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Thu, 13 Jun 2019 15:40:17 +0200 To: Richard Henderson , qemu-devel@nongnu.org References: <20190519201953.20161-1-richard.henderson@linaro.org> <20190519201953.20161-2-richard.henderson@linaro.org> From: Laurent Vivier Openpgp: preference=signencrypt Autocrypt: addr=laurent@vivier.eu; prefer-encrypt=mutual; keydata= mQINBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABtCJMYXVyZW50IFZp dmllciA8bGF1cmVudEB2aXZpZXIuZXU+iQI4BBMBAgAiBQJWBTDeAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRDzDDi9Py++PCEdD/oD8LD5UWxhQrMQCsUgLlXCSM7sxGLkwmmF ozqSSljEGRhffxZvO35wMFcdX9Z0QOabVoFTKrT04YmvbjsErh/dP5zeM/4EhUByeOS7s6Yl HubMXVQTkak9Wa9Eq6irYC6L41QNzz/oTwNEqL1weV1+XC3TNnht9B76lIaELyrJvRfgsp9M rE+PzGPo5h7QHWdL/Cmu8yOtPLa8Y6l/ywEJ040IoiAUfzRoaJs2csMXf0eU6gVBhCJ4bs91 jtWTXhkzdl4tdV+NOwj3j0ukPy+RjqeL2Ej+bomnPTOW8nAZ32dapmu7Fj7VApuQO/BSIHyO NkowMMjB46yohEepJaJZkcgseaus0x960c4ua/SUm/Nm6vioRsxyUmWd2nG0m089pp8LPopq WfAk1l4GciiMepp1Cxn7cnn1kmG6fhzedXZ/8FzsKjvx/aVeZwoEmucA42uGJ3Vk9TiVdZes lqMITkHqDIpHjC79xzlWkXOsDbA2UY/P18AtgJEZQPXbcrRBtdSifCuXdDfHvI+3exIdTpvj BfbgZAar8x+lcsQBugvktlQWPfAXZu4Shobi3/mDYMEDOE92dnNRD2ChNXg2IuvAL4OW40wh gXlkHC1ZgToNGoYVvGcZFug1NI+vCeCFchX+L3bXyLMg3rAfWMFPAZLzn42plIDMsBs+x2yP +bkCDQRWBSYZARAAvFJBFuX9A6eayxUPFaEczlMbGXugs0mazbOYGlyaWsiyfyc3PStHLFPj rSTaeJpPCjBJErwpZUN4BbpkBpaJiMuVO6egrC8Xy8/cnJakHPR2JPEvmj7Gm/L9DphTcE15 92rxXLesWzGBbuYxKsj8LEnrrvLyi3kNW6B5LY3Id+ZmU8YTQ2zLuGV5tLiWKKxc6s3eMXNq wrJTCzdVd6ThXrmUfAHbcFXOycUyf9vD+s+WKpcZzCXwKgm7x1LKsJx3UhuzT8ier1L363RW ZaJBZ9CTPiu8R5NCSn9V+BnrP3wlFbtLqXp6imGhazT9nJF86b5BVKpF8Vl3F0/Y+UZ4gUwL d9cmDKBcmQU/JaRUSWvvolNu1IewZZu3rFSVgcpdaj7F/1aC0t5vLdx9KQRyEAKvEOtCmP4m 38kU/6r33t3JuTJnkigda4+Sfu5kYGsogeYG6dNyjX5wpK5GJIJikEhdkwcLM+BUOOTi+I9u tX03BGSZo7FW/J7S9y0l5a8nooDs2gBRGmUgYKqQJHCDQyYut+hmcr+BGpUn9/pp2FTWijrP inb/Pc96YDQLQA1q2AeAFv3Rx3XoBTGl0RCY4KZ02c0kX/dm3eKfMX40XMegzlXCrqtzUk+N 8LeipEsnOoAQcEONAWWo1HcgUIgCjhJhBEF0AcELOQzitbJGG5UAEQEAAYkCHwQYAQIACQUC VgUmGQIbDAAKCRDzDDi9Py++PCD3D/9VCtydWDdOyMTJvEMRQGbx0GacqpydMEWbE3kUW0ha US5jz5gyJZHKR3wuf1En/3z+CEAEfP1M3xNGjZvpaKZXrgWaVWfXtGLoWAVTfE231NMQKGoB w2Dzx5ivIqxikXB6AanBSVpRpoaHWb06tPNxDL6SVV9lZpUn03DSR6gZEZvyPheNWkvz7bE6 FcqszV/PNvwm0C5Ju7NlJA8PBAQjkIorGnvN/vonbVh5GsRbhYPOc/JVwNNr63P76rZL8Gk/ hb3xtcIEi5CCzab45+URG/lzc6OV2nTj9Lg0SNcRhFZ2ILE3txrmI+aXmAu26+EkxLLfqCVT ohb2SffQha5KgGlOSBXustQSGH0yzzZVZb+HZPEvx6d/HjQ+t9sO1bCpEgPdZjyMuuMp9N1H ctbwGdQM2Qb5zgXO+8ZSzwC+6rHHIdtcB8PH2j+Nd88dVGYlWFKZ36ELeZxD7iJflsE8E8yg OpKgu3nD0ahBDqANU/ZmNNarBJEwvM2vfusmNnWm3QMIwxNuJghRyuFfx694Im1js0ZY3LEU JGSHFG4ZynA+ZFUPA6Xf0wHeJOxGKCGIyeKORsteIqgnkINW9fnKJw2pgk8qHkwVc3Vu+wGS