forked from Minki/linux
801c67b05f
It was hardcoded for one specific tracepoint, leftover from its initial user: 'perf trace'. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-j1jicvwljy5qx1nah4mkmyke@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
#define _GNU_SOURCE
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdbool.h>
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#include <sys/vfs.h>
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#include <sys/mount.h>
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#include <linux/kernel.h>
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#include "debugfs.h"
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char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
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static const char * const 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 * const *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 ((long)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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/* 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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return debugfs_mountpoint;
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}
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int debugfs__strerror_open(int err, char *buf, size_t size, const char *filename)
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{
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char sbuf[128];
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switch (err) {
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case ENOENT:
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snprintf(buf, size, "%s",
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"Error:\tUnable to find debugfs\n"
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"Hint:\tWas your kernel compiled with debugfs support?\n"
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"Hint:\tIs the debugfs filesystem mounted?\n"
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"Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
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break;
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case EACCES:
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snprintf(buf, size,
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"Error:\tNo permissions to read %s/%s\n"
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"Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
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debugfs_mountpoint, filename, debugfs_mountpoint);
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break;
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default:
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snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
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break;
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}
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return 0;
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}
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