are outlined in the file | |
11 | * "LICENSE" which should have been included with this file. If this | |
12 | * file is missing or damaged please contact Easy Software Products | |
13 | * at: | |
14 | * | |
15 | * Attn: CUPS Licensing Information | |
16 | * Easy Software Products | |
17 | * 44141 Airport View Drive, Suite 204 | |
18 | * Hollywood, Maryland 20636 USA | |
19 | * | |
20 | * Voice: (301) 373-9600 | |
21 | * EMail: cups-info@cups.org | |
22 | * WWW: http://www.cups.org | |
23 | * | |
24 | * This file is subject to the Apple OS-Developed Software exception. | |
25 | * | |
26 | * Contents: | |
27 | * | |
28 | * backendRunLoop() - Read and write print and back-channel data. | |
29 | */ | |
30 | ||
31 | /* | |
32 | * Include necessary headers. | |
33 | */ | |
34 | ||
35 | #include "backend-private.h" | |
36 | #include <sys/select.h> | |
37 | ||
38 | ||
39 | /* | |
40 | * 'backendRunLoop()' - Read and write print and back-channel data. | |
41 | */ | |
42 | ||
43 | ssize_t /* O - Total bytes on success, -1 on error */ | |
44 | backendRunLoop(int print_fd, /* I - Print file descriptor */ | |
45 | int device_fd, /* I - Device file descriptor */ | |
46 | int use_bc) /* I - Use back-channel? */ | |
47 | { | |
48 | int nfds; /* Maximum file descriptor value + 1 */ | |
49 | fd_set input, /* Input set for reading */ | |
50 | output; /* Output set for writing */ | |
51 | ssize_t print_bytes, /* Print bytes read */ | |
52 | bc_bytes, /* Backchannel bytes read */ | |
53 | total_bytes, /* Total bytes written */ | |
54 | bytes; /* Bytes written */ | |
55 | int paperout; /* "Paper out" status */ | |
56 | char print_buffer[8192], /* Print data buffer */ | |
57 | *print_ptr, /* Pointer into print data buffer */ | |
58 | bc_buffer[1024]; /* Back-channel data buffer */ | |
59 | #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET) | |
60 | struct sigaction action; /* Actions for POSIX signals */ | |
61 | #endif /* HAVE_SIGACTION && !HAVE_SIGSET */ | |
62 | ||
63 | ||
64 | /* | |
65 | * If we are printing data from a print driver on stdin, ignore SIGTERM | |
66 | * so that the driver can finish out any page data, e.g. to eject the | |
67 | * current page. We only do this for stdin printing as otherwise there | |
68 | * is no way to cancel a raw print job... | |
69 | */ | |
70 | ||
71 | if (!print_fd) | |
72 | { | |
73 | #ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */ | |
74 | sigset(SIGTERM, SIG_IGN); | |
75 | #elif defined(HAVE_SIGACTION) | |
76 | memset(&action, 0, sizeof(action)); | |
77 | ||
78 | sigemptyset(&action.sa_mask); | |
79 | action.sa_handler = SIG_IGN; | |
80 | sigaction(SIGTERM, &action, NULL); | |
81 | #else | |
82 | signal(SIGTERM, SIG_IGN); | |
83 | #endif /* HAVE_SIGSET */ | |
84 | } | |
85 | ||
86 | /* | |
87 | * Figure out the maximum file descriptor value to use with select()... | |
88 | */ | |
89 | ||
90 | nfds = (print_fd > device_fd ? print_fd : device_fd) + 1; | |
91 | ||
92 | /* | |
93 | * Now loop until we are out of data from print_fd... | |
94 | */ | |
95 | ||
96 | for (print_bytes = 0, print_ptr = print_buffer, paperout = 0, total_bytes = 0;;) | |
97 | { | |
98 | /* | |
99 | * Use select() to determine whether we have data to copy around... | |
100 | */ | |
101 | ||
102 | FD_ZERO(&input); | |
103 | if (!print_bytes) | |
104 | FD_SET(print_fd, &input); | |
105 | if (use_bc) | |
106 | FD_SET(device_fd, &input); | |
107 | ||
108 | FD_ZERO(&output); | |
109 | if (print_bytes) | |
110 | FD_SET(device_fd, &output); | |
111 | ||
112 | if (select(nfds, &input, &output, NULL, NULL) < 0) | |
113 | continue; /* Ignore errors here */ | |
114 | ||
115 | /* | |
116 | * Check if we have back-channel data ready... | |
117 | */ | |
118 | ||
119 | if (FD_ISSET(device_fd, &input)) | |
120 | { | |
121 | if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0) | |
122 | { | |
123 | fprintf(stderr, | |
124 | "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data!\n", | |
125 | CUPS_LLCAST bc_bytes); | |
126 | cupsBackChannelWrite(bc_buffer, bc_bytes, 1.0); | |
127 | } | |
128 | } | |
129 | ||
130 | /* | |
131 | * Check if we have print data ready... | |
132 | */ | |
133 | ||
134 | if (FD_ISSET(print_fd, &input)) | |
135 | { | |
136 | if ((print_bytes = read(print_fd, print_buffer, | |
137 | sizeof(print_buffer))) < 0) | |
138 | { | |
139 | /* | |
140 | * Read error - bail if we don't see EAGAIN or EINTR... | |
141 | */ | |
142 | ||
143 | if (errno != EAGAIN || errno != EINTR) | |
144 | { | |
145 | perror("ERROR: Unable to read print data"); | |
146 | return (-1); | |
147 | } | |
148 | ||
149 | print_bytes = 0; | |
150 | } | |
151 | else if (print_bytes == 0) | |
152 | { | |
153 | /* | |
154 | * End of file, break out of the loop... | |
155 | */ | |
156 | ||
157 | break; | |
158 | } | |
159 | ||
160 | print_ptr = print_buffer; | |
161 | } | |
162 | ||
163 | /* | |
164 | * Check if the device is ready to receive data and we have data to | |
165 | * send... | |
166 | */ | |
167 | ||
168 | if (print_bytes && FD_ISSET(device_fd, &output)) | |
169 | { | |
170 | if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0) | |
171 | { | |
172 | /* | |
173 | * Write error - bail if we don't see an error we can retry... | |
174 | */ | |
175 | ||
176 | if (errno == ENOSPC) | |
177 | { | |
178 | if (!paperout) | |
179 | { | |
180 | fputs("ERROR: Out of paper!\n", stderr); | |
181 | fputs("STATUS: +media-tray-empty-error\n", stderr); | |
182 | paperout = 1; | |
183 | } | |
184 | } | |
185 | else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY) | |
186 | { | |
187 | perror("ERROR: Unable to write print data"); | |
188 | return (-1); | |
189 | } | |
190 | } | |
191 | else | |
192 | { | |
193 | if (paperout) | |
194 | { | |
195 | fputs("STATUS: -media-tray-empty-error\n", stderr); | |
196 | paperout = 0; | |
197 | } | |
198 | ||
199 | fprintf(stderr, "DEBUG: Wrote %d bytes...\n", (int)bytes); | |
200 | ||
201 | print_bytes -= bytes; | |
202 | print_ptr += bytes; | |
203 | total_bytes += bytes; | |
204 | } | |
205 | } | |
206 | } | |
207 | ||
208 | /* | |
209 | * Return with success... | |
210 | */ | |
211 | ||
212 | return (total_bytes); | |
213 | } | |
214 | ||
215 | ||
216 | /* | |
f7faf1f5 | 217 | * End of "$Id: runloop.c 5594 2006-05-27 03:14:03Z mike $". |
ed486911 | 218 | */ |