This patch allows the tokenizer previously introduced for libselinux to
use any delimiter for tokenization. Delimiters may be squashed by
setting the squash_delim flag to 1. When any whitespace delimiter is used,
isspace() allows any whitespace character to be used as the delimiter.
Previously, read_spec_entries() trimmed whitespace and ignored comments and
empty lines. This functionality has been removed as is now the
responsiblity of the caller to implement.
Signed-off-by: Yuli Khodorkovskiy <ykhodorkovskiy@xxxxxxxxxx>
---
libselinux/src/label_android_property.c | 11 ++-
libselinux/src/label_file.h | 10 ++-
libselinux/src/label_internal.h | 7 +-
libselinux/src/label_support.c | 129 +++++++++++++++++++-------------
4 files changed, 97 insertions(+), 60 deletions(-)
diff --git a/libselinux/src/label_android_property.c b/libselinux/src/label_android_property.c
index 4af9896..5c06ed3 100644
--- a/libselinux/src/label_android_property.c
+++ b/libselinux/src/label_android_property.c
@@ -90,9 +90,14 @@ static int process_line(struct selabel_handle *rec,
spec_t *spec_arr = data->spec_arr;
unsigned int nspec = data->nspec;
- items = read_spec_entries(line_buf, 2, &prop, &context);
- if (items <= 0)
- return items;
+ trim_buf(&line_buf);
+
+ /* Skip comment lines and empty lines. */
+ if (*line_buf == '#' || *line_buf == '\0') {
+ return 0;
+ }
+
+ items = tokenize(line_buf, 1, ' ', 2, &prop, &context);
if (items != 2) {
selinux_log(SELINUX_WARNING,
"%s: line %u is missing fields, skipping\n", path,
diff --git a/libselinux/src/label_file.h b/libselinux/src/label_file.h
index db961ba..3499da1 100644
--- a/libselinux/src/label_file.h
+++ b/libselinux/src/label_file.h
@@ -387,10 +387,14 @@ static inline int process_line(struct selabel_handle *rec,
unsigned int nspec = data->nspec;
const char *errbuf = NULL;
- items = read_spec_entries(line_buf, 3, ®ex, &type, &context);
- if (items <= 0)
- return items;
+ trim_buf(&line_buf);
+ /* Skip comment lines and empty lines. */
+ if (*line_buf == '#' || *line_buf == '\0') {
+ return 0;
+ }
+
+ items = tokenize(line_buf, 1, ' ', 3, ®ex, &type, &context);
if (items < 2) {
COMPAT_LOG(SELINUX_WARNING,
"%s: line %u is missing fields, skipping\n", path,
diff --git a/libselinux/src/label_internal.h b/libselinux/src/label_internal.h
index 861eca1..81a4f37 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -108,9 +108,10 @@ compat_validate(struct selabel_handle *rec,
const char *path, unsigned lineno) hidden;
/*
- * The read_spec_entries function may be used to
- * replace sscanf to read entries from spec files.
+ * The tokenize function may be used to
+ * replace sscanf.
*/
-extern int read_spec_entries(char *line_buf, int num_args, ...);
+extern int tokenize(char *line_buf, int squash_delim, char delim, int num_args, ...);
+extern void trim_buf(char **buf);
#endif /* _SELABEL_INTERNAL_H_ */
diff --git a/libselinux/src/label_support.c b/libselinux/src/label_support.c
index b3ab8ab..08ef303 100644
--- a/libselinux/src/label_support.c
+++ b/libselinux/src/label_support.c
@@ -11,88 +11,115 @@
#include "label_internal.h"
/*
- * The read_spec_entries and read_spec_entry functions may be used to
- * replace sscanf to read entries from spec files. The file and
- * property services now use these.
+ * The tokenize and tokenize_str functions may be used to
+ * replace sscanf to read tokens from buffers.
