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![Xiao Guangrong](/assets/img/avatar_default.png)
Remove redundant code for 'perf trace' Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> LKML-Reference: <4B3870DE.7090500@cn.fujitsu.com> [ v2: resolved conflicts with recent changes ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
240 lines
4.5 KiB
C
240 lines
4.5 KiB
C
#include "util.h"
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#include "debugfs.h"
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#include "cache.h"
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static int debugfs_premounted;
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static char debugfs_mountpoint[MAX_PATH+1];
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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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/* use this to force a umount */
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void debugfs_force_cleanup(void)
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{
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debugfs_find_mountpoint();
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debugfs_premounted = 0;
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debugfs_umount();
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}
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/* construct a full path to a debugfs element */
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int debugfs_make_path(const char *element, char *buffer, int size)
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{
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int len;
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if (strlen(debugfs_mountpoint) == 0) {
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buffer[0] = '\0';
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return -1;
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}
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len = strlen(debugfs_mountpoint) + strlen(element) + 1;
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if (len >= size)
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return len+1;
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snprintf(buffer, size-1, "%s/%s", debugfs_mountpoint, element);
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return 0;
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}
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static int 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 = 1;
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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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die("Can't open /proc/mounts for read");
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while (fscanf(fp, "%*s %"
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STR(MAX_PATH)
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"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 = 1;
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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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int debugfs_valid_entry(const char *path)
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{
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struct stat st;
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if (stat(path, &st))
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return -errno;
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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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debugfs_premounted = 1;
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return debugfs_mountpoint;
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}
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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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strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
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debugfs_found = 1;
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return debugfs_mountpoint;
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}
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/* umount the debugfs */
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int debugfs_umount(void)
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{
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char umountcmd[128];
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int ret;
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/* if it was already mounted, leave it */
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if (debugfs_premounted)
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return 0;
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/* make sure it's a valid mount point */
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ret = debugfs_valid_mountpoint(debugfs_mountpoint);
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if (ret)
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return ret;
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snprintf(umountcmd, sizeof(umountcmd),
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"/bin/umount %s", debugfs_mountpoint);
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return system(umountcmd);
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}
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int debugfs_write(const char *entry, const char *value)
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{
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char path[MAX_PATH+1];
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int ret, count;
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int fd;
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/* construct the path */
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snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry);
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/* verify that it exists */
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ret = debugfs_valid_entry(path);
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if (ret)
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return ret;
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/* get how many chars we're going to write */
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count = strlen(value);
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/* open the debugfs entry */
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fd = open(path, O_RDWR);
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if (fd < 0)
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return -errno;
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while (count > 0) {
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/* write it */
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ret = write(fd, value, count);
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if (ret <= 0) {
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if (ret == EAGAIN)
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continue;
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close(fd);
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return -errno;
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}
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count -= ret;
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}
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/* close it */
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close(fd);
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/* return success */
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return 0;
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}
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/*
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* read a debugfs entry
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* returns the number of chars read or a negative errno
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*/
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int debugfs_read(const char *entry, char *buffer, size_t size)
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{
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char path[MAX_PATH+1];
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int ret;
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int fd;
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/* construct the path */
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snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry);
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/* verify that it exists */
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ret = debugfs_valid_entry(path);
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if (ret)
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return ret;
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/* open the debugfs entry */
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fd = open(path, O_RDONLY);
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if (fd < 0)
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return -errno;
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do {
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/* read it */
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ret = read(fd, buffer, size);
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if (ret == 0) {
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close(fd);
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return EOF;
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}
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} while (ret < 0 && errno == EAGAIN);
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/* close it */
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close(fd);
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/* make *sure* there's a null character at the end */
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buffer[ret] = '\0';
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/* return the number of chars read */
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return ret;
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}
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