1
2#ifdef HAVE_XORG_CONFIG_H
3#include <xorg-config.h>
4#endif
5
6#include <errno.h>
7#include <fcntl.h>
8#include <unistd.h>
9#include <sys/wait.h>
10#include <signal.h>
11#include "xf86_OSlib.h"
12#include "xf86.h"
13
14#define MODPROBE_PATH_FILE      "/proc/sys/kernel/modprobe"
15#define MAX_PATH                1024
16
17#if 0
18/* XFree86 #defines execl to be the xf86execl() function which does
19 * a fork AND exec.  We don't want that.  We want the regular,
20 * standard execl().
21 */
22#ifdef execl
23#undef execl
24#endif
25#endif
26
27/*
28 * Load a Linux kernel module.
29 * This is used by the DRI/DRM to load a DRM kernel module when
30 * the X server starts.  It could be used for other purposes in the future.
31 * Input:
32 *    modName - name of the kernel module (Ex: "tdfx")
33 * Return:
34 *    0 for failure, 1 for success
35 */
36int
37xf86LoadKernelModule(const char *modName)
38{
39    char mpPath[MAX_PATH] = "";
40    int fd = -1, status;
41    pid_t pid;
42
43    /* get the path to the modprobe program */
44    fd = open(MODPROBE_PATH_FILE, O_RDONLY);
45    if (fd >= 0) {
46        int count = read(fd, mpPath, MAX_PATH - 1);
47
48        if (count <= 0) {
49            mpPath[0] = 0;
50        }
51        else if (mpPath[count - 1] == '\n') {
52            mpPath[count - 1] = 0;      /* replaces \n with \0 */
53        }
54        close(fd);
55        /* if this worked, mpPath will be "/sbin/modprobe" or similar. */
56    }
57
58    if (mpPath[0] == 0) {
59        /* we failed to get the path from the system, use a default */
60        strcpy(mpPath, "/sbin/modprobe");
61    }
62
63    /* now fork/exec the modprobe command */
64    /*
65     * It would be good to capture stdout/stderr so that it can be directed
66     * to the log file.  modprobe errors currently are missing from the log
67     * file.
68     */
69    switch (pid = fork()) {
70    case 0:                    /* child */
71        /* change real/effective user ID to 0/0 as we need to
72         * preinstall agpgart module for some DRM modules
73         */
74        if (setreuid(0, 0)) {
75            xf86Msg(X_WARNING, "LoadKernelModule: "
76                    "Setting of real/effective user Id to 0/0 failed");
77        }
78        setenv("PATH", "/sbin", 1);
79        execl(mpPath, "modprobe", modName, NULL);
80        xf86Msg(X_WARNING, "LoadKernelModule %s\n", strerror(errno));
81        exit(EXIT_FAILURE);     /* if we get here the child's exec failed */
82        break;
83    case -1:                   /* fork failed */
84        return 0;
85    default:                   /* fork worked */
86    {
87        /* XXX we loop over waitpid() because it sometimes fails on
88         * the first attempt.  Don't know why!
89         */
90        int count = 0, p;
91
92        do {
93            p = waitpid(pid, &status, 0);
94        } while (p == -1 && count++ < 4);
95
96        if (p == -1) {
97            return 0;
98        }
99
100        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
101            return 1;           /* success! */
102        }
103        else {
104            return 0;
105        }
106    }
107    }
108
109    /* never get here */
110    return 0;
111}
112