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/* Copyright (c) 1999 Anthony Towns
* Copyright (c) 2000, 2002 Matthias Klose
*
* You may freely use, distribute, and modify this program.
*/
// Don't rely on /bin/sh and popen!
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/wait.h>
/* XXX: evil kludge, deal with arbitrary name lengths */
#ifndef PATH_MAX
#define PATH_MAX 4096
#endif
int check_predepends(void)
{
pid_t child;
switch(child = fork()) {
case -1:
/* fork failed */
return EXIT_FAILURE;
case 0:
/* i'm the child */
{
execl( "/usr/bin/dpkg", "/usr/bin/dpkg",
"--assert-support-predepends", NULL );
_exit(127);
}
default:
/* i'm the parent */
{
int status;
pid_t pid;
pid = wait(&status);
if (pid == child) {
if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
return EXIT_SUCCESS;
}
}
}
}
return EXIT_FAILURE;
}
char *check_diversion(void)
{
pid_t child;
int pipedes[2];
if (pipe(pipedes))
return NULL;
switch(child = fork()) {
case -1:
/* fork failed */
close(pipedes[0]);
close(pipedes[1]);
return NULL;
case 0:
/* i'm the child */
{
if (dup2(pipedes[STDOUT_FILENO], STDOUT_FILENO) < 0)
_exit(127);
close(pipedes[STDIN_FILENO]);
close(pipedes[STDOUT_FILENO]);
execl( "/usr/sbin/dpkg-divert", "/usr/sbin/dpkg-divert",
"--list", "/bin/sh", NULL );
_exit(127);
}
default:
/* i'm the parent */
{
static char line[1024];
FILE *fd;
close (pipedes[STDOUT_FILENO]);
fcntl (pipedes[STDIN_FILENO], F_SETFD, FD_CLOEXEC);
fd = fdopen (pipedes[STDIN_FILENO], "r");
while (fgets(line, 1024, fd) != NULL) {
line[strlen(line)-1] = '\0';
break;
}
fclose(fd);
return line;
}
}
return NULL;
}
const char *msg =
"As bash for Debian is destined to provide a working /bin/sh (pointing to\n"
"/bin/bash) your link will be overwritten by a default link.\n\n"
"If you don't want further upgrades to overwrite your customization,\n"
"please read /usr/share/doc/bash/README.Debian for a more permanent solution.\n\n"
"[Press RETURN to continue]";
int main(void) {
int targetlen;
char target[PATH_MAX+1], answer[1024];
if (check_predepends() != EXIT_SUCCESS) {
printf("\nPlease upgrade to a new version of dpkg\n\n");
return EXIT_FAILURE;
}
targetlen = readlink("/bin/sh", target, PATH_MAX);
if (targetlen == -1) {
// error reading link. Will be overwritten.
puts("The bash upgrade discovered that something is wrong with your /bin/sh link.");
puts(msg);
fgets(answer, 1024, stdin);
return EXIT_SUCCESS;
}
target[targetlen] = '\0';
if (strcmp(target, "bash") != 0 && strcmp(target, "/bin/bash") != 0) {
char *diversion = check_diversion();
if (diversion == NULL)
return EXIT_FAILURE;
// printf("diversion: /%s/\n", diversion);
if (strcmp(diversion, "") != 0)
// link is diverted
return EXIT_SUCCESS;
printf("The bash upgrade discovered that your /bin/sh link points to %s.\n", target);
puts(msg);
fgets(answer, 1024, stdin);
return EXIT_SUCCESS;
}
return EXIT_SUCCESS;
}
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