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.

diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
index 4a840cf..aff388b 100644 (file)
--- 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 1447e20..4e0b9f4 100644 (file)
--- 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;