From: Lennart Poettering Date: Mon, 16 Jun 2014 11:21:07 +0000 (+0200) Subject: tmpfiles: add new "L+" command as stronger version of "L", that removes the destinati... X-Git-Tag: v215~413 X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=2e78fa79bbaebb358d2657c397180d2d08d69b12 tmpfiles: add new "L+" command as stronger version of "L", that removes the destination before creating a symlink Also, make use of this for mtab as long as mount insists on creating it even if we invoke it with "-n". --- diff --git a/man/tmpfiles.d.xml b/man/tmpfiles.d.xml index 0081a6762..2d8af981e 100644 --- a/man/tmpfiles.d.xml +++ b/man/tmpfiles.d.xml @@ -174,7 +174,16 @@ L /tmp/foobar - - - - /dev/null L - Create a symlink if it does not exist yet. + L+ + Create a + symlink if it does not exist + yet. If suffixed with + + and a + file already exists where the + symlink is to be created it + will be removed and be + replaced by the + symlink. diff --git a/src/shared/util.c b/src/shared/util.c index d93a9680f..d840dedfc 100644 --- a/src/shared/util.c +++ b/src/shared/util.c @@ -4013,7 +4013,7 @@ int fopen_temporary(const char *path, FILE **_f, char **_temp_path) { assert(_f); assert(_temp_path); - t = strappend(path, ".XXXXXX"); + t = tempfn_xxxxxx(path); if (!t) return -ENOMEM; @@ -4125,42 +4125,21 @@ int vt_disallocate(const char *name) { } int symlink_atomic(const char *from, const char *to) { - char *x; - _cleanup_free_ char *t; - const char *fn; - size_t k; - uint64_t u; - unsigned i; - int r; + _cleanup_free_ char *t = NULL; assert(from); assert(to); - t = new(char, strlen(to) + 1 + 16 + 1); + t = tempfn_random(to); if (!t) return -ENOMEM; - fn = basename(to); - k = fn-to; - memcpy(t, to, k); - t[k] = '.'; - x = stpcpy(t+k+1, fn); - - u = random_u64(); - for (i = 0; i < 16; i++) { - *(x++) = hexchar(u & 0xF); - u >>= 4; - } - - *x = 0; - if (symlink(from, t) < 0) return -errno; if (rename(t, to) < 0) { - r = -errno; - unlink(t); - return r; + unlink_noerrno(t); + return -errno; } return 0; @@ -6669,3 +6648,51 @@ int fflush_and_check(FILE *f) { return 0; } + +char *tempfn_xxxxxx(const char *p) { + const char *fn; + char *t; + size_t k; + + assert(p); + + t = new(char, strlen(p) + 1 + 6 + 1); + if (!t) + return NULL; + + fn = basename(p); + k = fn - p; + + strcpy(stpcpy(stpcpy(mempcpy(t, p, k), "."), fn), "XXXXXX"); + + return t; +} + +char *tempfn_random(const char *p) { + const char *fn; + char *t, *x; + uint64_t u; + size_t k; + unsigned i; + + assert(p); + + t = new(char, strlen(p) + 1 + 16 + 1); + if (!t) + return NULL; + + fn = basename(p); + k = fn - p; + + x = stpcpy(stpcpy(mempcpy(t, p, k), "."), fn); + + u = random_u64(); + for (i = 0; i < 16; i++) { + *(x++) = hexchar(u & 0xF); + u >>= 4; + } + + *x = 0; + + return t; +} diff --git a/src/shared/util.h b/src/shared/util.h index 1796014f2..e8552410c 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -948,3 +948,6 @@ int umount_recursive(const char *target, int flags); int bind_remount_recursive(const char *prefix, bool ro); int fflush_and_check(FILE *f); + +char *tempfn_xxxxxx(const char *p); +char *tempfn_random(const char *p); diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c index 0fd2bd233..0c1c2b17f 100644 --- a/src/tmpfiles/tmpfiles.c +++ b/src/tmpfiles/tmpfiles.c @@ -103,6 +103,8 @@ typedef struct Item { bool keep_first_level:1; + bool force:1; + bool done:1; } Item; @@ -746,31 +748,38 @@ static int create_item(Item *i) { break; - case CREATE_SYMLINK: { - _cleanup_free_ char *x = NULL; + case CREATE_SYMLINK: label_context_set(i->path, S_IFLNK); r = symlink(i->argument, i->path); label_context_clear(); - if (r < 0 && errno != EEXIST) { - log_error("symlink(%s, %s) failed: %m", i->argument, i->path); - return -errno; - } - - r = readlink_malloc(i->path, &x); if (r < 0) { - log_error("readlink(%s) failed: %s", i->path, strerror(-r)); - return -errno; - } + _cleanup_free_ char *x = NULL; - if (!streq(i->argument, x)) { - log_error("%s is not the right symlink.", i->path); - return -EEXIST; + if (errno != EEXIST) { + log_error("symlink(%s, %s) failed: %m", i->argument, i->path); + return -errno; + } + + r = readlink_malloc(i->path, &x); + if (r < 0 || !streq(i->argument, x)) { + + if (i->force) { + label_context_set(i->path, S_IFLNK); + r = symlink_atomic(i->argument, i->path); + label_context_clear(); + + if (r < 0) { + log_error("symlink(%s, %s) failed: %m", i->argument, i->path); + return -errno; + } + } else + log_debug("%s is not a symlink or does not point to the correct path.", i->path); + } } break; - } case CREATE_BLOCK_DEVICE: case CREATE_CHAR_DEVICE: { @@ -1135,10 +1144,17 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) { return -EIO; } - if (strlen(action) > 2 || (strlen(action) > 1 && action[1] != '!')) { - log_error("[%s:%u] Unknown modifier '%s'", fname, line, action); + if (isempty(action)) { + log_error("[%s:%u] Command too short '%s'.", fname, line, action); return -EINVAL; - } else if (strlen(action) > 1 && !arg_boot) + } + + if (strlen(action) > 1 && !in_charset(action+1, "!+")) { + log_error("[%s:%u] Unknown modifiers in command '%s'", fname, line, action); + return -EINVAL; + } + + if (strchr(action+1, '!') && !arg_boot) return 0; type = action[0]; @@ -1147,6 +1163,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) { if (!i) return log_oom(); + i->force = !!strchr(action+1, '+'); + r = specifier_printf(path, specifier_table, NULL, &i->path); if (r < 0) { log_error("[%s:%u] Failed to replace specifiers: %s", fname, line, path); diff --git a/tmpfiles.d/etc.conf b/tmpfiles.d/etc.conf index 1294c9408..e809dff2a 100644 --- a/tmpfiles.d/etc.conf +++ b/tmpfiles.d/etc.conf @@ -9,5 +9,5 @@ L /etc/os-release - - - - ../usr/lib/os-release L /etc/localtime - - - - ../usr/share/zoneinfo/UTC -L /etc/mtab - - - - ../proc/self/mounts +L+ /etc/mtab - - - - ../proc/self/mounts L /etc/resolv.conf - - - - ../run/systemd/resolve/resolv.conf