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/*
* Source file:
* openpipe.c
*
* Contains openpipe - a replacement for the non-POSIX function popen.
* This returns an int rather than a FILE * to make it general purpose -
* fdopen can be used outside to convert this to a FILE *
*/
#define _POSIX_SOURCE
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#ifdef _ultrix
extern int close(int fildes);
extern int dup(int fildes);
extern pid_t fork(void);
extern int pipe(int fildes[2]);
#else
#include <unistd.h>
#endif
#include "trueprint.h"
#include "main.h"
#include "openpipe.h"
int
openpipe(const char *command, char *mode)
{
int fildes[2];
int parent_pipe_end;
int child_pipe_end;
char *child_pipe_mode;
if (strcmp(mode, "w") == 0) {
parent_pipe_end = 1; child_pipe_end = 0;
child_pipe_mode = "read";
} else if (strcmp(mode, "r") == 0) {
parent_pipe_end = 0; child_pipe_end = 1;
child_pipe_mode = "write";
} else {
(void)fprintf(stderr, "%s: Internal error: popen() called with bad mode %s", cmd_name, mode);
exit(2);
}
if (pipe(fildes) != 0) {
(void)fprintf(stderr, "%s: Cannot create pipe, %s\n", cmd_name, strerror(errno));
exit(2);
}
switch (fork()) {
case -1:
/* Error */
(void)fprintf(stderr, "%s: Cannot fork, %s\n", cmd_name, strerror(errno));
exit(2);
/*NOTREACHED*/
case 0:
/* Child process */
if (!((close(fildes[parent_pipe_end]) == 0) &&
(close(child_pipe_end) == 0) &&
(dup(fildes[child_pipe_end]) == child_pipe_end))) {
(void)fprintf(stderr,"%s: Cannot redirect %s for child, %s\n", cmd_name, child_pipe_mode, strerror(errno));
exit(2);
}
if (system(command) < 0) {
(void)fprintf(stderr,"%s: Cannot start pipe, %s\n",cmd_name, strerror(errno));
exit(2);
} else exit(0);
/*NOTREACHED*/
default:
/* Parent process */
if (close(fildes[child_pipe_end]) != 0) {
(void)fprintf(stderr,"%s: Cannot close %s end of pipe for parent, %s\n",cmd_name, child_pipe_mode, strerror(errno));
exit(2);
}
return fildes[parent_pipe_end];
}
}
FILE *
fopenpipe(const char *command, char *mode)
{
int handle;
handle = openpipe(command, mode);
return fdopen(handle, mode);
}
void
closepipe(int handle)
{
int statloc;
(void)close(handle);
(void)waitpid(-1, &statloc, WNOHANG);
}
void
fclosepipe(FILE *fp)
{
closepipe(fileno(fp));
}
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