From bc6a35fb7b02f068b901f22a56559996395cfd3b Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 4 Oct 2012 20:04:13 -0400 Subject: partial TLS support for dynamic-linked programs only TLS in the main program is supported so far; TLS defined in shared libraries will not work yet. --- src/env/__init_tls.c | 10 +++--- src/ldso/dynlink.c | 94 ++++++++++++++++++++++++++++++++++++++++------------ 2 files changed, 77 insertions(+), 27 deletions(-) (limited to 'src') diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c index 4a840cf2..aff388bd 100644 --- a/src/env/__init_tls.c +++ b/src/env/__init_tls.c @@ -7,13 +7,14 @@ #ifndef SHARED static void *image; -static size_t len, bss, align; +static size_t len, size, align; void *__copy_tls(unsigned char *mem, size_t cnt) { + mem += -size & (4*sizeof(size_t)-1); mem += ((uintptr_t)image - (uintptr_t)mem) & (align-1); memcpy(mem, image, len); - return mem + len + bss; + return mem + size; } static void *simple(void *p) @@ -53,13 +54,12 @@ void __init_tls(size_t *auxv) } if (!tls_phdr) return; - libc.tls_size = len+bss+align+4*sizeof(size_t)+sizeof(struct pthread); + libc.tls_size = size+align+8*sizeof(size_t)+sizeof(struct pthread); image = (void *)(base + tls_phdr->p_vaddr); len = tls_phdr->p_filesz; - bss = tls_phdr->p_memsz - len; + size = tls_phdr->p_memsz; align = tls_phdr->p_align; - if (align < 4*sizeof(size_t)) align = 4*sizeof(size_t); mem = __mmap(0, libc.tls_size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); if (mem == MAP_FAILED) a_crash(); diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index 1447e205..4e0b9f4e 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -67,6 +67,8 @@ struct dso { char relocated; char constructed; struct dso **deps; + void *tls_image; + size_t tls_len, tls_size, tls_align, tls_id; char *shortname; char buf[]; }; @@ -74,6 +76,7 @@ struct dso { #include "reloc.h" void __init_ssp(size_t *); +void *__install_initial_tls(void *); static struct dso *head, *tail, *libc; static char *env_path, *sys_path, *r_path; @@ -86,6 +89,7 @@ static jmp_buf rtld_fail; static pthread_rwlock_t lock; static struct debug debug; static size_t *auxv; +static size_t tls_cnt, tls_size; struct debug *_dl_debug_addr = &debug; @@ -278,7 +282,7 @@ static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phc } } -static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dynp) +static void *map_library(int fd, struct dso *dso) { Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)]; size_t phsize; @@ -290,6 +294,7 @@ static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dy unsigned prot; unsigned char *map, *base; size_t dyn; + size_t tls_image=0; size_t i; ssize_t l = read(fd, buf, sizeof buf); @@ -306,6 +311,12 @@ static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dy for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) { if (ph->p_type == PT_DYNAMIC) dyn = ph->p_vaddr; + if (ph->p_type == PT_TLS) { + tls_image = ph->p_vaddr; + dso->tls_align = ph->p_align; + dso->tls_len = ph->p_filesz; + dso->tls_size = ph->p_memsz; + } if (ph->p_type != PT_LOAD) continue; if (ph->p_vaddr < addr_min) { addr_min = ph->p_vaddr; @@ -360,9 +371,11 @@ static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dy } if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff), eh->e_phentsize, eh->e_phnum); - *lenp = map_len; - *basep = base; - *dynp = dyn; + dso->map = map; + dso->map_len = map_len; + dso->base = base; + dso->dynv = (void *)(base+dyn); + if (dso->tls_size) dso->tls_image = (void *)(base+tls_image); return map; error: munmap(map, map_len); @@ -402,7 +415,7 @@ static struct dso *load_library(const char *name) const char *pathname; unsigned char *base, *map; size_t dyno, map_len; - struct dso *p; + struct dso *p, temp_dso = {0}; int