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| author | Leandro Pereira <leandro.pereira@microsoft.com> | 2019-10-02 12:48:17 -0400 |
|---|---|---|
| committer | Carlos O'Donell <carlos@redhat.com> | 2019-10-18 15:55:33 -0400 |
| commit | 95c1056962a3f2297c94ce47f0eaf0c5b6563231 (patch) | |
| tree | 8e6566200a6a17bea0a7d0eb8285b83a248e973e | |
| parent | fed33b0fb03d1942a6713286176d42869c0f1580 (diff) | |
| download | glibc-95c1056962a3f2297c94ce47f0eaf0c5b6563231.zip glibc-95c1056962a3f2297c94ce47f0eaf0c5b6563231.tar.gz glibc-95c1056962a3f2297c94ce47f0eaf0c5b6563231.tar.bz2 | |
elf: Use nocancel pread64() instead of lseek()+read()
Transforms this, when linking in a shared object:
openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3"..., 832) = 832
lseek(3, 792, SEEK_SET) = 792
read(3, "\4\0\0\0\24\0\0\0"..., 68) = 68
fstat(3, {st_mode=S_IFREG|0755, st_size=6699224, ...}) = 0
lseek(3, 792, SEEK_SET) = 792
read(3, "\4\0\0\0\24\0\0\0"..., 68) = 68
lseek(3, 864, SEEK_SET) = 864
read(3, "\4\0\0\0\20\0\0\0"..., 32) = 32
Into this:
openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3"..., 832) = 832
pread(3, "\4\0\0\0\24\0\0\0"..., 68, 792) = 68
fstat(3, {st_mode=S_IFREG|0755, st_size=6699224, ...}) = 0
pread(3, "\4\0\0\0\24\0\0\0"..., 68, 792) = 68
pread(3, "\4\0\0\0\20\0\0\0"..., 32, 864) = 32
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
| -rw-r--r-- | elf/dl-load.c | 13 | ||||
| -rw-r--r-- | sysdeps/x86/dl-prop.h | 3 |
2 files changed, 7 insertions, 9 deletions
diff --git a/elf/dl-load.c b/elf/dl-load.c index 1ed7a7b..c1bc8c2 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1015,8 +1015,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, else { phdr = alloca (maplength); - __lseek (fd, header->e_phoff, SEEK_SET); - if ((size_t) __read_nocancel (fd, (void *) phdr, maplength) != maplength) + if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, + header->e_phoff) != maplength) { errstring = N_("cannot read file data"); goto call_lose_errno; @@ -1664,9 +1664,8 @@ open_verify (const char *name, int fd, else { phdr = alloca (maplength); - __lseek (fd, ehdr->e_phoff, SEEK_SET); - if ((size_t) __read_nocancel (fd, (void *) phdr, maplength) - != maplength) + if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, + ehdr->e_phoff) != maplength) { read_error: errval = errno; @@ -1704,8 +1703,8 @@ open_verify (const char *name, int fd, abi_note = abi_note_malloced; } - __lseek (fd, ph->p_offset, SEEK_SET); - if (__read_nocancel (fd, (void *) abi_note, size) != size) + if (__pread64_nocancel (fd, (void *) abi_note, size, + ph->p_offset) != size) { free (abi_note_malloced); goto read_error; diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h index a99eec1..fa5bd98 100644 --- a/sysdeps/x86/dl-prop.h +++ b/sysdeps/x86/dl-prop.h @@ -167,8 +167,7 @@ _dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph, note_malloced = malloc (size); note = note_malloced; } - __lseek (fd, ph->p_offset, SEEK_SET); - if (__read_nocancel (fd, (void *) note, size) != size) + if (__pread64_nocancel (fd, (void *) note, size, ph->p_offset) != size) { if (note_malloced) free (note_malloced); |