FYI I only tested this with checkfc...
> -----Original Message-----
> From: Roberts, William C
> Sent: Monday, September 19, 2016 2:45 PM
> To: selinux@xxxxxxxxxxxxx; seandroid-list@xxxxxxxxxxxxx; sds@xxxxxxxxxxxxx;
> jdanis@xxxxxxxxxx
> Cc: Roberts, William C <william.c.roberts@xxxxxxxxx>
> Subject: [RFC] mmap file_contexts and property_contexts:
>
> From: William Roberts <william.c.roberts@xxxxxxxxx>
>
> THIS IS WIP...
>
> Rather than using stdio and making copies, just mmap the files and use the
> pointers in place. The affect of this change, is that text file load time is now faster
> than binary load time by 4.7% when testing with a file_contexts file from the
> Android tree. Note that the Android doesn't use monstrous regexs.
>
> Times are the average of 3 runs.
>
> BEFORE:
> Text file allocs: 114803
> Text file load time: 0.266101
> Bin file allocs: 93073
> Bin file load time: 0.248757667
>
> AFTER:
> Text file allocs: 103933
> Text file load time: 0.236192667
> Bin file allocs: 87645
> Bin file load time: .247607333
>
> THINGS TO DO:
> 1. What's arm performance like?
> 2. What interfaces to backends are busted by this (if any)?
> 3. Test Android Properties
> 4. Im pretty sure this breaks sefcontext_compile, fix.
> 5. Test with PCRE2 enabled.
> 6. Spell check this message!
> 7. Run checkpatch
>
> Signed-off-by: William Roberts <william.c.roberts@xxxxxxxxx>
> ---
> libselinux/src/label.c | 2 -
> libselinux/src/label_android_property.c | 22 ++---
> libselinux/src/label_file.c | 140 +++++++++++++++++++-------------
> libselinux/src/label_file.h | 66 +++++++++------
> libselinux/src/label_internal.h | 3 +-
> libselinux/src/label_support.c | 79 ++++++++----------
> 6 files changed, 172 insertions(+), 140 deletions(-)
>
> diff --git a/libselinux/src/label.c b/libselinux/src/label.c index 963bfcb..d767b49
> 100644
> --- a/libselinux/src/label.c
> +++ b/libselinux/src/label.c
> @@ -15,8 +15,6 @@
> #include "callbacks.h"
> #include "label_internal.h"
>
> -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> -
> typedef int (*selabel_initfunc)(struct selabel_handle *rec,
> const struct selinux_opt *opts,
> unsigned nopts);
> diff --git a/libselinux/src/label_android_property.c
> b/libselinux/src/label_android_property.c
> index 290b438..2aac394 100644
> --- a/libselinux/src/label_android_property.c
> +++ b/libselinux/src/label_android_property.c
> @@ -85,13 +85,19 @@ static int process_line(struct selabel_handle *rec,
> int pass, unsigned lineno)
> {
> int items;
> - char *prop = NULL, *context = NULL;
> + union {
> + struct {
> + char *prop;
> + char *context;
> + };
> + char *array[2];
> + } found = { .array = { 0 } };
> struct saved_data *data = (struct saved_data *)rec->data;
> spec_t *spec_arr = data->spec_arr;
> unsigned int nspec = data->nspec;
> const char *errbuf = NULL;
>
> - items = read_spec_entries(line_buf, &errbuf, 2, &prop, &context);
> + items = read_spec_entries(line_buf, &errbuf, ARRAY_SIZE(found.array),
> +found.array);
> if (items < 0) {
> items = errno;
> selinux_log(SELINUX_ERROR,
> @@ -108,18 +114,14 @@ static int process_line(struct selabel_handle *rec,
> selinux_log(SELINUX_ERROR,
> "%s: line %u is missing fields\n", path,
> lineno);
> - free(prop);
> errno = EINVAL;
> return -1;
> }
>
> - if (pass == 0) {
> - free(prop);
> - free(context);
