diff options
| -rw-r--r-- | src/hostnamed.c | 2 | ||||
| -rw-r--r-- | src/shutdownd.c | 2 | ||||
| -rw-r--r-- | src/user-sessions.c | 2 | ||||
| -rw-r--r-- | src/util.c | 247 | ||||
| -rw-r--r-- | src/util.h | 29 |
5 files changed, 260 insertions, 22 deletions
diff --git a/src/hostnamed.c b/src/hostnamed.c index cf2172fd2c..68c5715b0e 100644 --- a/src/hostnamed.c +++ b/src/hostnamed.c @@ -201,7 +201,7 @@ static int write_data_static_hostname(void) { return 0; } - return write_one_line_file("/etc/hostname", data[PROP_STATIC_HOSTNAME]); + return write_one_line_file_atomic("/etc/hostname", data[PROP_STATIC_HOSTNAME]); } static int write_data_other(void) { diff --git a/src/shutdownd.c b/src/shutdownd.c index 8f765b4517..13819417c3 100644 --- a/src/shutdownd.c +++ b/src/shutdownd.c @@ -320,7 +320,7 @@ int main(int argc, char *argv[]) { log_info("Creating /run/nologin, blocking further logins..."); - if ((e = write_one_line_file("/run/nologin", "System is going down.")) < 0) + if ((e = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0) log_error("Failed to create /run/nologin: %s", strerror(-e)); else unlink_nologin = true; diff --git a/src/user-sessions.c b/src/user-sessions.c index e045b88c10..ffb8657436 100644 --- a/src/user-sessions.c +++ b/src/user-sessions.c @@ -67,7 +67,7 @@ int main(int argc, char*argv[]) { int r, q; char *cgroup_user_tree = NULL; - if ((r = write_one_line_file("/run/nologin", "System is going down.")) < 0) + if ((r = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0) log_error("Failed to create /run/nologin: %s", strerror(-r)); if ((q = cg_get_user_path(&cgroup_user_tree)) < 0) { diff --git a/src/util.c b/src/util.c index 81d247ca46..dfb153bbb6 100644 --- a/src/util.c +++ b/src/util.c @@ -567,6 +567,7 @@ int write_one_line_file(const char *fn, const char *line) { if (!(f = fopen(fn, "we"))) return -errno; + errno = 0; if (fputs(line, f) < 0) { r = -errno; goto finish; @@ -590,6 +591,64 @@ finish: return r; } +int fchmod_umask(int fd, mode_t m) { + mode_t u; + int r; + + u = umask(0777); + r = fchmod(fd, m & (~u)) < 0 ? -errno : 0; + umask(u); + + return r; +} + +int write_one_line_file_atomic(const char *fn, const char *line) { + FILE *f; + int r; + char *p; + + assert(fn); + assert(line); + + r = fopen_temporary(fn, &f, &p); + if (r < 0) + return r; + + fchmod_umask(fileno(f), 0644); + + errno = 0; + if (fputs(line, f) < 0) { + r = -errno; + goto finish; + } + + if (!endswith(line, "\n")) + fputc('\n', f); + + fflush(f); + + if (ferror(f)) { + if (errno != 0) + r = -errno; + else + r = -EIO; + } else { + if (rename(p, fn) < 0) + r = -errno; + else + r = 0; + } + +finish: + if (r < 0) + unlink(p); + + fclose(f); + free(p); + + return r; +} + int read_one_line_file(const char *fn, char **line) { FILE *f; int r; @@ -621,7 +680,7 @@ finish: return r; } -int read_full_file(const char *fn, char **contents) { +int read_full_file(const char *fn, char **contents, size_t *size) { FILE *f; int r; size_t n, l; @@ -636,6 +695,12 @@ int read_full_file(const char *fn, char **contents) { goto finish; } + /* Safety check */ + if (st.st_size > 4*1024*1024) { + r = -E2BIG; + goto finish; + } + n = st.st_size > 0 ? st.st_size : LINE_MAX; l = 0; @@ -680,6 +745,9 @@ int read_full_file(const char *fn, char **contents) { *contents = buf; buf = NULL; + if (size) + *size = l; + r = 0; finish: @@ -699,7 +767,7 @@ int parse_env_file( assert(fname); assert(separator); - if ((r = read_full_file(fname, &contents)) < 0) + if ((r = read_full_file(fname, &contents, NULL)) < 0) return r; p = contents; @@ -838,15 +906,17 @@ finish: } int write_env_file(const char *fname, char **l) { - - char **i; + char **i, *p; FILE *f; int r; - f = fopen(fname, "we"); - if (!f) - return -errno; + r = fopen_temporary(fname, &f, &p); + if (r < 0) + return r; + fchmod_umask(fileno(f), 0644); + + errno = 0; STRV_FOREACH(i, l) { fputs(*i, f); fputc('\n', f); @@ -854,8 +924,23 @@ int write_env_file(const char *fname, char **l) { fflush(f); - r = ferror(f) ? -errno : 0; + if (ferror(f)) { + if (errno != 0) + r = -errno; + else + r = -EIO; + } else { + if (rename(p, fname) < 