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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/lib/api/fs/fs.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/lib/api/fs/fs.c')
-rw-r--r-- | tools/lib/api/fs/fs.c | 558 |
1 files changed, 558 insertions, 0 deletions
diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c new file mode 100644 index 000000000..82f53d81a --- /dev/null +++ b/tools/lib/api/fs/fs.c @@ -0,0 +1,558 @@ +// SPDX-License-Identifier: GPL-2.0 +#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" +#include "debug-internal.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 + +#ifndef HUGETLBFS_MAGIC +#define HUGETLBFS_MAGIC 0x958458f6 +#endif + +#ifndef BPF_FS_MAGIC +#define BPF_FS_MAGIC 0xcafe4a11 +#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, +}; + +static const char * const hugetlbfs__known_mountpoints[] = { + 0, +}; + +static const char * const bpf_fs__known_mountpoints[] = { + "/sys/fs/bpf", + 0, +}; + +struct fs { + const char *name; + const char * const *mounts; + char path[PATH_MAX]; + bool found; + bool checked; + long magic; +}; + +enum { + FS__SYSFS = 0, + FS__PROCFS = 1, + FS__DEBUGFS = 2, + FS__TRACEFS = 3, + FS__HUGETLBFS = 4, + FS__BPF_FS = 5, +}; + +#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, + .checked = false, + }, + [FS__PROCFS] = { + .name = "proc", + .mounts = procfs__known_mountpoints, + .magic = PROC_SUPER_MAGIC, + .checked = false, + }, + [FS__DEBUGFS] = { + .name = "debugfs", + .mounts = debugfs__known_mountpoints, + .magic = DEBUGFS_MAGIC, + .checked = false, + }, + [FS__TRACEFS] = { + .name = "tracefs", + .mounts = tracefs__known_mountpoints, + .magic = TRACEFS_MAGIC, + .checked = false, + }, + [FS__HUGETLBFS] = { + .name = "hugetlbfs", + .mounts = hugetlbfs__known_mountpoints, + .magic = HUGETLBFS_MAGIC, + .checked = false, + }, + [FS__BPF_FS] = { + .name = "bpf", + .mounts = bpf_fs__known_mountpoints, + .magic = BPF_FS_MAGIC, + .checked = false, + }, +}; + +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); + fs->checked = true; + 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/admin-guide/sysfs-rules.rst + * 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; + fs->checked = true; + strncpy(fs->path, override_path, sizeof(fs->path) - 1); + fs->path[sizeof(fs->path) - 1] = '\0'; + 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; + + /* the mount point was already checked for the mount point + * but and did not exist, so return NULL to avoid scanning again. + * This makes the found and not found paths cost equivalent + * in case of multiple calls. + */ + if (fs->checked) + return NULL; + + 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); +FS(hugetlbfs, FS__HUGETLBFS); +FS(bpf_fs, FS__BPF_FS); + +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; +} + +static int filename__read_ull_base(const char *filename, + unsigned long long *value, int base) +{ + 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, base); + if (*value != ULLONG_MAX) + err = 0; + } + + close(fd); + return err; +} + +/* + * Parses @value out of @filename with strtoull. + * By using 16 for base to treat the number as hex. + */ +int filename__read_xll(const char *filename, unsigned long long *value) +{ + return filename__read_ull_base(filename, value, 16); +} + +/* + * Parses @value out of @filename with strtoull. + * By using 0 for base, the strtoull detects the + * base automatically (see man strtoull). + */ +int filename__read_ull(const char *filename, unsigned long long *value) +{ + return filename__read_ull_base(filename, value, 0); +} + +#define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */ + +int filename__read_str(const char *filename, char **buf, size_t *sizep) +{ + size_t size = 0, alloc_size = 0; + void *bf = NULL, *nbf; + int fd, n, err = 0; + char sbuf[STRERR_BUFSIZE]; + + fd = open(filename, O_RDONLY); + if (fd < 0) + return -errno; + + do { + if (size == alloc_size) { + alloc_size += BUFSIZ; + nbf = realloc(bf, alloc_size); + if (!nbf) { + err = -ENOMEM; + break; + } + + bf = nbf; + } + + n = read(fd, bf + size, alloc_size - size); + if (n < 0) { + if (size) { + pr_warn("read failed %d: %s\n", errno, + strerror_r(errno, sbuf, sizeof(sbuf))); + err = 0; + } else + err = -errno; + + break; + } + + size += n; + } while (n > 0); + + if (!err) { + *sizep = size; + *buf = bf; + } else + free(bf); + + close(fd); + return err; +} + +int filename__write_int(const char *filename, int value) +{ + int fd = open(filename, O_WRONLY), err = -1; + char buf[64]; + + if (fd < 0) + return err; + + sprintf(buf, "%d", value); + if (write(fd, buf, sizeof(buf)) == sizeof(buf)) + err = 0; + + close(fd); + return err; +} + +int procfs__read_str(const char *entry, char **buf, size_t *sizep) +{ + char path[PATH_MAX]; + const char *procfs = procfs__mountpoint(); + + if (!procfs) + return -1; + + snprintf(path, sizeof(path), "%s/%s", procfs, entry); + + return filename__read_str(path, buf, sizep); +} + +static int sysfs__read_ull_base(const char *entry, + unsigned long long *value, int base) +{ + 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_base(path, value, base); +} + +int sysfs__read_xll(const char *entry, unsigned long long *value) +{ + return sysfs__read_ull_base(entry, value, 16); +} + +int sysfs__read_ull(const char *entry, unsigned long long *value) +{ + return sysfs__read_ull_base(entry, value, 0); +} + +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 sysfs__read_str(const char *entry, char **buf, size_t *sizep) +{ + char path[PATH_MAX]; + const char *sysfs = sysfs__mountpoint(); + + if (!sysfs) + return -1; + + snprintf(path, sizeof(path), "%s/%s", sysfs, entry); + + return filename__read_str(path, buf, sizep); +} + +int sysfs__read_bool(const char *entry, bool *value) +{ + char *buf; + size_t size; + int ret; + + ret = sysfs__read_str(entry, &buf, &size); + if (ret < 0) + return ret; + + switch (buf[0]) { + case '1': + case 'y': + case 'Y': + *value = true; + break; + case '0': + case 'n': + case 'N': + *value = false; + break; + default: + ret = -1; + } + + free(buf); + + return ret; +} +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); +} + +int sysfs__write_int(const char *entry, int value) +{ + char path[PATH_MAX]; + const char *sysfs = sysfs__mountpoint(); + + if (!sysfs) + return -1; + + if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX) + return -1; + + return filename__write_int(path, value); +} |