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/* See LICENSE file for copyright and license details. */
#include <sys/socket.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static const char *argv0 = "editasroot/copier";
static void
copy_file(int destfd, const char *destfname, int srcfd, const char *srcfname)
{
char buf[BUFSIZ];
ssize_t r, w, p;
for (;;) {
r = read(srcfd, buf, sizeof(buf));
if (r <= 0) {
if (!r)
break;
fprintf(stderr, "%s: read %s: %s", argv0, srcfname, strerror(errno));
exit(1);
}
for (p = 0; p < r; p += w) {
w = write(destfd, buf, (size_t)(r - p));
if (r <= 0) {
fprintf(stderr, "%s: write %s: %s", argv0, destfname, strerror(errno));
exit(1);
}
}
}
}
int
main(int argc, char *argv[])
{
int filefd, parentfd;
const char *path;
ssize_t r;
char b;
if (!argc)
exit(1);
argv0 = *argv++;
if (--argc != 2)
exit(1);
path = argv[0];
parentfd = atoi(argv[1]);
filefd = open(path, O_RDWR); /* O_RDWR establishes that we can indeed write to the file */
if (filefd < 0) {
fprintf(stderr, "%s: open %s O_RDWR: %s\n", argv0, path, strerror(errno));
exit(1);
}
copy_file(parentfd, "<socket to parent>", filefd, path);
if (close(filefd)) {
fprintf(stderr, "%s: read %s: %s\n", argv0, path, strerror(errno));
exit(1);
}
if (shutdown(parentfd, SHUT_WR)) {
fprintf(stderr, "%s: shutdown <socket to parent> SHUT_WR: %s\n", argv0, strerror(errno));
exit(1);
}
r = read(parentfd, &b, 1);
if (r != 1) {
if (r)
fprintf(stderr, "%s: read %s: %s\n", argv0, path, strerror(errno));
exit(1);
}
filefd = open(path, O_WRONLY | O_TRUNC);
if (filefd < 0) {
fprintf(stderr, "%s: open %s O_WRONLY|O_TRUNC: %s\n", argv0, path, strerror(errno));
exit(1);
}
copy_file(filefd, path, parentfd, "<socket to parent>");
if (close(filefd)) {
fprintf(stderr, "%s: write %s: %s\n", argv0, path, strerror(errno));
exit(1);
}
if (close(parentfd)) {
fprintf(stderr, "%s: read <socket to parent>: %s\n", argv0, strerror(errno));
exit(1);
}
return 0;
}
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