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ed486911 | 1 | /* |
d09495fa | 2 | * "$Id: runloop.c 5776 2006-07-26 20:55:13Z 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" | |
d09495fa | 36 | #ifdef __hpux |
37 | # include <sys/time.h> | |
38 | #else | |
39 | # include <sys/select.h> | |
40 | #endif /* __hpux */ | |
ed486911 | 41 | |
42 | ||
43 | /* | |
44 | * 'backendRunLoop()' - Read and write print and back-channel data. | |
45 | */ | |
46 | ||
47 | ssize_t /* O - Total bytes on success, -1 on error */ | |
48 | backendRunLoop(int print_fd, /* I - Print file descriptor */ | |
49 | int device_fd, /* I - Device file descriptor */ | |
50 | int use_bc) /* I - Use back-channel? */ | |
51 | { | |
52 | int nfds; /* Maximum file descriptor value + 1 */ | |
53 | fd_set input, /* Input set for reading */ | |
54 | output; /* Output set for writing */ | |
55 | ssize_t print_bytes, /* Print bytes read */ | |
56 | bc_bytes, /* Backchannel bytes read */ | |
57 | total_bytes, /* Total bytes written */ | |
58 | bytes; /* Bytes written */ | |
59 | int paperout; /* "Paper out" status */ | |
8ca02f3c | 60 | int offline; /* "Off-line" status */ |
ed486911 | 61 | char print_buffer[8192], /* Print data buffer */ |
62 | *print_ptr, /* Pointer into print data buffer */ | |
63 | bc_buffer[1024]; /* Back-channel data buffer */ | |
64 | #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET) | |
65 | struct sigaction action; /* Actions for POSIX signals */ | |
66 | #endif /* HAVE_SIGACTION && !HAVE_SIGSET */ | |
67 | ||
68 | ||
8ca02f3c | 69 | fprintf(stderr, "DEBUG: backendRunLoop(print_fd=%d, device_fd=%d, use_bc=%d)\n", |
70 | print_fd, device_fd, use_bc); | |
71 | ||
ed486911 | 72 | /* |
73 | * If we are printing data from a print driver on stdin, ignore SIGTERM | |
74 | * so that the driver can finish out any page data, e.g. to eject the | |
75 | * current page. We only do this for stdin printing as otherwise there | |
76 | * is no way to cancel a raw print job... | |
77 | */ | |
78 | ||
79 | if (!print_fd) | |
80 | { | |
81 | #ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */ | |
82 | sigset(SIGTERM, SIG_IGN); | |
83 | #elif defined(HAVE_SIGACTION) | |
84 | memset(&action, 0, sizeof(action)); | |
85 | ||
86 | sigemptyset(&action.sa_mask); | |
87 | action.sa_handler = SIG_IGN; | |
88 | sigaction(SIGTERM, &action, NULL); | |
89 | #else | |
90 | signal(SIGTERM, SIG_IGN); | |
91 | #endif /* HAVE_SIGSET */ | |
92 | } | |
93 | ||
94 | /* | |
95 | * Figure out the maximum file descriptor value to use with select()... | |
96 | */ | |
97 | ||
98 | nfds = (print_fd > device_fd ? print_fd : device_fd) + 1; | |
99 | ||
100 | /* | |
101 | * Now loop until we are out of data from print_fd... | |
102 | */ | |
103 | ||
8ca02f3c | 104 | for (print_bytes = 0, print_ptr = print_buffer, offline = 0, paperout = 0, total_bytes = 0;;) |
ed486911 | 105 | { |
106 | /* | |
107 | * Use select() to determine whether we have data to copy around... | |
108 | */ | |
109 | ||
110 | FD_ZERO(&input); | |
111 | if (!print_bytes) | |
112 | FD_SET(print_fd, &input); | |
113 | if (use_bc) | |
114 | FD_SET(device_fd, &input); | |
115 | ||
116 | FD_ZERO(&output); | |
8ca02f3c | 117 | if (print_bytes || !use_bc) |
ed486911 | 118 | FD_SET(device_fd, &output); |
119 | ||
8ca02f3c | 120 | if (use_bc) |
121 | { | |
122 | if (select(nfds, &input, &output, NULL, NULL) < 0) | |
123 | { | |
124 | /* | |
125 | * Pause printing to clear any pending errors... | |
126 | */ | |
127 | ||
128 | if (errno == ENXIO && !offline) | |
129 | { | |
