367 lines
6.6 KiB
C
367 lines
6.6 KiB
C
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/* lpd 1.6 - Printer daemon Author: Kees J. Bot
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* 3 Dec 1989
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*/
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#define nil 0
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#include <stdio.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <termcap.h>
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char PRINTER[] = "/dev/lp";
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char SPOOL[] = "/usr/spool/lpd";
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char LOG[] = "/dev/log";
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void report(char *mess)
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{
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fprintf(stderr, "lpd: %s: %s\n", mess, strerror(errno));
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}
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void fatal(char *mess)
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{
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report(mess);
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exit(1);
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}
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char jobX[] = "jobXXXXXX";
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char tmpX[] = "tmpXXXXXX";
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void spoolerr(char *file)
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{
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unlink(jobX);
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unlink(tmpX);
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fatal(file);
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}
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void spool(char *path)
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/* Place a file into the spool directory, either by copying it, or by leaving
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* a reference.
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*/
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{
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char *file;
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int j, u;
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mktemp(jobX);
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file= mktemp(tmpX);
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if (path[0] == '/') {
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int f;
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if ((f= open(path, O_RDONLY)) >= 0) {
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close(f);
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file= path;
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}
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}
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if (file != path) {
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int c;
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FILE *t;
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if ((t= fopen(tmpX, "w")) == nil) spoolerr(tmpX);
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while ((c= getchar()) != EOF && putc(c, t) != EOF) {}
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if (ferror(stdin)) spoolerr(path);
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if (ferror(t) || fclose(t) == EOF) spoolerr(tmpX);
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fclose(stdin);
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}
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if ((j= open(jobX, O_WRONLY|O_CREAT|O_EXCL, 0000)) < 0) spoolerr(jobX);
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u= getuid();
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if (write(j, file, strlen(file)+1) < 0
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|| write(j, &u, sizeof(u)) < 0
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|| write(j, path, strlen(path)+1) < 0
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|| close(j) < 0
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|| chmod(jobX, 0600) < 0
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) spoolerr(jobX);
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}
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struct job {
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struct job *next;
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time_t age;
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char name[sizeof(jobX)];
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} *jobs = nil;
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int job(void)
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/* Look for print jobs in the spool directory. Make a list of them sorted
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* by age. Return true iff the list is nonempty.
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*/
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{
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DIR *spool;
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struct dirent *entry;
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struct job *newjob, **ajob;
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struct stat st;
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if (jobs != nil) return 1;
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if ((spool= opendir(".")) == nil) fatal(SPOOL);
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while ((entry= readdir(spool)) != nil) {
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if (strncmp(entry->d_name, "job", 3) != 0) continue;
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if (stat(entry->d_name, &st) < 0
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|| (st.st_mode & 0777) == 0000) continue;
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if ((newjob= malloc(sizeof(*newjob))) == nil) fatal("malloc()");
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newjob->age = st.st_mtime;
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strcpy(newjob->name, entry->d_name);
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ajob= &jobs;
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while (*ajob != nil && (*ajob)->age < newjob->age)
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ajob= &(*ajob)->next;
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newjob->next= *ajob;
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*ajob= newjob;
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}
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closedir(spool);
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return jobs != nil;
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}
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/* What to do with control-X:
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* 0 ignore,
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* 1 give up on controlling the printer, assume user knows how printer works,
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* 2 print.
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*/
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char control[] = {
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0, 1, 1, 1, 1, 1, 1, 0, /* \0, \a don't show. */
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2, 2, 2, 1, 2, 2, 1, 1, /* \b, \t, \n, \f, \r */
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1
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};
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int lp;
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char buf[BUFSIZ];
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int count, column, line, ncols = 80, nlines = 66;
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int flush(void)
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/* Copy the characters in the output buffer to the printer, with retries if
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* out of paper.
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*/
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{
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char *bp= buf;
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while (count > 0) {
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int retry = 0, complain = 0;
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int r;
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while ((r= write(lp, bp, count)) < 0) {
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if (errno != EAGAIN) fatal(PRINTER);
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if (retry == complain) {
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fprintf(stderr,
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"lpd: %s: Printer out of paper\n",
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PRINTER);
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complain= retry + 60;
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}
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sleep(1);
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retry++;
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}
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bp+= r;
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count-= r;
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}
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count = 0;
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}
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void put(int c)
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/* Send characters to the output buffer to be printed and do so if the buffer
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* is full. Track the position of the write-head in `column' and `line'.
