lxccontainer: remove stack allocations

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 06384f0692335c1e4e3414d5c57900b6653a91da..3a6696039f6bafc383a4d1c0fccacae14a68186f 100644 (file)
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -61,6 +61,7 @@
 #include "lxc.h"
 #include "lxccontainer.h"
 #include "lxclock.h"
+#include "memory_utils.h"
 #include "monitor.h"
 #include "namespace.h"
 #include "network.h"
@@ -120,13 +121,13 @@ static bool do_lxcapi_save_config(struct lxc_container *c, const char *alt_file)
 
 static bool config_file_exists(const char *lxcpath, const char *cname)
 {
+       __do_free char *fname;
        int ret;
        size_t len;
-       char *fname;
 
        /* $lxcpath + '/' + $cname + '/config' + \0 */
        len = strlen(lxcpath) + strlen(cname) + 9;
-       fname = alloca(len);
+       fname = must_realloc(NULL, len);
        ret = snprintf(fname, len, "%s/%s/config", lxcpath, cname);
        if (ret < 0 || (size_t)ret >= len)
                return false;
@@ -144,13 +145,13 @@ static bool config_file_exists(const char *lxcpath, const char *cname)
  */
 static int ongoing_create(struct lxc_container *c)
 {
+       __do_free char *path;
        int fd, ret;
        size_t len;
-       char *path;
        struct flock lk = {0};
 
        len = strlen(c->config_path) + strlen(c->name) + 10;
-       path = alloca(len);
+       path = must_realloc(NULL, len);
        ret = snprintf(path, len, "%s/%s/partial", c->config_path, c->name);
        if (ret < 0 || (size_t)ret >= len)
                return -1;
@@ -190,14 +191,14 @@ static int ongoing_create(struct lxc_container *c)
 
 static int create_partial(struct lxc_container *c)
 {
+       __do_free char *path;
        int fd, ret;
        size_t len;
-       char *path;
        struct flock lk = {0};
 
        /* $lxcpath + '/' + $name + '/partial' + \0 */
        len = strlen(c->config_path) + strlen(c->name) + 10;
-       path = alloca(len);
+       path = must_realloc(NULL, len);
        ret = snprintf(path, len, "%s/%s/partial", c->config_path, c->name);
        if (ret < 0 || (size_t)ret >= len)
                return -1;
@@ -227,15 +228,15 @@ static int create_partial(struct lxc_container *c)
 
 static void remove_partial(struct lxc_container *c, int fd)
 {
+       __do_free char *path;
        int ret;
        size_t len;
-       char *path;
 
        close(fd);
 
        /* $lxcpath + '/' + $name + '/partial' + \0 */
        len = strlen(c->config_path) + strlen(c->name) + 10;
-       path = alloca(len);
+       path = must_realloc(NULL, len);
        ret = snprintf(path, len, "%s/%s/partial", c->config_path, c->name);
        if (ret < 0 || (size_t)ret >= len)
                return;
@@ -768,26 +769,22 @@ static void push_arg(char ***argp, char *arg, int *nargs)
 
 static char **split_init_cmd(const char *incmd)
 {
-       size_t len, retlen;
-       char *copy, *p;
+       __do_free char *copy = NULL;
+       char *p;
        char **argv;
        int nargs = 0;
 
        if (!incmd)
                return NULL;
 
-       len = strlen(incmd) + 1;
-       copy = alloca(len);
-       retlen = strlcpy(copy, incmd, len);
-       if (retlen >= len)
-               return NULL;
+       copy = must_copy_string(incmd);
 
        do {
                argv = malloc(sizeof(char *));
        } while (!argv);
 
        argv[0] = NULL;
-       lxc_iterate_parts(p, copy, " ")
+       lxc_iterate_parts (p, copy, " ")
                push_arg(&argv, p, &nargs);
 
        if (nargs == 0) {
@@ -1209,9 +1206,9 @@ WRAP_API(bool, lxcapi_stop)
 
 static int do_create_container_dir(const char *path, struct lxc_conf *conf)
 {
+       __do_free char *p = NULL;
        int lasterr;
        size_t len;
-       char *p;
        int ret = -1;
 
        mode_t mask = umask(0002);
@@ -1226,9 +1223,7 @@ static int do_create_container_dir(const char *path, struct lxc_conf *conf)
                ret = 0;
        }
 
