diff options
| author | Jim Meyering <meyering@redhat.com> | 2012-07-15 18:18:03 +0200 |
|---|---|---|
| committer | Jim Meyering <meyering@redhat.com> | 2012-07-15 19:11:45 +0200 |
| commit | ac00d23e1a90dc5a8cd0f6de0e61eb401d5089d5 (patch) | |
| tree | e94876b4676c65ad8b8fa84d9f5d7320944ba5df | |
| parent | e380221333f4efd8d49b29b2690375c36eb90505 (diff) | |
| download | coreutils-ac00d23e1a90dc5a8cd0f6de0e61eb401d5089d5.tar.xz | |
pinky,who: fix bug in latest change
* src/system.h (stzncpy): New function.
* src/pinky.c (print_entry): Use stzncpy, not stpncpy.
The latter does not NUL-terminate. I assumed that strncpy was
the only function with such a horrible API. Today I learned that
stpncpy also may not NUL-terminate its result.
The bugs were introduced in commit v8.17-48-gf79263d.
* src/who.c (print_user): Likewise.
Thanks to Erik Auerswald for spotting my error.
| -rw-r--r-- | src/pinky.c | 6 | ||||
| -rw-r--r-- | src/system.h | 14 | ||||
| -rw-r--r-- | src/who.c | 4 |
3 files changed, 19 insertions, 5 deletions
diff --git a/src/pinky.c b/src/pinky.c index c01b12427..385949aa8 100644 --- a/src/pinky.c +++ b/src/pinky.c @@ -215,7 +215,7 @@ print_entry (const STRUCT_UTMP *utmp_ent) absolute file name in ut_line. */ if ( ! IS_ABSOLUTE_FILE_NAME (utmp_ent->ut_line)) p = stpcpy (p, DEV_DIR_WITH_TRAILING_SLASH); - stpncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line)); + stzncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line)); if (stat (line, &stats) == 0) { @@ -235,7 +235,7 @@ print_entry (const STRUCT_UTMP *utmp_ent) struct passwd *pw; char name[UT_USER_SIZE + 1]; - stpncpy (name, UT_USER (utmp_ent), UT_USER_SIZE); + stzncpy (name, UT_USER (utmp_ent), UT_USER_SIZE); pw = getpwnam (name); if (pw == NULL) /* TRANSLATORS: Real name is unknown; at most 19 characters. */ @@ -276,7 +276,7 @@ print_entry (const STRUCT_UTMP *utmp_ent) char *display = NULL; /* Copy the host name into UT_HOST, and ensure it's nul terminated. */ - stpncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host)); + stzncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host)); /* Look for an X display. */ display = strchr (ut_host, ':'); diff --git a/src/system.h b/src/system.h index 5e3b3cbde..6907603e6 100644 --- a/src/system.h +++ b/src/system.h @@ -626,6 +626,20 @@ The following directory is part of the cycle:\n %s\n"), \ } \ while (0) +/* Like stpncpy, but do ensure that the result is NUL-terminated, + and do not NUL-pad out to LEN. I.e., when strnlen (src, len) == len, + this function writes a NUL byte into dest[len]. Thus, the destination + buffer must be at least LEN+1 bytes long. */ +static inline char * +stzncpy (char *dest, char const *src, size_t len) +{ + char const *src_end = src + len; + while (src < src_end && *src) + *dest++ = *src++; + *dest = 0; + return dest; +} + #ifndef ARRAY_CARDINALITY # define ARRAY_CARDINALITY(Array) (sizeof (Array) / sizeof *(Array)) #endif @@ -350,7 +350,7 @@ print_user (const STRUCT_UTMP *utmp_ent, time_t boottime) absolute file name in ut_line. */ if ( ! IS_ABSOLUTE_FILE_NAME (utmp_ent->ut_line)) p = stpcpy (p, DEV_DIR_WITH_TRAILING_SLASH); - stpncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line)); + stzncpy (p, utmp_ent->ut_line, sizeof (utmp_ent->ut_line)); if (stat (line, &stats) == 0) { @@ -376,7 +376,7 @@ print_user (const STRUCT_UTMP *utmp_ent, time_t boottime) char *display = NULL; /* Copy the host name into UT_HOST, and ensure it's nul terminated. */ - stpncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host)); + stzncpy (ut_host, utmp_ent->ut_host, sizeof (utmp_ent->ut_host)); /* Look for an X display. */ display = strchr (ut_host, ':'); |