diff options
Diffstat (limited to 'pkgs/development/tools/misc/saleae-logic/preload.c')
| -rw-r--r-- | pkgs/development/tools/misc/saleae-logic/preload.c | 269 |
1 files changed, 248 insertions, 21 deletions
diff --git a/pkgs/development/tools/misc/saleae-logic/preload.c b/pkgs/development/tools/misc/saleae-logic/preload.c index 6b3632db97bb..b4451e4d99f7 100644 --- a/pkgs/development/tools/misc/saleae-logic/preload.c +++ b/pkgs/development/tools/misc/saleae-logic/preload.c @@ -2,17 +2,20 @@ * LD_PRELOAD trick to make Saleae Logic work from a read-only installation * directory. * - * Saleae Logic tries to write to the ./Settings/settings.xml file, relative to - * its installation directory. Because the nix store is read-only, we have to - * redirect access to this file somewhere else. Here's the map: + * Saleae Logic tries to write to a few directories inside its installation + * directory. Because the Nix store is read-only, we have to redirect access to + * this file somewhere else. Here's the map: * - * $out/Settings/settings.xml => $HOME/.saleae-logic-settings.xml + * $out/Settings/ => $HOME/.saleae-logic/Settings/ + * $out/Databases/ => $HOME/.saleae-logic/Databases/ + * $out/Errors/ => $HOME/.saleae-logic/Errors/ + * $out/Calibration/ => $HOME/.saleae-logic/Calibration/ * * This also makes the software multi-user aware :-) * - * NOTE: The next Logic version is supposed to have command line parameters for - * configuring where the Settings/ directory is located, but until then we have - * to use this. + * NOTE: AFAIK (Bjørn Forsman), Logic version 1.2+ was supposed to have a + * command line parameter for redirecting these write operations, but + * apparently that feature got postponed. * * Usage: * gcc -shared -fPIC -DOUT="$out" preload.c -o preload.so -ldl @@ -33,30 +36,65 @@ #include <limits.h> #include <sys/stat.h> #include <sys/types.h> +#include <errno.h> #ifndef OUT #error Missing OUT define - path to the installation directory. #endif +/* + * TODO: How to properly wrap "open", which is declared as a variadic function + * in glibc? The man page lists these signatures: + * + * int open(const char *pathname, int flags); + * int open(const char *pathname, int flags, mode_t mode); + * + * But using either signature in this code cause a compile error, because + * glibc has declared the function as "int open(const char *, int, ...)". + * Same thing with "openat". + * + * For now we discard the variadic args. It seems to work. + * + * Relevant: + * http://stackoverflow.com/questions/28462523/how-to-wrap-ioctlint-d-unsigned-long-request-using-ld-preload + */ typedef FILE *(*fopen_func_t)(const char *path, const char *mode); typedef FILE *(*fopen64_func_t)(const char *path, const char *mode); +typedef int (*open_func_t)(const char *pathname, int flags, ...); +typedef int (*open64_func_t)(const char *pathname, int flags, ...); +typedef int (*openat_func_t)(int dirfd, const char *pathname, int flags, ...); +typedef int (*openat64_func_t)(int dirfd, const char *pathname, int flags, ...); +typedef int (*xstat_func_t)(int vers, const char *pathname, struct stat *buf); +typedef int (*xstat64_func_t)(int vers, const char *pathname, struct stat64 *buf); +typedef int (*access_func_t)(const char *pathname, int mode); +typedef int (*faccessat_func_t)(int dirfd, const char *pathname, int mode, int flags); +typedef int (*unlink_func_t)(const char *pathname); /* - * Redirect $out/Settings/settings.xml => $HOME/.saleae-logic-settings.xml. No - * other paths are changed. Path is truncated if bigger than PATH_MAX. + * Redirect $out/{Settings,Databases,Errors,Calibration}/ => $HOME/.saleae-logic/. + * Path is truncated if bigger than PATH_MAX. * * @param pathname Original file path. * @param buffer Pointer to a buffer of size PATH_MAX bytes that this function * will write the new redirected path to (if needed). * * @return