Date: Thu, 25 Sep 2014 19:08:06 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r272125 - head/lib/libproc Message-ID: <201409251908.s8PJ86LK039436@svn.freebsd.org>
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Author: markj Date: Thu Sep 25 19:08:06 2014 New Revision: 272125 URL: http://svnweb.freebsd.org/changeset/base/272125 Log: Factor out some of the duplicated code in the symbol lookup functions, in preparation for adding userland CTF support to DTrace. MFC after: 1 month Sponsored by: EMC / Isilon Storage Division Modified: head/lib/libproc/proc_sym.c Modified: head/lib/libproc/proc_sym.c ============================================================================== --- head/lib/libproc/proc_sym.c Thu Sep 25 18:54:36 2014 (r272124) +++ head/lib/libproc/proc_sym.c Thu Sep 25 19:08:06 2014 (r272125) @@ -26,20 +26,20 @@ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. - * - * $FreeBSD$ */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + #include <sys/types.h> #include <sys/user.h> #include <assert.h> #include <err.h> -#include <stdio.h> +#include <fcntl.h> #include <libgen.h> -#include <string.h> +#include <stdio.h> #include <stdlib.h> -#include <fcntl.h> #include <string.h> #include <unistd.h> #include <libutil.h> @@ -228,22 +228,56 @@ proc_addr2map(struct proc_handle *p, uin return (NULL); } +/* + * Look up the symbol at addr, returning a copy of the symbol and its name. + */ +static int +lookup_addr(Elf *e, Elf_Scn *scn, u_long stridx, uintptr_t off, uintptr_t addr, + const char **name, GElf_Sym *symcopy) +{ + GElf_Sym sym; + Elf_Data *data; + const char *s; + uint64_t rsym; + int i; + + if ((data = elf_getdata(scn, NULL)) == NULL) { + DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1)); + return (1); + } + for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { + rsym = off + sym.st_value; + if (addr >= rsym && addr < rsym + sym.st_size) { + s = elf_strptr(e, stridx, sym.st_name); + if (s != NULL) { + *name = s; + memcpy(symcopy, &sym, sizeof(*symcopy)); + /* + * DTrace expects the st_value to contain + * only the address relative to the start of + * the function. + */ + symcopy->st_value = rsym; + return (0); + } + } + } + return (1); +} + int proc_addr2sym(struct proc_handle *p, uintptr_t addr, char *name, size_t namesz, GElf_Sym *symcopy) { + GElf_Ehdr ehdr; + GElf_Shdr shdr; Elf *e; Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL; - Elf_Data *data; - GElf_Shdr shdr; - GElf_Sym sym; - GElf_Ehdr ehdr; - int fd, error = -1; - size_t i; - uint64_t rsym; prmap_t *map; - char *s; - unsigned long symtabstridx = 0, dynsymstridx = 0; + const char *s; + uintptr_t off; + u_long symtabstridx = 0, dynsymstridx = 0; + int fd, error = -1; if ((map = proc_addr2map(p, addr)) == NULL) return (-1); @@ -259,6 +293,7 @@ proc_addr2sym(struct proc_handle *p, uin DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1)); goto err2; } + /* * Find the index of the STRTAB and SYMTAB sections to locate * symbol names. @@ -275,80 +310,25 @@ proc_addr2sym(struct proc_handle *p, uin dynsymscn = scn; dynsymstridx = shdr.sh_link; break; - default: - break; - } - } - /* - * Iterate over the Dynamic Symbols table to find the symbol. - * Then look up the string name in STRTAB (.dynstr) - */ - if ((data = elf_getdata(dynsymscn, NULL)) == NULL) { - DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1)); - goto symtab; - } - i = 0; - while (gelf_getsym(data, i++, &sym) != NULL) { - /* - * Calculate the address mapped to the virtual memory - * by rtld. - */ - if (ehdr.e_type != ET_EXEC) - rsym = map->pr_vaddr + sym.st_value; - else - rsym = sym.st_value; - if (addr >= rsym && addr < rsym + sym.st_size) { - s = elf_strptr(e, dynsymstridx, sym.st_name); - if (s) { - demangle(s, name, namesz); - memcpy(symcopy, &sym, sizeof(sym)); - /* - * DTrace expects the st_value to contain - * only the address relative to the start of - * the function. - */ - symcopy->st_value = rsym; - error = 0; - goto out; - } } } -symtab: + + off = ehdr.e_type == ET_EXEC ? 0 : map->pr_vaddr; + /* - * Iterate over the Symbols Table to find the symbol. - * Then look up the string name in STRTAB (.dynstr) + * First look up the symbol in the dynsymtab, and fall back to the + * symtab if the lookup fails. */ - if ((data = elf_getdata(symtabscn, NULL)) == NULL) { - DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1)); - goto err2; - } - i = 0; - while (gelf_getsym(data, i++, &sym) != NULL) { - /* - * Calculate the address mapped to the virtual memory - * by rtld. - */ - if (ehdr.e_type != ET_EXEC) - rsym = map->pr_vaddr + sym.st_value; - else - rsym = sym.st_value; - if (addr >= rsym && addr < rsym + sym.st_size) { - s = elf_strptr(e, symtabstridx, sym.st_name); - if (s) { - demangle(s, name, namesz); - memcpy(symcopy, &sym, sizeof(sym)); - /* - * DTrace expects the st_value to contain - * only the address relative to the start of - * the function. - */ - symcopy->st_value = rsym; - error = 0; - goto out; - } - } - } + error = lookup_addr(e, dynsymscn, dynsymstridx, off, addr, &s, symcopy); + if (error == 0) + goto out; + + error = lookup_addr(e, symtabscn, symtabstridx, off, addr, &s, symcopy); + if (error == 0) + goto out; + out: + demangle(s, name, namesz); err2: elf_end(e); err1: @@ -363,7 +343,7 @@ proc_name2map(struct proc_handle *p, con { size_t i; int cnt; - prmap_t *map; + prmap_t *map = NULL; char tmppath[MAXPATHLEN]; struct kinfo_vmentry *kves, *kve; rd_loadobj_t *rdl; @@ -382,30 +362,52 @@ proc_name2map(struct proc_handle *p, con basename_r(kve->kve_path, tmppath); if (strcmp(tmppath, name) == 0) { map = proc_addr2map(p, kve->kve_start); - free(kves); - return (map); + break; } } free(kves); - return (NULL); - } - if ((name == NULL || strcmp(name, "a.out") == 0) && - p->rdexec != NULL) { + } else + for (i = 0; i < p->nobjs; i++) { + rdl = &p->rdobjs[i]; + basename_r(rdl->rdl_path, tmppath); + if (strcmp(tmppath, name) == 0) { + if ((map = malloc(sizeof(*map))) == NULL) + return (NULL); + proc_rdl2prmap(rdl, map); + break; + } + } + + if (map == NULL && strcmp(name, "a.out") == 0 && p->rdexec != NULL) map = proc_addr2map(p, p->rdexec->rdl_saddr); - return (map); + + return (map); +} + +/* + * Look up the symbol with the given name and return a copy of it. + */ +static int +lookup_name(Elf *e, Elf_Scn *scn, u_long stridx, const char *symbol, + GElf_Sym *symcopy) +{ + GElf_Sym sym; + Elf_Data *data; + char *s; + int i; + + if ((data = elf_getdata(scn, NULL)) == NULL) { + DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1)); + return (1); } - for (i = 