ZiJK0xFusPQehjWTHn9WjMG1zvQ5TQQHxau/2FkP45+nRPco6vVFQe8JmgtRF8WFJA== Message-ID: Date: Thu, 13 Jun 2019 15:40:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190519201953.20161-2-richard.henderson@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:WcSBLS37zdrLcR48/DIYRQNIRaWZUhjzungkQQNm0oFNB1V5MHm tQnvevrqogHXV6z+2QUDO/xJmFka9879zeNCOWHHZD6tar1KdO7hxEATDgqZMi2Ws98m1M9 tQEvWHCpTTlRTKzyqlTei9UvNsYueVeNl3q7O3UERk2ceFLkxAE9JwRKePSGZeBF8VgcTHH rX0Kp0d2Quho2e2rHmDKg== X-UI-Out-Filterresults: notjunk:1;V03:K0:5DBNCfX1tgM=:im0ykGCT67SKtct8BZO0OY DCMeN5w7DtXEibL8Q8m54+T74fzhU3mghsjjuuXvJj7iuzP5ZdcqgZPmT5p1Uk4QXwyb63gCz q0JdF4XCJtvPaxC58j0T6wdmLBF3j235aeyXo+d7yWEvU3GqHX/sx/HvFaMJL/xrBLIZV9PrS Fg2v6om/cneO0nW3FTvjNlP2gCTanSAV41hwyD+vBjBHqu9MvjHr/2ekZdBjP67Sl5UEUT1me 3NFRzgmwrCqUqdOOIj0U7BYOdP5Q9Dai9eqe/4zs/kToVWXyVO07UKeakqbxJDi4g+c3iot1C txs/BMJUc/6DCLmVih6ns2kdkmrP+uGJMiHgN5+vGGqiglX+DcBEZldloI6zfTw3JzuIc6hPh 0jPdSNuwHnDWPxjF/8fSF2RsIVsgy/tmUdksoF/Jspbap6GPoig+hL0LvSIrbqRE4o7t14vYf awPJUvOgDUsX7XhGYNxnPJ7oSD5mcxGb25bx0ZNgLUe4vlU6xG71U3CDe2pfStYMmO4Fg0t6w eLX15Q8giLgOGXeHwK7nHuYVypvkzjSbBvQNZSuUM0E1pQ1s9T/a5Ch8cLQsPvmzDGMPZCN7r gCKe3uYhYSEl9I8HLC48GkPHgHox4wdQMIXEuVdeqef7wZYOJVKF73WOLVk+p43/ryuoVAUWW LpagFkK67TZkFafVnNgJV7Wn+sXGbu/1OdYlcMeE05c7y+mwkedEnVkpdFqNGkjG+S3WT1r6S rjb12gvafJcmSwqvdGvafyxU3Q3arDAtF4VsljscQ4QUdEqY+s1FWVldGH4= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 212.227.17.10 Subject: Re: [Qemu-devel] [PATCH 01/13] util/path: Do not cache all filenames at startup X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Le 19/05/2019 à 22:19, Richard Henderson a écrit : > If one uses -L $PATH to point to a full chroot, the startup time > is significant. In addition, the existing probing algorithm fails > to handle symlink loops. > > Instead, probe individual paths on demand. Cache both positive > and negative results within $PATH, so that any one filename is > probed only once. > > Use glib filename functions for clarity. > > Signed-off-by: Richard Henderson > --- > util/path.c | 201 ++++++++++++---------------------------------------- > 1 file changed, 47 insertions(+), 154 deletions(-) > > diff --git a/util/path.c b/util/path.c > index 7f9fc272fb..8e174eb436 100644 > --- a/util/path.c > +++ b/util/path.c > @@ -8,170 +8,63 @@ > #include > #include "qemu/cutils.h" > #include "qemu/path.h" > +#include "qemu/thread.h" > > -struct pathelem > -{ > - /* Name of this, eg. lib */ > - char *name; > - /* Full path name, eg. /usr/gnemul/x86-linux/lib. */ > - char *pathname; > - struct pathelem *parent; > - /* Children */ > - unsigned int num_entries; > - struct pathelem *entries[0]; > -}; > - > -static struct pathelem *base; > - > -/* First N chars of S1 match S2, and S2 is N chars long. */ > -static int strneq(const char *s1, unsigned int n, const char *s2) > -{ > - unsigned int i; > - > - for (i = 0; i < n; i++) > - if (s1[i] != s2[i]) > - return 0; > - return s2[i] == 0; > -} > - > -static struct pathelem *add_entry(struct pathelem *root, const char *name, > - unsigned type); > - > -static struct pathelem *new_entry(const char *root, > - struct pathelem *parent, > - const char *name) > -{ > - struct pathelem *new = g_malloc(sizeof(*new)); > - new->name = g_strdup(name); > - new->pathname = g_strdup_printf("%s/%s", root, name); > - new->num_entries = 0; > - return new; > -} > - > -#define streq(a,b) (strcmp((a), (b)) == 0) > - > -/* Not all systems provide this feature */ > -#if defined(DT_DIR) && defined(DT_UNKNOWN) && defined(DT_LNK) > -# define dirent_type(dirent) ((dirent)->d_type) > -# define is_dir_maybe(type) \ > - ((type) == DT_DIR || (type) == DT_UNKNOWN || (type) == DT_LNK) > -#else > -# define dirent_type(dirent) (1) > -# define is_dir_maybe(type) (type) > -#endif > - > -static struct pathelem *add_dir_maybe(struct pathelem *path) > -{ > - DIR *dir; > - > - if ((dir = opendir(path->pathname)) != NULL) { > - struct dirent *dirent; > - > - while ((dirent = readdir(dir)) != NULL) { > - if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){ > - path = add_entry(path, dirent->d_name, dirent_type(dirent)); > - } > - } > - closedir(dir); > - } > - return path; > -} > - > -static struct pathelem *add_entry(struct pathelem *root, const char *name, > - unsigned type) > -{ > - struct pathelem **e; > - > - root->num_entries++; > - > - root = g_realloc(root, sizeof(*root) > - + sizeof(root->entries[0])*root->num_entries); > - e = &root->entries[root->num_entries-1]; > - > - *e = new_entry(root->pathname, root, name); > - if (is_dir_maybe(type)) { > - *e = add_dir_maybe(*e); > - } > - > - return root; > -} > - > -/* This needs to be done after tree is stabilized (ie. no more reallocs!). */ > -static void set_parents(struct pathelem *child, struct pathelem *parent) > -{ > - unsigned int i; > - > - child->parent = parent; > - for (i = 0; i < child->num_entries; i++) > - set_parents(child->entries[i], child); > -} > - > -/* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */ > -static const char * > -follow_path(const struct pathelem *cursor, const char *name) > -{ > - unsigned int i, namelen; > - > - name += strspn(name, "/"); > - namelen = strcspn(name, "/"); > - > - if (namelen == 0) > - return cursor->pathname; > - > - if (strneq(name, namelen, "..")) > - return follow_path(cursor->parent, name + namelen); > - > - if (strneq(name, namelen, ".")) > - return follow_path(cursor, name + namelen); > - > - for (i = 0; i < cursor->num_entries; i++) > - if (strneq(name, namelen, cursor->entries[i]->name)) > - return follow_path(cursor->entries[i], name + namelen); > - > - /* Not found */ > - return NULL; > -} > +static const char *base; > +static GHashTable *hash; > +static QemuMutex lock; > > void init_paths(const char *prefix) > { > - char pref_buf[PATH_MAX]; > - > - if (prefix[0] == '\0' || > - !strcmp(prefix, "/")) > + if (prefix[0] == '\0' || !strcmp(prefix, "/")) { > return; > - > - if (prefix[0] != '/') { > - char *cwd = getcwd(NULL, 0); > - size_t pref_buf_len = sizeof(pref_buf); > - > - if (!cwd) > - abort(); > - pstrcpy(pref_buf, sizeof(pref_buf), cwd); > - pstrcat(pref_buf, pref_buf_len, "/"); > - pstrcat(pref_buf, pref_buf_len, prefix); > - free(cwd); > - } else > - pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1); > - > - base = new_entry("", NULL, pref_buf); > - base = add_dir_maybe(base); > - if (base->num_entries == 0) { > - g_free(base->pathname); > - g_free(base->name); > - g_free(base); > - base = NULL; > - } else { > - set_parents(base, base); > } > + > + if (prefix[0] == '/') { > + base = g_strdup(prefix); > + } else { > + char *cwd = g_get_current_dir(); > + base = g_build_filename(cwd, prefix, NULL); > + g_free(cwd); > + } > + > + hash = g_hash_table_new(g_str_hash, g_str_equal); > + qemu_mutex_init(&lock); > } > > /* Look for path in emulation dir, otherwise return name. */ > const char *path(const char *name) > { > - /* Only do absolute paths: quick and dirty, but should mostly be OK. > - Could do relative by tracking cwd. */ > - if (!base || !name || name[0] != '/') > - return name; > + gpointer key, value; > + const char *ret; > > - return follow_path(base, name) ?: name; > + /* Only do absolute paths: quick and dirty, but should mostly be OK. */ > + if (!base || !name || name[0] != '/') { > + return name; > + } > + > + qemu_mutex_lock(&lock); > + > + /* Have we looked up this file before? */ > + if (g_hash_table_lookup_extended(hash, name, &key, &value)) { > + ret = value ? value : name; > + } else { > + char *save = g_strdup(name); > + char *full = g_build_filename(base, name, NULL); > + > + /* Look for the path; record the result, pass or fail. */ > + if (access(full, F_OK) == 0) { > + /* Exists. */ > + g_hash_table_insert(hash, save, full); > + ret = full; > + } else { > + /* Does not exist. */ > + g_free(full); > + g_hash_table_insert(hash, save, NULL); > + ret = name; > + } > + } > + > + qemu_mutex_unlock(&lock); > + return ret; > } > Reviewed-by: Laurent Vivier Tested-by: Laurent Vivier Thanks, Laurent