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*/
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{
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buf[count++] = c;
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switch (c) {
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case '\f':
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column = 0;
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line = 0;
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break;
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case '\r':
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column = 0;
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break;
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case '\n':
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line++;
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break;
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case '\b':
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column--;
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break;
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default:
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if (++column > ncols) { line++; column= 1; }
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}
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if (line == nlines) line= 0;
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if (count == BUFSIZ) flush();
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}
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void print(FILE *f)
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/* Send the contents of an open file to the printer. Expand tabs and change
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* linefeed to a carriage-return linefeed sequence. Print a formfeed at the
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* end if needed to reach the top of the next page. If a control character
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* is printed that we do not know about, then the user is assumed to know
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* what they are doing, so output processing is disabled.
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*/
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{
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int c;
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count= column= line= 0;
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while ((c= getc(f)) != EOF) {
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if (c < ' ') {
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switch (control[c]) {
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case 0: continue; /* Ignore this one. */
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case 1:
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/* Can't handle this junk, assume smart user. */
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do {
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buf[count++] = c;
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if (count == BUFSIZ) flush();
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} while ((c= getc(f)) != EOF);
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flush();
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return;
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case 2: /* fine */;
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}
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}
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switch (c) {
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case '\n':
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put('\r');
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put('\n');
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break;
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case '\t':
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do {
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put(' ');
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} while (column & 07);
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break;
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case '\b':
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if (column > 0) put(c);
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break;
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default:
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put(c);
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}
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}
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if (column > 0) { put('\r'); put('\n'); }
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if (line > 0) put('\f');
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flush();
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return;
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}
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void joberr(char *job)
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{
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fprintf(stderr, "lpd: something is wrong with %s\n", job);
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if (unlink(job) < 0) fatal("can't remove it");
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}
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void work(void)
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/* Print all the jobs in the job list. */
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{
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FILE *j, *f;
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char file[PATH_MAX+1], *pf=file;
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int c;
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struct job *job;
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job= jobs;
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jobs= jobs->next;
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if ((j= fopen(job->name, "r")) == nil) {
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joberr(job->name);
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return;
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}
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do {
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if (pf == file + sizeof(file) || (c= getc(j)) == EOF) {
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fclose(j);
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joberr(job->name);
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return;
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}
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*pf++ = c;
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} while (c != 0);
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fclose(j);
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if ((f= fopen(file, "r")) == nil)
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fprintf(stderr, "lpd: can't read %s\n", file);
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else {
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print(f);
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fclose(f);
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}
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if (file[0] != '/' && unlink(file) < 0) report(file);
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if (unlink(job->name) < 0) fatal(job->name);
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free(job);
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}
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void getcap(void)
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/* Find the line printer dimensions in the termcap database under "lp". */
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{
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char printcap[1024];
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int n;
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if (tgetent(printcap, "lp") == 1) {
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if ((n= tgetnum("co")) > 0) ncols= n;
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if ((n= tgetnum("li")) > 0) nlines= n;
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}
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}
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void haunt(void)
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/* Become a daemon, print jobs while there are any, exit. */
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{
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int fd;
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if ((fd= open("/dev/tty", O_RDONLY)) != -1) {
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/* We have a controlling tty! Disconnect. */
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close(fd);
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switch(fork()) {
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case -1: fatal("can't fork");
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case 0: break;
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default: exit(0);
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}
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if ((fd= open("/dev/null", O_RDONLY)) < 0) fatal("/dev/null");
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dup2(fd, 0);
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close(fd);
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if ((fd= open(LOG, O_WRONLY)) < 0) fatal(LOG);
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dup2(fd, 1);
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dup2(fd, 2);
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close(fd);
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setsid();
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}
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getcap();
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do {
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if ((lp= open(PRINTER, O_WRONLY)) < 0) {
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/* Another lpd? */
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if (errno == EBUSY) exit(0);
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fatal(PRINTER);
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}
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while (job()) work();
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close(lp);
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} while (job());
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}
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int main(int argc, char **argv)
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{
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if (argc > 2) {
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fprintf(stderr, "Usage: %s [path | stdin < path]\n", argv[0]);
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exit(1);
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}
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umask(0077);
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if (chdir(SPOOL) < 0) fatal(SPOOL);
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if (argc == 2) spool(argv[1]);
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haunt();
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}
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