nixpkgs/pkgs/applications/networking/browsers/mozilla-plugins/google-talk-plugin/preload.c
2016-05-11 20:18:30 +02:00

61 lines
1.6 KiB
C

/* Google Talk Plugin executes a helper program in /opt. This
LD_PRELOAD library intercepts execvp() calls to redirect them to
the corresponding location in $out. */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
char origDir [] = "/opt/google/talkplugin";
char realDir [] = OUT "/libexec/google/talkplugin";
const char * rewrite(const char * path, char * buf)
{
if (strncmp(path, origDir, sizeof(origDir) - 1) != 0) return path;
if (snprintf(buf, PATH_MAX, "%s%s", realDir, path + sizeof(origDir) - 1) >= PATH_MAX)
abort();
return buf;
}
int execvp(const char * path, char * const argv[])
{
int (*_execvp) (const char *, char * const argv[]) = dlsym(RTLD_NEXT, "execvp");
char buf[PATH_MAX];
return _execvp(rewrite(path, buf), argv);
}
int open(const char *path, int flags, ...)
{
char buf[PATH_MAX];
int (*_open) (const char *, int, mode_t) = dlsym(RTLD_NEXT, "open");
mode_t mode = 0;
if (flags & O_CREAT) {
va_list ap;
va_start(ap, flags);
mode = va_arg(ap, mode_t);
va_end(ap);
}
return _open(rewrite(path, buf), flags, mode);
}
int open64(const char *path, int flags, ...)
{
char buf[PATH_MAX];
int (*_open64) (const char *, int, mode_t) = dlsym(RTLD_NEXT, "open64");
mode_t mode = 0;
if (flags & O_CREAT) {
va_list ap;
va_start(ap, flags);
mode = va_arg(ap, mode_t);
va_end(ap);
}
return _open64(rewrite(path, buf), flags, mode);
}