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Remove unneeded calls to access(2) from rtld(1); just call open(2) instead.

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The result looks like this:

--- przed       2017-10-21 23:19:21.445034000 +0100
+++ po  2017-10-21 23:18:50.031865000 +0100
@@ -11,7 +11,6 @@ mmap(0x0,102,PROT_READ,MAP_PRIVATE,3,0x0)      = 343665418
 close(3)                                        = 0 (0x0)
 open("/usr/local/etc/libmap.d",O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC,0165) ERR#2 'No such file or directory'
 munmap(0x80067d000,102)                                 = 0 (0x0)
-access("/usr/local/lib/libintl.so.8",F_OK)      = 0 (0x0)
 openat(AT_FDCWD,"/usr/local/lib/libintl.so.8",O_RDONLY|O_CLOEXEC|O_VERIFY,00) = 3 (0x3)
 fstat(3,{ mode=-rw-r--r-- ,inode=642560,size=55188,blksize=32768 }) = 0 (0x0)
 mmap(0x0,4096,PROT_READ,MAP_PRIVATE|MAP_PREFAULT_READ,3,0x0) = 34366541824 (0x80067d000)
@@ -20,14 +19,13 @@ mmap(0x800877000,40960,PROT_READ|PROT_EXEC,MAP_PRIVATE
 mmap(0x800a81000,4096,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_FIXED|MAP_PREFAULT_READ,3,0xa000) = 34370752512 (0x800a81000)
 munmap(0x80067d000,4096)                        = 0 (0x0)
 close(3)                                        = 0 (0x0)
-access("/usr/local/lib/libc.so.7",F_OK)                 ERR#2 'No such file or directory'
+openat(AT_FDCWD,"/usr/local/lib/libc.so.7",O_RDONLY|O_CLOEXEC|O_VERIFY,00) ERR#2 'No such file or directory'
 openat(AT_FDCWD,"/var/run/ld-elf.so.hints",O_RDONLY|O_CLOEXEC,00) = 3 (0x3)
 read(3,"Ehnt\^A\0\0\0\M^@\0\0\0\M-2\0\0"...,128) = 128 (0x80)
 fstat(3,{ mode=-r--r--r-- ,inode=970684,size=306,blksize=32768 }) = 0 (0x0)
 lseek(3,0x80,SEEK_SET)                          = 128 (0x80)
 read(3,"/lib:/usr/lib:/usr/lib/compat:/u"...,178) = 178 (0xb2)
 close(3)                                        = 0 (0x0)
-access("/lib/libc.so.7",F_OK)                   = 0 (0x0)
 openat(AT_FDCWD,"/lib/libc.so.7",O_RDONLY|O_CLOEXEC|O_VERIFY,00) = 3 (0x3)
 fstat(3,{ mode=-r--r--r-- ,inode=1605239,size=1910320,blksize=32768 }) = 0 (0x0)
 mmap(0x0,4096,PROT_READ,MAP_PRIVATE|MAP_PREFAULT_READ,3,0x0) = 34366541824 (0x80067d000)

Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D12766
This commit is contained in:
Edward Tomasz Napierala 2017-10-24 12:56:08 +00:00
parent 2fe071d971
commit b4ed9a87f9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=324953
1 changed files with 23 additions and 13 deletions
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36
libexec/rtld-elf/rtld.c
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@ -138,7 +138,7 @@ static int rtld_dirname(const char *, char *);
static int rtld_dirname_abs(const char *, char *);
static void *rtld_dlopen(const char *name, int fd, int mode);
static void rtld_exit(void);
static char *search_library_path(const char *, const char *);
static char *search_library_path(const char *, const char *, int *);
static char *search_library_pathfds(const char *, const char *, int *);
static const void **get_program_var_addr(const char *, RtldLockState *);
static void set_program_var(const char *, const void *);
@ -1620,52 +1620,52 @@ find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
* nodeflib.
*/
if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
pathname = search_library_path(name, ld_library_path);
pathname = search_library_path(name, ld_library_path, fdp);
if (pathname != NULL)
return (pathname);
if (refobj != NULL) {
pathname = search_library_path(name, refobj->rpath);
pathname = search_library_path(name, refobj->rpath, fdp);
if (pathname != NULL)
return (pathname);
}
pathname = search_library_pathfds(name, ld_library_dirs, fdp);
if (pathname != NULL)
return (pathname);
pathname = search_library_path(name, gethints(false));
pathname = search_library_path(name, gethints(false), fdp);
if (pathname != NULL)
return (pathname);
pathname = search_library_path(name, ld_standard_library_path);
pathname = search_library_path(name, ld_standard_library_path, fdp);
if (pathname != NULL)
return (pathname);
} else {
nodeflib = objgiven ? refobj->z_nodeflib : false;
if (objgiven) {
pathname = search_library_path(name, refobj->rpath);
pathname = search_library_path(name, refobj->rpath, fdp);
if (pathname != NULL)
return (pathname);
}
if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
pathname = search_library_path(name, obj_main->rpath);
pathname = search_library_path(name, obj_main->rpath, fdp);
if (pathname != NULL)
return (pathname);
}
pathname = search_library_path(name, ld_library_path);
pathname = search_library_path(name, ld_library_path, fdp);
if (pathname != NULL)
return (pathname);
if (objgiven) {
pathname = search_library_path(name, refobj->runpath);
pathname = search_library_path(name, refobj->runpath, fdp);
if (pathname != NULL)
return (pathname);
}
pathname = search_library_pathfds(name, ld_library_dirs, fdp);
if (pathname != NULL)
return (pathname);
pathname = search_library_path(name, gethints(nodeflib));
pathname = search_library_path(name, gethints(nodeflib), fdp);
if (pathname != NULL)
return (pathname);
if (objgiven && !nodeflib) {
pathname = search_library_path(name,
ld_standard_library_path);
ld_standard_library_path, fdp);
if (pathname != NULL)
return (pathname);
}
@ -3022,12 +3022,14 @@ struct try_library_args {
size_t namelen;
char *buffer;
size_t buflen;
int fd;
};
static void *
try_library_path(const char *dir, size_t dirlen, void *param)
{
struct try_library_args *arg;
int fd;
arg = param;
if (*dir == '/' || trust) {
@ -3042,17 +3044,23 @@ try_library_path(const char *dir, size_t dirlen, void *param)
strcpy(pathname + dirlen + 1, arg->name);
dbg(" Trying \"%s\"", pathname);
if (access(pathname, F_OK) == 0) { /* We found it */
fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
if (fd >= 0) {
dbg(" Opened \"%s\", fd %d", pathname, fd);
pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
strcpy(pathname, arg->buffer);
arg->fd = fd;
return (pathname);
} else {
dbg(" Failed to open \"%s\": %s",
pathname, rtld_strerror(errno));
}
}
return (NULL);
}
static char *
search_library_path(const char *name, const char *path)
search_library_path(const char *name, const char *path, int *fdp)
{
char *p;
struct try_library_args arg;
@ -3064,8 +3072,10 @@ search_library_path(const char *name, const char *path)
arg.namelen = strlen(name);
arg.buffer = xmalloc(PATH_MAX);
arg.buflen = PATH_MAX;
arg.fd = -1;
p = path_enumerate(path, try_library_path, &arg);
*fdp = arg.fd;
free(arg.buffer);