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Diffstat (limited to 'usr/src/lib/libproc/common/Psymtab.c')
-rw-r--r--usr/src/lib/libproc/common/Psymtab.c244
1 files changed, 242 insertions, 2 deletions
diff --git a/usr/src/lib/libproc/common/Psymtab.c b/usr/src/lib/libproc/common/Psymtab.c
index 62354f9a7b..a3e0d07ae2 100644
--- a/usr/src/lib/libproc/common/Psymtab.c
+++ b/usr/src/lib/libproc/common/Psymtab.c
@@ -21,7 +21,7 @@
/*
* Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013, Joyent, Inc. All rights reserved.
+ * Copyright (c) 2015, Joyent, Inc. All rights reserved.
* Copyright (c) 2013 by Delphix. All rights reserved.
*/
@@ -43,6 +43,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
+#include <sys/crc32.h>
#include "libproc.h"
#include "Pcontrol.h"
@@ -61,6 +62,7 @@ static int read_ehdr32(struct ps_prochandle *, Elf32_Ehdr *, uint_t *,
static int read_ehdr64(struct ps_prochandle *, Elf64_Ehdr *, uint_t *,
uintptr_t);
#endif
+static uint32_t psym_crc32[] = { CRC32_TABLE };
#define DATA_TYPES \
((1 << STT_OBJECT) | (1 << STT_FUNC) | \
@@ -184,6 +186,7 @@ file_info_new(struct ps_prochandle *P, map_info_t *mptr)
mptr->map_file = fptr;
fptr->file_ref = 1;
fptr->file_fd = -1;
+ fptr->file_dbgfile = -1;
P->num_files++;
/*
@@ -274,6 +277,10 @@ file_info_free(struct ps_prochandle *P, file_info_t *fptr)
free(fptr->file_elfmem);
if (fptr->file_fd >= 0)
(void) close(fptr->file_fd);
+ if (fptr->file_dbgelf)
+ (void) elf_end(fptr->file_dbgelf);
+ if (fptr->file_dbgfile >= 0)
+ (void) close(fptr->file_dbgfile);
if (fptr->file_ctfp) {
ctf_close(fptr->file_ctfp);
free(fptr->file_ctf_buf);
@@ -1567,6 +1574,170 @@ build_fake_elf(struct ps_prochandle *P, file_info_t *fptr, GElf_Ehdr *ehdr,
}
/*
+ * Try and find the file described by path in the file system and validate that
+ * it matches our CRC before we try and process it for symbol information.
+ *
+ * Before we valiate if it's a crc, we check to ensure that it's a normal file
+ * and not anything else.
+ */
+static boolean_t
+build_alt_debug(file_info_t *fptr, const char *path, uint32_t crc)
+{
+ int fd;
+ struct stat st;
+ Elf *elf;
+ Elf_Scn *scn;
+ GElf_Shdr symshdr, strshdr;
+ Elf_Data *symdata, *strdata;
+ uint32_t c = -1U;
+
+ if ((fd = open(path, O_RDONLY)) < 0)
+ return (B_FALSE);
+
+ if (fstat(fd, &st) != 0) {
+ (void) close(fd);
+ return (B_FALSE);
+ }
+
+ if (S_ISREG(st.st_mode) == 0) {
+ (void) close(fd);
+ return (B_FALSE);
+ }
+
+ for (;;) {
+ char buf[4096];
+ ssize_t ret = read(fd, buf, sizeof (buf));
+ if (ret == -1) {
+ if (ret == EINTR)
+ continue;
+ (void) close(fd);
+ return (B_FALSE);
+ }
+ if (ret == 0) {
+ c = ~c;
+ if (c != crc) {
+ dprintf("crc mismatch, found: 0x%x "
+ "expected 0x%x\n", c, crc);
+ (void) close(fd);
+ return (B_FALSE);
+ }
+ break;
+ }
+ CRC32(c, buf, ret, c, psym_crc32);
+ }
+
+ elf = elf_begin(fd, ELF_C_READ, NULL);
+ if (elf == NULL) {
+ (void) close(fd);
+ return (B_FALSE);
+ }
+
+ if (elf_kind(elf) != ELF_K_ELF) {
+ goto fail;
+ }
+
+ /*
+ * Do two passes, first see if we have a symbol header, then see if we
+ * can find the corresponding linked string table.
+ */
+ scn = NULL;
+ for (scn = elf_nextscn(elf, scn); scn != NULL;
+ scn = elf_nextscn(elf, scn)) {
+
+ if (gelf_getshdr(scn, &symshdr) == NULL)
+ goto fail;
+
+ if (symshdr.sh_type != SHT_SYMTAB)
+ continue;
+
+ if ((symdata = elf_getdata(scn, NULL)) == NULL)
+ goto fail;
+
+ break;
+ }
+ if (scn == NULL)
+ goto fail;
+
+ if ((scn = elf_getscn(elf, symshdr.sh_link)) == NULL)
+ goto fail;
+
+ if (gelf_getshdr(scn, &strshdr) == NULL)
+ goto fail;
+
+ if ((strdata = elf_getdata(scn, NULL)) == NULL)
+ goto fail;
+
+ fptr->file_symtab.sym_data_pri = symdata;
+ fptr->file_symtab.sym_symn += symshdr.sh_size / symshdr.sh_entsize;
+ fptr->file_symtab.sym_strs = strdata->d_buf;
+ fptr->file_symtab.sym_strsz = strdata->d_size;
+ fptr->file_symtab.sym_hdr_pri = symshdr;
+ fptr->file_symtab.sym_strhdr = strshdr;
+
+ dprintf("successfully loaded additional debug symbols for %s from %s\n",
+ fptr->file_rname, path);
+
+ fptr->file_dbgfile = fd;
+ fptr->file_dbgelf = elf;
+ return (B_TRUE);
+fail:
+ (void) elf_end(elf);
+ (void) close(fd);
+ return (B_FALSE);
+}
+
+/*
+ * We're here because the object in question has no symbol information, that's a
+ * bit unfortunate. However, we've found that there's a .gnu_debuglink sitting
+ * around. By convention that means that given the current location of the
+ * object on disk, and the debug name that we found in the binary we need to
+ * search the following locations for a matching file.