> - } else if (pass == 1) {
> + if (pass == 1) {
> /* On the second pass, process and store the specification in
> spec. */
> - spec_arr[nspec].property_key = prop;
> - spec_arr[nspec].lr.ctx_raw = context;
> + spec_arr[nspec].property_key = found.prop;
> + spec_arr[nspec].lr.ctx_raw = found.context;
>
> if (rec->validating) {
> if (selabel_validate(rec, &spec_arr[nspec].lr) < 0) { @@ -
> 234,7 +236,7 @@ static void closef(struct selabel_handle *rec)
> for (i = 0; i < data->nspec; i++) {
> spec = &data->spec_arr[i];
> free(spec->property_key);
> - free(spec->lr.ctx_raw);
> + //free(spec->lr.ctx_raw);
> free(spec->lr.ctx_trans);
> }
>
> diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index
> 7156825..4dc440e 100644
> --- a/libselinux/src/label_file.c
> +++ b/libselinux/src/label_file.c
> @@ -96,43 +96,64 @@ static int nodups_specs(struct saved_data *data, const
> char *path)
> return rc;
> }
>
> -static int process_text_file(FILE *fp, const char *prefix,
> - struct selabel_handle *rec, const char *path)
> +static inline struct saved_data *rec_to_data(struct selabel_handle
> +*rec) {
> + return (struct saved_data *)rec->data; }
> +
> +static char *mmap_area_get_line(struct mmap_area *area) {
> + size_t len = area->next_len;
> + if (!len)
> + return NULL;
> +
> + char *start = area->next_addr;
> + char *end = memchr(start, '\n', len);
> +
> + /* the file may not end with a newline */
> + if (!end)
> + end = (char *)area->next_addr + len - 1;
> +
> + *end = '\0';
> + /* len includes null byte */
> + len = end - start;
> +
> + area->next_len -= len + 1;
> + area->next_addr = ++end;
> + return start;
> +}
> +
> +static int process_text_file(const char *path, const char *prefix,
> + struct selabel_handle *rec)
> {
> int rc;
> - size_t line_len;
> unsigned int lineno = 0;
> - char *line_buf = NULL;
> + char *line_buf;
> + struct mmap_area *areas = rec_to_data(rec)->mmap_areas;
> +
> + /* mmap_area_get_line() and process_line() require mutable string
> pointers */
> + rc = mprotect(areas->addr, areas->len, PROT_READ | PROT_WRITE);
> + if (rc < 0)
> + goto out;
>
> - while (getline(&line_buf, &line_len, fp) > 0) {
> + while ( (line_buf = mmap_area_get_line(areas)) ) {
> rc = process_line(rec, path, prefix, line_buf, ++lineno);
> if (rc)
> goto out;
> }
> rc = 0;
> out:
> - free(line_buf);
> return rc;
> }
>
> -static int load_mmap(FILE *fp, size_t len, struct selabel_handle *rec,
> - const char *path)
> +static int mmap_file(FILE *fp, size_t len, struct saved_data *data)
> {
> - struct saved_data *data = (struct saved_data *)rec->data;
> - int rc;
> - char *addr, *str_buf;
> - int *stem_map;
> - struct mmap_area *mmap_area;
> - uint32_t i, magic, version;
> - uint32_t entry_len, stem_map_len, regex_array_len;
> - const char *reg_version;
> -
> - mmap_area = malloc(sizeof(*mmap_area));
> + struct mmap_area *mmap_area = malloc(sizeof(*mmap_area));
> if (!mmap_area) {
> return -1;
> }
>
> - addr = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
> + void *addr = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
> if (addr == MAP_FAILED) {
> free(mmap_area);
> perror("mmap");
> @@ -145,17 +166,26 @@ static int load_mmap(FILE *fp, size_t len, struct
> selabel_handle *rec,
> mmap_area->next = data->mmap_areas;
> data->mmap_areas = mmap_area;
>
> - /* check if this looks like an fcontext file */
