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/* See LICENSE file for copyright and license details. */
#include "common.h"
const char *argv0 = "editasroot/copier";
int
main(int argc, char *argv[])
{
int filefd, parentfd, ok;
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]);
/* Send content of file to parent */
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, NULL);
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);
}
/* Wait for parent to start sending the new file content,
* so that O_TRUNC does not cause the file to be truncated
* without new content being sent in case the parent exited
* abnormally. */
r = recv(parentfd, &b, 1, MSG_PEEK);
if (r <= 0) {
if (r < 0)
fprintf(stderr, "%s: read %s: %s\n", argv0, path, strerror(errno));
exit(1);
}
/* Rewrite file with content sent from parent */
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>", &ok);
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);
}
if (!ok) {
fprintf(stderr, "%s: parent exited before sending file termination message, file may be truncated\n", argv0);
exit(1);
}
return 0;
}
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