130 | fputs("STATE: +offline-error\n", stderr); | |
131 | fputs("INFO: Printer is currently off-line.\n", stderr); | |
132 | offline = 1; | |
133 | } | |
134 | ||
135 | sleep(1); | |
136 | continue; | |
137 | } | |
138 | } | |
ed486911 | 139 | |
140 | /* | |
141 | * Check if we have back-channel data ready... | |
142 | */ | |
143 | ||
144 | if (FD_ISSET(device_fd, &input)) | |
145 | { | |
146 | if ((bc_bytes = read(device_fd, bc_buffer, sizeof(bc_buffer))) > 0) | |
147 | { | |
148 | fprintf(stderr, | |
149 | "DEBUG: Received " CUPS_LLFMT " bytes of back-channel data!\n", | |
150 | CUPS_LLCAST bc_bytes); | |
151 | cupsBackChannelWrite(bc_buffer, bc_bytes, 1.0); | |
152 | } | |
153 | } | |
154 | ||
155 | /* | |
156 | * Check if we have print data ready... | |
157 | */ | |
158 | ||
159 | if (FD_ISSET(print_fd, &input)) | |
160 | { | |
161 | if ((print_bytes = read(print_fd, print_buffer, | |
162 | sizeof(print_buffer))) < 0) | |
163 | { | |
164 | /* | |
165 | * Read error - bail if we don't see EAGAIN or EINTR... | |
166 | */ | |
167 | ||
168 | if (errno != EAGAIN || errno != EINTR) | |
169 | { | |
170 | perror("ERROR: Unable to read print data"); | |
171 | return (-1); | |
172 | } | |
173 | ||
174 | print_bytes = 0; | |
175 | } | |
176 | else if (print_bytes == 0) | |
177 | { | |
178 | /* | |
179 | * End of file, break out of the loop... | |
180 | */ | |
181 | ||
182 | break; | |
183 | } | |
184 | ||
185 | print_ptr = print_buffer; | |
8ca02f3c | 186 | |
187 | fprintf(stderr, "DEBUG: Read %d bytes of print data...\n", | |
188 | (int)print_bytes); | |
ed486911 | 189 | } |
190 | ||
191 | /* | |
192 | * Check if the device is ready to receive data and we have data to | |
193 | * send... | |
194 | */ | |
195 | ||
196 | if (print_bytes && FD_ISSET(device_fd, &output)) | |
197 | { | |
198 | if ((bytes = write(device_fd, print_ptr, print_bytes)) < 0) | |
199 | { | |
200 | /* | |
201 | * Write error - bail if we don't see an error we can retry... | |
202 | */ | |
203 | ||
204 | if (errno == ENOSPC) | |
205 | { | |
206 | if (!paperout) | |
207 | { | |
208 | fputs("ERROR: Out of paper!\n", stderr); | |
209 | fputs("STATUS: +media-tray-empty-error\n", stderr); | |
210 | paperout = 1; | |
211 | } | |
212 | } | |
8ca02f3c | 213 | else if (errno == ENXIO) |
214 | { | |
215 | if (!offline) | |
216 | { | |
217 | fputs("STATE: +offline-error\n", stderr); | |
218 | fputs("INFO: Printer is currently off-line.\n", stderr); | |
219 | offline = 1; | |
220 | } | |
221 | } | |
ed486911 | 222 | else if (errno != EAGAIN && errno != EINTR && errno != ENOTTY) |
223 | { | |
224 | perror("ERROR: Unable to write print data"); | |
225 | return (-1); | |
226 | } | |
227 | } | |
228 | else | |
229 | { | |
230 | if (paperout) | |
231 | { | |
232 | fputs("STATUS: -media-tray-empty-error\n", stderr); | |
233 | paperout = 0; | |
234 | } | |
235 | ||
8ca02f3c | 236 | if (offline) |
237 | { | |
238 | fputs("STATE: -offline-error\n", stderr); | |
239 | fputs("INFO: Printer is now on-line.\n", stderr); | |
240 | offline = 0; | |
241 | } | |
242 | ||
243 | fprintf(stderr, "DEBUG: Wrote %d bytes of print data...\n", (int)bytes); | |
ed486911 | 244 | |
245 | print_bytes -= bytes; | |
246 | print_ptr += bytes; | |
247 | total_bytes += bytes; | |
248 | } | |
249 | } | |
250 | } | |
251 | ||
252 | /* | |
253 | * Return with success... | |
254 | */ | |
255 | ||
256 | return (total_bytes); | |
257 | } | |
258 | ||
259 | ||
260 | /* | |
d09495fa | 261 | * End of "$Id: runloop.c 5776 2006-07-26 20:55:13Z mike $". |
ed486911 | 262 | */ |