> - rc = next_entry(&magic, mmap_area, sizeof(uint32_t));
> - if (rc < 0 || magic != SELINUX_MAGIC_COMPILED_FCONTEXT)
> - return -1;
> + return 0;
> +}
> +
> +static int process_binary_file(const char *path, struct selabel_handle
> +*rec) {
> + struct saved_data *data = (struct saved_data *)rec->data;
> + int rc;
> + char *str_buf;
> + int *stem_map;
> + struct mmap_area *mmap_area = data->mmap_areas;
> + uint32_t i, version;
> + uint32_t entry_len, stem_map_len, regex_array_len;
> + size_t len;
>
> /* check if this version is higher than we understand */
> rc = next_entry(&version, mmap_area, sizeof(uint32_t));
> if (rc < 0 || version > SELINUX_COMPILED_FCONTEXT_MAX_VERS)
> return -1;
>
> - reg_version = regex_version();
> + const char *reg_version = regex_version();
> if (!reg_version)
> return -1;
>
> @@ -235,12 +265,11 @@ static int load_mmap(FILE *fp, size_t len, struct
> selabel_handle *rec,
> /* store the mapping between old and new */
> newid = find_stem(data, buf, stem_len);
> if (newid < 0) {
> - newid = store_stem(data, buf, stem_len);
> + newid = store_stem(data, buf, stem_len, true);
> if (newid < 0) {
> rc = newid;
> goto out;
> }
> - data->stem_arr[newid].from_mmap = 1;
> }
> stem_map[i] = newid;
> }
> @@ -262,7 +291,6 @@ static int load_mmap(FILE *fp, size_t len, struct
> selabel_handle *rec,
> goto out;
>
> spec = &data->spec_arr[data->nspec];
> - spec->from_mmap = 1;
>
> /* Process context */
> rc = next_entry(&entry_len, mmap_area, sizeof(uint32_t)); @@ -
> 271,22 +299,10 @@ static int load_mmap(FILE *fp, size_t len, struct
> selabel_handle *rec,
> goto out;
> }
>
> - str_buf = malloc(entry_len);
> - if (!str_buf) {
> - rc = -1;
> - goto out;
> - }
> - rc = next_entry(str_buf, mmap_area, entry_len);
> + rc = next_pstr(&spec->lr.ctx_raw, mmap_area, entry_len);
> if (rc < 0)
> goto out;
>
> - if (str_buf[entry_len - 1] != '\0') {
> - free(str_buf);
> - rc = -1;
> - goto out;
> - }
> - spec->lr.ctx_raw = str_buf;
> -
> if (strcmp(spec->lr.ctx_raw, "<<none>>") && rec->validating) {
> if (selabel_validate(rec, &spec->lr) < 0) {
> selinux_log(SELINUX_ERROR,
> @@ -401,17 +417,29 @@ static char *rolling_append(char *current, const char
> *suffix, size_t max)
> return current;
> }
>
> -static bool fcontext_is_binary(FILE *fp)
> +static inline int mmap_area_rewind(struct mmap_area *area, size_t
> +bytes) {
> + if (area->next_len + bytes > area->len)
> + return -1;
> +
> + area->next_addr = (char *) area->next_addr - bytes;
> + area->next_len += bytes;
> + return 0;
> +}
> +
> +static bool fcontext_is_binary(struct mmap_area *area)
> {
> uint32_t magic;
> + bool is_binary = false;
>
> - size_t len = fread(&magic, sizeof(magic), 1, fp);
> - rewind(fp);
> + int rc = next_entry(&magic, area, sizeof(magic));
>
> - return (len && (magic == SELINUX_MAGIC_COMPILED_FCONTEXT));
> -}
> + is_binary = (!rc && (magic == SELINUX_MAGIC_COMPILED_FCONTEXT));
> + if (!is_binary)
> + mmap_area_rewind(area, sizeof(magic));
>
> -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> + return is_binary;
> +}
>
> static FILE *open_file(const char *path, const char *suffix,
> char *save_path, size_t len, struct stat *sb, bool open_oldest) @@ -
> 504,12 +532,17 @@ static int process_file(const char *path, const char *suffix,
> if (fp == NULL)
> return -1;
>
> - rc = fcontext_is_binary(fp) ?
