1 files changed, 106 insertions, 0 deletions
diff --git a/usr.bin/gprof/elf.c b/usr.bin/gprof/elf.c
new file mode 100644
index 0000000..3a59f53
--- /dev/null
+++ b/usr.bin/gprof/elf.c
@@ -0,0 +1,106 @@
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <elf.h>
+#include <err.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "gprof.h"
+
+static bool wantsym(const Elf_Sym *, const char *);
+
+/* Things which get -E excluded by default. */
+static char	*excludes[] = { ".mcount", "_mcleanup", NULL };
+
+int
+elf_getnfile(const char *filename, char ***defaultEs)
+{
+    int fd;
+    Elf_Ehdr h;
+    struct stat s;
+    void *mapbase;
+    const char *base;
+    const Elf_Shdr *shdrs;
+    const Elf_Shdr *sh_symtab;
+    const Elf_Shdr *sh_strtab;
+    const char *strtab;
+    const Elf_Sym *symtab;
+    int symtabct;
+    int i;
+
+    if ((fd = open(filename, O_RDONLY)) == -1)
+	err(1, "%s", filename);
+    if (read(fd, &h, sizeof h) != sizeof h || !IS_ELF(h)) {
+	close(fd);
+	return -1;
+    }
+    if (fstat(fd, &s) == -1)
+	err(1, "Cannot fstat %s", filename);
+    if ((mapbase = mmap(0, s.st_size, PROT_READ, MAP_SHARED, fd, 0)) ==
+      MAP_FAILED)
+	err(1, "Cannot mmap %s", filename);
+    close(fd);
+
+    base = (const char *)mapbase;
+    shdrs = (const Elf_Shdr *)(base + h.e_shoff);
+
+    /* Find the symbol table and associated string table section. */
+    for (i = 1;  i < h.e_shnum;  i++)
+	if (shdrs[i].sh_type == SHT_SYMTAB)
+	    break;
+    if (i == h.e_shnum)
+	errx(1, "%s has no symbol table", filename);
+    sh_symtab = &shdrs[i];
+    sh_strtab = &shdrs[sh_symtab->sh_link];
+
+    symtab = (const Elf_Sym *)(base + sh_symtab->sh_offset);
+    symtabct = sh_symtab->sh_size / sh_symtab->sh_entsize;
+    strtab = (const char *)(base + sh_strtab->sh_offset);
+
+    /* Count the symbols that we're interested in. */
+    nname = 0;
+    for (i = 1;  i < symtabct;  i++)
+	if (wantsym(&symtab[i], strtab))
+	    nname++;
+
+    /* Allocate memory for them, plus a terminating entry. */
+    if ((nl = (nltype *)calloc(nname + 1, sizeof(nltype))) == NULL)
+	errx(1, "Insufficient memory for symbol table");
+
+    /* Read them in. */
+    npe = nl;
+    for (i = 1;  i < symtabct;  i++) {
+	const Elf_Sym *sym = &symtab[i];
+
+	if (wantsym(sym, strtab)) {
+	    npe->value = sym->st_value;
+	    npe->name = strtab + sym->st_name;
+	    npe++;
+	}
+    }
+    npe->value = -1;
+
+    *defaultEs = excludes;
+    return 0;
+}
+
+static bool
+wantsym(const Elf_Sym *sym, const char *strtab)
+{
+    int type;
+    int bind;
+
+    type = ELF_ST_TYPE(sym->st_info);
+    bind = ELF_ST_BIND(sym->st_info);
+
+    if (type != STT_FUNC ||
+      bind == STB_WEAK ||
+      (aflag && bind == STB_LOCAL) ||
+      (uflag && strchr(strtab + sym->st_name, '.') != NULL))
+	return 0;
+
+    return 1;
+}