+ *
+ * <dirname>/.debug/<debug-name>
+ * /usr/lib/debug/<dirname>/<debug-name>
+ *
+ * In the future, we should consider supporting looking in the prefix's
+ * lib/debug directory for a matching object.
+ */
+static void
+find_alt_debug(file_info_t *fptr, const char *name, uint32_t crc)
+{
+ boolean_t r;
+ char *dup = NULL, *path = NULL, *dname;
+
+ dprintf("find_alt_debug: looking for %s, crc 0x%x\n", name, crc);
+ if (fptr->file_rname == NULL) {
+ dprintf("find_alt_debug: encountered null file_rname\n");
+ return;
+ }
+
+ dup = strdup(fptr->file_rname);
+ if (dup == NULL)
+ return;
+
+ dname = dirname(dup);
+ if (asprintf(&path, "%s/.debug/%s", dname, name) != -1) {
+ dprintf("attempting to load alternate debug information "
+ "from %s\n", path);
+ r = build_alt_debug(fptr, path, crc);
+ free(path);
+ if (r == B_TRUE)
+ goto out;
+ }
+
+ if (asprintf(&path, "/usr/lib/debug/%s/%s", dname, name) != -1) {
+ dprintf("attempting to load alternate debug information "
+ "from %s\n", path);
+ r = build_alt_debug(fptr, path, crc);
+ free(path);
+ if (r == B_TRUE)
+ goto out;
+ }
+out:
+ free(dup);
+}
+
+/*
* Build the symbol table for the given mapped file.
*/
void
@@ -1587,7 +1758,8 @@ Pbuild_file_symtab(struct ps_prochandle *P, file_info_t *fptr)
GElf_Shdr c_shdr;
Elf_Data *c_data;
const char *c_name;
- } *cp, *cache = NULL, *dyn = NULL, *plt = NULL, *ctf = NULL;
+ } *cp, *cache = NULL, *dyn = NULL, *plt = NULL, *ctf = NULL,
+ *dbglink = NULL;
if (fptr->file_init)
return; /* We've already processed this file */
@@ -1813,7 +1985,69 @@ Pbuild_file_symtab(struct ps_prochandle *P, file_info_t *fptr)
continue;
}
ctf = cp;
+ } else if (strcmp(cp->c_name, ".gnu_debuglink") == 0) {
+ dprintf("found .gnu_debuglink section for %s\n",
+ fptr->file_rname);
+ /*
+ * Let's make sure of a few things before we do this.
+ */
+ if (cp->c_shdr.sh_type == SHT_PROGBITS &&
+ cp->c_data->d_buf != NULL) {
+ dprintf(".gnu_debuglink pases initial "
+ "sanity\n");
+ dbglink = cp;
+ }
+ }
+ }
+
+ /*
+ * If we haven't found any symbol table information and we have found a
+ * .gnu_debuglink, it's time to try and figure out where we might find
+ * this. To do so, we're going to first verify that the elf data seems
+ * somewhat sane, eg. the elf data should be a string, so we want to
+ * verify we have a null-terminator.
+ */
+ if (fptr->file_symtab.sym_data_pri == NULL && dbglink != NULL) {
+ char *c = dbglink->c_data->d_buf;
+ size_t i;
+ boolean_t found = B_FALSE;
+ Elf_Data *ed = dbglink->c_data;
+ uint32_t crc;
+
+ for (i = 0; i < ed->d_size; i++) {
+ if (c[i] == '\0') {
+ uintptr_t off;
+ dprintf("got .gnu_debuglink terminator at "
+ "offset %lu\n", (unsigned long)i);
+ /*
+ * After the null terminator, there should be
+ * padding, followed by a 4 byte CRC of the
+ * file. If we don't see this, we're going to
+ * assume this is bogus.
+ */
+ if ((i % sizeof (uint32_t)) == 0) {
+ i += 4;
+ } else {
+ i += sizeof (uint32_t) -
+ (i % sizeof (uint32_t));
+ }
+ if (i + sizeof (uint32_t) ==
+ dbglink->c_data->d_size) {
+ found = B_TRUE;
+ off = (uintptr_t)ed->d_buf + i;
+ crc = *(uint32_t *)off;
+ } else {
+ dprintf(".gnu_debuglink size mismatch, "
+ "expected: %lu, found: %lu\n",
+ (unsigned long)i,
+ (unsigned long)ed->d_size);
+ }
+ break;
+ }
}
+
+ if (found == B_TRUE)
+ find_alt_debug(fptr, dbglink->c_data->d_buf, crc);
}
/*
@@ -1943,7 +2177,13 @@ bad:
fptr->file_elfmem = NULL;
}
(void) close(fptr->file_fd);
+ if (fptr->file_dbgelf != NULL)
+ (void) elf_end(fptr->file_dbgelf);
+ fptr->file_dbgelf = NULL;
+ if (fptr->file_dbgfile >= 0)
+ (void) close(fptr->file_dbgfile);
fptr->file_fd = -1;
+ fptr->file_dbgfile = -1;
}
/*
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-28 12:00:11 +0000