112 lines
2.4 KiB
C
112 lines
2.4 KiB
C
#include "util.h"
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#include "debugfs.h"
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#include "cache.h"
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#include <linux/kernel.h>
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#include <sys/mount.h>
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char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
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char tracing_events_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing/events";
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static const char *debugfs_known_mountpoints[] = {
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"/sys/kernel/debug/",
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"/debug/",
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0,
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};
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static bool debugfs_found;
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/* find the path to the mounted debugfs */
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const char *debugfs_find_mountpoint(void)
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{
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const char **ptr;
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char type[100];
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FILE *fp;
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if (debugfs_found)
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return (const char *) debugfs_mountpoint;
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ptr = debugfs_known_mountpoints;
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while (*ptr) {
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if (debugfs_valid_mountpoint(*ptr) == 0) {
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debugfs_found = true;
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strcpy(debugfs_mountpoint, *ptr);
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return debugfs_mountpoint;
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}
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ptr++;
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}
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/* give up and parse /proc/mounts */
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fp = fopen("/proc/mounts", "r");
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if (fp == NULL)
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return NULL;
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while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
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debugfs_mountpoint, type) == 2) {
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if (strcmp(type, "debugfs") == 0)
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break;
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}
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fclose(fp);
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if (strcmp(type, "debugfs") != 0)
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return NULL;
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debugfs_found = true;
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return debugfs_mountpoint;
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}
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/* verify that a mountpoint is actually a debugfs instance */
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int debugfs_valid_mountpoint(const char *debugfs)
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{
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struct statfs st_fs;
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if (statfs(debugfs, &st_fs) < 0)
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return -ENOENT;
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else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
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return -ENOENT;
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return 0;
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}
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static void debugfs_set_tracing_events_path(const char *mountpoint)
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{
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snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s",
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mountpoint, "tracing/events");
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}
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/* mount the debugfs somewhere if it's not mounted */
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char *debugfs_mount(const char *mountpoint)
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{
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/* see if it's already mounted */
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if (debugfs_find_mountpoint())
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goto out;
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/* if not mounted and no argument */
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if (mountpoint == NULL) {
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/* see if environment variable set */
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mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);
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/* if no environment variable, use default */
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if (mountpoint == NULL)
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mountpoint = "/sys/kernel/debug";
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}
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if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
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return NULL;
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/* save the mountpoint */
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debugfs_found = true;
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strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
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out:
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debugfs_set_tracing_events_path(debugfs_mountpoint);
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return debugfs_mountpoint;
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}
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void debugfs_set_path(const char *mountpoint)
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{
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snprintf(debugfs_mountpoint, sizeof(debugfs_mountpoint), "%s", mountpoint);
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debugfs_set_tracing_events_path(mountpoint);
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}
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