0) + r = -errno; + else + r = 0; + } + + if (r < 0) + unlink(p); + fclose(f); + free(p); return r; } @@ -4778,6 +4863,152 @@ int hwclock_set_time(const struct tm *tm) { return err; } +int copy_file(const char *from, const char *to) { + int r, fdf, fdt; + + assert(from); + assert(to); + + fdf = open(from, O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fdf < 0) + return -errno; + + fdt = open(to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY, 0644); + if (fdt < 0) { + close_nointr_nofail(fdf); + return -errno; + } + + for (;;) { + char buf[PIPE_BUF]; + ssize_t n, k; + + n = read(fdf, buf, sizeof(buf)); + if (n < 0) { + r = -errno; + + close_nointr_nofail(fdf); + close_nointr(fdt); + unlink(to); + + return r; + } + + if (n == 0) + break; + + errno = 0; + k = loop_write(fdt, buf, n, false); + if (n != k) { + r = k < 0 ? k : (errno ? -errno : -EIO); + + close_nointr_nofail(fdf); + close_nointr(fdt); + + unlink(to); + return r; + } + } + + close_nointr_nofail(fdf); + r = close_nointr(fdt); + + if (r < 0) { + unlink(to); + return r; + } + + return 0; +} + +int symlink_or_copy(const char *from, const char *to) { + char *pf = NULL, *pt = NULL; + struct stat a, b; + int r; + + assert(from); + assert(to); + + if (parent_of_path(from, &pf) < 0 || + parent_of_path(to, &pt) < 0) { + r = -ENOMEM; + goto finish; + } + + if (stat(pf, &a) < 0 || + stat(pt, &b) < 0) { + r = -errno; + goto finish; + } + + if (a.st_dev != b.st_dev) { + free(pf); + free(pt); + + return copy_file(from, to); + } + + if (symlink(from, to) < 0) { + r = -errno; + goto finish; + } + + r = 0; + +finish: + free(pf); + free(pt); + + return r; +} + +int symlink_or_copy_atomic(const char *from, const char *to) { + char *t, *x; + const char *fn; + size_t k; + unsigned long long ull; + unsigned i; + int r; + + assert(from); + assert(to); + + t = new(char, strlen(to) + 1 + 16 + 1); + if (!t) + return -ENOMEM; + + fn = file_name_from_path(to); + k = fn-to; + memcpy(t, to, k); + t[k] = '.'; + x = stpcpy(t+k+1, fn); + + ull = random_ull(); + for (i = 0; i < 16; i++) { + *(x++) = hexchar(ull & 0xF); + ull >>= 4; + } + + *x = 0; + + r = symlink_or_copy(from, t); + if (r < 0) { + unlink(t); + free(t); + return r; + } + + if (rename(t, to) < 0) { + r = -errno; + unlink(t); + free(t); + return r; + } + + free(t); + return r; +} + static const char *const ioprio_class_table[] = { [IOPRIO_CLASS_NONE] = "none", [IOPRIO_CLASS_RT] = "realtime", diff --git a/src/util.h b/src/util.h index 15dfe17d3b..bd98b654fd 100644 --- a/src/util.h +++ b/src/util.h @@ -200,8 +200,9 @@ pid_t get_parent_of_pid(pid_t pid, pid_t *ppid); int get_starttime_of_pid(pid_t pid, unsigned long long *st); int write_one_line_file(const char *fn, const char *line); +int write_one_line_file_atomic(const char *fn, const char *line); int read_one_line_file(const char *fn, char **line); -int read_full_file(const char *fn, char **contents); +int read_full_file(const char *fn, char **contents, size_t *size); int parse_env_file(const char *fname, const char *separator, ...) _sentinel_; int load_env_file(const char *fname, char ***l); @@ -422,6 +423,22 @@ int terminal_vhangup(const char *name); int vt_disallocate(const char *name); +int copy_file(const char *from, const char *to); +int symlink_or_copy(const char *from, const char *to); +int symlink_or_copy_atomic(const char *from, const char *to); + +int fchmod_umask(int fd, mode_t mode); + +int conf_files_list(char ***strv, const char *suffix, const char *dir, ...); + +bool hwclock_is_localtime(void); + +int hwclock_apply_localtime_delta(void); + +int hwclock_get_time(struct tm *tm); + +int hwclock_set_time(const struct tm *tm); + #define NULSTR_FOREACH(i, l) \ for ((i) = (l); (i) && *(i); (i) = strchr((i), 0)+1) @@ -454,14 +471,4 @@ int signal_from_string(const char *s); int signal_from_string_try_harder(const char *s); -int conf_files_list(char ***strv, const char *suffix, const char *dir, ...); - -bool hwclock_is_localtime(void); - -int hwclock_apply_localtime_delta(void); - -int hwclock_get_time(struct tm *tm); - -int hwclock_set_time(const struct tm *tm); - #endif |