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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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dd6dda27a8
Add tracefs_configured() to return true if tracefs is configured in the kernel (succeeds to find tracefs), and debugfs_configured() if debugfs is configured in the kernel (succeeds to find debugfs). Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20150202193553.190606690@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
118 lines
2.8 KiB
C
118 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 <unistd.h>
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#include <stdbool.h>
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#include <sys/vfs.h>
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#include <sys/types.h>
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#include <sys/stat.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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#ifndef DEBUGFS_DEFAULT_PATH
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#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
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#endif
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char debugfs_mountpoint[PATH_MAX + 1] = DEBUGFS_DEFAULT_PATH;
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static const char * const debugfs_known_mountpoints[] = {
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DEBUGFS_DEFAULT_PATH,
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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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bool debugfs_configured(void)
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{
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return debugfs_find_mountpoint() != NULL;
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}
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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 *ret;
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if (debugfs_found)
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return (const char *)debugfs_mountpoint;
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ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC,
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debugfs_mountpoint, PATH_MAX + 1,
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debugfs_known_mountpoints);
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if (ret)
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debugfs_found = true;
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return ret;
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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 = DEBUGFS_DEFAULT_PATH;
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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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if (debugfs_found) {
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snprintf(buf, size,
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"Error:\tFile %s/%s not found.\n"
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"Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
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debugfs_mountpoint, filename);
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break;
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}
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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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int debugfs__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name)
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{
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char path[PATH_MAX];
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snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*");
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return debugfs__strerror_open(err, buf, size, path);
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}
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