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synced 2025-07-11 10:01:57 +03:00
Skip unnecessary stat() calls in walkdir().
Some kernels can tell us the type of a "dirent", so we can avoid a call to stat() or lstat() in many cases. Define a new function get_dirent_type() to contain that logic, for use by the backend and frontend versions of walkdir(), and perhaps other callers in future. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Juan José Santamaría Flecha <juanjo.santamaria@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKG%2BFzxupGGN4GpUdbzZN%2Btn6FQPHo8w0Q%2BAPH5Wz8RG%2Bww%40mail.gmail.com
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@ -56,6 +56,7 @@ OBJS_COMMON = \
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exec.o \
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f2s.o \
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file_perm.o \
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file_utils.o \
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hashfn.o \
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ip.o \
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jsonapi.o \
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@ -91,7 +92,6 @@ endif
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OBJS_FRONTEND = \
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$(OBJS_COMMON) \
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fe_memutils.o \
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file_utils.o \
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logging.o \
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restricted_token.o \
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sprompt.o
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@ -14,10 +14,10 @@
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*/
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#ifndef FRONTEND
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#error "This file is not expected to be compiled for backend code"
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#endif
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#include "postgres.h"
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#else
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#include "postgres_fe.h"
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#endif
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#include <dirent.h>
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#include <fcntl.h>
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@ -25,8 +25,11 @@
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#include <unistd.h>
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#include "common/file_utils.h"
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#ifdef FRONTEND
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#include "common/logging.h"
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#endif
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#ifdef FRONTEND
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/* Define PG_FLUSH_DATA_WORKS if we have an implementation for pg_flush_data */
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#if defined(HAVE_SYNC_FILE_RANGE)
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@ -167,8 +170,6 @@ walkdir(const char *path,
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while (errno = 0, (de = readdir(dir)) != NULL)
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{
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char subpath[MAXPGPATH * 2];
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struct stat fst;
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int sret;
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if (strcmp(de->d_name, ".") == 0 ||
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strcmp(de->d_name, "..") == 0)
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@ -176,21 +177,23 @@ walkdir(const char *path,
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snprintf(subpath, sizeof(subpath), "%s/%s", path, de->d_name);
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if (process_symlinks)
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sret = stat(subpath, &fst);
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else
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sret = lstat(subpath, &fst);
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if (sret < 0)
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switch (get_dirent_type(subpath, de, process_symlinks, PG_LOG_ERROR))
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{
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pg_log_error("could not stat file \"%s\": %m", subpath);
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continue;
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}
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case PGFILETYPE_REG:
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(*action) (subpath, false);
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break;
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case PGFILETYPE_DIR:
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walkdir(subpath, action, false);
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break;
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default:
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if (S_ISREG(fst.st_mode))
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(*action) (subpath, false);
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else if (S_ISDIR(fst.st_mode))
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walkdir(subpath, action, false);
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/*
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* Errors are already reported directly by get_dirent_type(),
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* and any remaining symlinks and unknown file types are
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* ignored.
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*/
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break;
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}
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}
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if (errno)
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@ -394,3 +397,73 @@ durable_rename(const char *oldfile, const char *newfile)
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return 0;
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}
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#endif /* FRONTEND */
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/*
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* Return the type of a directory entry.
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*
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* In frontend code, elevel should be a level from logging.h; in backend code
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* it should be a level from elog.h.
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*/
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PGFileType
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get_dirent_type(const char *path,
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const struct dirent *de,
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bool look_through_symlinks,
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int elevel)
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{
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PGFileType result;
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/*
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* Some systems tell us the type directly in the dirent struct, but that's
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* a BSD and Linux extension not required by POSIX. Even when the
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* interface is present, sometimes the type is unknown, depending on the
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* filesystem.
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*/
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#if defined(DT_REG) && defined(DT_DIR) && defined(DT_LNK)
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if (de->d_type == DT_REG)
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result = PGFILETYPE_REG;
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else if (de->d_type == DT_DIR)
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result = PGFILETYPE_DIR;
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else if (de->d_type == DT_LNK && !look_through_symlinks)
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result = PGFILETYPE_LNK;
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else
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result = PGFILETYPE_UNKNOWN;
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#else
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result = PGFILETYPE_UNKNOWN;
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#endif
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if (result == PGFILETYPE_UNKNOWN)
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{
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struct stat fst;
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int sret;
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if (look_through_symlinks)
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sret = stat(path, &fst);
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else
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sret = lstat(path, &fst);
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if (sret < 0)
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{
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result = PGFILETYPE_ERROR;
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#ifdef FRONTEND
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pg_log_generic(elevel, "could not stat file \"%s\": %m", path);
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#else
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ereport(elevel,
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(errcode_for_file_access(),
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errmsg("could not stat file \"%s\": %m", path)));
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#endif
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}
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else if (S_ISREG(fst.st_mode))
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result = PGFILETYPE_REG;
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else if (S_ISDIR(fst.st_mode))
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result = PGFILETYPE_DIR;
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#ifdef S_ISLNK
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else if (S_ISLNK(fst.st_mode))
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result = PGFILETYPE_LNK;
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#endif
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}
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return result;
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}
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