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/* $XFree86: xc/programs/Xserver/hw/xfree86/os-support/linux/lnx_kmod.c,v 3.6 2001/10/31 22:50:30 tsi Exp $ */
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#include "xf86_OSlib.h"
#include "xf86.h"
#define MODPROBE_PATH_FILE "/proc/sys/kernel/modprobe"
#define MAX_PATH 1024
#if 0
/* XFree86 #defines execl to be the xf86execl() function which does
* a fork AND exec. We don't want that. We want the regular,
* standard execl().
*/
#ifdef execl
#undef execl
#endif
#endif
/*
* Load a Linux kernel module.
* This is used by the DRI/DRM to load a DRM kernel module when
* the X server starts. It could be used for other purposes in the future.
* Input:
* modName - name of the kernel module (Ex: "tdfx")
* Return:
* 0 for failure, 1 for success
*/
int
xf86LoadKernelModule(const char *modName)
{
char mpPath[MAX_PATH] = "";
int fd = -1, status, n;
pid_t pid;
/* get the path to the modprobe program */
fd = open(MODPROBE_PATH_FILE, O_RDONLY);
if (fd >= 0) {
int count = read(fd, mpPath, MAX_PATH - 1);
if (count <= 0) {
mpPath[0] = 0;
}
else if (mpPath[count - 1] == '\n') {
mpPath[count - 1] = 0; /* replaces \n with \0 */
}
close(fd);
/* if this worked, mpPath will be "/sbin/modprobe" or similar. */
}
if (mpPath[0] == 0) {
/* we failed to get the path from the system, use a default */
strcpy(mpPath, "/sbin/modprobe");
}
/* now fork/exec the modprobe command */
/*
* It would be good to capture stdout/stderr so that it can be directed
* to the log file. modprobe errors currently are missing from the log
* file.
*/
switch (pid = fork()) {
case 0: /* child */
/* change real/effective user ID to 0/0 as we need to
* preinstall agpgart module for some DRM modules
*/
if (setreuid(0,0)) {
xf86Msg(X_WARNING,"LoadKernelModule: "
"Setting of real/effective user Id to 0/0 failed");
}
setenv("PATH","/sbin",1);
n = execl(mpPath, "modprobe", modName, NULL);
xf86Msg(X_WARNING,"LoadKernelModule %s\n",strerror(errno));
exit(EXIT_FAILURE); /* if we get here the child's exec failed */
break;
case -1: /* fork failed */
return 0;
default: /* fork worked */
{
/* XXX we loop over waitpid() because it sometimes fails on
* the first attempt. Don't know why!
*/
int count = 0, p;
do {
p = waitpid(pid, &status, 0);
} while (p == -1 && count++ < 4);
if (p == -1) {
return 0;
}
if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
return 1; /* success! */
}
else {
return 0;
}
}
}
/* never get here */
return 0;
}
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