Pointer to the resulting path. It will either be equal to the - * pathname or buffer argument. + * pathname (no redirect) or buffer argument (was redirected). */ static const char *redirect(const char *pathname, char *buffer) { const char *homepath; const char *new_path; static char have_warned; + const char *remainder; + static char have_initialized; + static size_t out_strlen; + static size_t settings_strlen; + static size_t databases_strlen; + static size_t errors_strlen; + static size_t calibration_strlen; + int ret; + int i; homepath = getenv("HOME"); if (!homepath) { @@ -67,9 +105,59 @@ static const char *redirect(const char *pathname, char *buffer) } } + if (!have_initialized) { + /* + * The directories that Saleae Logic expects to find. + * The first element is intentionally empty (create base dir). + */ + char *dirs[] = {"", "/Settings", "/Databases", "/Errors", "/Calibration"}; + char old_settings_path[PATH_MAX]; + access_func_t orig_access; + + out_strlen = strlen(OUT); + settings_strlen = out_strlen + strlen("/Settings"); + databases_strlen = out_strlen + strlen("/Databases"); + errors_strlen = out_strlen + strlen("/Errors"); + calibration_strlen = out_strlen + strlen("/Calibration"); + for (i = 0; i < sizeof dirs / sizeof dirs[0]; i++) { + snprintf(buffer, PATH_MAX, "%s/.saleae-logic%s", homepath, dirs[i]); + buffer[PATH_MAX-1] = '\0'; + ret = mkdir(buffer, 0755); + if (0 != ret && errno != EEXIST) { + fprintf(stderr, "ERROR: Failed to create directory \"%s\": %s\n", + buffer, strerror(errno)); + return NULL; + } + } + + /* + * Automatic migration of the settings file: + * ~/.saleae-logic-settings.xml => ~/.saleae-logic/Settings/settings.xml + */ + snprintf(old_settings_path, PATH_MAX, "%s/.saleae-logic-settings.xml", homepath); + old_settings_path[PATH_MAX-1] = '\0'; + orig_access = (access_func_t)dlsym(RTLD_NEXT, "access"); + if (orig_access(old_settings_path, F_OK) == 0) { + snprintf(buffer, PATH_MAX, "%s/.saleae-logic/Settings/settings.xml", homepath); + buffer[PATH_MAX-1] = '\0'; + ret = rename(old_settings_path, buffer); + if (ret != 0) { + fprintf(stderr, "WARN: Failed to move %s to %s", + old_settings_path, buffer); + } + } + + have_initialized = 1; + } + new_path = pathname; - if (strcmp(OUT "/Settings/settings.xml", pathname) == 0) { - snprintf(buffer, PATH_MAX, "%s/.saleae-logic-settings.xml", homepath); + remainder = pathname + out_strlen; + + if ((strncmp(OUT "/Settings", pathname, settings_strlen) == 0) || + (strncmp(OUT "/Databases", pathname, databases_strlen) == 0) || + (strncmp(OUT "/Errors", pathname, errors_strlen) == 0) || + (strncmp(OUT "/Calibration", pathname, calibration_strlen) == 0)) { + snprintf(buffer, PATH_MAX, "%s/.saleae-logic%s", homepath, remainder); buffer[PATH_MAX-1] = '\0'; new_path = buffer; } @@ -79,36 +167,175 @@ static const char *redirect(const char *pathname, char *buffer) FILE *fopen(const char *pathname, const char *mode) { - FILE *fp; const char *path; char buffer[PATH_MAX]; fopen_func_t orig_fopen; orig_fopen = (fopen_func_t)dlsym(RTLD_NEXT, "fopen"); path = redirect(pathname, buffer); - fp = orig_fopen(path, mode); - if (path != pathname && getenv("PRELOAD_DEBUG")) { - fprintf(stderr, "preload_debug: fopen(\"%s\", \"%s\") => \"%s\": fp=%p\n", pathname, mode, path, fp); + fprintf(stderr, "preload_debug: fopen(\"%s\", \"%s\") => \"%s\"\n", pathname, mode, path); } - return fp; + return orig_fopen(path, mode); } FILE *fopen64(const char *pathname, const char *mode) { - FILE *fp; const char *path; char buffer[PATH_MAX]; fopen64_func_t orig_fopen64; orig_fopen64 = (fopen64_func_t)dlsym(RTLD_NEXT, "fopen64"); path = redirect(pathname, buffer); - fp = orig_fopen64(path, mode); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: fopen64(\"%s\", \"%s\") => \"%s\"\n", pathname, mode, path); + } + + return orig_fopen64(path, mode); +} + +int open(const