Often a file is expected to hold an integral value. Existing functions
will use a C stdlib function like atoi or strtol to parse the file.
These operations are error prone, with complicated error conditions
(atoi returns 0 if not a number, and is undefined behaviour if not in
range. strtol returns 0 if not a number, and LONG_MIN/MAX if not in
range + sets errno to ERANGE).
Signed-off-by: Benjamin Gray <bg...@linux.ibm.com>
---
v4: * Implement as C functions, remove macros
* Declare parsers for intmax_t, uintmax_t
* Stop validating the remaining buffer after a null terminator
* Set errno to match the return code
---
.../testing/selftests/powerpc/include/utils.h | 7 +
tools/testing/selftests/powerpc/pmu/lib.c | 6 +-
tools/testing/selftests/powerpc/utils.c | 126 +++++++++++++++++-
3 files changed, 132 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/powerpc/include/utils.h
b/tools/testing/selftests/powerpc/include/utils.h
index de5e3790f397..7c1fa385824c 100644
--- a/tools/testing/selftests/powerpc/include/utils.h
+++ b/tools/testing/selftests/powerpc/include/utils.h
@@ -33,6 +33,13 @@ void *get_auxv_entry(int type);
int pick_online_cpu(void);
+int parse_intmax(const char *buffer, size_t count, intmax_t *result, int base);
+int parse_uintmax(const char *buffer, size_t count, uintmax_t *result, int
base);
+int parse_int(const char *buffer, size_t count, int *result, int base);
+int parse_uint(const char *buffer, size_t count, unsigned int *result, int
base);
+int parse_long(const char *buffer, size_t count, long *result, int base);
+int parse_ulong(const char *buffer, size_t count, unsigned long *result, int
base);
+
int read_file(const char *path, char *buf, size_t count, size_t *len);
int write_file(const char *path, const char *buf, size_t count);
int read_debugfs_file(const char *debugfs_file, char *buf, size_t count);
diff --git a/tools/testing/selftests/powerpc/pmu/lib.c
b/tools/testing/selftests/powerpc/pmu/lib.c
index 960915304a65..1cfc13a25aee 100644
--- a/tools/testing/selftests/powerpc/pmu/lib.c
+++ b/tools/testing/selftests/powerpc/pmu/lib.c
@@ -192,7 +192,6 @@ bool require_paranoia_below(int level)
{
int err;
long current;
- char *end;
char buf[16] = {0};
err = read_file(PARANOID_PATH, buf, sizeof(buf) - 1, NULL);
@@ -201,9 +200,8 @@ bool require_paranoia_below(int level)
return false;
}
- current = strtol(buf, &end, 10);
-
- if (end == buf) {
+ err = parse_long(buf, sizeof(buf), ¤t, 10);
+ if (err) {
printf("Couldn't parse " PARANOID_PATH "?\n");
return false;
}
diff --git a/tools/testing/selftests/powerpc/utils.c
b/tools/testing/selftests/powerpc/utils.c
index 495299a79f50..ddfd871881bf 100644
--- a/tools/testing/selftests/powerpc/utils.c
+++ b/tools/testing/selftests/powerpc/utils.c
@@ -8,6 +8,8 @@
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
#include <link.h>
#include <sched.h>
#include <stdio.h>
@@ -123,6 +125,126 @@ int write_debugfs_file(const char *subpath, const char
*buf, size_t count)
return write_file(path, buf, count);
}
+static int validate_int_parse(const char *buffer, size_t count, char *end)
+{
+ int err = 0;
+
+ /* Require at least one digit */
+ if (end == buffer) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ /* Require all remaining characters be whitespace-ish */
+ for (; end < buffer + count; end++) {
+ if (*end == '\0')
+ break;
+
+ if (*end != ' ' && *end != '\n') {
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+out:
+ errno = -err;
+ return err;
+}
+
+static int parse_bounded_int(const char *buffer, size_t count, intmax_t
*result,
+ int base, intmax_t min, intmax_t max)
+{
+ int err;
+ char *end;
+
+ errno = 0;
+ *result = strtoimax(buffer, &end, base);
+
+ if (errno)
+ return -errno;
+
+ err = validate_int_parse(buffer, count, end);
+ if (err)
+ goto out;
+
+ if (*result < min || *result > max)
+ err = -EOVERFLOW;
+
+out:
+ errno = -err;
+ return err;
+}
+
+static int parse_bounded_uint(const char *buffer, size_t count, uintmax_t
*result,
+ int base, uintmax_t max)
+{
+ int err = 0;
+ char *end;
+
+ errno = 0;
+ *result = strtoumax(buffer, &end, base);
+
+ if (errno)
+ return -errno;
+
+ err = validate_int_parse(buffer, count, end);
+ if (err)
+ goto out;
+
+ if (*result > max)
+ err = -EOVERFLOW;
+
+out:
+ errno = -err;
+ return err;
+}
+
+int parse_intmax(const char *buffer, size_t count, intmax_t *result, int base)
+{
+ return parse_bounded_int(buffer, count, result, base, INTMAX_MIN,
INTMAX_MAX);
+}
+
+int parse_uintmax(const char *buffer, size_t count, uintmax_t *result, int
base)
+{
+ return parse_bounded_uint(buffer, count, result, base, UINTMAX_MAX);
+}
+
+int parse_int(const char *buffer, size_t count, int *result, int base)
+{
+ intmax_t parsed;
+ int err = parse_bounded_int(buffer, count, &parsed, base, INT_MIN,
INT_MAX);
+
+ *result = parsed;
+ return err;
+}
+
+int parse_uint(const char *buffer, size_t count, unsigned int *result, int
base)
+{
+ uintmax_t parsed;
+ int err = parse_bounded_uint(buffer, count, &parsed, base, UINT_MAX);
+
+ *result = parsed;
+ return err;
+}
+
+int parse_long(const char *buffer, size_t count, long *result, int base)
+{
+ intmax_t parsed;
+ int err = parse_bounded_int(buffer, count, &parsed, base, LONG_MIN,
LONG_MAX);
+
+ *result = parsed;
+ return err;
+}
+
+int parse_ulong(const char *buffer, size_t count, unsigned long *result, int
base)
+{
+ uintmax_t parsed;
+ int err = parse_bounded_uint(buffer, count, &parsed, base, ULONG_MAX);
+
+ *result = parsed;
+ return err;
+}
+
void *find_auxv_entry(int type, char *auxv)
{
ElfW(auxv_t) *p;
@@ -224,9 +346,7 @@ int read_debugfs_int(const char *debugfs_file, int *result)
if (err)
return err;
- *result = atoi(value);
-
- return 0;
+ return parse_int(value, sizeof(value), result, 10);
}
int write_debugfs_int(const char *debugfs_file, int result)
--
2.39.1