> - load_mmap(fp, sb.st_size, rec, found_path) :
> - process_text_file(fp, prefix, rec, found_path);
> + rc = mmap_file(fp, sb.st_size, rec_to_data(rec));
> + if (rc < 0) {
> + fclose(fp);
> + return -1;
> + }
> +
> + rc = fcontext_is_binary(rec_to_data(rec)->mmap_areas) ?
> + process_binary_file(found_path, rec) :
> + process_text_file(found_path, prefix, rec);
> if (!rc)
> - rc = digest_add_specfile(digest, fp, NULL, sb.st_size,
> - found_path);
> + rc = digest_add_specfile(digest, fp, NULL, sb.st_size,
> found_path);
>
> fclose(fp);
>
> @@ -613,12 +646,7 @@ static void closef(struct selabel_handle *rec)
> for (i = 0; i < data->nspec; i++) {
> spec = &data->spec_arr[i];
> free(spec->lr.ctx_trans);
> - free(spec->lr.ctx_raw);
> regex_data_free(spec->regex);
> - if (spec->from_mmap)
> - continue;
> - free(spec->regex_str);
> - free(spec->type_str);
> }
>
> for (i = 0; i < (unsigned int)data->num_stems; i++) { diff --git
> a/libselinux/src/label_file.h b/libselinux/src/label_file.h index 88f4294..2704906
> 100644
> --- a/libselinux/src/label_file.h
> +++ b/libselinux/src/label_file.h
> @@ -37,7 +37,6 @@ struct spec {
> int matches; /* number of matching pathnames */
> int stem_id; /* indicates which stem-compression item */
> char hasMetaChars; /* regular expression has meta-chars */
> - char from_mmap; /* this spec is from an mmap of the data
> */
> size_t prefix_len; /* length of fixed path prefix */
> };
>
> @@ -255,7 +254,7 @@ static inline int find_stem(struct saved_data *data, const
> char *buf, }
>
> /* returns the index of the new stored object */ -static inline int
> store_stem(struct saved_data *data, char *buf, int stem_len)
> +static inline int store_stem(struct saved_data *data, char *buf, int
> +stem_len, bool from_mmap)
> {
> int num = data->num_stems;
>
> @@ -271,7 +270,7 @@ static inline int store_stem(struct saved_data *data, char
> *buf, int stem_len)
> }
> data->stem_arr[num].len = stem_len;
> data->stem_arr[num].buf = buf;
> - data->stem_arr[num].from_mmap = 0;
> + data->stem_arr[num].from_mmap = from_mmap;
> data->num_stems++;
>
> return num;
> @@ -298,7 +297,7 @@ static inline int find_stem_from_spec(struct saved_data
> *data, const char *buf)
> if (!stem)
> return -1;
>
> - return store_stem(data, stem, stem_len);
> + return store_stem(data, stem, stem_len, false);
> }
>
> /* This will always check for buffer over-runs and either read the next entry @@
> -317,6 +316,22 @@ static inline int next_entry(void *buf, struct mmap_area *fp,
> size_t bytes)
> return 0;
> }
>
> +static inline int next_pstr(char **str, struct mmap_area *fp, size_t
> +len) {
> + if (len > fp->next_len)
> + return -1;
> +
> + char *tmp = (char *)fp->next_addr;
> + if (tmp[len-1] != '\0')
> + return -1;
> +
> + *str = tmp;
> +
> + fp->next_addr = (char *)fp->next_addr + len;
> + fp->next_len -= len;
> + return 0;
> +}
> +
> static inline int compile_regex(struct saved_data *data, struct spec *spec,
> const char **errbuf)
> {
> @@ -375,13 +390,21 @@ static inline int process_line(struct selabel_handle *rec,
> char *line_buf, unsigned lineno)
> {
> int items, len, rc;
> - char *regex = NULL, *type = NULL, *context = NULL;
> + union {
> + struct {
> + char *regex;
> + char *type;
> + char *context;
> + };
> + char *array[3];