char *pathname, int flags, ...) +{ + const char *path; + char buffer[PATH_MAX]; + open_func_t orig_open; + + orig_open = (open_func_t)dlsym(RTLD_NEXT, "open"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: open(\"%s\", ...) => \"%s\"\n", pathname, path); + } + + return orig_open(path, flags); +} + +int open64(const char *pathname, int flags, ...) +{ + const char *path; + char buffer[PATH_MAX]; + open64_func_t orig_open64; + + orig_open64 = (open64_func_t)dlsym(RTLD_NEXT, "open64"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: open64(\"%s\", ...) => \"%s\"\n", pathname, path); + } + return orig_open64(path, flags); +} + +int openat(int dirfd, const char *pathname, int flags, ...) +{ + const char *path; + char buffer[PATH_MAX]; + openat_func_t orig_openat; + + orig_openat = (openat_func_t)dlsym(RTLD_NEXT, "openat"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: openat(%d, \"%s\", %#x) => \"%s\"\n", dirfd, pathname, flags, path); + } + + return orig_openat(dirfd, path, flags); +} + +int openat64(int dirfd, const char *pathname, int flags, ...) +{ + const char *path; + char buffer[PATH_MAX]; + openat64_func_t orig_openat64; + + orig_openat64 = (openat64_func_t)dlsym(RTLD_NEXT, "openat64"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: openat64(%d, \"%s\", %#x) => \"%s\"\n", dirfd, pathname, flags, path); + } + + return orig_openat64(dirfd, path, flags); +} + +/* + * Notes about "stat". + * + * The stat function is special, at least in glibc, in that it cannot be + * directly overridden by LD_PRELOAD, due to it being inline wrapper around + * __xstat. The __xstat functions take one extra parameter, a version number, + * to indicate what "struct stat" should look like. This trick allows changing + * the contents of mode_t without changing the shared library major number. See + * sys/stat.h header for more info. + */ +int __xstat(int vers, const char *pathname, struct stat *buf) +{ + const char *path; + char buffer[PATH_MAX]; + xstat_func_t orig_xstat; + + orig_xstat = (xstat_func_t)dlsym(RTLD_NEXT, "__xstat"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: (__x)stat(\"%s\", ...) => \"%s\"\n", pathname, path); + } + + return orig_xstat(vers, path, buf); +} + +int __xstat64(int vers, const char *pathname, struct stat64 *buf) +{ + const char *path; + char buffer[PATH_MAX]; + xstat64_func_t orig_xstat64; + + orig_xstat64 = (xstat64_func_t)dlsym(RTLD_NEXT, "__xstat64"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: (__x)stat64(\"%s\", ...) => \"%s\"\n", pathname, path); + } + + return orig_xstat64(vers, path, buf); +} + +int access(const char *pathname, int mode) +{ + const char *path; + char buffer[PATH_MAX]; + access_func_t orig_access; + + orig_access = (access_func_t)dlsym(RTLD_NEXT, "access"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: access(\"%s\", ...) => \"%s\"\n", pathname, path); + } + + return orig_access(path, mode); +} + +int faccessat(int dirfd, const char *pathname, int mode, int flags) +{ + const char *path; + char buffer[PATH_MAX]; + faccessat_func_t orig_faccessat; + + orig_faccessat = (faccessat_func_t)dlsym(RTLD_NEXT, "faccessat"); + path = redirect(pathname, buffer); + if (path != pathname && getenv("PRELOAD_DEBUG")) { + fprintf(stderr, "preload_debug: faccessat(\"%s\", ...) => \"%s\"\n", pathname, path); + } + + return orig_faccessat(dirfd, path, mode, flags); +} + +int unlink(const char *pathname) +{ + const char *path; + char buffer[PATH_MAX]; + unlink_func_t orig_unlink; + + orig_unlink = (unlink_func_t)dlsym(RTLD_NEXT, "unlink"); + path = redirect(pathname, buffer); if (path != pathname && getenv("PRELOAD_DEBUG")) { - fprintf(stderr, "preload_debug: fopen64(\"%s\", \"%s\") => \"%s\": fp=%p\n", pathname, mode, path, fp); + fprintf(stderr, "preload_debug: unlink(\"%s\") => \"%s\"\n", pathname, path); } - return fp; + return orig_unlink(path); } |