From d3c1e14b41ef931cf5c1d3e8e26e22daa9854589 Mon Sep 17 00:00:00 2001 From: Edwin Groothuis Date: Thu, 3 Jul 2008 22:30:18 +0000 Subject: [PATCH] Extract the determination of the kind of (dynamic) executable from the main-loop into a seperate function. Instead of using hardcoded environment variables, define them in a lookup table. For the rest, no functionality changes. Approved by: bde (mentor) MFC after: 1 week --- usr.bin/ldd/ldd.c | 201 +++++++++++++++++++++++++++------------------- 1 file changed, 120 insertions(+), 81 deletions(-) diff --git a/usr.bin/ldd/ldd.c b/usr.bin/ldd/ldd.c index a580d24f4ab3..2d276b1287c8 100644 --- a/usr.bin/ldd/ldd.c +++ b/usr.bin/ldd/ldd.c @@ -47,13 +47,28 @@ __FBSDID("$FreeBSD$"); #include "extern.h" -static void -usage(void) -{ +static int is_executable(const char *fname, int fd, int *is_shlib, + int *type); +static void usage(void); - fprintf(stderr, "usage: ldd [-a] [-v] [-f format] program ...\n"); - exit(1); -} +#define TYPE_UNKNOWN 0 +#define TYPE_AOUT 1 +#define TYPE_ELF 2 /* Architecture default */ + +#define ENV_OBJECTS 0 +#define ENV_OBJECTS_FMT1 1 +#define ENV_OBJECTS_FMT2 2 +#define ENV_OBJECTS_PROGNAME 3 +#define ENV_OBJECTS_ALL 4 +#define ENV_LAST 5 + +const char *envdef[ENV_LAST] = { + "LD_TRACE_LOADED_OBJECTS", + "LD_TRACE_LOADED_OBJECTS_FMT1", + "LD_TRACE_LOADED_OBJECTS_FMT2", + "LD_TRACE_LOADED_OBJECTS_PROGNAME", + "LD_TRACE_LOADED_OBJECTS_ALL", +}; int main(int argc, char *argv[]) @@ -104,95 +119,35 @@ main(int argc, char *argv[]) } #endif - /* ld.so magic */ - setenv("LD_TRACE_LOADED_OBJECTS", "yes", 1); - if (fmt1 != NULL) - setenv("LD_TRACE_LOADED_OBJECTS_FMT1", fmt1, 1); - if (fmt2 != NULL) - setenv("LD_TRACE_LOADED_OBJECTS_FMT2", fmt2, 1); - rval = 0; for (; argc > 0; argc--, argv++) { - int fd, n, status, file_ok, is_shlib; - union { - struct exec aout; - Elf_Ehdr elf; - } hdr; + int fd, status, is_shlib, rv, type; + const char **env; + + env = envdef; /* Temporary placeholder */ if ((fd = open(*argv, O_RDONLY, 0)) < 0) { warn("%s", *argv); rval |= 1; continue; } - if ((n = read(fd, &hdr, sizeof(hdr))) == -1) { - warn("%s: can't read program header", *argv); - close(fd); - rval |= 1; - continue; - } - - file_ok = 1; - is_shlib = 0; - if ((size_t)n >= sizeof(hdr.aout) && !N_BADMAG(hdr.aout)) { - /* a.out file */ - if ((N_GETFLAG(hdr.aout) & EX_DPMASK) != EX_DYNAMIC -#if 1 /* Compatibility */ - || hdr.aout.a_entry < __LDPGSZ -#endif - ) { - warnx("%s: not a dynamic executable", *argv); - file_ok = 0; - } - } else if ((size_t)n >= sizeof(hdr.elf) && IS_ELF(hdr.elf)) { - Elf_Ehdr ehdr; - Elf_Phdr phdr; - int dynamic, i; - - dynamic = 0; - - if (lseek(fd, 0, SEEK_SET) == -1 || - read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr) || - lseek(fd, ehdr.e_phoff, SEEK_SET) == -1) { - warnx("%s: can't read program header", *argv); - file_ok = 0; - } else { - for (i = 0; i < ehdr.e_phnum; i++) { - if (read(fd, &phdr, ehdr.e_phentsize) - != sizeof(phdr)) { - warnx("%s: can't read program header", - *argv); - file_ok = 0; - break; - } - if (phdr.p_type == PT_DYNAMIC) - dynamic = 1; - } - } - if (!dynamic) { - warnx("%s: not a dynamic executable", *argv); - file_ok = 0; - } else if (hdr.elf.e_type == ET_DYN) { - if (hdr.elf.e_ident[EI_OSABI] & ELFOSABI_FREEBSD) { - is_shlib = 1; - } else { - warnx("%s: not a FreeBSD ELF shared " - "object", *argv); - file_ok = 0; - } - } - } else { - warnx("%s: not a dynamic executable", *argv); - file_ok = 0; - } + rv = is_executable(*argv, fd, &is_shlib, &type); close(fd); - if (!file_ok) { + if (rv == 0) { rval |= 1; continue; } - setenv("LD_TRACE_LOADED_OBJECTS_PROGNAME", *argv, 1); + /* ld.so magic */ + setenv(env[ENV_OBJECTS], "yes", 1); + if (fmt1 != NULL) + setenv(env[ENV_OBJECTS_FMT1], fmt1, 1); + if (fmt2 != NULL) + setenv(env[ENV_OBJECTS_FMT2], fmt2, 1); + + setenv(env[ENV_OBJECTS_PROGNAME], *argv, 1); if (aflag) - setenv("LD_TRACE_LOADED_OBJECTS_ALL", "1", 1); + setenv(env[ENV_OBJECTS_ALL], "1", 1); else if (fmt1 == NULL && fmt2 == NULL) /* Default formats */ printf("%s:\n", *argv); @@ -230,3 +185,87 @@ main(int argc, char *argv[]) return rval; } + +static void +usage(void) +{ + + fprintf(stderr, "usage: ldd [-a] [-v] [-f format] program ...\n"); + exit(1); +} + +static int +is_executable(const char *fname, int fd, int *is_shlib, int *type) +{ + union { + struct exec aout; + Elf_Ehdr elf; + } hdr; + int n; + + *is_shlib = 0; + *type = TYPE_UNKNOWN; + + if ((n = read(fd, &hdr, sizeof(hdr))) == -1) { + warn("%s: can't read program header", fname); + return (0); + } + + if ((size_t)n >= sizeof(hdr.aout) && !N_BADMAG(hdr.aout)) { + /* a.out file */ + if ((N_GETFLAG(hdr.aout) & EX_DPMASK) != EX_DYNAMIC +#if 1 /* Compatibility */ + || hdr.aout.a_entry < __LDPGSZ +#endif + ) { + warnx("%s: not a dynamic executable", fname); + return (0); + } + *type = TYPE_AOUT; + return (1); + } + + if ((size_t)n >= sizeof(hdr.elf) && IS_ELF(hdr.elf) && + hdr.elf.e_ident[EI_CLASS] == ELF_TARG_CLASS) { + /* Handle default ELF objects on this architecture */ + Elf_Phdr phdr; + int dynamic, i; + + dynamic = 0; + *type = TYPE_ELF; + + if (lseek(fd, hdr.elf.e_phoff, SEEK_SET) == -1) { + warnx("%s: header too short", fname); + return (0); + } + for (i = 0; i < hdr.elf.e_phnum; i++) { + if (read(fd, &phdr, hdr.elf.e_phentsize) + != sizeof(phdr)) { + warnx("%s: can't read program header", fname); + return (0); + } + if (phdr.p_type == PT_DYNAMIC) { + dynamic = 1; + break; + } + } + + if (!dynamic) { + warnx("%s: not a dynamic ELF executable", fname); + return (0); + } + if (hdr.elf.e_type == ET_DYN) { + if (hdr.elf.e_ident[EI_OSABI] & ELFOSABI_FREEBSD) { + *is_shlib = 1; + return (1); + } + warnx("%s: not a FreeBSD ELF shared object", fname); + return (0); + } + + return (1); + } + + warnx("%s: not a dynamic executable", fname); + return (0); +}