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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 | #include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/vfs.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>
#include "fs.h"
#define _STR(x) #x
#define STR(x) _STR(x)
#ifndef SYSFS_MAGIC
#define SYSFS_MAGIC 0x62656572
#endif
#ifndef PROC_SUPER_MAGIC
#define PROC_SUPER_MAGIC 0x9fa0
#endif
#ifndef DEBUGFS_MAGIC
#define DEBUGFS_MAGIC 0x64626720
#endif
#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC 0x74726163
#endif
static const char * const sysfs__fs_known_mountpoints[] = {
"/sys",
0,
};
static const char * const procfs__known_mountpoints[] = {
"/proc",
0,
};
#ifndef DEBUGFS_DEFAULT_PATH
#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
#endif
static const char * const debugfs__known_mountpoints[] = {
DEBUGFS_DEFAULT_PATH,
"/debug",
0,
};
#ifndef TRACEFS_DEFAULT_PATH
#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
#endif
static const char * const tracefs__known_mountpoints[] = {
TRACEFS_DEFAULT_PATH,
"/sys/kernel/debug/tracing",
"/tracing",
"/trace",
0,
};
struct fs {
const char *name;
const char * const *mounts;
char path[PATH_MAX];
bool found;
long magic;
};
enum {
FS__SYSFS = 0,
FS__PROCFS = 1,
FS__DEBUGFS = 2,
FS__TRACEFS = 3,
};
#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC 0x74726163
#endif
static struct fs fs__entries[] = {
[FS__SYSFS] = {
.name = "sysfs",
.mounts = sysfs__fs_known_mountpoints,
.magic = SYSFS_MAGIC,
},
[FS__PROCFS] = {
.name = "proc",
.mounts = procfs__known_mountpoints,
.magic = PROC_SUPER_MAGIC,
},
[FS__DEBUGFS] = {
.name = "debugfs",
.mounts = debugfs__known_mountpoints,
.magic = DEBUGFS_MAGIC,
},
[FS__TRACEFS] = {
.name = "tracefs",
.mounts = tracefs__known_mountpoints,
.magic = TRACEFS_MAGIC,
},
};
static bool fs__read_mounts(struct fs *fs)
{
bool found = false;
char type[100];
FILE *fp;
fp = fopen("/proc/mounts", "r");
if (fp == NULL)
return NULL;
while (!found &&
fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
fs->path, type) == 2) {
if (strcmp(type, fs->name) == 0)
found = true;
}
fclose(fp);
return fs->found = found;
}
static int fs__valid_mount(const char *fs, long magic)
{
struct statfs st_fs;
if (statfs(fs, &st_fs) < 0)
return -ENOENT;
else if ((long)st_fs.f_type != magic)
return -ENOENT;
return 0;
}
static bool fs__check_mounts(struct fs *fs)
{
const char * const *ptr;
ptr = fs->mounts;
while (*ptr) {
if (fs__valid_mount(*ptr, fs->magic) == 0) {
fs->found = true;
strcpy(fs->path, *ptr);
return true;
}
ptr++;
}
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;
if (fs__read_mounts(fs))
return fs->path;
return NULL;
}
static const char *fs__mountpoint(int idx)
{
struct fs *fs = &fs__entries[idx];
if (fs->found)
return (const char *)fs->path;
return fs__get_mountpoint(fs);
}
static const char *mount_overload(struct fs *fs)
{
size_t name_len = strlen(fs->name);
/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
char upper_name[5 + name_len + 12 + 1];
snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
mem_toupper(upper_name, name_len);
return getenv(upper_name) ?: *fs->mounts;
}
static const char *fs__mount(int idx)
{
struct fs *fs = &fs__entries[idx];
const char *mountpoint;
if (fs__mountpoint(idx))
return (const char *)fs->path;
mountpoint = mount_overload(fs);
if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
return NULL;
return fs__check_mounts(fs) ? fs->path : NULL;
}
#define FS(name, idx) \
const char *name##__mountpoint(void) \
{ \
return fs__mountpoint(idx); \
} \
\
const char *name##__mount(void) \
{ \
return fs__mount(idx); \
} \
\
bool name##__configured(void) \
{ \
return name##__mountpoint() != NULL; \
}
FS(sysfs, FS__SYSFS);
FS(procfs, FS__PROCFS);
FS(debugfs, FS__DEBUGFS);
FS(tracefs, FS__TRACEFS);
int filename__read_int(const char *filename, int *value)
{
char line[64];
int fd = open(filename, O_RDONLY), err = -1;
if (fd < 0)
return -1;
if (read(fd, line, sizeof(line)) > 0) {
*value = atoi(line);
err = 0;
}
close(fd);
return err;
}
int filename__read_ull(const char *filename, unsigned long long *value)
{
char line[64];
int fd = open(filename, O_RDONLY), err = -1;
if (fd < 0)
return -1;
if (read(fd, line, sizeof(line)) > 0) {
*value = strtoull(line, NULL, 10);
if (*value != ULLONG_MAX)
err = 0;
}
close(fd);
return err;
}
int sysfs__read_ull(const char *entry, unsigned long long *value)
{
char path[PATH_MAX];
const char *sysfs = sysfs__mountpoint();
if (!sysfs)
return -1;
snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
return filename__read_ull(path, value);
}
int sysfs__read_int(const char *entry, int *value)
{
char path[PATH_MAX];
const char *sysfs = sysfs__mountpoint();
if (!sysfs)
return -1;
snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
return filename__read_int(path, value);
}
int sysctl__read_int(const char *sysctl, int *value)
{
char path[PATH_MAX];
const char *procfs = procfs__mountpoint();
if (!procfs)
return -1;
snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
return filename__read_int(path, value);
}
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