fd; struct stat st; @@ -469,21 +482,21 @@ static struct dso *load_library(const char *name) return p; } } - map = map_library(fd, &map_len, &base, &dyno); + map = map_library(fd, &temp_dso); close(fd); if (!map) return 0; - p = calloc(1, sizeof *p + strlen(pathname) + 1); + p = malloc(sizeof *p + strlen(pathname) + 1); if (!p) { munmap(map, map_len); return 0; } - - p->map = map; - p->map_len = map_len; - p->base = base; - p->dynv = (void *)(base + dyno); + memcpy(p, &temp_dso, sizeof temp_dso); decode_dyn(p); - + if (p->tls_image) { + p->tls_id = ++tls_cnt; + tls_size += p->tls_size + p->tls_align + 8*sizeof(size_t) - 1 + & -4*sizeof(size_t); + } p->dev = st.st_dev; p->ino = st.st_ino; p->refcnt = 1; @@ -622,6 +635,25 @@ void _dl_debug_state(void) { } +void *__copy_tls(unsigned char *mem, size_t cnt) +{ + struct dso *p; + void **dtv = (void *)mem; + dtv[0] = (void *)cnt; + mem = (void *)(dtv + cnt + 1); + for (p=tail; p; p=p->prev) { + if (p->tls_id-1 >= cnt) continue; + mem += -p->tls_len & (4*sizeof(size_t)-1); + mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) + & (p->tls_align-1); + dtv[p->tls_id] = mem; + memcpy(mem, p->tls_image, p->tls_len); + mem += p->tls_size; + } + ((pthread_t)mem)->dtv = dtv; + return mem; +} + void *__dynlink(int argc, char **argv) { size_t aux[AUX_CNT] = {0}; @@ -676,6 +708,7 @@ void *__dynlink(int argc, char **argv) if (aux[AT_PHDR]) { size_t interp_off = 0; + size_t tls_image = 0; /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */ phdr = (void *)aux[AT_PHDR]; for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) { @@ -683,7 +716,14 @@ void *__dynlink(int argc, char **argv) app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr); else if (phdr->p_type == PT_INTERP) interp_off = (size_t)phdr->p_vaddr; + else if (phdr->p_type == PT_TLS) { + tls_image = phdr->p_vaddr; + app->tls_len = phdr->p_filesz; + app->tls_size = phdr->p_memsz; + app->tls_align = phdr->p_align; + } } + if (app->tls_size) app->tls_image = (char *)app->base + tls_image; if (interp_off) lib->name = (char *)app->base + interp_off; app->name = argv[0]; app->dynv = (void *)(app->base + find_dyn( @@ -709,7 +749,7 @@ void *__dynlink(int argc, char **argv) _exit(1); } runtime = 1; - ehdr = (void *)map_library(fd, &app->map_len, &app->base, &dyno); + ehdr = (void *)map_library(fd, app); if (!ehdr) { dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]); _exit(1); @@ -718,9 +758,13 @@ void *__dynlink(int argc, char **argv) close(fd); lib->name = ldname; app->name = argv[0]; - app->dynv = (void *)(app->base + dyno); aux[AT_ENTRY] = ehdr->e_entry; } + if (app->tls_size) { + app->tls_id = ++tls_cnt; + tls_size += app->tls_size+app->tls_align + 8*sizeof(size_t)-1 + & -4*sizeof(size_t); + } app->global = 1; app->constructed = 1; decode_dyn(app); @@ -791,8 +835,19 @@ void *__dynlink(int argc, char **argv) debug.state = 0; _dl_debug_state(); - /* Stand-in until real TLS support is added to dynamic linker */ - __libc.tls_size = sizeof(struct pthread) + 4*sizeof(size_t); + tls_size += sizeof(struct pthread) + 4*sizeof(size_t); + __libc.tls_size = tls_size; + __libc.tls_cnt = tls_cnt; + if (tls_cnt) { + void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE, + MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); + if (mem==MAP_FAILED || + !__install_initial_tls(__copy_tls(mem, tls_cnt))) { + dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n", + argv[0], tls_size); + _exit(127); + } + } if (ssp_used) __init_ssp(auxv); do_init_fini(tail); @@ -807,11 +862,6 @@ void *__dynlink(int argc, char **argv) return (void *)aux[AT_ENTRY]; } -void *__copy_tls(unsigned char *mem, size_t cnt) -{ - return mem; -} - void *dlopen(const char *file, int mode) { struct dso *volatile p, *orig_tail = tail, *next; -- cgit v1.2.1