perf tools: Allow overriding sysfs and proc finding with env var

/* TODO merge/factor in debugfs.c here */

#include <ctype.h>

#include <errno.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/vfs.h>

	return false;

}

static void mem_toupper(char *f, size_t len)

{

	while (len) {

		*f = toupper(*f);

		f++;

		len--;

	}

}

/*

 * Check for "NAME_PATH" environment variable to override fs location (for

 * testing). This matches the recommendation in Documentation/sysfs-rules.txt

 * for SYSFS_PATH.

 */

static bool fs__env_override(struct fs *fs)

{

	char *override_path;

	size_t name_len = strlen(fs->name);

	/* name + "_PATH" + '\0' */

	char upper_name[name_len + 5 + 1];

	memcpy(upper_name, fs->name, name_len);

	mem_toupper(upper_name, name_len);

	strcpy(&upper_name[name_len], "_PATH");

	override_path = getenv(upper_name);

	if (!override_path)

		return false;

	fs->found = true;

	strncpy(fs->path, override_path, sizeof(fs->path));

	return true;

}

static const char *fs__get_mountpoint(struct fs *fs)

{

	if (fs__env_override(fs))

		return fs->path;

	if (fs__check_mounts(fs))

		return fs->path;

	return fs__read_mounts(fs) ? fs->path : NULL;

	if (fs__read_mounts(fs))

		return fs->path;

	return NULL;

}

static const char *fs__mountpoint(int idx)