*/
-/* Read an entry from a spec file (e.g. file_contexts) */
-static inline int read_spec_entry(char **entry, char **ptr, int *len)
+/* Read a token from a buffer */
+static inline int tokenize_str(int squash_delim, char delim, char **str, char **ptr, int *len)
{
- *entry = NULL;
- char *tmp_buf = NULL;
+ char *tmp_buf = *ptr;
+ *str = NULL;
+
+ while (**ptr != '\0') {
+ if (isspace(delim) && isspace(**ptr)) {
+ (*ptr)++;
+ break;
+ } else if (!isspace(delim) && **ptr == delim) {
+ (*ptr)++;
+ break;
+ }
- while (isspace(**ptr) && **ptr != '\0')
(*ptr)++;
+ }
- tmp_buf = *ptr;
- *len = 0;
+ *len = *ptr - tmp_buf;
+ /* If the end of the string has not been reached, this will ensure the
+ * delimiter is not included when returning the token.
+ */
+ if (**ptr != '\0') {
+ (*len)--;
+ }
- while (!isspace(**ptr) && **ptr != '\0') {
- (*ptr)++;
- (*len)++;
+ *str = strndup(tmp_buf, *len);
+ if (!*str) {
+ return -1;
}
- if (*len) {
- *entry = strndup(tmp_buf, *len);
- if (!*entry)
- return -1;
+ while (**ptr != '\0' && squash_delim == 1) {
+ if (isspace(delim) && isspace(**ptr)) {
+ (*ptr)++;
+ } else if (!isspace(delim) && **ptr == delim) {
+ (*ptr)++;
+ } else {
+ break;
+ }
}
return 0;
}
/*
- * line_buf - Buffer containing the spec entries .
- * num_args - The number of spec parameter entries to process.
- * ... - A 'char **spec_entry' for each parameter.
+ * line_buf - Buffer containing string to tokenize.
+ * squash_delim - Whether or not to squash repeating delimiters in input data.
+ * Set to 1 to squash_delimiter or 0 to disable squashing delimiter.
+ * delim - The delimiter used to tokenize line_buf. A whitespace delimiter will
+ * be tokenized using isspace().
+ * num_args - The number of parameter entries to process.
+ * ... - A 'char **' for each parameter.
* returns - The number of items processed.
*
- * This function calls read_spec_entry() to do the actual string processing.
+ * This function calls tokenize_str() to do the actual string processing. The
+ * caller is responsible for calling free() on each additional argument. The
+ * function will not tokenize more than num_args and the last argument will
+ * contain the remaining content of line_buf.
*/
-int hidden read_spec_entries(char *line_buf, int num_args, ...)
+int tokenize(char *line_buf, int squash_delim, char delim, int num_args, ...)
{
- char **spec_entry, *buf_p;
- int len, rc, items, entry_len = 0;
+ char **arg, *buf_p;
+ int rc, items, arg_len = 0;
va_list ap;
- len = strlen(line_buf);
- if (line_buf[len - 1] == '\n')
- line_buf[len - 1] = '\0';
- else
- /* Handle case if line not \n terminated by bumping
- * the len for the check below (as the line is NUL
- * terminated by getline(3)) */
- len++;
-
buf_p = line_buf;
- while (isspace(*buf_p))
- buf_p++;
- /* Skip comment lines and empty lines. */
- if (*buf_p == '#' || *buf_p == '\0')
- return 0;
-
- /* Process the spec file entries */
+ /* Process the arguments */
va_start(ap, num_args);
- items = 0;
- while (items < num_args) {
- spec_entry = va_arg(ap, char **);
+ for (items = 0; items < num_args && *buf_p != '\0'; items++) {
+ arg = va_arg(ap, char **);
+
+ /* Save the remainder of the string in arg */
+ if (items == num_args - 1) {
+ *arg = strdup(buf_p);
+ if (*arg == NULL) {
+ goto exit;
+ }
- if (len - 1 == buf_p - line_buf) {
- va_end(ap);
- return items;
+ continue;
}
- rc = read_spec_entry(spec_entry, &buf_p, &entry_len);
+ rc = tokenize_str(squash_delim, delim, arg, &buf_p, &arg_len);
if (rc < 0) {
- va_end(ap);
- return rc;
+ goto exit;
}
- if (entry_len)
- items++;
}
+
+exit:
va_end(ap);
return items;
}
+
+/* This function removes leading whitespace. If the buffer ends in a newline,
+ * the newline is removed.
+ */
+void trim_buf(char **buf)
+{
+ int len = strlen(*buf);
+ if ((*buf)[len - 1] == '\n') {
+ (*buf)[len - 1] = '\0';
+ }
+
+ while (isspace(**buf)) {
+ (*buf)++;
+ }
+}
--
1.9.3
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