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#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <nbcompat.h>
#if HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#if HAVE_ERR_H
#include <err.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDIO_H
#include <stdio.h>
#endif
#include "lib.h"
/*
* If the supplied callback is not NULL, then call it.
*/
static void call_callback(void (*callback)(void))
{
if (callback != NULL) {
callback();
}
}
/*
* create pipe, fork and exec file with arguments in argv
* child takes stdin from pipe, set up fp for parent to
* output to pipe, and return this information.
*/
pipe_to_system_t *pipe_to_system_begin(const char *file, char *const argv[],
void (*cleanup_callback)(void))
{
pipe_to_system_t *retval;
retval = malloc(sizeof(pipe_to_system_t));
if (retval == NULL) {
call_callback(cleanup_callback);
errx(2, "can't get pipe space");
}
retval->cleanup = cleanup_callback;
if (pipe(retval->fds) == -1) {
call_callback(retval->cleanup);
errx(2, "cannot create pipe");
}
retval->pid = fork();
if (retval->pid == -1) {
call_callback(retval->cleanup);
errx(2, "cannot fork process for %s", file);
}
if (retval->pid == 0) { /* The child */
if (retval->fds[0] != 0) {
dup2(retval->fds[0], 0);
close(retval->fds[0]);
}
close(retval->fds[1]);
execvp(file, argv);
warn("failed to execute %s command", file);
_exit(2);
}
/* Meanwhile, back in the parent process ... */
close(retval->fds[0]);
retval->fp = fdopen(retval->fds[1], "w");
if (retval->fp == NULL) {
call_callback(retval->cleanup);
errx(2, "fdopen failed");
}
return retval;
}
/*
* close pipe and wait for child to exit. on non-zero exit status,
* call cleanup callback. return exit status.
*/
int pipe_to_system_end(pipe_to_system_t *to_pipe)
{
int status;
int wait_ret;
fclose(to_pipe->fp);
do {
wait_ret = waitpid(to_pipe->pid, &status, 0);
} while (wait_ret == -1 && errno == EINTR);
if (wait_ret < 0) {
call_callback(to_pipe->cleanup);
errx(2, "waitpid returned failure");
}
if (!WIFEXITED(status)) {
call_callback(to_pipe->cleanup);
errx(2, "waitpid: process terminated abnormally");
}
free(to_pipe);
return WEXITSTATUS(status);
}
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