> + } found = { .array = { 0 } };
> +
> struct saved_data *data = (struct saved_data *)rec->data;
> struct spec *spec_arr;
> unsigned int nspec = data->nspec;
> const char *errbuf = NULL;
>
> - items = read_spec_entries(line_buf, &errbuf, 3, ®ex, &type,
> &context);
> + items = read_spec_entries(line_buf, &errbuf, ARRAY_SIZE(found.array),
> +found.array);
> if (items < 0) {
> rc = errno;
> selinux_log(SELINUX_ERROR,
> @@ -398,22 +421,17 @@ static inline int process_line(struct selabel_handle *rec,
> COMPAT_LOG(SELINUX_ERROR,
> "%s: line %u is missing fields\n", path,
> lineno);
> - if (items == 1)
> - free(regex);
> errno = EINVAL;
> return -1;
> } else if (items == 2) {
> /* The type field is optional. */
> - context = type;
> - type = 0;
> + found.context = found.type;
> + found.type = NULL;
> }
>
> - len = get_stem_from_spec(regex);
> - if (len && prefix && strncmp(prefix, regex, len)) {
> + len = get_stem_from_spec(found.regex);
> + if (len && prefix && strncmp(prefix, found.regex, len)) {
> /* Stem of regex does not match requested prefix, discard. */
> - free(regex);
> - free(type);
> - free(context);
> return 0;
> }
>
> @@ -424,13 +442,13 @@ static inline int process_line(struct selabel_handle *rec,
> spec_arr = data->spec_arr;
>
> /* process and store the specification in spec. */
> - spec_arr[nspec].stem_id = find_stem_from_spec(data, regex);
> - spec_arr[nspec].regex_str = regex;
> + spec_arr[nspec].stem_id = find_stem_from_spec(data, found.regex);
> + spec_arr[nspec].regex_str = found.regex;
>
> - spec_arr[nspec].type_str = type;
> + spec_arr[nspec].type_str = found.type;
> spec_arr[nspec].mode = 0;
>
> - spec_arr[nspec].lr.ctx_raw = context;
> + spec_arr[nspec].lr.ctx_raw = found.context;
>
> /*
> * bump data->nspecs to cause closef() to cover it in its free @@ -442,18
> +460,18 @@ static inline int process_line(struct selabel_handle *rec,
> && compile_regex(data, &spec_arr[nspec], &errbuf)) {
> COMPAT_LOG(SELINUX_ERROR,
> "%s: line %u has invalid regex %s: %s\n",
> - path, lineno, regex, errbuf);
> + path, lineno, found.regex, errbuf);
> errno = EINVAL;
> return -1;
> }
>
> - if (type) {
> - mode_t mode = string_to_mode(type);
> + if (found.type) {
> + mode_t mode = string_to_mode(found.type);
>
> if (mode == (mode_t)-1) {
> COMPAT_LOG(SELINUX_ERROR,
> "%s: line %u has invalid file type %s\n",
> - path, lineno, type);
> + path, lineno, found.type);
> errno = EINVAL;
> return -1;
> }
> @@ -464,7 +482,7 @@ static inline int process_line(struct selabel_handle *rec,
> * any meta characters in the RE */
> spec_hasMetaChars(&spec_arr[nspec]);
>
> - if (strcmp(context, "<<none>>") && rec->validating)
> + if (strcmp(found.context, "<<none>>") && rec->validating)
> compat_validate(rec, &spec_arr[nspec].lr, path, lineno);
>
> return 0;
> diff --git a/libselinux/src/label_internal.h b/libselinux/src/label_internal.h index
> aa48fff..e40d68b 100644
> --- a/libselinux/src/label_internal.h
> +++ b/libselinux/src/label_internal.h
> @@ -136,10 +136,11 @@ compat_validate(struct selabel_handle *rec,
> struct selabel_lookup_rec *contexts,
> const char *path, unsigned lineno) hidden;
>
> +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> /*
> * The read_spec_entries function may be used to
> * replace sscanf to read entries from spec files.
