gno/bin/tee/tee.c

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/*
* tee - send a copy of stdin to a file as well as stdout.
*
* Version 1.1 by Devin Reade <gdr@myrias.ab.ca>
*
* tee originally appeared with Gno v1.x, but was fully buffered.
* This is a complete re-write which uses full buffering for the
* output file, but _no_ buffering on stdin and stdout.
*/
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>
#include <unistd.h>
#include "getopt.h"
#ifdef CHECK_STACK
void begin_stack_check(void);
int end_stack_check(void);
# define STACKSTART begin_stack_check()
# define STACKEND(n) { \
fprintf(stderr,"stack usage: %d bytes\n",end_stack_check()); \
return n; \
}
#else
# define STACKSTART
# define STACKEND(n) return n
#endif
#define BUFFERSIZE 512
#define USAGE { \
fprintf(stderr,"%s %s\nUsage:\t%s %s\n",argv[0],versionstr,argv[0], \
usagestr); \
STACKEND(-1); \
}
char *versionstr="version 1.1 by Devin Reade";
char *usagestr="[ -ai ] filename\n\
\t-a\tappend to filename\n\
\t-i\tignore SIGINT\n";
char buf2[BUFFERSIZE];
int main (int argc, char **argv) {
int c;
char *mode, buf;
FILE *fp, *fp2;
extern int optind;
/* initialization */
STACKSTART;
mode = "w+";
/* parse the command line */
while ((c = getopt(argc, argv, "aiV")) != EOF)
switch (c) {
case 'a':
/* append to instead of truncate output file*/
mode = "a+";
break;
case 'i':
/* ignore SIGINT */
signal(SIGINT,SIG_IGN);
break;
case 'V': /*FALLTHROUGH*/
default:
USAGE;
/*NOTREACHED*/
}
if ((argc - optind) < 1) USAGE;
/* open the output file */
if ((fp = fopen(argv[optind],mode)) == NULL) {
perror("opening master file");
STACKEND(1);
}
/* loop until done with the first file */
for(;;) {
int done = 0;
switch (read(STDIN_FILENO,&buf,1)) {
case -1:
fclose(fp);
STACKEND(1);
/*NOTREACHED*/
case 0:
done=1;
break;
default:
write(STDOUT_FILENO,&buf,1);
fputc(buf,fp);
break;
}
if (done) break;
}
/* make additional copies if necessary */
optind++;
if (argc<=optind) {
fclose(fp);
STACKEND(0);
}
while (argc>optind) {
size_t count;
/* rewind the master file */
rewind(fp);
/* open the new file */
if ((fp2 = fopen(argv[optind],mode)) == NULL) {
perror("opening duplicate file");
fclose(fp);
STACKEND(1);
}
/* make the copy */
while (!feof(fp) && !(ferror(fp))) {
count = fread(buf2,sizeof(char),BUFFERSIZE,fp);
if (count>0) {
fwrite(buf2,sizeof(char),count,fp2);
if (ferror(fp2)) {
perror("writing duplicate file");
fclose(fp);
fclose(fp2);
STACKEND(1);
}
}
}
fclose(fp2);
if (ferror(fp)) {
perror("reading master file");
fclose(fp);
STACKEND(1);
}
optind++;
}
fclose(fp);
STACKEND(0);
}