0; i < p->nobjs; i++) { - rdl = &p->rdobjs[i]; - basename_r(rdl->rdl_path, tmppath); - if (strcmp(tmppath, name) == 0) { - if ((map = malloc(sizeof(*map))) == NULL) - return (NULL); - proc_rdl2prmap(rdl, map); - return (map); + for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { + s = elf_strptr(e, stridx, sym.st_name); + if (s != NULL && strcmp(s, symbol) == 0) { + memcpy(symcopy, &sym, sizeof(*symcopy)); + return (0); } } - - return (NULL); + return (1); } int @@ -414,15 +416,12 @@ proc_name2sym(struct proc_handle *p, con { Elf *e; Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL; - Elf_Data *data; GElf_Shdr shdr; - GElf_Sym sym; GElf_Ehdr ehdr; - int fd, error = -1; - size_t i; prmap_t *map; - char *s; - unsigned long symtabstridx = 0, dynsymstridx = 0; + uintptr_t off; + u_long symtabstridx = 0, dynsymstridx = 0; + int fd, error = -1; if ((map = proc_name2map(p, object)) == NULL) { DPRINTFX("ERROR: couldn't find object %s", object); @@ -456,46 +455,25 @@ proc_name2sym(struct proc_handle *p, con dynsymscn = scn; dynsymstridx = shdr.sh_link; break; - default: - break; - } - } - /* - * Iterate over the Dynamic Symbols table to find the symbol. - * Then look up the string name in STRTAB (.dynstr) - */ - if ((data = elf_getdata(dynsymscn, NULL))) { - i = 0; - while (gelf_getsym(data, i++, &sym) != NULL) { - s = elf_strptr(e, dynsymstridx, sym.st_name); - if (s && strcmp(s, symbol) == 0) { - memcpy(symcopy, &sym, sizeof(sym)); - if (ehdr.e_type != ET_EXEC) - symcopy->st_value += map->pr_vaddr; - error = 0; - goto out; - } } } + /* - * Iterate over the Symbols Table to find the symbol. - * Then look up the string name in STRTAB (.dynstr) + * First look up the symbol in the dynsymtab, and fall back to the + * symtab if the lookup fails. */ - if ((data = elf_getdata(symtabscn, NULL))) { - i = 0; - while (gelf_getsym(data, i++, &sym) != NULL) { - s = elf_strptr(e, symtabstridx, sym.st_name); - if (s && strcmp(s, symbol) == 0) { - memcpy(symcopy, &sym, sizeof(sym)); - if (ehdr.e_type != ET_EXEC) - symcopy->st_value += map->pr_vaddr; - error = 0; - goto out; - } - } - } + error = lookup_name(e, dynsymscn, dynsymstridx, symbol, symcopy); + if (error == 0) + goto out; + + error = lookup_name(e, symtabscn, symtabstridx, symbol, symcopy); + if (error == 0) + goto out; + out: - DPRINTFX("found addr 0x%lx for %s", symcopy->st_value, symbol); + off = ehdr.e_type == ET_EXEC ? 0 : map->pr_vaddr; + symcopy->st_value += off; + err2: elf_end(e); err1: @@ -506,7 +484,6 @@ err0: return (error); } - int proc_iter_symbyaddr(struct proc_handle *p, const char *object, int which, int mask, proc_sym_f *func, void *cd) @@ -543,7 +520,7 @@ proc_iter_symbyaddr(struct proc_handle * scn = NULL; while ((scn = elf_nextscn(e, scn)) != NULL) { gelf_getshdr(scn, &shdr); - if (which == PR_SYMTAB && + if (which == PR_SYMTAB && shdr.sh_type == SHT_SYMTAB) { foundscn = scn; break; @@ -560,8 +537,7 @@ proc_iter_symbyaddr(struct proc_handle * DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1)); goto err2; } - i = 0; - while (gelf_getsym(data, i++, &sym) != NULL) { + for (i = 0; gelf_getsym(data, i, &sym) != NULL; i++) { if (GELF_ST_BIND(sym.st_info) == STB_LOCAL && (mask & BIND_LOCAL) == 0) continue;
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