-       len = strlen(path);
-       p = alloca(len + 1);
-       (void)strlcpy(p, path, len + 1);
+       p = must_copy_string(path);
 
        if (!lxc_list_empty(&conf->id_map)) {
                ret = chown_mapped_root(p, conf);
@@ -1270,9 +1265,9 @@ static struct lxc_storage *do_storage_create(struct lxc_container *c,
                                             const char *type,
                                             struct bdev_specs *specs)
 {
+       __do_free char *dest;
        int ret;
        size_t len;
-       char *dest;
        struct lxc_storage *bdev;
 
        /* rootfs.path or lxcpath/lxcname/rootfs */
@@ -1280,12 +1275,12 @@ static struct lxc_storage *do_storage_create(struct lxc_container *c,
            (access(c->lxc_conf->rootfs.path, F_OK) == 0)) {
                const char *rpath = c->lxc_conf->rootfs.path;
                len = strlen(rpath) + 1;
-               dest = alloca(len);
+               dest = must_realloc(NULL, len);
                ret = snprintf(dest, len, "%s", rpath);
        } else {
                const char *lxcpath = do_lxcapi_get_config_path(c);
                len = strlen(c->name) + strlen(lxcpath) + 9;
-               dest = alloca(len);
+               dest = must_realloc(NULL, len);
                ret = snprintf(dest, len, "%s/%s/rootfs", lxcpath, c->name);
        }
        if (ret < 0 || (size_t)ret >= len)
@@ -3407,12 +3402,12 @@ err:
 
 static int copyhooks(struct lxc_container *oldc, struct lxc_container *c)
 {
+       __do_free char *cpath;
        int i, len, ret;
        struct lxc_list *it;
-       char *cpath;
 
        len = strlen(oldc->config_path) + strlen(oldc->name) + 3;
-       cpath = alloca(len);
+       cpath = must_realloc(NULL, len);
        ret = snprintf(cpath, len, "%s/%s/", oldc->config_path, oldc->name);
        if (ret < 0 || ret >= len)
                return -1;
@@ -3570,13 +3565,14 @@ static bool add_rdepends(struct lxc_container *c, struct lxc_container *c0)
 bool should_default_to_snapshot(struct lxc_container *c0,
                                struct lxc_container *c1)
 {
+       __do_free char *p0, *p1;
        int ret;
        size_t l0 = strlen(c0->config_path) + strlen(c0->name) + 2;
        size_t l1 = strlen(c1->config_path) + strlen(c1->name) + 2;
-       char *p0 = alloca(l0 + 1);
-       char *p1 = alloca(l1 + 1);
        char *rootfs = c0->lxc_conf->rootfs.path;
 
+       p0 = must_realloc(NULL, l0 + 1);
+       p1 = must_realloc(NULL, l1 + 1);
        ret = snprintf(p0, l0, "%s/%s", c0->config_path, c0->name);
        if (ret < 0 || ret >= l0)
                return false;
@@ -4098,11 +4094,11 @@ static int lxcapi_attach_run_wait(struct lxc_container *c, lxc_attach_options_t
 
 static int get_next_index(const char *lxcpath, char *cname)
 {
-       char *fname;
+       __do_free char *fname;
        struct stat sb;
        int i = 0, ret;
 
-       fname = alloca(strlen(lxcpath) + 20);
+       fname = must_realloc(NULL, strlen(lxcpath) + 20);
 
        while (1) {
                sprintf(fname, "%s/snap%d", lxcpath, i);
@@ -4148,6 +4144,7 @@ static bool get_snappath_dir(struct lxc_container *c, char *snappath)
 
 static int do_lxcapi_snapshot(struct lxc_container *c, const char *commentfile)
 {
+       __do_free char *dfnam = NULL;
        int i, flags, ret;
        time_t timer;
        struct tm tm_info;
@@ -4211,7 +4208,7 @@ static int do_lxcapi_snapshot(struct lxc_container *c, const char *commentfile)
 
        strftime(buffer, 25, "%Y:%m:%d %H:%M:%S", &tm_info);
 
-       char *dfnam = alloca(strlen(snappath) + strlen(newname) + 5);
+       dfnam = must_realloc(NULL, strlen(snappath) + strlen(newname) + 5);
        sprintf(dfnam, "%s/%s/ts", snappath, newname);
        f = fopen(dfnam, "w");
        if (!f) {
@@ -4232,10 +4229,11 @@ static int do_lxcapi_snapshot(struct lxc_container *c, const char *commentfile)
        }
 
        if (commentfile) {
+               __do_free char *path;
                /* $p / $name / comment \0 */
                int len = strlen(snappath) + strlen(newname) + 10;
-               char *path = alloca(len);
 
+               path = must_realloc(NULL, len);
                sprintf(path, "%s/%s/comment", snappath, newname);
                return copy_file(commentfile, path) < 0 ? -1 : i;
        }