> */
> -extern int read_spec_entries(char *line_buf, const char **errbuf, int num_args,
> ...);
> +extern int hidden read_spec_entries(char *line_buf, const char
> +**errbuf, unsigned int num, char *found[]);
>
> #endif /* _SELABEL_INTERNAL_H_ */
> diff --git a/libselinux/src/label_support.c b/libselinux/src/label_support.c index
> 26f9ef1..3f5728d 100644
> --- a/libselinux/src/label_support.c
> +++ b/libselinux/src/label_support.c
> @@ -17,39 +17,40 @@
> * Read an entry from a spec file (e.g. file_contexts)
> * entry - Buffer to allocate for the entry.
> * ptr - current location of the line to be processed.
> - * returns - 0 on success and *entry is set to be a null
> - * terminated value. On Error it returns -1 and
> - * errno will be set.
> + * returns - a pointer to the begining of the string.
> + * that is the
> *
> */
> -static inline int read_spec_entry(char **entry, char **ptr, int *len, const char
> **errbuf)
> +static inline char *read_spec_entry(char **current, const char
> +**errbuf)
> {
> - *entry = NULL;
> - char *tmp_buf = NULL;
> -
> - while (isspace(**ptr) && **ptr != '\0')
> - (*ptr)++;
> + if(!**current) {
> + (*current)++;
> + return NULL;
> + }
>
> - tmp_buf = *ptr;
> - *len = 0;
> + while (isspace(**current) && **current != '\0')
> + (*current)++;
>
> - while (!isspace(**ptr) && **ptr != '\0') {
> - if (!isascii(**ptr)) {
> + char *start = *current;
> + while (!isspace(**current) && **current != '\0') {
> + if (!isascii(**current)) {
> errno = EINVAL;
> *errbuf = "Non-ASCII characters found";
> - return -1;
> + return NULL;
> }
> - (*ptr)++;
> - (*len)++;
> + (*current)++;
> }
>
> - if (*len) {
> - *entry = strndup(tmp_buf, *len);
> - if (!*entry)
> - return -1;
> - }
> + char *end = *current;
>
> - return 0;
> + if (start == end)
> + return NULL;
> +
> + if (*end != '\0') {
> + *end = '\0';
> + (*current)++;
> + }
> + return start;
> }
>
> /*
> @@ -63,15 +64,13 @@ static inline int read_spec_entry(char **entry, char **ptr,
> int *len, const char
> * This function calls read_spec_entry() to do the actual string processing.
> * As such, can return anything from that function as well.
> */
> -int hidden read_spec_entries(char *line_buf, const char **errbuf, int num_args,
> ...)
> +int hidden read_spec_entries(char *line_buf, const char **errbuf,
> +unsigned int num, char *found[])
> {
> - char **spec_entry, *buf_p;
> - int len, rc, items, entry_len = 0;
> - va_list ap;
> -
> + char*buf_p;
> + unsigned int items = 0;
> *errbuf = NULL;
>
> - len = strlen(line_buf);
> + size_t len = strlen(line_buf);
> if (line_buf[len - 1] == '\n')
> line_buf[len - 1] = '\0';
> else
> @@ -89,26 +88,12 @@ int hidden read_spec_entries(char *line_buf, const char
> **errbuf, int num_args,
> return 0;
>
> /* Process the spec file entries */
> - va_start(ap, num_args);
> -
> - items = 0;
> - while (items < num_args) {
> - spec_entry = va_arg(ap, char **);
> -
> - if (len - 1 == buf_p - line_buf) {
> - va_end(ap);
> - return items;
> - }
> -
> - rc = read_spec_entry(spec_entry, &buf_p, &entry_len, errbuf);
> - if (rc < 0) {
> - va_end(ap);
> - return rc;
> - }
> - if (entry_len)
> - items++;
> + while (items < num) {
> + found[items] = read_spec_entry(&buf_p, errbuf);
> + if (!found[items])
> + break;
> + items++;
> }
> - va_end(ap);
> return items;
> }
>
> --
> 1.9.1
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